Defence Research and
Development Canada
Recherche et développement
pour la défense Canada
Assessment of Lower Leg Injury from
Land Mine Blast – Phase 2
Follow up Tests with a Modified Frangible Surrogate Lower
Leg and Comparison with Cadaver Test Data
D.M. Bergeron, G.G. Coley, and R.W. Fall
DRDC Suffield
I.B. Anderson
Canadian Forces Medical Group
Terms of release: The information contained herein is proprietary to Her Majesty and is provided to the recipient on
the understanding that it will be used for information and evaluation purposes only. Any commercial use including use
for manufacture is prohibited. Release to third parties of this publication or information contained herein is prohibited
without the prior written consent of Defence R&D Canada.
Technical Report
DRDC Suffield TR 2007-070
March 2007
Assessment of Lower Leg Injury from
Land Mine Blast – Phase 2
Follow up Tests with a Modified Frangible Surrogate Lower Leg
and Comparison with Cadaver Test Data
D. M. Bergeron, G. G. Coley, R. W. Fall
DRDC Suffield
I. B. Anderson
Canadian Forces Medical Group
Terms of release: The information contained herein is proprietary to Her Majesty and is provided to the
recipient on the understanding that it will be used for information and evaluation purposes only. Any commercial
use including use for manufacture is prohibited. Release to third parties of this publication or information
contained herein is prohibited without the prior written consent of Defence R&D Canada.
Defence R&D Canada – Suffield
Technical Report
DRDC Suffield TR 2007-070
March 2007
Principal Author
Dr. Denis M. Bergeron
Approved by
Dr. Chris Weickert
Head Military Engineering Section/Director, Canadian Centre for Mine Action
Technologies
Approved for release by
Dr. Paul D’Agostino
Chair, DRDC Suffield Document Review Panel
© Her Majesty the Queen in Right of Canada as represented by the Minister of National
Defence, 2007
© Sa Majesté la Reine (en droit du Canada), telle que représentée par le ministre de la Défense
nationale, 2007
Abstract
In 1999, the Canadian Centre for Mine Action Technologies (CCMAT) evaluated the
suitability of a frangible leg model to assess the performance of mine-protective footwear.
The model performance was satisfactory, but the strength of some bones needed to be
adjusted. Furthermore, M14 mines could not be obtained in time for these tests which made it
difficult to compare the results against those from cadaver tests done in the United States. In
2001, the same frangible leg model, now having improved bones, was evaluated in a second
test series using M14 mines.
This report presents the results from the 2001 test series. The improved model performed
notably better than the previous model. The results compared well against the cadaver test
results, although some further improvements could be made to increase its realism. However,
the frangible leg model can be used, as is, to assess the performance of protective footwear
against anti-personnel mines, provided the user accounts for the strengths and weaknesses of
the model.
Résumé
En 1999, le Centre canadien de technologies de déminage (CCTD) a évalué la pertinence d’un
modèle de jambe frangible visant à évaluer le rendement d’une chaussure de protection contre
les mines. Le rendement du modèle était satisfaisant mais la force sur certains os a dû être
ajustée. De plus, les mines M14 n’avaient pas pu être obtenues pour ces essais et il a été
difficile de comparer les résultats avec ceux des essais sur les cadavres effectués au ÉtatsUnis. En 2001, le même modèle de jambe frangible, ayant maintenant des os améliorés, a été
évalué durant une seconde série d’essais, en utilisant des mines M14.
Ce rapport présente les résultats de la série de tests de 2001. Le modèle amélioré a eu un bien
meilleur rendement que le modèle précédent. Ces résultats étaient comparables aux résultats
des essais effectués avec des cadavres bien que d’autres améliorations permettraient d’en
augmenter le réalisme. Le modèle de la jambe frangible peut cependant être utilisé tel quel
pour évaluer le rendement des chaussures de protection contre les mines antipersonnel, dans la
mesure où l’utilisateur tient compte des forces et des faiblesses de ce modèle.
DRDC Suffield TR 2007-070
i
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ii
DRDC Suffield TR 2007-070
Executive summary
Assessment of Lower Leg Injury from Land Mine Blast – Phase 2
D. M. Bergeron, G. G. Coley, R. W. Fall, I. B. Anderson; DRDC Suffield TR 2007-070;
Defence R&D Canada – Suffield; March 2007.
In 1999, the Canadian Centre for Mine Action Technologies (CCMAT) assessed a frangible
surrogate leg (FSL) to evaluate the performance of mine-protective footwear. The main
recommendations from the these tests were to decrease the strength of the calcaneus and talus
bones of the FSL, use only the lower segment of the FSL since the damage was concentrated
in the distal leg, acquire M14 mines, and then repeat the assessment. Other recommendations
included using only the Mine Trauma Score (MTS) during the post-test medical examination,
and improving the flash x-ray setup to obtain more information about the evolution of the
damage.
By early 2001, these recommendations had been implemented and CCMAT purchased twelve
frangible surrogate lower leg (FSLL) specimens. Eight FSLLs had softer calcaneus and talus
bones, while the other four had the original hard version of these bones. The FSLL tests were
performed over a three-day period in March 2001. Ten tests were performed against the M14
mine and the remaining two tests were against the PMA-2 mine. These tests and results are
described in this report.
Flash radiography was used to quantify the process of early damage to the distal leg. The M14
mine caused significant destruction to the FSLL when it was used with a regular combat boot.
The main damage process was one of total disruption due to overpressure. When the same
mine was used against an FSLL ’protected’ by a blast boot with an overboot, a different
damage process resulted. The impingement of detonation products destroyed the sole of the
overboot and accelerated its metal blast deflector to a velocity around 120 m/s. The lower
deflector impacted the sole of the blast boot and transferred part of its vertical momentum to
the blast deflector contained in the sole of the blast boot, which reached a peak velocity of
around 65 m/s. The blast boot was not breached, indicating that the damage process was one
of blunt trauma due to the impact by the blast deflectors.
When the FSLL with blast boot and overboot was tested against a PMA-2 mine, the greater
explosive mass accelerated the blast deflector of the overboot to a velocity of 240 m/s. The
following impact with the blast deflector of the blast boot accelerated the latter to a velocity of
at least 90 m/s, since this blast deflector was still accelerating at the longest x-ray time of 500
µs. The larger impact velocity caused a large overpressure in the distal leg, which burst from
the inside out.
The M14 test results against a blast boot with overboot revealed that the soft and hard
calcaneus and talus bones produced different responses. The hard bones resulted in three
salvageable injuries out of four tests. The soft bones produced the opposite result with only
one out of four tests producing a salvageable injury, while each of the other tests would have
led to an amputations.
DRDC Suffield TR 2007-070
iii
A comparison of the FSLL bone damage with the bone damage recorded during LEAP
revealed that more tuning of the calcaneus and, perhaps, of the talus is required to increase the
level of bio-fidelity of the FSLL. The tibia results indicated that the FSLL tibia clearly
requires further work. During LEAP, transverse fractures of the tibia were never observed
when exposed to the M14 while using the blast boot with an overboot. The FSLL produced a
single or multiple transverse fracture of the tibia each time. It is suspected that this problem
has its roots in the high strain rate behaviour of the FSLL material. Fortunately, this weakness
of the tibia should not prevent the use of the FSLL as a diagnostic tool. Such breaks can
simply be ignored during the damage analysis. The authors estimate that the damage to the
calcaneus and talus is more important. Since the goal of any protective system is to prevent
the loss of these two bones, failure of the calcaneus and talus indicates that the protective
system failed.
The flash x-rays and the load cell results demonstrated the importance of maintaining very
tight control over geometry. Placement of the mine below the foot appears to have a strong
influence on loading and, therefore, on the resulting injuries.
iv
DRDC Suffield TR 2007-070
Sommaire
Assessment of Lower Leg Injury from Land Mine Blast – Phase 2
D. M. Bergeron, G. G. Coley, R. W. Fall, I. B. Anderson; DRDC Suffield TR 2007-070;
R & D pour la défense Canada – Suffield; mars 2007.
En 1999, le Centre canadien de technologies de déminage (CCTD) a évalué un modèle de
jambe de remplacement frangible (FSL) visant à évaluer le rendement d’une chaussure de
protection contre les mines. Les recommandations principales résultant de ces essais
consistaient à diminuer la force du calcanéum et du talus de la jambe frangible, de n’utiliser
que le segment inférieur de la jambe frangible puisque le dommage est concentré sur la jambe
distale, de faire l’acquisition de mines M14 et de répéter ainsi l’évaluation. D’autres
recommandations consistaient à n’inclure que le Score du trauma causé par les mines durant
l’examen médical du post-test et d’améliorer la configuration de la radiographie éclair pour
obtenir plus de renseignements au sujet de l’évolution du dommage.
Ces recommandations ont été implémentées au début de 2001 et le CCTD a acheté douze
spécimens de jambes inférieures frangibles de remplacement. Huit de ces jambes frangibles
avaient un calcanéum et un talus plus mou alors que les quatre autres avaient la version
originale de ces os. Les essais sur les jambes frangibles ont été effectués durant une période
de trois jours en mai 2001. Dix essais ont été effectués avec des mines M14 et les deux autres
avec des mines PMA-2. Ces essais et leurs résultats sont décrits dans ce rapport.
On a utilisé la radiographie éclair pour quantifier le processus des premiers dommages
infligés à la jambe distale. La mine M14 causait une destruction importante de la jambe
frangible quand elle était utilisée avec une botte de combat normale. Le processus principal du
dommage consistait en une disruption totale causée par la surpression. Quand la même mine
était utilisée contre une jambe frangible « protégée » par une botte de protection contre le
souffle ayant un couvre-chaussure, il en a résulté un processus de dommage différent. La
collision des produits de détonation a détruit la semelle du couvre-chaussure et a accéléré le
déflecteur de souffle métallique à une vélocité d’environ 120 m/s. Le déflecteur inférieur a
impacté la semelle de la botte de protection contre le souffle et a transféré une partie de sa
quantité de mouvement vertical au déflecteur de souffle contenu dans la semelle de la botte de
protection contre le souffle qui a atteint une vélocité de crête d’environ 65m/s. La botte de
protection contre le souffle n’a pas été trouée ce qui indique que le processus du dommage
consistait en un traumatisme contondant causé par l’impact des déflecteurs de souffle.
Quand la jambe inférieure frangible de remplacement portant la botte de protection contre le
souffle ayant un couvre-chaussure a été testée à nouveau contre une mine PMA-2, la masse
explosive plus importante a accéléré le déflecteur de souffle du couvre-chaussure à une
vélocité de 240 m/s. L’impact suivant avec le déflecteur du souffle de la botte de protection
contre le souffle a accéléré cette dernière à une vélocité d’au moins 90 m/s, puisque le
déflecteur de souffle accélérait encore à la vitesse la plus haute de 500 µs. Cette vélocité plus
importante de l’impact a causé une surpression dans la jambe distale qui a éclaté de l’intérieur
vers l’extérieur.
DRDC Suffield TR 2007-070
v
Les résultats des essais M14 avec la botte de protection contre le souffle ont révélé que les os
du calcanéum et talus produisaient des réponses différentes. Les os durs ont résulté en trois
blessures récupérables sur les quatre essais. Les os mous ont produit des résultats opposés
puisqu’un seul des quatre essais a produit une blessure récupérable, alors que les autres essais
auraient abouti en amputations.
Une comparaison des dommages des os sur la jambe frangible FSLL, ayant des dommages
aux os enregistrés durant LEAP, a révélé que d’autres réglages du calcanéum et peut-être
aussi du talus sont requis pour augmenter le niveau de bio-fidélité de la jambe inférieure
frangible de remplacement. Les résultats du tibia indiquent clairement que le tibia de la jambe
inférieure frangible de remplacement exige des améliorations. Durant LEAP, on n’a jamais
observé de fractures transversales du tibia quand celui-ci était exposé à la mine M14 avec la
botte de protection contre le souffle ayant un couvre-chaussure. La jambe inférieure frangible
de remplacement a produit une fracture simple ou des fractures multiples sur le tibia à chaque
fois. On suspecte que ce problème provient du comportement de haute vitesse de déformation
des matériaux de la jambe. Heureusement, cette faiblesse dans le tibia ne devrait pas
empêcher l’utilisation de la jambe inférieure frangible de remplacement comme outil de
diagnostic. De telles brisures ne peuvent pas simplement être ignorées durant l’analyse des
dommages. Les auteurs estiment que les dommages au calcanéum et talus sont plus
importants. Le but de tout système de protection étant d’éviter la perte de ces deux os, les
dommages infligés au calcanéum et talus indiquent que le système de protection a échoué.
La radiographie éclair et les résultats du dynamomètre piézoélectrique indiquent l’importance
de maintenir un contrôle très étroit de la géométrie. Le placement de la mine sous le pied
semble influencer fortement la charge et par conséquent les blessures qui en résultent.
vi
DRDC Suffield TR 2007-070
Table of contents
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Résumé . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Executive summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
iii
Sommaire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
v
Table of contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
vii
List of figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ix
List of tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
xii
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
xiii
1
2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
1.1
Main Conclusions from the First FSL Tests . . . . . . . . . . . . . . . . . .
2
1.2
Recommendations from the First FSL Tests . . . . . . . . . . . . . . . . .
4
Test Objectives and Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
2.1
Description of the FSLL and its Preparation . . . . . . . . . . . . . . . . .
7
2.2
Experimental Set-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
2.2.1
Soil and Explosive Charges . . . . . . . . . . . . . . . . . . . . . .
14
Experimental Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
2.3.1
Mine and FSLL Placement . . . . . . . . . . . . . . . . . . . . . .
16
2.3.2
Post-Test Actions . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
2.3.3
Post-Test Medical Assessments . . . . . . . . . . . . . . . . . . . .
16
Physical and Medical Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19
3.1
Analysis of the Flash X-Ray Imagery . . . . . . . . . . . . . . . . . . . . .
19
3.2
Summary of Boot Damage . . . . . . . . . . . . . . . . . . . . . . . . . . .
28
3.2.1
Damage to an Unprotected Combat Boot . . . . . . . . . . . . . .
28
3.2.2
Damage to a Blast Boot with an Overboot . . . . . . . . . . . . .
29
2.3
3
DRDC Suffield TR 2007-070
vii
3.3
MTS Scores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30
3.4
Bone Damage Scores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31
3.4.1
Unprotected Combat Boot against the M14 Mine . . . . . . . . . .
35
3.4.2
Blast Boot with Overboot against the PMA-2 Mine . . . . . . . .
35
3.4.3
Blast Boot with Overboot against the M14 Mine . . . . . . . . . .
35
Load Cell Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
38
CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
40
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
42
List of symbols/abbreviations/acronyms/initialisms . . . . . . . . . . . . . . . . . .
43
Annex A: Detailed Boot Damage Assessments . . . . . . . . . . . . . . . . . . . . .
45
Annex B: Detailed Medical Assessments . . . . . . . . . . . . . . . . . . . . . . . .
71
3.5
4
Annex C: Data Records from the Load Cells . . . . . . . . . . . . . . . . . . . . . . 111
viii
DRDC Suffield TR 2007-070
List of figures
Figure 1:
Frangible Surrogate Lower Leg with soft core inserts (shown at the bottom of
the picture) in the calcaneus and talus bones (photo courtesy of DSTO, Australia)
8
Series of operations required to prepare the FSLL for testing. From upper left
to lower right: a) alignment rigs; b) gluing the counterweight plate; c) fixing
the counterweight to the FSLL; d) preparation of FSLL for gelatine pouring; e)
trimming of FSLL for total mass; f) painting on the nylon skin . . . . . . . .
9
Figure 3:
Experimental set-up used for the second test series . . . . . . . . . . . . . . .
11
Figure 4:
Flash x-ray arrangement used during the second test series to obtain two
images per shot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
The specimens were examined by a qualified surgeon in a veterinary operating
room . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18
Flash x-ray images of an M14 mine explosion under a combat boot; timings
from upper left to lower right are: 50.0 µs, 102.0 µs, 155.5 µs and 256.1 µs . .
20
Flash x-ray images of an M14 mine explosion under a blast boot with
overboot; timings from upper left to lower right are: 102.0 µs, 152.6 µs, 255.4
µs and 506.4 µs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22
Flash x-ray images of a PMA-2 mine explosion under a blast boot with
overboot; timings from upper left to lower rigt are: 105.3 µs, 152.6 µs, 255.4 µs
and 505.2 µs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23
Eight reference points used to extract data from the flash x-ray images . . . .
24
Figure 10: Upper surface trajectory for the lower and upper blast deflectors versus time
and mine type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25
Figure 11: Trajectory for the average y values of the calcaneus for the three test conditions
25
Figure 12: Trajectory for the average y values of the tibia for the three test conditions . .
26
Figure 13: Average bone scores for the M14 mine against the Blast Boot with Overboot .
36
Figure 2:
Figure 5:
Figure 6:
Figure 7:
Figure 8:
Figure 9:
Figure 14: Flash x-rays of an M14 mine explosion under the blast boot with overboot at
206 µs (left) and 706 µs into the event. The same overlays were drawn over the
calcaneus and tibia to highlight changes. . . . . . . . . . . . . . . . . . . . .
37
Figure 15: The off-axis location of the load vector relative to the long axis of the tibia
generates a positive moment at the centre of the this bone . . . . . . . . . . .
39
DRDC Suffield TR 2007-070
ix
Figure A.1: Canadian Army Combat Boot. The same nomenclature applies to the US
Army Combat Boot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
46
Figure A.2: Blast Boot (above) and attenuator plate (below). . . . . . . . . . . . . . . .
47
Figure A.3: Overboot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
48
Figure A.4: Damage to boots for shot 701/M01072D . . . . . . . . . . . . . . . . . . . .
49
Figure A.5: Damage to boots for shot 702/M01071C . . . . . . . . . . . . . . . . . . . .
51
Figure A.6: Damage to boots for shot 703/M01071A . . . . . . . . . . . . . . . . . . . .
53
Figure A.7: Damage to boots for shot 704/M01072A . . . . . . . . . . . . . . . . . . . .
55
Figure A.8: Damage to boots for shot 705/M01071B . . . . . . . . . . . . . . . . . . . .
56
Figure A.9: Damage to boots for shot 706/M01072E . . . . . . . . . . . . . . . . . . . .
58
Figure A.10:Damage to boots for shot 707/M01072B . . . . . . . . . . . . . . . . . . . .
60
Figure A.11:Damage to boots for shot 708/M01072C . . . . . . . . . . . . . . . . . . . .
61
Figure A.12:Damage to boots for shot 709/M01072F . . . . . . . . . . . . . . . . . . . .
63
Figure A.13:Damage to boots for shot 710/M01073A . . . . . . . . . . . . . . . . . . . .
64
Figure A.14:Damage to boots for shot 711/M01073B . . . . . . . . . . . . . . . . . . . .
66
Figure A.15:Damage to boots for shot 712/M01073C . . . . . . . . . . . . . . . . . . . .
69
Figure C.1: Coordinate system for the load cell measurements. . . . . . . . . . . . . . . . 112
Figure C.2: Fx record for FSLL ID 701 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Figure C.3: Fy record for FSLL ID 701 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Figure C.4: Fz record for FSLL ID 701 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Figure C.5: Mx record for FSLL ID 701 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Figure C.6: My record for FSLL ID 701 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
x
DRDC Suffield TR 2007-070
Figure C.7: Mz record for FSLL ID 701 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Figure C.8: Fx record for FSLL ID 703 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Figure C.9: Fy record for FSLL ID 703 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Figure C.10:Fz record for FSLL ID 703 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Figure C.11:Mx record for FSLL ID 703 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Figure C.12:My record for FSLL ID 703 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Figure C.13:Fx record for FSLL ID 705 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Figure C.14:Fy record for FSLL ID 705 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Figure C.15:Fz record for FSLL ID 705 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Figure C.16:Mx record for FSLL ID 705 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Figure C.17:My record for FSLL ID 705 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Figure C.18:Mz record for FSLL ID 705 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Figure C.19:Fx record for FSLL ID 706 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Figure C.20:Fy record for FSLL ID 706 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Figure C.21:Fz record for FSLL ID 706 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Figure C.22:Mx record for FSLL ID 706 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
DRDC Suffield TR 2007-070
xi
Figure C.23:My record for FSLL ID 706 fitted with a blast boot with overboot against an
M14 mine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
List of tables
Table 1:
Test matrix for the March 2001 FSLL test series.
. . . . . . . . . . . . . . .
6
Table 2:
Jig and mass properties for each FSLL specimen . . . . . . . . . . . . . . . .
12
Table 3:
Flash x-ray timings for this second test series
. . . . . . . . . . . . . . . . .
15
Table 4:
Vertical velocity estimates from curve fits to the upper surface position of the
blast deflectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27
Vertical velocity estimates from linear fits to the calcaneus and distal tibia
position data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27
Table 5:
Table 6:
Weight of boots and overboots before and after each test
. . . . . . . . . . .
29
Table 7:
Summary of the MTS scores assigned to each FSLL; the data is ordered by
protection type and then by increasing explosive mass . . . . . . . . . . . . .
31
Table 8:
Summary of relevant MTS scores obtained during LEAP
. . . . . . . . . . .
32
Table 9:
Crude scoring system used to compare the level of bone damage between
LEAP and FSLL tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
32
Table 10:
Summary of damage to some of the bones of the FSLL specimens . . . . . . .
33
Table 11:
Summary of relevant bone damage during the LEAP study, deduced from [3] .
34
Table A.1: Table of Contents Annex A . . . . . . . . . . . . . . . . . . . . . . . . . .
45
Table B.1: Table of Contents Annex B . . . . . . . . . . . . . . . . . . . . . . . . . .
72
Table C.1: Table of Contents Annex C . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Table C.2: Summary of minimum and maximum values of the records
. . . . . . . . . . 112
Table C.3: Key parameters for the normal force and its integrated values at different times 113
xii
DRDC Suffield TR 2007-070
Acknowledgements
A project needs the contributions from many individuals to be successful. Unfortunately,
only a few names appear on a report and, too often, essential contributions from individuals
working in the background are forgotten soon after the project is over. Here, the authors
would like to list the personnel that contributed to this project, from start to finish, both
to thank these people, but also to stress the importance of a team effort to achieve the
successful outcome of a project. We are indebted to (not in any particular order):
Jim Roseveare, Paul Schile, Dan Roseveare and Doug Roseveare of Amtech for their hard
work to prepare the test set-up and support during the tests;
Gurdev Boghal, John Staats and Wilfred Pudwell of the DRDC Suffield Experimental
Model Shop for manufacturing the FSLL counterweights;
Brian Galozowski of DRDC Suffield Technical Support Section for manufacturing the FSLL
alignment rig on short notice;
Scott Trebble and Randy Lynde of the DRDC Suffield Photo Instrumentation for their hard
work in documenting the tests and later digitizing the x-rays;
Darrell Boechler of DRDC Suffield and Blair Mullin of Amtech for running the electronic
instrumentation;
Tom Storrie and John Paul Zakordonski, from DRDC Suffield, for their expert support and
producing outstanding flash x-ray images;
Ellory Sanderson, from the Aberdeen Test Center, USA and Dr Dale Bass, from the University of Virginia, USA, for the loan of their tibia load cells;
The Diagnostics Imaging Staff of the Medicine Hat Regional hospital for putting in long
hours during evenings, after a long work day, to produce medical x-rays and CT scans of
the specimens;
Dr Robert Harris of the US Army, for reviewing the medical data and MTS scores;
Dave Ulriksen and Sgt G. Handford of CFB Suffield for medical support during the experiments;
Garth Woolf, Jim Forbes and Lyle Catton of DRDC Suffield for preparing and handling
the explosives;
Bob Martin and Paul Mast, the FTOs for looking after everyones safety;
Betty McIvor, Vicky Roberts and Shelley Ewing for their help during report preparation
and reproduction.
DRDC Suffield TR 2007-070
xiii
This list clearly shows that even a simple project such as this one requires a full team to
succeed. Many thanks to all! We hope that we did not forget anyone. If we did, please
accept our sincere apologies.
xiv
DRDC Suffield TR 2007-070
1
Introduction
In 1999, the Canadian Centre for Mine Action Technologies (CCMAT) sponsored twentyfive anti-personnel (AP) mine blast tests [1] to determine whether or not the Australian
Frangible Surrogate Leg (FSL) is suitable to assess the performance of mine-protective
footwear. The CCMAT test results indicated that the FSL had the main attributes to
perform this role: repeatability and sensitivity. Repeatability refers to the ability of the
model to reproduce the same results, within reason, when subjected to the same explosive
stimulus. Sensitivity refers to the ability of the model to produce distinct results as the
explosive stimulus or the protection level is changed. This conclusion was reached mainly
due to the level of damage imparted to the FSL bones.
The 1999 tests also uncovered some of the FSL limitations. First, the strength of the
calcaneus and talus bones was up to three times stronger than its human counterpart,
unnecessarily increasing the level of damage to the tibia and fibula bones above. Second,
the ballistic gelatine representing the soft tissues in the FSL did not allow deep penetration
of high-pressure gas into the leg, as occurs in the human leg. Despite these shortfalls, the
FSL demonstrated its potential to be a good tool to assess protective footwear against AP
mine blast. But for such a tool to be truly useful, it is necessary to calibrate its response
to mine blast against an existing database of mine blast injuries, a process referred to as
developing injury criteria.
When planning the 1999 CCMAT FSL tests, it had been hoped to obtain M14 mines and
reproduce the test conditions from the US-sponsored Lower Extremity Assessment Program
(LEAP) [2, 3]. The program subjected human cadaver legs to AP mine blasts and medical
personnel examined the subjects and recorded the injuries. There were a total of thirtyseven landmine blasts using three mine types: M14 (29 g Tetryl), PMA-2 (100 g TNT),
and PMN (240 g TNT). The cadavers were fitted with improvised sandals, standard combat
boots, or mine-protective boots. In many cases, supplementary mine-protective footwear
was used in conjunction with the basic footwear.
Unfortunately, M14 mines could not be obtained in time for the CCMAT test series and the
PMA-3 mine was used as a replacement. The PMA-3 is more powerful than the M14, which
meant that, even if the FSL had performed perfectly, one-to-one comparison with LEAP
could not have been done. Given this course of events, CCMAT nevertheless proceeded
with the tests, concentrating its effort on assessing the FSL. Tight control over the test
parameters allowed CCMAT to work on the following secondary objectives:
• Obtain structural response data for mines with an explosive mass between those of
the M14 and PMA-2 mines that were used during LEAP;
• Evaluate the relative protective performance of a small selection of footwear strictly
based on damage to the FSL; and
• Acquire physical data using strain gauges and a load cell to determine their potential
as instrumentation for the FSL.
DRDC Suffield TR 2007-070
1
1.1
Main Conclusions from the First FSL Tests
The CCMAT FSL tests performed in 1999 provided insight into the mine blast injury process. High quality flash x-ray images of the FSL and footwear showed that a hemispherical
zone of high-pressure gas imparts localized damage to those parts of the footwear in the
immediate vicinity of the mine. When the basic footwear was used without supplemenR
tary mine-protective footwear, including the Wellco
mine-protective boot, even the small
PMA-3 mine destroyed the basic footwear and a significant portion of the FSL within. The
R
overboot or the Med-Eng
supplementary mine-protective footwear, such as the Wellco
TM
Systems Spider Boot , played a sacrificial role, diverting some of the force of the explosion while distancing the inner footwear from the zone of very high-pressure closest to the
mine. This significantly reduced the damage to the FSL.
R
R
The tests involving a Wellco
boot with a Wellco
overboot revealed the existence of
a region of increased pressure that is roughly aligned with the vertical axis of symmetry
through the centre of the mine. Along this axis, there was enhanced deformation of the metal
R
blast deflector embedded in the sole of the Wellco
blast boot. With the boot/overboot
combination, the momentum transfer along this axis was large enough to deform both blast
deflectors. Flash x-ray images also showed that for the larger mines, e.g., the PMA-2, the
force of the impact was sufficient to pulverize the calcaneus and talus. In fact, for this mine,
the foot was seen to literally burst, ripping the boot open in the process. It was clear that
the damage to the leg starts distally and travels upwards, but remains relatively localized.
Furthermore, the damage to both the footwear and the FSL increased proportionally with
the explosive mass.
The flash x-ray images of the tests on the Canadian Army combat boot showed that the
steel shank in the sole of this boot undergoes substantial deformation. It sometimes pushed
against the sole of the FSL foot with sufficient force to penetrate the soft tissues of the
FSL, which suggests that dense objects in the sole of a boot can become projectiles under
the large force from a land mine explosion–a principle that should be taken into account
for future designs of protective footwear.
The medical assessments from the first test series provided a vehicle to compare the performance of the FSL against the LEAP database, despite the differences in mine types. The
study confirmed that an ideal scoring system does not exist for mine blast trauma. The
AIS and NISSA scales were too coarse and relied on systemic responses that only exist with
live patients, making these scoring systems unsuitable for a model such as the FSL. The
ICRC score was more applicable, but it focuses on victims with fragmentation mine injuries
and lumped all leg injuries from mine blast into only two categories: below or above knee
amputations. The MTS scoring system remained the only option that could be applied to
a synthetic model and with sufficient sensitivity to differentiate between various levels of
lower leg mine trauma.
For small mines against unprotected footwear, the MTS scores obtained with the FSL model
were lower than those obtained with the LEAP model. This was contradictory given that
the PMA-3 mine contains more explosive than the M14. However, this result is partly
2
DRDC Suffield TR 2007-070
attributable to the use of gelatine to simulate soft tissues in the FSL. Gelatine greatly
attenuates the vertical propagation of the detonation products, while in human tissues the
gas travels between self-dissecting planes along the facia that divide the compartments of
the leg. Thus, obtaining lower MTS scores with the FSL relative to LEAP is consistent
with one conclusion from the LEAP study: that, for unprotected footwear, the amputation
level was largely determined from the extent of soft tissue damage.
R
When the Wellco
overboot was used against the smaller mines, it produced a useful range
of damage to the FSL. It was found that mine class and protective footwear were the main
factors affecting the MTS scores. The inner footwear type had little influence on medical
outcomes. However, the MTS scores for the FSL differed enough from those for LEAP
that it warranted a closer look at the physical details of the injuries. The MTS scores were
therefore broken down into two components: one corresponding to the amputation level,
and one to the extent of soft tissue contamination. Considering the MTS score in this
manner revealed more clearly some of the differences in behaviour between the FSL and
cadaver models. The soft tissue scores indicated that the FSL skin is significantly more
fragile than human skin. However, the selection of skin type for the FSL was driven by
cost and was not deemed to be as important as the difference in amputation level. During
the first phase tests, the FSL under-predicted the amputation level for small mines despite
using the more powerful PMA-3 mine instead of the M14. For the larger PMA-2 mine,
the FSL over-predicted the amputation level. In order to explain this behaviour, it was
necessary to examine details of the bone damage extracted from the medical reports for the
FSL and LEAP studies.
A scoring system was designed based on four levels of bone damage, from intact to completely crushed or missing. It considered five bones: calcaneus, talus, pilon area, tibia, and
fibula. Although coarse, this scoring system proved sufficiently sensitive to capture gross
differences in bone behaviour. Applying this system to bone damage in both the FSL and
LEAP studies produced consistent results. The unprotected cases produced a more severe
score than the protected cases for a given mine. For the same protection level, the score
severity increased gradually with mine size. This scoring system also captured the localization of bone injuries, generally producing a more severe score for the most distal bones
and gradually decreasing in severity as one moved proximally. This bone damage scoring
system clearly showed that the FSL calcaneus did not behave properly. It often survived
or suffered only minor damage where the same bone in the cadaver model was destroyed.
The survival of this bone meant that too much force was transferred further up the leg,
increasing the level of damage to the talus, pilon area and the long bones of the lower leg.
The FSL instrumentation during the first test series demonstrated that strain gauges would
be difficult to use without extensive calibration. The main difficulty resides in the nonuniform cross-section of human bones combined with the complex geometry of the ankle
joint that connects to the two long bones and makes it difficult to capture the exact stress
flow distribution through these bones. To resolve this issue, it might be necessary to use
a different strain gauge arrangement in combination with changes to the cross-section of a
short segment of the tibia. The load cell data proved more useful, showing that the addition
of protective footwear changes the load profile with respect to time. It was surmised that
DRDC Suffield TR 2007-070
3
the additional mass of the blast deflectors helps to reduce peak force transmission to the
bones, but that this additional mass continues to exert a push on the leg for a longer period
of time compared to unprotected footwear. It was also noted that the introduction of a
dissimilar material in the tibia generates a stress riser that caused artificial bone breaks
where the bone meets with the interface cups of the load cell.
1.2
Recommendations from the First FSL Tests
Although the September 1999 CCMAT tests were considered successful, several shortfalls
were noted. These first tests were structured to explore the performance of the FSL, but because only a limited number of FSL specimens were purchased, only one test was performed
for a most combinations of basic footwear, supplementary mine-protective footwear, and
mine type. Repeatability was assessed for only a few cases. More tests with selected configurations were needed in order to assess the repeatability of the FSL with more confidence.
However, two factors had the greatest impact on the first tests. First, the substitution of
the PMA-3 mine for the M14 changed the load imparted to the footwear and FSL, thereby
making it very difficult to directly compare the FSL and LEAP data. Second, the most
distal bones of the Mk IV FSL, the calcaneus and talus, were much too strong and needed
to be softened before the FSL could fulfill its potential as a test tool for AP mine blast
testing. Thus, based on the results and observations made during the first CCMAT test
series, seven recommendations were made:
• Acquire M14 mines for the purposes of performing a limited number of additional
tests against a modified FSL model. These tests should concentrate on fewer footwear
combinations and mine types to further investigate the repeatability of the model;
• Decrease the strength of the calcaneus and talus bones of the FSL to levels commensurate with their human counterparts;
• Consider using only the lower segment of the FSL given that AP mine damage is
strongly localized in the distal segment of the leg;
• In future tests, discontinue the use of the AIS, NISSA and ICRC scoring systems
and use only the MTS scores in combination with some form of bone injury scoring
system;
• Attempt to improve the flash x-ray set-up to obtain more images per test and use
variable timings to record the deformation process, allowing to determine the impact
speed of the blast deflectors on the sole of the foot;
• Investigate the possibility of increasing the skin strength, taking into consideration
that skin behaviour might not affect the overall usefulness of the model if the scoring
system focuses on bone damage;
• Consider alternatives to measure the effective load through the tibia or tibia/fibula
combination. This might include a modification of the cross-section over a small
segment of the tibia.
4
DRDC Suffield TR 2007-070
By early 2001, the first five recommendations had been implemented. Canada had obtained
M14 land mines from the United States under the auspices of the two countries humanitarian
demining programs. This transfer of land mines was carried out in accordance with the
R&D provision built into the Ottawa treaty to ban AP land mines. The manufacturer of the
FSL had decreased the strength of the calcaneus and talus bones to mimic the corresponding
human bones and could provide a lower leg version that had been renamed the Frangible
Surrogate Lower Leg (FSLL). The flash x-ray set-up had also been modified to maximize
the data that could be obtained with this imaging technique.
The last two recommendations were not implemented. It was decided that increasing the
skin strength was not necessary given the existing limitations imposed by the uniform
ballistic gelatine. Finally, it had been considered to modify the tibia by building in a load
cell using the same material as the bones, but it was decided to report this modification to
a later date once the results from the second test series were fully analysed.
Thus, with the main recommendations having been implemented, CCMAT sponsored the
purchase of twelve FSLL specimens and preparations for a second series of tests were initiated. The new specimens arrived at Suffield at the beginning of March 2001. Following
final preparations, the tests were done over a three-day period, from the 12th to the 14th
of March 2001. This report provides the details about the FSLL, its preparation, the test
methodology and the results from these tests.
DRDC Suffield TR 2007-070
5
2
Test Objectives and Methodology
This second test series was designed to address four main objectives. These were:
• Verify that the soft bones improves the fidelity of the FSLL model to reproduce the
type of injury observed during LEAP;
• Verify the repeatability of the FSLL by subjecting the model to the same test conditions multiple times;
• Record the early damage process and velocity imparted to the blast deflectors within
R
the Wellco
boot and overboot using time-spaced flash x-ray imaging; and
• Repeat the LEAP conditions as closely as feasible to allow a direct comparison with
the LEAP data.
In order to reach these objectives, twelve FSLL were ordered and subjected to three basic
test conditions. One test condition was repeated eight times. Ten tests were done with
the M14 mine, while the larger PMA-2 mine was used for two tests. The basic footwear
R
was limited to the Wellco
blast boot for ten tests and the US army combat boot for
R
two tests. The additional protective footwear was limited to the Wellco
blast overboot.
Thus the mines and footwear conditions were identical to those used during LEAP. Table 1
summarises the test conditions. The FSLL ID number was used as a cross-reference.
Table 1: Test matrix for the March 2001 FSLL test series.
FSLL ID
TEST ID
BONE
TYPE
BOOT
TYPE
PROTECTION
THREAT
LOAD
CELL
701
702
703
704
705
706
707
708
709
710
711
712
M1072D
M1071C
M1071A
M1072A
M1071B
M1072E
M1072B
M1072C
M1072F
M1073A
M1073B
M1073C
Hard
Hard
Hard
Hard
Soft
Soft
Soft
Soft
Soft
Soft
Soft
Soft
R
Wellco
R
Wellco
R
Wellco
R
Wellco
R
Wellco
R
Wellco
R
Wellco
R
Wellco
Combat
Combat
R
Wellco
R
Wellco
Overboot
Overboot
Overboot
Overboot
Overboot
Overboot
Overboot
Overboot
None
None
Overboot
Overboot
M14
M14
M14
M14
M14
M14
M14
M14
M14
M14
PMA-2
PMA-2
Yes
No
Yes
No
Yes
Yes
No
No
No
No
No
No
Notes:
(1) The mine was located under the heel, aligned under the tibia, for all tests
R
(2) The overboot refers to the Wellco
mine blast overboot.
The test conditions were the same for FSLL ID numbers 701 to 708, inclusive, but four
specimens had hard calcaneus and talus bones while the other specimens had the soft version
of these bones. This was done to quantify the effect of this factor on bone damage. A load
cell was used in half of the tests, which introduces the possibility of changing the way the
tibia and fibula break. However, the results from the first test series clearly demonstrated
6
DRDC Suffield TR 2007-070
that the damage is inflicted on the most distal portion first and travels upward. It was
therefore assumed that the location of the load cell in the mid-tibia would have minimal
influence on the damage pattern to the foot and ankle regions.
2.1
Description of the FSLL and its Preparation
Based on the observations from during the first test series, it was determined that the
injury process might be broken down into a short-term (first millisecond) and a long-term
response, where the short-term response is characterized by plastic response of the distal
leg while the long-term response corresponds to the vertical momentum and jump of the
overall model. Thus, only the lower portion of the model is truly required to capture the
relevant bone damage and the overall mass of the model can be maintained within some
tolerance by adding mass above the knee level. Keeping the mass constant allows one to
compare the jump from one test to the next. Furthermore, it is believed that the mass
above the distal leg, here called the reaction mass, can influence the extent of damage to
the distal leg. Suppose for example that the model vertical motion is constrained so that
no jump is allowed. This imparts greater stress in the long bones, making it more likely
that these bones will fail.
The FSLL specimens for the second test series used tibia and fibula bones that were identical
to those from the first test series. Strain gauges had been fitted to the long bones to provide
continuity with the data from the first test series, not as main diagnostics. The bones of the
fore and mid foot were also identical, but the calcaneus and talus bones were constructed
around a porous core so that the overall static strength of these soft bones was comparable
to the strength of their human counterparts. Figure 1 shows the FSLL and the porous
inserts for the talus (lower left) and calcaneus (lower right) bones. The FSLL specimens
were also fitted with an adaptor plate to receive the reaction mass. This plate was fixed to
the top of the tibia using nylon threaded inserts and nuts.
Approximately 100 person-hours were required to fit the reaction masses to the FSLL
specimens prior to test. This operation requires several steps as depicted in Figure 2.
Reaction masses were machined from round aluminium stock. A hole at the lower end
matched the diameter of the stainless steel insert plates fitted to the FSLL specimens. The
upper end had been drilled and tapped to fit an eyebolt so that the finished FSLL specimens
could be attached to the crossbeam above the test platform (see later in this Chapter).
Alignment jigs were constructed from wood to control the alignment of the reaction mass
relative to the tibia. This is an important step towards controlling the geometry of the
model from test to test. The jigs were also constructed so that the lower part of the FSLL
gelatine mould could be used to position of the foot of the FSLL. Each FSLL specimen was
positioned in a jig (Figure 2a) and a reaction mass was temporarily slid over the shaft of
the adaptor plate.
The next step was to adjust the alignment between the reaction mass and the tibia using
the nylon nuts, and then fix the latter by melting a generous portion of the polyamide glue,
making sure to fill the full space between the adaptor plate and the upper section of the
DRDC Suffield TR 2007-070
7
Figure 1: Frangible Surrogate Lower Leg with soft core inserts (shown at the bottom of the picture)
in the calcaneus and talus bones (photo courtesy of DSTO, Australia)
8
DRDC Suffield TR 2007-070
a
b
c
d
e
f
Figure 2: Series of operations required to prepare the FSLL for testing. From upper left to lower
right: a) alignment rigs; b) gluing the counterweight plate; c) fixing the counterweight to the FSLL;
d) preparation of FSLL for gelatine pouring; e) trimming of FSLL for total mass; f) painting on the
nylon skin
DRDC Suffield TR 2007-070
9
tibia. This was achieved by starting under the middle of the adaptor plate and working
outward (Figure 2b). Once the polyamide glue had set, the reaction mass was pulled out,
the FSLL specimen was removed from the jig and the two components were fixed to each
other using a tight fitting pin that could be inserted using light tapping with a hammer
(Figure 2c). The next step was to add gelatine to completely cover the FSLL knee region
and the lower end of the reaction mass. Three FSLL moulds had been provided by the
manufacturer for this purpose. Each FSLL was therefore fitted inside a mould and placed
vertically on the floor (lower left in Figure 2d). Melted ballistic gelatine was then poured
in the mould and the latter was moved to a freezer at 4◦ C for overnight curing.
Once curing of the gelatine was complete, the FSLL was removed from the mould and
gelatine was trimmed (Figure 2e) from the upper part of the FSLL to adjust the total mass
to approximately 9.4 kg. The next step was to add a strain gauge on the surface of the
foot, below the calcaneus, which would be used to record the time of arrival of the shock
wave. The nylon skin was then fitted over the leg and melted into the superficial layer of the
gelatine using a paintbrush and hot water (Figure 2f). The load cell was inserted into four
FSLLs after the initial trimming operation. The steps to insert the load cell into the tibia
were described in [1]. This required the removal of gelatine, removal of a tibia segment,
R
potting in of receiver cups with 5-Minute
epoxy, installation of the load cell, refilling of
◦
the gelatine and further curing at 4 C. The bottom strain gauge and the skin were then
installed.
The start and final mass properties for each FSLL are listed in Table 2. It is seen that the
average final mass for the regular FSLL specimens varied from 9.39 kg to 9.48 kg with an
average final mass of 9.44 kg. The FSLL specimens that were fitted with a load cell had a
similar mass after the initial trimming, but their mass was allowed to float to the new final
mass after inclusion of the load cell. The final mass for those FSLL specimens varied from
9.83 kg to 10.69 kg, with an average mass of 10.14 kg. It is therefore seen that the mass of
the FSLL specimens was relatively well controlled.
2.2
Experimental Set-up
Figure 3 shows the experimental set-up used during the second test series. A wooden
platform 2.4 m × 2.4 m was suspended 0.75 m above the surface of a concrete pad with
eighteen 100 mm × 100 mm posts. Eight posts were located at the edges of a hole in the
centre of the platform that received a soil container constructed from 12 mm thick steel.
The dimensions of the container were 500 mm × 400 mm with a depth of 300 mm. The
centre of the container, defined as Ground Zero (GZ), could be found from the intersection
of twine attached to four nails fixed to the platform. A beam ran above the platform at a
height of 1.5 m with another piece of lumber intersecting the beam at 90◦ above GZ. These
beams were used to attach and stabilize the FSLL specimen. They were also needed to
protect the cables running to the FSLL instrumentation.
The main instrumentation used during these tests included six strain gauge channels, and
five or six channels for the load cells. These load cells were the same ones used during the
10
DRDC Suffield TR 2007-070
Crossbeam and
stabilisation beam
Reference pressure
transducer
FSLL
Instrumentation
cable
Flash x−ray film
cassette
Flash x−ray heads
Figure 3: Experimental set-up used for the second test series
DRDC Suffield TR 2007-070
11
Table 2: Jig and mass properties for each FSLL specimen
FSLL ID
JIG ID
START MASS
(KG)(1)
REACTION MASS
(KG)
FINAL MASS
(KG)
701
702
703
704
705
706
707
708
709
710
711
712
2
3
1
3
1
2
1
2
3
1
2
3
4.43
Not recorded
4.57
4.76
Not recorded
4.87
4.88
4.89
4.90
4.86
4.89
4.88
3.02
3.08
3.07
3.07
3.03
3.07
3.03
3.07
3.07
3.03
3.02
3.03
9.94(2)
9.39
9.83(2)
9.46
10.09(2)
10.69(2)
9.45
9.44
9.46
9.48
9.42
9.43
Notes:
(1) This is the mass of the FSLL as received from the manufacturer,
including the adapterplate.
(2) The mass includes the load cell inserted in the middle of the tibia
after the initial trimming operation.
first test series and during the LEAP study. The only other electronic instrumentation was
a free-field pressure transducer mounted in a flat dish pointing to GZ. The only function
of this pressure transducer was to confirm that high-detonation of the mine had occurred.
A high-speed video and high-speed film camera were placed 13 m from GZ to record the
side view of the FSLL. A second high-speed video was placed 17.5 m from GZ to record the
head-on view of the FSLL. In addition, up to three regular 8 mm video cameras were used
to record various views of the event.
Given the importance of the information obtained from the flash x-ray equipment during
the first test series, this equipment was used again. However, a fresh x-ray cassette was used
to obtain two images for each test. The flash x-ray arrangement (Figure 4) took advantage
of optics and geometry to generate two images that the human mind would construe as
being taken from the same point of view. The x-ray pulsers were placed as close to each
other as possible. Two regular x-ray films were also placed as close as possible within a
single film cassette, while the heel-to-toe axis of the FSLL was aligned parallel to the face
of the x-ray film cassette. This meant that the FSLL was misaligned by 23◦ relative to each
x-ray film. For the film located on the right-hand side, the toes of the FSLL were closer to
the right edge of the image. This was reversed for the left-hand side film. The length of
the FSLL projection on the films is then a function of the magnification factor (1.245), the
lateral dimension x and the 23◦ misalignment angle.
The magnification factor is normally used with the point of zero error (PZE) on each
film to determine the real position of the object being imaged. The PZE is defined by
the perpendicular from the film to the pulser and was determined by laser alignment for
each test. Lead lines were taped to the face of the film cassette to generate crosshairs on
each film. Using geometry about the PZE, the magnification factor, and the orthogonal
12
DRDC Suffield TR 2007-070
Note: All dimensions are in inches
Figure 4: Flash x-ray arrangement used during the second test series to obtain two images per shot
DRDC Suffield TR 2007-070
13
alignment error, it was possible to determine the exact position of any point of the FSLL
from its position on the x-ray films using the following magnification factor formulas:
M FRHS =
D cos(23) − x sin(23)
d cos(23)
M FLHS =
D cos(23) + x sin(23)
d cos(23)
where D is the total distance from the x-ray source to the film, d is the distance from
the x-ray source to the object, and x is the lateral distance from the vertical feducia line.
A recommendation from the first test series was to record the evolution of the footwear
deformation and lower bone displacements during the early part of the injury process. In
order to reach this goal despite the limitation that only two flash x-ray images could be
generated per shot, it was necessary to make two assumptions: First, that the FSLL mass
and initial geometry of the set-up would be identical for each shot; and second, that the
impulsive stimulus generated by all mines of a given type would be the same from one test
to the next. In reality, there are always small variations in mass, geometry, and mine blast
output from one shot to the next, hence the importance of maintaining tight control over
the experimental procedure. It will be shown later in this report that the geometry must
be controlled very tightly to ensure accuracy. The timings for each x-ray were determined
roughly prior to the test series and adjusted as results became available. Thus, based on
the test matrix given in Table 1, three flash x-ray timing sequences were used as follows:
• For M14 versus BB/OB: 50, 100, 150, 200, 250, 400, 500, and 700 µs;
• For M14 versus CB: 50, 100, 150 and 250 µs; and
• For PMA-2 versus BB/OB: 100, 150, 250 and 500 µs.
These flash x-ray times are nominal. In reality, small variations occur, but the exact
discharge times of the pulsers are recorded to an accuracy of 0.1 µs. Table 3 lists the actual
flash x-ray firing times for each test. (Note: the nominal timings were repeated for both the
hard and soft bone versions of the FSLL for the first test condition (M14 versus BB/OB)).
2.2.1 Soil and Explosive Charges
The soil used for these tests was medium sand purchased in bags locally. The humidity
level was very low–less than 1 per cent–to reproduce the same basic soil conditions that
were used during the first CCMAT FSL tests and during the LEAP tests. It is known that
humidity can have a strong influence on mine blast output. Thus, maintaining low soil
humidity is the best method to maintain tight control over this experimental parameter.
The two mine types used in these tests, the M14 and PMA-2, are described in References[3]
and [1], respectively. The preparation for the M14 mines included the removing a large
14
DRDC Suffield TR 2007-070
Table 3: Flash x-ray timings for this second test series
FSLL ID
MINE
FOOTWEAR(1)
X-RAY HEAD 1
TIME (µs)
X-RAY HEAD 2
TIME (µs)
701(2)
702
703(2)
704
705(2)
706(2)
707
708
709
710
711
712
M14
M14
M14
M14
M14
M14
M14
M14
M14
M14
PMA-2
PMA-2
BB/OB
BB/OB
BB/OB
BB/OB
BB/OB
BB/OB
BB/OB
BB/OB
CB
CB
BB/OB
BB/OB
52.1
152.1
202.1
102.2
102.0
55.4
205.6
152.6
50.0
102.0
105.3
152.6
255.4
505.4
682.5
405.6
407.1
255.4
705.6
506.4
155.5
256.1
255.4
505.2
Notes:
R
(1) CB = combat boot; BB = Wellco
blast boot;
R
OB = Wellco
blast overboot.
(2) This specimen had a load cell inserted in the middle of the tibia.
metallic washer from the base, arming the mine, and depressing the pressure plate. This
placed the M14 mine in the same condition as during an incident in the field. The M14 was
fired using a remote fire control system employing a RP-87 detonator inserted in the base
of the mine, where the actual detonator would normally be. Approximately 0.33 g of Deta
R
Sheet
was used as a booster.
The preparation and burial conditions for the PMA-2 mine were identical to those used
during the first test series. Only the main charge was used. This mine has a top initiating
fuse that stands proud of the main body. Detonation is initiated by depressing a star-shaped
plunger. Total height of the fuse and plunger above the mine body is approximately 20 mm
with the fuse depressed. Thus, a cylindrical cardboard spacer, 20 mm in height, was used
to locate the PMA-2 mine body at the appropriate depth below the footwear. Detonation
was achieved in the same manner as for the M14 mines.
2.3
Experimental Procedures
This section provides details about the sequence of events that took place prior to and
immediately after a shot. Prior to bringing out the FSLL, preparation of the platform
included filling the soil container with new sand and carrying out all instrumentation checks.
Filling the soil container involved removing old sand to a disposal site and pouring in new
dry sand from 20 kg bags. No attempt was made to pack the sand. Previous experience had
shown that a loose pour of the sand results in consistent soil density from shot to shot. The
sand was levelled using a straight edge and excess sand was removed. Finally, the platform
was cleaned for general work site safety and video quality.
All instrumentation external to the FSLL was checked for functionality and prepared for the
DRDC Suffield TR 2007-070
15
shot. This included loading and aligning the film cassettes for the flash x-ray system. The
film was loaded in the high-speed camera and the high-speed videos were set and armed.
Finally, the fire control systems was checked and put in the safe mode, ready for placement
of the explosive charge and positioning of the FSLL over the mine. Once these steps were
completed, all non-essential personnel left the site and final preparations were made.
2.3.1 Mine and FSLL Placement
As with the LEAP and previous CCMAT tests, the mines were placed in the middle of
the steel container. The M14 was buried flush with the sand surface while the PMA-2 was
buried such that the top of the cardboard spacer was flush with the sand surface.
Placement of the FSLL was done in the same manner as during the first test series. The
centre of the heel of the boot was aligned on the crosshairs, without the explosive charge
being present. The FSL was held manually in the vertical position while the rope that ran
vertically from the eyebolt on top of the reaction mass to the crossbeam was adjusted so
that the FSLL would not sink more than about 10 mm into the surface of the sand. After
this step, tension on four strings that ran from the top of the FSLL to overhead attachment
points was adjusted to hold the FSLL in the vertical position. When the FSLL stood up
satisfactorily, it was tilted to move the foot sufficiently far to allow placement of the mine.
The FSLL was then carefully located over the charge, final 35 mm pictures were taken,
the site was vacated, final data acquisition and instrumentation checks were made, and the
charge was fired.
2.3.2 Post-Test Actions
Immediately following each test, the specimen was photographed and superficial damage
to the leg was noted. The specimen was then removed from the test platform to the
preparation site where any footwear remaining attached to the specimen was removed and
placed in reinforced plastic bags. The footwear and FSLL specimen were weighed and
mass changes were noted. The specimen was then returned to refrigerated storage pending
medical assessment. If a load cell was present, the leg was dissected in a pre-arranged
manner to remove the load cell and replaced with a spacer.
The area surrounding ground zero was combed for pieces of boot, overboot and/or FSLL
fragments. Since these tests were conducted outdoors without any fragment containment,
numerous fragments were never found and, with the exception of the most obvious fragments, it could not be confirmed after the first shot that any small fragment found had
originated from the latest shot.
2.3.3 Post-Test Medical Assessments
At the end of each days trials, the specimens were taken to the Medicine Hat Regional Hospital where they underwent standard medical x-ray and Computerized axial Tomographic
imaging (CT scan). The specimens were then returned to cold storage and transported
16
DRDC Suffield TR 2007-070
back to the research facility the next day. A radiologist inspected the x-rays and reported
on each specimen. Copies of these reports are given in Annex B.
The CT scan data were printed on film for immediate inspection and stored on digital
medium for off-site processing at the Adelaide University Hospital, Australia, where 3D
sagittal reconstruction was carried out. The 3D results were displayed as rotating images
on a regular PC. However, these 3D reconstructions were not available to the examining
surgeon when performing the post-test dissections.
The specimens were examined and dissected by an experienced general surgeon (Figure 5).
He was blinded to the protective equipment and type of mine used for the tests. Medical
assessments were carried out in a single batch in a veterinarian operating room. The
procedure used to inspect each specimen was the same used during the first test series.
The specimens were taken from cold storage to the operating room. The x-rays and CT
images were compared with the appearance of the specimen immediately before dissection
and used to correlate the injury pattern found on dissection with that seen on the images,
making note of:
• Completeness of specimen and if any part was clearly missing;
• Perforations of the witness layer (nylon mesh); and
• Evidence of contamination (presence of sand, gravel, or textile adhering to the gelatine).
The specimen was then examined in detail. The intrinsic stability of the ankle joint was
tested and obvious laxity noted. The model was then destructively dissected starting distally. The witness layer was removed starting at the foot and progressing to the ankle,
distal leg and just-below-knee areas. Splits and defects in the gelatine were noted and the
gelatine stripped from the surrogate bones, which were then manipulated to confirm their
integrity. Fractures in the bones were noted together with coincident abnormalities on diagnostic imaging. When bone and gelatine were shattered, reassembly of the tissue was
attempted in order to estimate missing tissue. Joints were closely examined to determine
stability. The presence of load cells in the distal tibia was noted and a careful assessment
of the type of fracturing in this area noted. A simple fracture at the lower end of the load
cell fixation was discounted as artefact. A comminuted fracture of the tibia that extended
up to the load cell was considered a legitimate abnormality.
Using the sum total of injuries for each specimen, each specimen was assigned an MTS
score. Another experienced surgeon, who had access to the 3D CT reconstructions, later
reviewed these scores. The scores from these two surgeons agreed for the majority of the
tests, but there were exceptions that resulted in small differences. The results from the
dissections and resulting MTS scores are given in Annex B.
DRDC Suffield TR 2007-070
17
Figure 5: The specimens were examined by a qualified surgeon in a veterinary operating room
18
DRDC Suffield TR 2007-070
3
Physical and Medical Results
To provide insight into the mechanisms associated with mine blast trauma, the flash x-ray
images are discussed first. Since velocity is indicative of the effective momentum transfer
due to the mine explosion, there was a special effort during the present tests to determine
R
the velocity imparted to the blast deflectors located within the Wellco
equipment. The
final physical state of the footwear is described and medical assessments, Mine Trauma
Scores and bone scores are detailed. Finally, an attempt is made to correlate the FSLL
results to those from LEAP.
3.1
Analysis of the Flash X-Ray Imagery
The flash x-ray observations from the first test series revealed several features of the processes taking place during mine blast trauma to the lower leg. Improvements permitted
observation refinements. Figures 6 through 8 show results for the three test conditions
considered during the present test series.
Figure 6 shows the early progression of damage, from 50 to 250 µs, for an unprotected
combat boot exposed to a M14 mine. The net result for this mine-footwear combination is
traumatic amputation of the foot. The flash x-ray demonstrates that it takes approximately
100 µs for the high-pressure gas to punch through the sole of the combat boot. There is
negligible motion of the foot during this time. At 150 µs, damage to the foot starts to occur.
By 250 µs, the calcaneus bone is losing its definition near the lower extremity, indicating
that it is being pulverized locally. Furthermore, it can be seen that the calcaneus bone is
rotating, as indicated by the change in angle of the upper rear surface of this bone. The
hemispherical nature of the high-pressure gas bubble is clearly seen on the x-rays. The shape
of the remaining portion of the sole is a good indicator of the shape of the gas bubble. It
can be surmised how this push is causing bone dislocation in the mid- and forefoot regions.
At this early time, the damage is localized around the distal portion of the lower extremity,
but the onset of soft tissue stripping along the long bones of the leg also begins.
Figures 7 and 8 show the early progression of damage, from 100 to 500 µs, for a blast boot
with an overboot against the M14 and PMA-2 mines, respectively. Although the two events
are similar, there are significant differences that can be attributed to the larger amount of
explosive in the PMA-2 mine. Comparing the images at 500 µs, it is apparent that the
diameter of the crater for the PMA-2 is much larger than for the M14. The density of soil
at the lip of the expanding crater is also greater for the PMA-2 than for the M14 at 250
µs. These differences are a direct consequence of the larger amount of hot gas produced
by the larger mine. The larger push from the PMA-2 causes a more violent collapse of the
blast deflectors. By comparing the deformation of the blast deflectors for the two mines
at similar times, the following differences can be seen. At 100 µs, only the lower deflector
started to deform; the upper deflector has not yet been affected. The M14 produces a
focussed deformation of the lower deflector while the PMA-2 deforms the latter over a
greater area and with more force, as indicated by the greater amount of crushing. At 150
µs, the sole of the inner boot has been compressed and the upper blast deflector started to
DRDC Suffield TR 2007-070
19
Figure 6: Flash x-ray images of an M14 mine explosion under a combat boot; timings from upper
left to lower right are: 50.0 µs, 102.0 µs, 155.5 µs and 256.1 µs
20
DRDC Suffield TR 2007-070
respond. By 250 µs, the lower blast deflector for the M14 mine has lost momentum and is
significantly displaced relative to the upper blast deflector. For the PMA-2 mine, the lower
deflector is still pushing against the upper deflector. In both cases, the upper deflector is
curved upward and pushes against the sole of the FSLL. The upper blast deflector also
exhibits more crushing for the PMA-2 than for the M14. By 500 µs, both blast deflectors
are moving upward under the continued push of the expanding gas. For the PMA-2, the
upper blast deflector displays more upward curvature and more crushing. This deflector
has also compressed the sole of the FSLL more than for the M14.
The flash x-ray images were analysed to extract the position of eight specific points, as
shown in Figure 9. Points 1 to 4 were selected to determine the deformation of the blast
deflectors as a function of time and mine type. The x (left to right) position for these
points roughly corresponds to the point of minimum thickness of each deflector. Points 5
to 8 were selected to measure the transmission of the impact force to the calcaneus and
tibia. Thus, points 5 and 6 are two easily identifiable points on the calcaneus while points
7 and 8 define a line across the lower end of the tibia. Only the y coordinates were used to
estimate vertical displacement with time.
The results from this analysis are shown graphically in Figures 10, 11 and 12. Figure 10
shows the vertical position of the highest point on the upper surface of the lower and
upper blast deflectors as a function of time. As can be seen, there is significant scatter
of the data, which is attributed to variations in the initial position of the FSLL model.
The set-up procedure called for applying the free weight of the model on top of the mine.
However, the model sank until it found an equilibrium position because dry sand was used.
The previous x-ray images demonstrated that the upper blast deflector starts to respond
some time between 100 and 150 µs. Thus, if the initial position had been maintained, the
first four points for the M14 upper deflector curve would all be at the same height, yet
the vertical position of the top deflector upper surface varies by as much as 14 mm. The
average height for these four points is 33.6 mm with a standard deviation of 6.5 mm. It
should be noted that this error might also be attributable to the relative position of the
upper footwear in the overboot. Irrespective of the exact source of this variation, the very
short time intervals involved with flash x-ray measurements require very tight control over
position. For example, an error of 1 mm in location for x-ray images captured over a 50
µs interval generates a velocity error of 1 mm/0.05 ms = 20 m/s. The best way to achieve
high positional accuracy would be to use a test rig to hold the FSLL specimens in their
initial position. Such a rig could also guide the initial motion of the model.
Despite the variations in the initial position of the FSLL specimens, the points extracted
nevertheless display trends. It was therefore decided to perform least square fits of third
order polynomials to the M14 data and second order polynomials to the PMA-2 data. There
are only four points for the PMA-2 data, which limits the order of the polynomial fit. The R2
value for the curve fits was greater than 0.93 for all curves with the exception of the Upper
Deflector/M14 curve that had a R2 value of 0.77. The first derivative of these curve fits was
then used to estimate vertical velocity. Table 4 lists the velocity values computed in this
manner. It is seen that the greater explosive content of the PMA-2 imparts approximately
twice the vertical velocity to the lower deflector in comparison with the M14 mine, i.e.,
DRDC Suffield TR 2007-070
21
Figure 7: Flash x-ray images of an M14 mine explosion under a blast boot with overboot; timings
from upper left to lower right are: 102.0 µs, 152.6 µs, 255.4 µs and 506.4 µs
22
DRDC Suffield TR 2007-070
Figure 8: Flash x-ray images of a PMA-2 mine explosion under a blast boot with overboot; timings
from upper left to lower rigt are: 105.3 µs, 152.6 µs, 255.4 µs and 505.2 µs
DRDC Suffield TR 2007-070
23
7
8
6
5
4
3
2
1
Figure 9: Eight reference points used to extract data from the flash x-ray images
24
DRDC Suffield TR 2007-070
Figure 10: Upper surface trajectory for the lower and upper blast deflectors versus time and mine
type
Figure 11: Trajectory for the average y values of the calcaneus for the three test conditions
DRDC Suffield TR 2007-070
25
Figure 12: Trajectory for the average y values of the tibia for the three test conditions
about 240 m/s versus 120 m/s. Another feature of the data is the rapid deceleration of the
lower deflector as it compresses the rubber of the sole and impacts the upper deflector.
The third order fit to the M14 data displays an inflection point; which more or less reflects
the flat portion of the curve up to 200 µs, which is indicative of the delayed response of this
deflector. The curve fit to the M14 data suggests that the velocity of the upper deflector
peaks at 65 m/s approximately 400 µs after detonation. The higher energy content of the
PMA-2 might explain the continued acceleration of the upper deflector, which reaches a
velocity around 90 m/s at 500 µs. These values are consistent with the initial velocity
values for the respective lower deflectors and for conservation of momentum principles.
The vertical momentum transfer to the calcaneus was estimated from the average y values of
points 5 and 6, while the corresponding values for the tibia was estimated from the average
y values of points 7 and 8. The resulting points are plotted in Figure 11 for the calcaneus,
and Figure 12 for the tibia. Again, the scatter of the data is apparent, but linear curve fits
through the data reveal the expected trend, i.e., that these bones are displaced vertically
with time. The slopes of these lines are given in Table 5. They provide an indication of the
vertical velocity imparted to these bones as a function of footwear and mine type.
The velocity of the distal tibia is significantly less than that of the calcaneus. This large
difference is apparent despite the variations in the initial position of the specimens. The
general trend of the slopes — a factor 5 to 12 — clearly indicates that the M14 imparts
much more vertical velocity to the bones when the FSLL is fitted with only the combat boot
26
DRDC Suffield TR 2007-070
Table 4: Vertical velocity estimates from curve fits to the upper surface position of the blast deflectors
M14 MINE
PMA-2 MINE
Time (µs)
Lower Deflector
(m/s)
Upper Deflector
(m/s)
Lower Deflector
(m/s)
Upper Deflector
(m/s)
50
100
200
300
400
500
118
113
101
85
66
44
-47 (1)
-17(1)
28
56
65
57
243
221
178
134
91
48
38(2)
44
55
67
78
90
Notes:
(1) This value is physically impossible; it is an artefact from
the curve fitting procedure due to imperfect data.
(2) This value is an artefact from the curve fitting procedure since the lower
deflector has not yet impacted the upper deflector at this early time.
Table 5: Vertical velocity estimates from linear fits to the calcaneus and distal tibia position data
BONE
M14 Vs CB (m/s)
M14 Vs BB/OB (m/s)
PMA-2 Vs BB/OB (m/s)
Calcaneus
Distal Tibia
66.5
27.5
12.5
2.2
17.4
1.8
Notes:
R
CB designates the Combat Boot; BB the Wellco
Blast Boot;
R
and OB the Wellco
Blast Overboot
DRDC Suffield TR 2007-070
27
as compared to a blast boot with overboot. Similarly, the data suggests that the PMA-2
mine imparts more vertical velocity to the calcaneus bone than the M14 mine, but the net
transmission to the tibia is approximately the same. Thus, despite the uncertainty with
the positional accuracy, it is seen that the data indicates trends that are consistent with
the level of protection and mine type.
The above vertical velocity measurements provide insight into the transmission of momentum from the mine, through the footwear, and into the distal leg. We first consider the
process for the case when only a regular combat boot is worn. For this case, it is seen
that the sole of the boot provides no protection. Furthermore, the foot is very close to the
mine so that the expanding gas imparts significant momentum to the calcaneus and tibia
bones. There nevertheless appears to be some energy dissipation at play since the distal
tibia velocity is approximately half of the velocity of the calcaneus.
When protective footwear selected for these experiments is used, it is seen that momentum is
very quickly redistributed over the time period covered by the flash x-ray observations. The
PMA-2 mine imparts approximately twice as much momentum to the lower deflector than
the smaller M14 mine. The lower deflector slows down quickly as it compresses the rubber
situated immediately above and then impacts the upper blast deflector. The momentum of
the second deflector reaches a value approximately half of that for the lower deflector, at
least for the M14 mine. For the PMA-2 mine, the data suggests that the upper deflector
is still accelerating at the maximum flash x-ray time of 500 µs. The upper blast deflector
then impacts the lower surface of the foot over an area slightly in front of the calcaneus
bone, causing a backward rotation of this bone and pushing the heel through, or nearly
through, the back of the foot. This, in itself, is an energy dissipation mechanism such that
less momentum gets transmitted to the distal tibia. The vertical velocities recorded for
these two bones suggest that wearing protective footwear greatly reduces the momentum
transfer to these bones when compared with regular boots.
3.2
Summary of Boot Damage
A detailed post-test examination of the boots and protective footwear was conducted (see
Annex A). This section presents a summary. It was generally found that a given test
condition produced a consistent level of damage to the footwear from one test to the next.
A special effort was made during this second test series to comb the area after each test
and recover as much of the boot as possible. The weight of the boot and overboot was also
measured prior to and immediately after each test, as listed in Table 6.
3.2.1 Damage to an Unprotected Combat Boot
Only two tests were performed against an unprotected US Army combat boot, both versus
the small M14 mine. In each case, there was catastrophic failure of the boot. The heel was
completely destroyed along with the insole and most of the upper. There was nothing left of
the upper behind the line of the quarter/rear vamp seam. All that was left of the quarter is
the eyelet flap and a strip up to 45 mm wide that attaches to the toe thread and front vamp.
28
DRDC Suffield TR 2007-070
Table 6: Weight of boots and overboots before and after each test
FSL ID
701
702
703
704
705
706
707
708
709
710
711
712
BOOT
OVERBOOT
Before (kg)
After (kg)
Before (kg)
After (kg)
1.150
1.156
1.167
1.127
1.144
1.238
1.175
1.086
0.996
0.963
1.234
1.152
1.150
1.156
1.167
1.127
1.144
1.238
1.175
1.086
0.822
0.723
1.270
1.176
1.164
1.130
1.140
1.132
1.129
1.180
1.139
1.171
Not applicable
Not applicable
1.142
1.128
1.066
1.099
1.099
1.120
1.086
1.062
1.001
1.090
Not applicable
Not applicable
1.030
0.963
The latter portion of the boot was still recognisable and relatively undamaged, highlighting
the localized nature of the traumatic amputation for this mine size. The average mass of
the boot fragments recovered represented 79% of the initial mass.
3.2.2 Damage to a Blast Boot with an Overboot
This particular combination of footwear was exposed eight times to the M14 mine and twice
to the PMA-2 mine during these tests. For those tests against the M14 mine, there was
minimal external damage to the BB. In each case, the force of the impact was sufficient to
permanently bend the sole into an exaggerated arch. In several cases, there was separation
of the sole from the upper along the rear portion of the boot. In a few cases, there was also
a small tear of the upper in front of the rear vamp. Damage to the interior of the boot was
minor, consisting of tears in the insole foam. In one case, there was a split in the bottom of
the sole, most likely due to unusual failure of the blast deflector. Damage to the overboot
was also consistent, with the rear being destroyed each time. The vamp often tore along
the back stitching line and on each side along the sole interface. The blast attenuator and
deflector were often extracted under the force of the explosion. The average mass of the
fragments recovered was 94% of the initial mass.
When the BB/OB was subjected to the blast of a PMA-2 mine, the damage to the footwear
was extensive. The heel of the overboot outer sole was destroyed and the blast deflector
was flattened and separated from the overboot. The attenuator was fully crushed at the
back and partially crushed along the remaining length. The Kevlar insole and lateral side
panels remained attached to the outer sole in the front of the overboot. The side panels
separated over most of the length of the sole in one case, but remained mostly attached in
the other case. For both tests, the overboot was found in near proximity to the FSLL and
inner boot.
The inner boot also suffered considerably more damage than against a M14 mine. The outer
DRDC Suffield TR 2007-070
29
sole remained relatively intact, but it was permanently bent upward into an exaggerated
arch. There was extensive separation of the upper from the outer sole over most of the rear
of the boot. The blast deflector was visible from the inner side of the sole, revealing that it
had been fully crushed near the back and partially crushed over the remaining length. The
Kevlar insole was uneven in the upper heel surface and longitudinal cracks were visible in
the foam. Small fragments of ballistic gelatine (flesh) were embedded in part of the sole.
The upper separated from the outer sole and the Kevlar insole. A vertical tear, starting at
the mid point of the heel cap and running upward, was indicative that the pressure exerted
on the FSLL foot caused the latter to burst, extruding bones and gelatine through the boot
upper. This process was sufficiently violent to cause part of the upper to tear away from
the boot.
The mass values from Table 6 indicate that 88% of the total overboot mass was recovered.
The mass for the inner boots increased by 2.5%. This increase is attributed to contamination
from the bursting FSLL model, part of which was embedded in the broken footwear.
3.3
MTS Scores
Each FSLL specimen was x-rayed in a clinical setting and a surgeon then performed a
physical exam. The physical damage was noted and an MTS score was assigned. Another
surgeon reviewed these scores at a later time. Annex B presents the x-ray reports and
the detailed accounts of the clinical dissections performed by the first surgeon. Table 7
presents a summary of the MTS scores assigned by the surgeons. The medical examiners
were blind to the footwear and type of threat that each specimen had been exposed to.
Table 8 presents the corresponding MTS scores obtained during LEAP.
The MTS results demonstrate that three factors influence the medical outcome: mine type,
footwear and the construction of the calcaneus and talus bones. Let us first consider the
results for the M14 mine. Each test against a combat boot resulted in a MTS score of
2B. Although this is consistent with the results obtained during the first test series, it is
less than the MTS scores of 3, 3, 3, 3, and 4 that were obtained during LEAP. The LEAP
scores were primarily attributed to the extent of soft tissue injury. The results for the FSLL
therefore confirm the limitation of ballistic gelatine to simulate soft tissue. The results for
the M14/boot/overboot combination illustrate the effect of bone type on MTS score. The
hard bones resulted in higher MTS scores (1A, 2A, 2A, 2A/2B) relative to the tests against
the softer bones (1A, 1A, 1A, 2A/1A). Both surgeons agreed that the results against the
harder bones would have resulted in a below knee amputation in three out of four tests.
This is the inverse of the results for the softer bones. One surgeon even estimated that all
four cases were salvageable. This proves that the material characteristics for a frangible
surrogate must be selected with care to achieve realism with model performance.
Exposing the combination of boot and overboot to the PMA-2 mine confirmed that explosive
mass has a strong influence on medical outcome. MTS scores of 2B, 2B/3 were obtained,
indicating that a traumatic amputation should be expected for this larger mine despite the
use of protective footwear. The flash x-ray provided insight into the nature of the injury
30
DRDC Suffield TR 2007-070
Table 7: Summary of the MTS scores assigned to each FSLL; the data is ordered by protection type
and then by increasing explosive mass
SHOT ID
FOOTWEAR
PROTECTION
EXPLOSIVE
MTS(1)
709/M01072F
710/M01073A
701/M01072D
702/M01071C
703/M01071A
704/M01072A
705/M01071B
706/M01072E
707/M01072C
708/M01073B
711/M01073B
712/M01073C
Combat Boot
Combat Boot
Blast Boot
Blast Boot
Blast Boot
Blast Boot
Blast Boot
Blast Boot
Blast Boot
Blast Boot
Blast Boot
Blast Boot
None
None
Overboot
Overboot
Overboot
Overboot
Overboot
Overboot
Overboot
Overboot
Overbott
Overboot
M14
M14
M14
M14
M14
M14
M14
M14
M14
M14
PMA-2
PMA-2
2B
2B
1A
1A
2A/1A
1A
2A/2B
1A
2A
2A
2B
2B/3
Note:
(1) When present, the second score was assigned by the reviewing examiner
mechanism as compared to the tests against mines with a smaller amount of explosive.
These results were comparable to those obtained during LEAP.
3.4
Bone Damage Scores
The MTS scores, although useful, do not provide sufficient detail to assess the FSLL performance in terms of mechanical damage to individual bones. During the LEAP study, bone
damage increased gradually from simple fractures, to compound fractures, to severe comminution. In the worst cases, some bones were pulverized to such an extent that they could
no longer be recognized. In general, the level of damage increased with the magnitude of
the impact applied to the foot, i.e., with increasing explosive mass or decreasing protection.
To account for this progression, a scoring system was defined to analyse the results from
the first FSL test series. The scores reflect the level of damage to individual bones using
the four levels defined in Table 9. A simple linear numerical score, from 0 to 3, was assigned
to each level so that bone damage could be ranked. Although relatively crude, this system
successfully captured the gross differences in FSL performance for the first FSL test series.
This crude scoring system was used to assess the level of damage to the bones based strictly
on the written medical assessments contained in this report and the LEAP Volume II [3]
report. Five bones were considered: calcaneus, talus, the pilon area (the interface between
the talus and the long bones), tibia and fibula. The scores obtained from this analysis are
listed in Table 10 and Table 11 for the FSLL and LEAP tests, respectively. An average
for each bone was also computed for the blast boot/overboot combination versus the M14
mine.
DRDC Suffield TR 2007-070
31
Table 8: Summary of relevant MTS scores obtained during LEAP
SHOT ID
FOOTWEAR
Boot
Boot
Boot
Boot
Boot
PROTECTION
EXPLOSIVE
MTS
None
None
None
None
None
M14
M14
M14
M14
M14
3
3
3
3
4
PS1
PS2
PS4
PS6
01
Combat
Combat
Combat
Combat
Combat
PS7
03
06
08
10
Blast
Blast
Blast
Blast
Blast
Boot
Boot
Boot
Boot
Boot
Overboot
Overboot
Overboot
Overboot
Overboot
M14
M14
M14
M14
M14
1
2A
2
2A
1
09
15
16
17
18
Blast
Blast
Blast
Blast
Blast
Boot
Boot
Boot
Boot
Boot
Overboot
Overboot
Overboot
Overboot
Overboot
PMA-2
PMA-2
PMA-2
PMA-2
PMA-2
2B
3
3
2B
2B
Table 9: Crude scoring system used to compare the level of bone damage between LEAP and FSLL
tests
32
DESCRIPTOR
SCORE
LEVEL OF DAMAGE
I
S
C
M
0
1
2
3
Bone is intact, no physical damage is reported
Simple fracture of the bone, could inlcude up to 2 fractures
Compound (> 2 breaks) or comminuted fracture of the bone
Highly comminuted fracture with missing bone material
DRDC Suffield TR 2007-070
MINE
TALUS
PILON
709/M01072F
710/M01073A
CB
CB
M14
M14
M
M
C
M
I
S
701/M01072F
702/M01072F
703/M01072F
704/M01072F
BB/OB
BB/OB
BB/OB
BB/OB
M14
M14
M14
M14
S
I
S
I
C
S
C
S
C
C
S
S
0.5
1.5
S
S
C
C
Average score per bone
705/M01072F
706/M01072F
707/M01072F
708/M01072F
BB/OB
BB/OB
BB/OB
BB/OB
M14
M14
M14
m14
Average score per bone
M14
PMA-2
FIBULA
FOOTWEAR
TIBIA
SHOT ID
CALCANEUS
Table 10: Summary of damage to some of the bones of the FSLL specimens
BONE
SCORE
AVERAGE
SCORE
SOFT
TISSUES
S
S
S
I
7
8
7.5
B
B
C
C
C
C
S
S
S
S
8
6
8
5
1.5
2.0
1.0
C
C
C
C
C
C
I
C
C
C
S
C
C
C
I
S
1.5
2.0
1.5
1.75
1.0
M
M
M
M
C
M
S
C
C
C
9
8
5
9
7.75
12.0
A
A
A
A
A/B
A
A
A
711/M01073B
712/M01073C
BB/OB
BB/OB
Note:
The MTS soft tissue damage descriptors are also reported here for
completeness. The bone score is for the five bones. The average score is for the same protective footwear
against the M14 mine.
DRDC Suffield TR 2007-070
11
13
6.75
B
B
33
MINE
TALUS
PILON
01
CB
M14
M
S
C
03
06
08
10
BB/OB
BB/OB
BB/OB
BB/OB
M14
M14
M14
M14
C
C
C
C
S
S
C
C
C
S
C
I
Average score per bone
2.0
1.5
09
15
16
17
18
M
M
M
C
M
S
C
C
C
C
Note:
34
BB/OB
BB/OB
BB/OB
BB/OB
BB/OB
PMA-2
PMA-2
PMA-2
PMA-2
PMA-2
FIBULA
FOOTWEAR
TIBIA
SHOT ID
CALCANEUS
Table 11: Summary of relevant bone damage during the LEAP study, deduced from [3]
BONE
SCORE
AVERAGE
SCORE
SOFT
TISSUES
S
S
8
8.0
B
I
I
I
I
C
I
S
I
7
4
7
4
1.25
0.0
0.75
C
C
C
I
C
I
C
C
S
S
S
S/C
C
S
S
7
10.5
11
6
9
5.5
8.7
A
N
A
N
B
B
B
B
B
The MTS soft tissue damage descriptors are also reported here for completeness.
The bone score is for the five bones. The average score is for the same protective footwear
against the M14 mine.
DRDC Suffield TR 2007-070
3.4.1 Unprotected Combat Boot against the M14 Mine
The average score of 7.5 for the FSLL versus 8.0 for LEAP suggests that the FSLL performed
well for a M14 mine against an unprotected combat boot. However, comparing the damage
on a bone-to-bone basis shows many differences. In each case, the calcaneus was damaged
extensively, being broken into small fragments. The damage to the talus of the FSLL was
extensive for each of the two tests while the LEAP study reports only a simple fracture
to this same bone. The pilon area was damaged significantly during LEAP, but appeared
to suffer much less damage with the FSLL. Finally, the damage to the long bones (tibia
and fibula) of the FSLL appeared to be similar to that observed during LEAP. The above
comparison is made using only one test for LEAP. More importantly, the x-rays from
LEAP were not available to make a detailed count of bone fragments, which might be a
more objective method when ranking the level of comminution. Despite these limitations,
it is seen that the FSLL model captured the essence of bone damage. There was extensive
damage to the lower bones, and less damage to the long bones.
3.4.2 Blast Boot with Overboot against the PMA-2 Mine
The average score of 12.0 for the FSLL versus 8.7 for LEAP suggests that the FSLL did
not perform well for a blast boot with overboot against the larger PMA-2 mine. Again, it
is important to compare the results on a bone-to-bone basis given the wide variation of the
LEAP scores (from 6 to 11). The LEAP tests always resulted in very extensive damage
to the calcaneus. This was also the case for the two FSLL tests. The level of damage to
the talus of the FSLL was also extensive, while LEAP appeared to produce severe, but less
extensive damage to the same bone. The level of damage to the pilon area was extensive
for four out of five of the LEAP tests, and both FSLL tests. It should be noted that one
LEAP test did not damage the pilon area, which is suspicious given the amount of explosive
in the PMA-2 mine. Finally, the FSLL tests produced simple and compound fractures of
the long bones. This was also the case for five LEAP tests (in one test, the tibia remained
intact).
Thus, from a broad perspective, the FSLL did not perform badly. It reproduced the level
of damage to the calcaneus, talus and pilon area. The calcaneus was damaged extensively,
just as it was during LEAP. The damage to the long bones was also similar in most cases.
However, it was clear that the PMA-2 is an overmatch for the protection level considered
here, and both the LEAP and FSLL results indicate that traumatic amputation would
occur.
3.4.3 Blast Boot with Overboot against the M14 Mine
This combination of threat and protection is particularly well suited to compare the performance of the FSLL against the LEAP data. The MTS scores indicate that this combination
is near the threshold of damage that requires amputation. The M14 produced a blast that
was sufficient to break the bones of the test models (cadaver for LEAP and FSLL), but
not sufficient to breach the inner footwear. Hence, all bones were salvaged and could be
inspected. Furthermore, twelve tests were performed, four for LEAP, four for the FSLL
DRDC Suffield TR 2007-070
35
Figure 13: Average bone scores for the M14 mine against the Blast Boot with Overboot
with hard bones, and four for the FSLL with soft bones. The average bone score for LEAP
was 5.5, while the corresponding scores for the FSLL were 6.75 for the soft bone configuration and 7.75 for the hard bone configuration. Figure 13 provides a graphical comparison
of bone scores obtained for each of the three models, i.e., human cadaver, FSLL with hard
bones and FSLL with soft calcaneus and soft talus.
The human calcaneus is very susceptible to damage during a mine explosion. This bone
sustained a high level of comminution every time during the LEAP tests. By comparison,
the hard version of the FSLL calcaneus, FSLL(H), was intact in two out of four tests
and displayed only a simple fracture in the other two tests. The soft version of the FSLL
calcaneus, the FSLL(S), fared better, exhibiting a high level of comminution during two out
of four tests and a simple fracture for the other two tests. Although this is an improvement
over the FSLL(H) results, the results suggest that further softening of this bone is required
to reproduce the LEAP results. This result is somewhat unexpected given that the strength
of the FSLL(S) calcaneus had been tested statically against freshly extracted human bones.
The answer might lie in the high strain rate behaviour of the FSLL materials relative to
human bone. During LEAP, the talus was always fractured, with simple fractures for two
out or four tests and comminuted fractures for the remaining tests. The hard version of
the FSLL talus, FSLL(H), produced the same results. However, the results for the soft
version of the FSLL talus, FSLL(S), produced a high level of comminution during each of
36
DRDC Suffield TR 2007-070
Figure 14: Flash x-rays of an M14 mine explosion under the blast boot with overboot at 206 µs
(left) and 706 µs into the event. The same overlays were drawn over the calcaneus and tibia to
highlight changes.
the four tests. This suggests that the hard version of this bone should be used in the future,
but reducing the strength of the calcaneus might correct this situation. To clarify this last
statement, it is useful to consider some details of the events that take place during the mine
explosion, as shown in Figure 14.
The earlier x-ray shows that the impact has not yet reached the underside of the foot.
The lower blast deflector is in the process of transmitting vertical momentum to the upper
deflector. The x-ray taken 500 µs later shows both deflectors deformed and pushing against
the sole of the foot. The overlay drawn over the calcaneus clearly shows that the deflectors
contact the lower inside of this bone and cause it to rotate. Dislocation of the calcaneus
from the bones in the mid-foot has started. In addition to the rotation, the calcaneus is
pushing on the talus, which is itself transferring the force to the distal tibia. There is a
direct correlation between the strength of the calcaneus and its ability to transfer force to
the talus. Thus, if the strength of the FSLL(S) calcaneus is decreased further, the force
transfer to the talus will be reduced as well and the current strength of the FSLL(S) talus
might be adequate to reproduce the LEAP results.
The bone damage results for breaks of the tibia show a clear difference between the LEAP
and FSLL results. Each of the four LEAP tests left the tibia intact, i.e., did not cause a
break of the shaft. On the other hand, the shaft of the FSLL tibia broke every time. All
DRDC Suffield TR 2007-070
37
four tests with the hard version of the calcaneus and talus resulted in multiple breaks of
the tibia. This also occurred three out of four times when the soft version of these bones
was used, while the fourth test resulted in a simple break. This might indicate that the
softer bones reduce the transfer of load, but there is insufficient data to draw any conclusion
other than that the FSLL tibia does not reproduce the behaviour observed during the LEAP
study.
Similarly, the wide range of damage to the fibula observed during LEAP makes it difficult
to draw any conclusion about the performance of the reproduction of this bone used in the
FSLL. However, it is important to note that the fibula is not the main load-bearing bone
of the lower leg. Thus, it is more important to correct the behaviour of the tibia.
3.5
Load Cell Results
A load cell was installed in four FSLL specimens that were subjected to the same test
conditions. The full data records are provided in Annex C. Table C1 gives a summary of
minimum and maximum values along with the associated times. For any given test, the
peak force Fz was 10 to 20 times greater than the corresponding forces Fx and Fy . This
was a direct consequence of placing the mine directly below the long axis of the tibia, which
produced a predominantly vertical load. The average time of arrival of the load at the load
cell was 0.41 ms (0.38 to 0.45 ms) after detonation and peaked around an average time of
1.09 ms (0.99 to 1.14 ms). The maximum vertical load ranged from 4312 to 4515 lbf for
three of the four tests, while the last test produced a peak load of 5523 lbf . The average
peak force was 4668 lbf . The 25% load increase for the fourth test prompted us to examine
the flash x-rays more closely. This revealed significant difference in the placement of the
FSLL specimen from test to test. For the first three tests with a load cell, the vertical
cross-hair line cleared the front of the tibia. For the last test, it overlapped the front of the
tibia. This is approximately a 10 mm difference in placement, which put the long axis of the
tibia more directly in line with the mine. It is suspected that this difference in placement
is the reason for the increased vertical loading. This result suggests that it is imperative to
maintain a very tight control over the placement of the surrogate over the mine.
All four load cell traces for Fz had the same form. The load recorded went negative and
did not climb back to zero for 7 to 9 ms after peaking. For the shot against FSLL No. 703,
the recovery time was much shorter, only 3 ms. The difference in recovery time is very
apparent when considering the integral of the vertical force at four times (see Table C2):
1.5, 2, 5 and 10 ms after detonation. The integral values at 10 ms are representative of the
maximum value attained, which varied from 6865 to 7681 in-lbf for three of the four tests,
and 4834 in-lbf for the fourth test. The last result corresponds to the test with the quickest
recovery. Using the integral value at 10 ms as a reference, it is seen that the majority of
the impulse is delivered early during the blast event. Approximately 40% to 60% of the
impulse had been delivered to the tibia 1.5 ms after detonation. This increased to 70% to
95% at 5 ms after detonation.
The moments about the three axes were measured at the mid-tibia location. The peak
values are compiled in Table C2. It is seen that the magnitude of the moment Mz , i.e.,
38
DRDC Suffield TR 2007-070
Figure 15: The off-axis location of the load vector relative to the long axis of the tibia generates a
positive moment at the centre of the this bone
torque about the long axis of the tibia, was ten to twenty times smaller than the magnitude
for the corresponding moments Mx and My . This is attributed to the fact that the load
vector was predominantly along the long axis of tibia, which resulted primarily in bending
loads, not torsion loads. The bending moments Mx and My displayed a strong bias towards
generating positive peak moments that were approximately five times greater than the
corresponding negative peak moments. The offset for the fore-aft moment, Mx , is due to
the load axis being forward of the tibia, as shown in Figure 15. Thus, the load puts the
front of the tibia in compression and the rear in tension. Figure 15 also shows a rear view
of the tibia-fibula. It is seen that the load vector passes to the right of the tibia, which
creates a positive moment at the centre of the tibia. Thus, it is seen that the moments
are generated by a combination of offsets between the load vector and the long-axis of the
tibia, as well as the geometry of the bones.
DRDC Suffield TR 2007-070
39
4
CONCLUSIONS
This report presented the results from twelve tests done in March 2001 to assess the FSLL,
which is an updated version of the FSL that had been tested earlier in 1999. The new model
was limited to the distal segment of the leg (below the knee) and included softer calcaneus
and talus bones. Four FSLL specimens with the original hard bones were tested to provide
a direct comparison of performance with the newer soft bones. A load cell was installed in
the mid-tibia of four specimens. Ten tests were performed against the M14 mine so that
the results could be compared to those from LEAP. The remaining two tests were against
PMA-2 mines.
The improved flash x-ray technique produced excellent quality x-rays that were used to
quantify the process of early damage to the distal leg. The M14 mine caused significant
destruction to the FSLL when it was used with a regular combat boot. The main damage
process was one of total disruption due to overpressure. The examining surgeons determined
that these would result in below-knee amputations. When the M14 mine was used against a
FSLL protected by a blast boot with overboot, a shift in the damage process was observed.
For these test conditions, it was determined from the x-rays that the impingement of detonation products destroys the sole of the overboot and accelerates the metal blast deflector
to a velocity of around 120 m/s. The lower deflector impacted on the sole of the blast boot,
transferring part of its vertical momentum to the blast deflector contained in the sole of
the blast boot. The latter reached a peak velocity around 65 m/s. The blast boot was not
breached, thus, the damage process was one of blunt trauma due to the impact of the blast
deflectors. The examining surgeons determined that the injuries to some FSLL specimen
were salvageable, i.e., they required no amputation, while others would have necessitated a
below-knee amputation.
When the FSLL with blast boot and overboot was tested against a PMA-2 mine, the increase
of explosive mass resulted in significantly greater velocity, 240 m/s, of the overboot blast
deflectors. This resulted in a correspondingly higher velocity of the blast boot deflector (at
least 90 m/s). The blast deflector contained in the sole of the blast boot was still accelerating
at the longest x-ray time: 500 µs. The larger impact velocity caused a large overpressure
in the distal leg, which burst from inside out. The examining surgeons determined that
these were below-knee amputations. Comparison of the M14 test results against a blast
boot with overboot revealed that the soft and hard calcaneus and talus bones produced
markedly different responses. One surgeon estimated that the hard bones would result in
three salvageable injuries out of four tests, while a second surgeon estimated that all four
injuries would have been salvageable. For the soft bones, both surgeons estimated that
an amputation would have been required for three tests, while the fourth test produced a
salvageable injury.
When comparing the bone damage from the above eight tests to the bone damage recorded
during LEAP, the soft calcaneus bone version of the FSLL produced results that are in closer
agreement with those from LEAP. However, significant differences remained. During LEAP,
the calcaneus bone was severely damaged during each test. Although the soft calcaneus
40
DRDC Suffield TR 2007-070
of the FSLL was damaged each time, it apparently was not damaged to the same level
as in LEAP. This suggests that weakening the bones further might increase the realism of
the FSLL. Paradoxically, the hard talus version of the FSLL produced results that were in
closer agreement with the LEAP results. It appears that the soft talus is too soft. However,
it is not known what effect a softer calcaneus would have on the talus.
The results for the tibia are split into two separate categories. The behaviour of the pilon,
the interface surface between the tibia and the talus, was similar to that observed during
LEAP. However, the behaviour of the long bone portion of the FSLL tibia displayed a
significant bias compared to the LEAP results. During LEAP, transverse fractures of the
tibia were never observed when exposed to the M14 while using the blast boot with an
overboot. The FSLL produced a single or multiple transverse fracture of the tibia each
time. It can be concluded from this result that the tibia does not react correctly under
high strain rate. Thickening the bone, or using stronger materials (at high strain rate) to
construct this bone, might solve this problem.
The weakness of the tibia does not prevent the use of the FSLL as a diagnostic tool. Such
breaks can simply be ignored during the damage analysis. The authors estimate that the
damage to the calcaneus and talus are more important. The goal of any protective system
is to prevent the loss of these two bones. Thus, if these bones fail badly during a test, the
protective system also failed.
The flash x-rays and the load cell proved to be useful diagnostic tools during these tests.
The x-rays were used to determine the main damage mechanisms. The load cell provided a
quantitative measure of compression and the bending moment transverse to the long axis of
the tibia. The results showed that compression is sensitive to placement of the mine below
the foot. This became apparent when a small shift of approximately 10 mm produced a
25% change of this load. These results demonstrated the importance of maintaining very
tight control over geometry. Free placement of the FSLL, or any other test device for that
matter, over the mine appears to have a strong influence on loading, and therefore on the
resulting injuries. It is therefore recommended that:
• A test rig should be designed and used with the test device in order to maintain
accurate control over geometry, particularly in regard to the relative location of the
mine under the foot.
• Zero preload should be used to avoid sinking of the footwear and specimen into the
soil surface, thereby changing the standoff between the mine and the footwear.
• A load cell should be used with specimens like the FSLL. An alternative is to build
such a load cell into the design of the tibia.
• Further tuning of the FSLL bones might be required. In order of priority: the strength
of the calcaneus should be further reduced and the high strain rate strength of the
tibia should be increased.
DRDC Suffield TR 2007-070
41
References
[1] (2000), Landmine Casualty Data Report: Deminer Injuries.
[2] (1999), Final Report of the Lower Extremity Assessment Program (LEAP) - Volume I,
(Report ATC-8199) LEAP.
[3] R.M.Harris, M.S.Rountree, L.V.Griffin, R.A.Hayda, T.Bice, and S.J.Mannion (2000), Final
Report of the Lower Extremity Assessment Program (LEAP) - Volume II, (Report ATC-8199)
LEAP.
42
DRDC Suffield TR 2007-070
List of symbols/abbreviations/acronyms/initialisms
AIS
AP
AT
BB
CB
CCMAT
CDN
CFSL
CT
DRDCS
DSTO
FSL
GZ
HDP
ICRC
LEAP
MESS
MTS
NISSSA
NSN
OB
OTF
PMA
PMN
R&D
RDX
RMS
SB
STF
TNT
UPMAH
US
VS
Abbreviated Injury Scale
Anti-Personnel
Anti-Tank
Blast Boot
Combat Boot
Canadian Centre for Mine Action Technologies
Canadian
CCMAT FSL program
Computer Tomography
Defence R& D Canada - Suffield
Defence Science and Technology Organization
Frangible Surrogate Leg
Ground Zero
Humanitarian Demining Program
International Committee of the Red Cross
Lower Extremity Assessment Program
Mangled Extremity Severity Score
Mine Trauma Score
Nerve, Ischemia, Soft-Tissue, Skeletal, Shock an Age of patient injury score
Nato Stock Number
Overboot
Object to Film
Designator for [former] Yugoslav anti-personnel mines
Designator for Russian-made anti-personnel mines
Research and Development
Cyclonite
Root Mean Square
Spider Boot
Source to Film
Trinitrotoluene
Designator for [former] Yugoslav anti-personnel mine fuses
United States
Designator for Italian anti-personnel mines
DRDC Suffield TR 2007-070
43
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44
DRDC Suffield TR 2007-070
Annex A: Detailed Boot Damage Assessments
This Annex provides a detailed assessment of the physical damage imparted to the boots and
protective overboots used during the CFSL program. To ease cross-reference, a short table lists the
test conditions for individual shots. This data precedes a series of pictures followed by a detailed
description of the damage. In general, the description includes a summary of the overall damage,
a description of the damage to the boot fitted to the FSL specimen, and then, if applicable, a
R
description of the damage to the additional protective footwear such as the Wellco
overboot or
TM
the Spider Boot . The terminology used to describe various parts of the boots and overboots is
shown on the next three pages.
Table A.1: Table of Contents Annex A
FSLL/Shot ID
Load Cell
Bone Type
Boot Type
Protection
Mine
Page
701/M01072D
702/M01071C
703/M01071A
704/M01072A
705/M01071B
706/M01072E
707/M01072B
708/M01072C
709/M01072F
710/M01073A
711/M01073B
712/M01073C
Yes
No
Yes
No
Yes
Yes
No
No
No
No
No
No
Hard
Hard
Hard
Hard
Soft
Soft
Soft
Soft
Soft
Soft
Soft
Soft
R
Blast (Wellco
)
R
Blast (Wellco
)
R
Blast (Wellco
)
R
Blast (Wellco
)
R
Blast (Wellco
)
R
Blast (Wellco
)
R
Blast (Wellco
)
R
Blast (Wellco
)
Combat (US)
Combat (US)
R
Blast (Wellco
)
R
Blast (Wellco
)
Overboot
Overboot
Overboot
Overboot
Overboot
Overboot
Overboot
Overboot
None
None
Overboot
Overboot
M14
M14
M14
M14
M14
M14
M14
M14
M14
M14
PMA-2
PMA-2
49
51
53
55
56
58
60
61
63
64
65
68
DRDC Suffield TR 2007-070
45
Figure A.1: Canadian Army Combat Boot. The same nomenclature applies to the US Army
Combat Boot.
46
DRDC Suffield TR 2007-070
Figure A.2: Blast Boot (above) and attenuator plate (below).
DRDC Suffield TR 2007-070
47
Figure A.3: Overboot
48
DRDC Suffield TR 2007-070
Shot ID
701/M01072D
Load Cell
Yes
Bone Type
Hard
Boot Type
R
Wellco
Overboot
R
Wellco
Explosive
M14
Figure A.4: Damage to boots for shot 701/M01072D
Description of Boot Damage:
Summary:
Deformation of the boot sole but no breaching of the boot. Overboot heel destroyed. Little damage
to overboot upper.
Boot:
The centreline ridge of the heel and mid foot portion of the outer sole has been bent upward by just
over 5 mm. Based on the disassembly of the boot from trial M99263B (for example), it is expected
that the attenuator will be partially crushed and the deflector plate will be bent upward by about
5-10 mm. There is a 30 mm long spot just on the medial side of the boot centreline at the heel where
the upper meets the outer sole. It appears that the upper may have just started to separate from
the sole. The only other apparent damage to the upper is that the counter seems to have cracked at
the medial backstrap seam. The foam insole shows a small, 5 mm long crack and a 20 mm long star
shaped crack in the heel along. The Kevlar insole has bulged upward slightly at the front of the heel
cap. A nail or staple leg has also been driven upward just ahead of the bulge. While it punctured
the bottom of the foam insole, it may not have completely penetrated through to its upper surface.
DRDC Suffield TR 2007-070
49
Overboot:
The heel cap of the overboots outer sole has been destroyed, leaving the crushed attenuator and the
attenuator plate still attached. The blast deflector plate has been separated from the sole and has
been pinched, flattened bent upward by 15 mm and split along the crease. The 15 mm long split
occurs at the point of maximum deformation. A split in the remains of the outer sole runs from
the centreline diagonally forward to the medial side, stopping about 20 mm short of the toe treads.
The outer sole has separated from the upper side panels and the Kevlar insole up to the toe treads.
There is a slight bulge in the upper surface of the Kevlar insoles heel. Otherwise the Kevlar insole
appears undamaged. While the backstrap remains attached to the bottom of the Kevlar insole, both
side panels have separated from the insole near the heel. Measuring around the curve of the insole
from the heel centreline, the separated area extends 50 mm on the medial side and 150 mm on the
lateral side. The bottom 50-60 mm of both side panels has also separated from the backstrap. The
covering fabric on the lateral side panel shows a 30 mm long vertical tear about 80 mm in front of
the rear edge of the panel. The covering fabric on the medial side panel shows 4 vertical tears at 30
mm, 50 mm, 90 mm, and 135 mm ahead of the rear edge of the panel. The measure 10 mm, 25 mm,
50 mm, and 10 mm respectively. Both ventilation inserts are present although their inside flanges
have been bent slightly. The toecap appears intact and undamaged.
50
DRDC Suffield TR 2007-070
Shot ID
702/M01071C
Load Cell
No
Bone Type
Hard
Boot Type
R
Wellco
Overboot
R
Wellco
Explosive
M14
Figure A.5: Damage to boots for shot 702/M01071C
Description of Boot Damage:
Summary:
Boot outer sole bent upward and sole/upper separation just starting. Overboot heel destroyed with
minimal damage to the upper.
Boot:
The outer sole of the boot has been bent upward by about 10 mm and there is a 65 mm long
split beside the heel cap centreline, which completely penetrates through to the blast deflector.
Separation between the upper and the outer sole can be seen in a slight separation measuring 40
mm long just at the medial side of the heel centreline. There is a 10 mm long shallow cut in the
outer surface layer of the medial side vamp just at the front edge of the counter. There may be a
crack in the upper edge of the counter just on the lateral side of the backstrap. There is a slight
bulge in the upper surface of the Kevlar insole near the front of the heel cap. There is also a sharp
nail or stable protruding at the start of the toe treads near the later side. Two tears, measuring 15
mm and 35 mm can be seen in the foam insole.
DRDC Suffield TR 2007-070
51
Overboot:
The outer sole heel has been destroyed. Tears run from the front of the heel cap to about the middle
of the mid foot area. The crushed attenuator, the attenuator plate, and the blast deflector, which
has been pinched, flattened and bent upward by 20 mm are still attached. Both side panels and the
Kevlar insole are attached to the outer sole from the front of the attenuator forward. The medial
side panel has separated from the Kevlar insert up to the toe tread area. On the lateral side the
separation ends at the front of the heel cap. The outer covering fabric on both sides is attached
to the whole remainder of the outer sole. The Kevlar insole has been twisted up on the lateral
heel corner, and the upper surface is bulged and uneven. The medial side panel has a broken rear
buckle. Both ventilation inserts are present and the rear one shows a small amount of damage to
the outer flange. A single 60 mm long vertical tear is present in the outer covering fabric 90 mm
ahead of the rear edge of the panel. But for a few stretched stitches at the top, the medial side panel
has separated entirely from the backstrap. The backstrap and lateral side panel have separated
completely. The lateral side panel, which is still connected to the medial panel by the facing, shows
3 vertical tears in the outer covering fabric. Measuring 20 mm, 60 mm, and 40 mm, they occur 20
mm, 40 mm, and 80 mm ahead of the rear edge of the panel. The rear buckle is still present has
been broken. The toecap is undamaged.
52
DRDC Suffield TR 2007-070
Shot ID
703/M01071A
Load Cell
Yes
Bone Type
Hard
Boot Type
R
Wellco
Overboot
R
Wellco
Explosive
M14
Figure A.6: Damage to boots for shot 703/M01071A
Description of Boot Damage:
Summary:
Boot sole is bent upward slightly. Overboot heel is destroyed with minimal damage to the upper.
Boot:
The outer sole of the boot has been bent upward in the heel and mid foot area by 5-10 mm, and there
is a 20 mm long cut beside the heel cap centreline ridge. There is an area about 35 mm long centred
on the medial backstrap seam where the upper and the outer sole just started to separate. Feeling
the counter reveals breaks on both the later and medial sides and one at the medial backstrap seam.
There is a shallow diagonal cut in the outer surface layer than runs forward 30 mm from the front
of the heel cap. The inside of the rear-most medial side toe tread lug shows an indentation that
appears to have been made by a sharp edged object, although this may simply be a mark left by
the manufacturing process. There may be a slight bulge in the upper surface of the Kevlar insole
just at the front of the heel cap but it is very slight. The foam insole shows a puncture and a 25
mm long crack, both of which fully penetrate the heel of the insole.
Overboot:
The overboot outer sole heel has been destroyed. Several cracks radiate from the heel centreline into
the mid foot area. The blast deflector, found separate from the overboot, has been bent by 15-20
mm and has been pinched, flattened and split along the crease. This split measures only 10 mm on
the bottom surface but the top surface (the inside of the crease) shows tearing 45 mm long. The
side panels and Kevlar insole are attached to the outer sole only in the front 120 mm of the boot
but the outer covering fabric is attached to the outer sole on the medial side all the way back to
the end of the sole. On the lateral side they are attached to a point 20 mm behind the toe tread
area. The upper surface of the Kevlar insole is bulged and uneven in the mid foot and heel. The
lateral side panel is attached to the Kevlar insole everywhere except in the heel cap area. On the
medial side the side panel has separated from the insole from the back of the panel to just under
the ventilation inserts. Both inserts are still in the medial side panel, although both show slight
damage to their inner and outer flanges. The medial side rear buckle is broken, and there a 30 mm,
80 mm, and 15 mm long tears at the end of the outer sole remains, and then back 35 mm and 60
mm behind that. The bottom 40 mm of the panel has separated from the backstrap. On the lateral
DRDC Suffield TR 2007-070
53
side panel there is a 20 mm long vertical tear 15 mm ahead of the backstrap seam, and a 70 mm
long vertical tear 60 mm from the seam. The rear buckle has been broken. The toecap is undamaged.
54
DRDC Suffield TR 2007-070
Shot ID
704/M01072A
Load Cell
No
Bone Type
Hard
Boot Type
R
Wellco
Overboot
R
Wellco
Explosive
M14
Figure A.7: Damage to boots for shot 704/M01072A
Description of Boot Damage:
Summary:
Slight deformation of boot outer sole. Overboot heel is destroyed with minimal damage to the upper.
Boot:
The only visible signs of damage to the outside of the boot area a 5-10 mm upward bend in the heel
cap and mid foot area, and a 10 mm long shallow cut in the outer surface layer of the vamp right at
the front of the heel cap on the lateral side. There may be a crack in the front 30 mm of the medial
side of the counter. The heel and mid foot areas of the Kevlar insole are bulged and uneven. Two
tears, measuring 15 mm and 25 mm show in the heel of the foam insole.
Overboot:
The overboots outer sole heel has been destroyed leaving cracks that run into the mid foot area.
The back 60 mm of the heel cap was found separately but almost completely intact. The blast deflector, also found separately has been pinched, flattened and bent upward by 20 mm. The crushed
attenuator and its plate are still attached to the overboot. The side panels have separated from
the Kevlar insole for about 70 mm on either side of the backstrap but are otherwise well attached.
The side panels and Kevlar insole are attached to the outer sole only in the 120 mm at the front of
the overboot. The outer covering fabric on both sides is attached to almost all of what remains of
the outer sole. The lateral side panel shows only a single vertical tear in the outer covering fabric.
It measures 50 mm long and occurs 60 mm ahead of the backstrap seam. The bottom 50 mm of
the backstrap has separated from the medial side panel, which shows 2 vertical tears in the outer
covering fabric. They measure 80 mm and 20 mm and occur 80 mm and 115 mm ahead of the
backstrap seam. Both ventilation inserts are missing. The toecap is undamaged.
DRDC Suffield TR 2007-070
55
Shot ID
705/M01071B
Load Cell
Yes
Bone Type
Soft/Hard
Boot Type
R
Wellco
Overboot
R
Wellco
Explosive
M14
Figure A.8: Damage to boots for shot 705/M01071B
Description of Boot Damage:
Summary:
Boot outer sole is slightly deformed. Overboot heel is destroyed. Overboot side panels are minimally
damaged.
Boot:
The outer sole of the boot has a 55 mm long slice about 5 mm off the centreline ridge of the heel
cap, which has penetrated through to the deflector plate. There is a 10 mm long cut in the outside
of the rear-most lateral side heel tread lug. The heel and mid foot area have been bent upward by
about 10 mm. The upper has just begun to separate from the outer sole in an area 30 mm to the
medial side and 50 mm to the lateral side of the heel centreline. The upper surface of the foam
insole shows a small puncture and a 15 mm long tear right near the back of the heel. The puncture
did not fully penetrate the insole. Aside from a slight upward bulge of the Kevlar insole at the front
of the heel cap, the only visible damage to the inside of the boot is a small area on the lateral mid
foot area where there is a raised sharp edge in the Kevlar insole. This is probably due to (i) a raised
crack in the insole, or (ii) a protruding nail or staple.
Overboot:
The heel cap of the overboot has been blown off. The rear 60 mm of the heel cap was recovered in
one piece that has mulitple cracks leading out and up from the centreline. A crack runs through the
mid foot area just beside the centreline ridge almost to the start of the toe tread. The blast deflector,
which has been pinched, flattened, and bent upward by 20 mm also shows a 10 mm tear right at
the back of the crease. This piece remains in the overboot sole along with the attenuator, which
has been crushed at the rear, and the attenuator plate. The Kevlar insole and both side panels are
attached to the outer sole from the front end of the attenuator forward. The outer covering fabric
on both side panels remains attached to the outer sole for virtually the entire length of what is left
of the outer sole. The Kevlar insole has an upward bulge on the lateral side of the heel. The front
buckle on the medial side panel has been broken. Both ventilation inserts are present but the lower
edges of both inserts on both inside and outside of the panel have been bent slightly. The outer
covering fabric has vertical tears measuring 40 mm and 60 mm, located at the front of the heel cap,
56
DRDC Suffield TR 2007-070
and 20 mm back toward the heel. The medial side panel has separated cleanly at the backstrap
seam but remains attached to the lateral side panel via the facing. The outer, bottom 100 mm of the
backstrap has peeled from the lateral side panel but the upper portion and the entire inner portion
remain attached. Vertical tears in the outer covering fabric measure 35 mm, 60 mm, 15 mm, and
10 mm, and are located 25 mm, 65 mm, 90 mm and 120 mm respectively from the rear edge of the
side panel. The toecap is intact and undamaged.
DRDC Suffield TR 2007-070
57
Shot ID
706/M01072E
Load Cell
Yes
Bone Type
Hard/Soft
Boot Type
R
Wellco
Overboot
R
Wellco
Explosive
M14
Figure A.9: Damage to boots for shot 706/M01072E
Description of Boot Damage:
Summary:
Boot upper and outer sole have separated, and sole has suffered mild deformation. Overboot heel
destroyed with minimal damage to the side panels.
Boot:
The outer sole of the boot has been bent into an exaggerated arch in the heel cap and mid foot area.
There is a 30 mm long horizontal crack in the front, medial edge of the counter. A vertical crack in
the counter can be felt about 45 mm on the lateral side of the heel centreline. The back of the upper
has separated from the outer sole from the medial front edge of the heel cap to 40 mm beyond the
heel centreline on the lateral side. Peeling back the heel cap reveals that the blast deflector has been
bent upward by almost 10 mm. Aside from a slight unevenness on the top surface of the Kevlar
insole, there is a protruding, sharp staple leg on the medial side right at the middle of the foot arch.
A 5 mm long crack has penetrated the foam insole.
Overboot:
58
DRDC Suffield TR 2007-070
The overboot heel cap has been destroyed leaving several tears through the mid foot section of the
outer sole. The rear half of the attenuator has been crushed leaving the front half mostly undamaged. The attenuator and attenuator plate remain in the overboot while the blast deflector plate was
recovered separately. The deflector plate has been pinched, flattened, and bent upward by about
15 mm. There is a 15 mm long tear in the metal right at the back end of the crease. The outer
covering fabric remains attached to the remains of the outer sole for almost all of the soles length on
both sides. For the medial side panel, the Kevlar insole and the outer sole are only attached from
130 mm of the front of the overboot. On the lateral side, the panel is attached to the Kevlar insole
for almost the entire length of the side panel. The side-panel/insole combination is only attached to
the outer sole in the toe tread area. The upper surface of the Kevlar insole has a bulge in the lateral
heel area and unevenness through the heel and mid foot areas. Both side panels have separated from
the backstrap, but the backstrap remains tied to the medial side panel by a few stretched threads at
the top of the panel. The two panels are still held together via the facing. Both ventilation inserts
in the medial side panel are present and both have had their inner and outer bottom edges bent.
The outer covering fabric on the medial side panel has one vertical tear 40 mm long about 85 mm
ahead of the rear edge of the panel. A sharp nail or staple has been embedded in the outer covering
fabric just below the front ventilation insert. On the later side the only visible damage to the side
panel is a set of 3 vertical tears. At 10 mm, 50 mm, and 15 mm long, they are located 35 mm, 70
mm, and 130 mm ahead of the rear edge of the panel. The toecap is intact and undamaged.
DRDC Suffield TR 2007-070
59
Shot ID
707/M01072B
Load Cell
No
Bone Type
Hard/Soft
Boot Type
R
Wellco
Overboot
R
Wellco
Explosive
M14
Figure A.10: Damage to boots for shot 707/M01072B
Description of Boot Damage:
Summary:
Deformation of the boot sole but no breaching of the boot. Overboot heel destroyed. Little damage
to overboot upper.
Boot:
The boot upper appears undamaged except for an 80 mm long area from the heel centreline around
to the lateral side where the upper has separated from the outer sole. There is a 20 mm long slice
in the heel cap but it does not seem to have completely penetrated the rubber. There is also an
indentation right at the rear edge of the heel cap centre ridge, which implies an impact of a sharp
edge. There is a 10 mm long crack in the outer surface of the upper right at the leading edge of
the counter on the medial side, but the crack does not appear to have penetrated the leather. The
counter has also been broken in vertical lines at the lateral and medial backstrap seams, and seems
to have come loose from the sole for the forward 75 mm on the medial side. The foam insole shows
a 20 mm long crack at the heel.
Overboot:
The overboot heel has been destroyed, leaving the blast deflector, the attenuator and the attenuator
plate in the sole. The blast deflector has been pinched and bent upward by about 15 mm, and there
is a 15-20 mm long tear at the back end of its crease. The outer sole and Kevlar insole are separated
as far forward as the toe treads but the side panel covering fabric has maintained contact with the
outer sole for 40 mm into the mid foot area on the medial side and for 60 mm on the lateral side. The
Kevlar insole has some bulging and unevenness in its upper heel area, but no other visible damage
is present. The medial side panel has separated cleanly at the backstrap seam but is still connected
to the lateral side panel via the facing. Both ventilation inserts are still present and show not signs
of damage. Tears measuring 10 mm, 15 mm and 60 mm are evident in the outer covering fabric in
the area between the rear edge of the panel and the ventilation inserts. The upper 25 mm of the
lateral side panel is still attached to the backstrap. Aside from 15 mm, 20 mm and 40 mm tears
in the heel cap area of the outer covering fabric, there are no signs of damage to the lateral side panel.
60
DRDC Suffield TR 2007-070
Shot ID
708/M01072C
Load Cell
No
Bone Type
Hard/Soft
Boot Type
R
Wellco
Overboot
R
Wellco
Explosive
M14
Figure A.11: Damage to boots for shot 708/M01072C
Description of Boot Damage:
Summary:
Boot sole deformed and partially separated from upper. Two tears in boot upper. Overboot heel
cap destroyed with minimal damage to upper.
Boot:
The outer sole of the boot has been bent upward and the upper has separated from the outer sole in
an area 75 mm on either side of the heel centreline. Peeling the heel cap back reveals that the blast
deflector has been bent upward by about 10 mm and the attenuator has been partially crushed.
There is a 50 mm long diagonal tear in the rear vamp starting at the front of the heel cap on the
medial side. A 10 mm long tear appears at the same location on the lateral side. A vertical tear
through the vamp runs along the backstrap location from the outer sole to the vamp/quarter seam.
At this location the counter has been broken through; there is another crack in the counter about
half way around on the lateral side. Aside from a slight bulge on the top surface of the Kevlar insole
at the front of the heel cap, and two tears in the foam insole, there is no visible damage inside the
DRDC Suffield TR 2007-070
61
boot. Overboot:
The heel cap of the overboot outer sole has been destroyed, leaving the blast deflector, the attenuator and the attenuator plate still attached. The deflector plate has been bent upward by 10-15 mm
and the back of the attenuator crushed. The outer covering fabric on both sides is attached to the
full length of what remains of the outer sole. On the lateral side the rear 40 mm of the side panel
has separated from the Kevlar insole and on the medial side, 160 mm. The Kevlar insole is attached
to the outer sole in the toe tread area. The heel and mid foot section of the Kevlar sole show some
bulging and unevenness. The bottom 100 mm of the backstrap has broken away from the lateral
side panel, and the bottom 40 mm from the medial side panel. On the medial side there are vertical
tears in the outer covering fabric measuring 15 mm, and 40 mm, at 55 mm, and 80 mm from the
backstrap seam. Both ventilation inserts are still present and the rear only shows slight damage to
the outer flange On the lateral side there are two vertical tears in the outer covering fabric. The
first, at 25 mm ahead of the backstrap seam is 30 mm long. The second at 80 mm from the seam
is 55 mm long. The toecap is undamaged.
62
DRDC Suffield TR 2007-070
Shot ID
709/M01072F
Load Cell
No
Bone Type
Hard/Soft
Boot Type
Combat (US)
Overboot
None
Explosive
M14
Figure A.12: Damage to boots for shot 709/M01072F
Description of Boot Damage:
Summary:
Boot is completely destroyed behind the toe tread.
Boot:
All but the front 15 mm of the heel cap has been blown away along with the insole, and upper
portion of the boot. A tear runs from the heel cap centreline forward about 10 mm into the toe
tread section about 25 mm off to the medial side of the boot centreline. Several smaller cracks are
visible in the remains of the heel cap. The leather insole is split along both edges of the fibre shank,
which is cracked and badly delaminated. Tears in the foam insole parallel those in the leather insole
There is nothing left of the upper behind the line of the quarter/rear vamp seam. On the medial
side the upper has been removed in a line from the front of the heel cap back. The bottom 100 mm
of the remaining section of the quarter is badly torn and only held on by a 15 mm wide fragment.
Aside from that piece, all that is left of the quarter is the eyelet flap and a strip up to 45 mm wide.
On the lateral side the quarter is torn from the outer sole at the quarter/vamp seam. The tear
follows the seam up and forward for about 70 mm. The tear then runs up to the eyelet flap seam
whereupon it branches 40 mm down toward the toe and 70 mm straight up along the seam. After
70 mm the tear runs off diagonally to the rear leaving a 130 mm wide flap (as measured right at
the top of the boot). The bottom three speed-lace eyelets have been partially torn from their hole
in the eyelet flap.
DRDC Suffield TR 2007-070
63
Shot ID
710/M01073A
Load Cell
No
Bone Type
Hard/Soft
Boot Type
Combat (US)
Overboot
None
Explosive
M14
Figure A.13: Damage to boots for shot 710/M01073A
Description of Boot Damage:
Summary:
Boot is completely destroyed behind the toe tread.
Boot:
The rear portion of the boot has been destroyed. The heel cap has been destroyed leaving a crack
through the mid foot area as far as the toe treads. The crack follows the medial edge of the shank.
The shank is missing and both the leather insole and the foam insole have been torn along the lateral side of the shank to its forward end. The rear of the upper has torn away at the quarter/vamp
seam. The tongue and front portion of the quarters remain attached to the vamp only at their lower
extremities. Several of the lower eyelets have been pulled out.
64
DRDC Suffield TR 2007-070
Shot ID
711/M01073B
Load Cell
No
Bone Type
Hard/Soft
Boot Type
R
Wellco
Overboot
R
Wellco
Explosive
PMA-2
Description of Boot Damage:
Summary:
Boot heel damaged and separated from upper. Upper torn open. Overboot heel destroyed and side
panels partially separated from outer sole.
Boot:
The only visible damage to the outer sole of the boot is it has been bent up into an exaggerated
arch. The upper separated from the outer sole from the start of the toe treads on the medial side,
and around the heel to the forward/rear vamp seam on the lateral side. This exposes the blast
deflector, attenuator and attenuator plate, which are still attached to the boot. The deflector plate
was flattened and bent upward by about 10-15 mm. The attenuator was completely crushed in the
rear area and partially crushed in the front. The Kevlar insole has been twisted leaving the lateral
heel corner higher than the medial corner. Aside from this and some unevenness in the upper heel
surface, the Kevlar insole does not show any visible damage. The upper surface of the foam insole
shows a series of longitudinal cracks right near the arch support that spans a length of 110 mm.
These have not penetrated through the insole. A 50 mm long tear that penetrates the insole is found
along the lateral side at about the same mid foot position. Small fragments of the ballistic gelatine
(flesh) are embedded in this tear. A 30 mm diameter, three-armed, star-shaped tear right under
the heel contains several small bone fragments. The rear 35 mm of the heel edge contains a 45 mm
wide T-shaped tear. In addition to separating from the outer sole, the upper has separated from
the Kevlar insole on the medial side from the start of the toe treads back. There is a vertical tear
starting at the mid point of the heel cap that runs up through both the vamp and quarter, and then
runs along beside the eyelet flap to the top of the quarter. From the shape of the cut, or tear, it is
strongly suspected, however, that the top 80 mm along the side of the eyelet flap was deliberately
cut to get the boot off the remains of the leg. Another tear begins at the front edge of the heel
cap and runs diagonally forward as far as the vamp/quarter seam, whereupon it runs horizontally
along the seam 25 mm forward and 50 mm back. The vamp in this area shows some minor surface
cracks and the upper end of the reinforcing band on the quarter has been peeled up from under
the lace-clamping eyelet. The bottom two eyelets have been pulled, stretching their holes in the
leather eyelet flap. On the rear portion of the lateral side upper, the counter portion of the vamp
has been pulled from the outer sole, and has been torn vertically at the middle of the backstrap as
far up as the vamp/quarter seam. A horizontal tear along that seam runs 40 mm forward. There is
nothing left of the counter on the medial side. On the lateral side, the vamp from the backstrap to
the front of the heel cap is left dangling by a 15 mm wide scrap near the heel corner. This area was
torn along the bottom of the vamp/quarter seam 155 mm forward from the backstrap centreline.
A vertical tear runs from the front of the heel cap to the vamp/quarter seam. About half of the
counter remains on the lateral side, but it is cracked and torn.
Overboot:
The heel of the overboot outer sole has been destroyed and about half of the later side of the mid
foot area is only attached by a small tag of rubber at the extreme outer edge. The blast deflector
has been separated from the overboot and has been flattened, bent upward by about 15 mm, and
slightly pinched. The attenuator, which is still attached with the attenuator plate to the Kevlar
insole, has been fully crushed at the back and partially crushed along the result of its length. The
Kevlar insole and lateral side panel are attached to the outer sole only in the front 150 mm of the
overboot. The lateral side panels outer coving cloth is attached to the outer sole for the front 240
mm. The lateral side panel has separated from the Kevlar insole in the heel cap area. The medial
DRDC Suffield TR 2007-070
65
Figure A.14: Damage to boots for shot 711/M01073B
66
DRDC Suffield TR 2007-070
side panel separated from the Kevlar insole and outer sole from the middle of the toe treads back.
The upper surface of the Kevlar insole is warped and uneven but does not appear to be breached
or broken. The medial side panel has separated cleanly at the backstrap seam, has a broken rear
buckle and both of its ventilation inserts are missing. The outer covering cloth shows a tear that
starts at the front of the heel cap, runs diagonally forward to the rear buckle strap and then forward
to the front buckle strap. The facing has been broken and torn from the upper edge of the panel
from the front buckle back. The rear buckle has been broken on the lateral side panel and the facing
is only attached from the front buckle forward; 50 mm of loose facing hangs behind the front buckle.
The outer covering fabric has two vertical tears in the heel cap area. Measuring 30 mm and 50 mm,
they occur 20 mm and 70 mm (respectively) from the rear edge of the side panel. The toecap is
intact and undamaged and the backstrap was recovered separate from the overboot.
DRDC Suffield TR 2007-070
67
Shot ID
712/M01073C
Load Cell
No
Bone Type
Hard/Soft
Boot Type
R
Wellco
Overboot
R
Wellco
Explosive
PMA-2
Description of Boot Damage:
Summary:
Boot heel cap separated from upper. Major tears in the rear part of the upper. Overboot heel
destroyed, and side panels are half separated from the sole.
Boot:
There is a 50 mm long crack that has fully penetrated the rubber along the heel cap centreline ridge.
The upper has separated from the forward/rear vamp seam on the medial side, around the heel to
the lateral backstrap seam location. Peeling the heel cap back reveals that the blast deflector has
been flattened and bent upward by about 10-15 mm and that the rear half of the attenuator has
been crushed. The medial side of the rear vamp has a 60 mm long tear that follows the forward/rear
vamp seam. Another tear, 30 mm long occurs at the front of the heel cap. There is also a 170 mm
long tear that runs through the vamp and quarter right at the medial side backstrap seam. This
crack also runs through the counter. On the lateral side there is a 15 mm tear in the outer surface
layer of the vamp about 55 mm behind the front of the heel cap. Just 15 mm behind the front of
the heel cap is a 130 mm vertical tear running from the outer sole almost to the eyelet flap. The
bottom three eyelets on the lateral side have been torn our. In addition to the complete break in
the counter at the backstrap seam, there are multiple tears and fractures on both sides in the rest
of the counter. The upper surface of the Kevlar insole has a slight unevenness but does not show
any other visible signs of damage. The foam insole has a large star shaped crack right under the
heel. Arms of this crack reach from the extreme rear edge of the insole through to the front of the
arch support.
Overboot:
The outer sole of the overboot has had the heel cap destroyed and cracks run forward and out
through the mid foot area, stopping 25 mm from the toe treads. The crushed attenuator and the
bent, flattened blast deflector plate were recovered separate from the overboot. The deflector plate
has been bent about 20 mm. Only the front 120 mm of the outer sole is still attached to the Kevlar
insert and the side panels, although the outer covering fabric on both sides is still attached to the
outer sole to the mid foot area. The upper surface of the Kevlar insole has unevenness to the rear
half of the surface, and there is a 5-10 mm cut in the upper layer about 25 mm from the extreme rear
edge. The lateral side panel has a broken rear buckle and four vertical tears in the outer covering
fabric. At 20 mm, 50 mm, 75 mm, and 130 mm ahead of the rear edge of the panel these tears
measure 30 mm, 20 mm, 55 mm, and 45 mm. The front 100 mm of facing is still attached to the
side panel and 530 mm of facing is hanging free. The remainder of the facing is attached to the
medial side panel, which also has a broken rear buckle. Vertical tears measuring 15 mm, 15 mm,
and 40 mm are seen 35 mm, 60 mm and 90 mm ahead of the rear edge of the side panel. Another
tear begins right where the outer sole ends and runs diagonally up to the rear buckle attachment
strap. This tear goes through the area of the rear ventilation insert. Both inserts are missing and
there is more tearing where the front insert was pulled out. Both side panels separated cleanly at
the backstrap seam, and the toecap is undamaged.
68
DRDC Suffield TR 2007-070
Figure A.15: Damage to boots for shot 712/M01073C
DRDC Suffield TR 2007-070
69
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70
DRDC Suffield TR 2007-070
Annex B: Detailed Medical Assessments
This Annex provides a detailed assessment of the injuries imparted to the Frangible Surrogate
Lower Leg specimen as a function of footwear and explosive type. The results were compiled from
the radiologist report from the local hospital, the post-test examination conducted by a surgeon,
and from the 3D reconstructions of the CT imagery.
The data is organised in order of the FSLL ID. For each test, the data includes the radiologist
report, at least four pictures extracted from the 3D bone rendition of the CT scans, and a written
description of the results for the shot. A header table presents a summary of the key conditions for
this particular test, including:
Shot ID: the ID consists of two components. The first component is the FSLL ID number. The
number after the oblique bar is the shot ID, which is composed of a letter followed by 5 numbers
that are the last two digits of the year and the Julian day in which the test was performed, and
another letter indicating the number of tests performed that same day, i.e., A for the first test of
the day, B for the second test, etc.;
Load Cell: indicates whether or not a force transducer (load cell) was used in the mid-tibia;
Bone Type: During the first test series, all bones were of the hard type, which proved too strong
for the calcaneus and talus bones, thereby affecting the medical scores; softer materials were used
in the construction of these bones during the second test series;
Boot Type: indicates whether the boot fitted on the specimen was the standard US Army combat
R
boot or the Wellco
blast boot;
R
Overboot: indicates when the Wellco
blast overshoe was used;
Explosive: states the land mine that was used for the test.
The sections that follow are:
Pre-Test Notes: list the Shot ID and describes any special condition(s) for that particular test;
Post-Test Damage Assessment: describes of gross situation immediately following the test, including
the visual state of the footwear;
Post-Test Diagnostic Imaging: describes the assessment from medical examination of the 3D reconstruction of the CT scan. The x-ray imaging is available from the hospital report at the beginning
of each FSLL assessment;
Post-Test Clinical Examination Notes: provides the details obtained from the dissection of the specimen;
Overall Assessment: gives a synopsis of the diagnostic from the dissection and damage inflicted to
the specimen;
Recommended Treatment of Injury: states whether or not an amputation would be recommended,
the level of the amputation and gives an assessment of the likelihood of neurological or vascular
damage to a real leg;
MTS Score: lists the likely medical score in accordance with the Mine Trauma Scoring system.
DRDC Suffield TR 2007-070
71
Table B.1: Table of Contents Annex B
72
Shot ID
Load Cell
Bone Type
Boot Type
Overboot
Mine
Page
701/M01072D
702/M01071C
703/M01071A
704/M01072A
705/M01071B
706/M01072E
707/M01072B
708/M01072C
709/M01072F
710/M01073A
711/M01073B
712/M01073C
Yes
No
Yes
No
Yes
Yes
No
No
No
No
No
No
Hard
Hard
Hard
Hard
Soft
Soft
Soft
Soft
Soft
Soft
Soft
Soft
R
Blast (Wellco
)
Blast (Wellco R )
R
Blast (Wellco
)
R
Blast (Wellco
)
R
Blast (Wellco
)
R
Blast (Wellco
)
R
Blast (Wellco
)
R
Blast (Wellco
)
Combat (US)
Combat (US)
R
Blast (Wellco
)
R
Blast (Wellco
)
Overboot
Overboot
Overboot
Overboot
Overboot
Overboot
Overboot
Overboot
None
None
Overboot
Overboot
M14
M14
M14
M14
M14
M14
M14
M14
M14
M14
PMA-2
PMA-2
74
78
82
85
88
91
94
97
100
103
105
108
DRDC Suffield TR 2007-070
Shot ID
701/M01072D
DRDC Suffield TR 2007-070
Load Cell
Yes
Bone Type
Hard
Boot Type
R
Wellco
Overboot
R
Wellco
Explosive
M14
73
Pre Test Notes:
M01072D leg ID #701. Mine was centred under heel of overboot.
Post Test Damage Assessment:
Deformation of the boot sole but no breaching of the boot. Overboot heel destroyed. Little damage
to overboot upper.
Post Test Diagnostic Imaging:
CT scans show that the patient has a stress monitor in the tibial shaft. The proximal cuff is
110mm distal to the tibial articular surface. The patient has a transverse fracture of the tibial shaft
at the level of the proximal stress monitor cuff. No significant displacement. There is a non-displaced
transverse fracture in the tibial shaft at the level of the inferior cuff of the stress monitor. 50 mm
inferior to the inferior cuff of the stress monitor, there are transverse fractures through the tibial
and fibular shafts. The tibial fragment is displaced distally 10 mm. The proximal fibular fracture
fragment is displaced posteriorly 20 mm and is distracted 12 mm. 50 mm proximal to the distal
articular surface, there is a comminuted, interarticular fracture. This is generally T-shaped with
the stem pointing laterally. The fragments are separated by up to 5 mm. The talus is fragmented
throughout. There are numerous fracture fragments, which vary in size from a few millimetres to
several centimetres. A longitudinal fracture is present along the medial aspect of the calcaneus. No
significant displacement. No fractures are present in the talar block. Non-displaced fractures are
present in the distal shafts of the first and second metatarsals and at the base of the fifth metatarsal.
74
DRDC Suffield TR 2007-070
Non-displaced disarticulations are present between the calcaneus/talus and the tarsals, and at the
tarsometatarsal junction.
Post Test Clinical Examination Notes:
Simple fracture 2nd MT
Gelatine split on plantar surface of foot one area on dorsum.
Ligaments intact. Impression is the talus is badly comminuted but
no displacementand periosteal and vascular structures would be
intact. Skin essentially intact but gelatine splitting suggests some
contusion. Com # talus; simple fracture calcaneus
Ankle Joint / Plafont:
Tibia / Fibula: Fracture distal tibia with vertical oriented fracture line, Transverse
fracture lower 1/3 tibia.
Soft Tissue:
Contamination: moderate
a. Fore Foot:
b. Hind Foot:
c.
d.
e.
f.
Overall Assessment:
Fractured talus may cause problems with pain and avascular necrosis. An immediate
amputation would not be necessary.
Recommended Treatment of Injury:
a. Amputation:
NO
b. Level:
n/a
c. Likelihood of neurologic/vascular injury: Avascular necrosis involving talus.
MTS Score:
1A
DRDC Suffield TR 2007-070
75
Shot ID
702/M01071C
76
Load Cell
No
Bone Type
Hard
Boot Type
R
Wellco
Overboot
R
Wellco
Explosive
M14
DRDC Suffield TR 2007-070
DRDC Suffield TR 2007-070
77
Pre Test Notes:
M01071C leg ID #702. Mine was centred under heel of overboot.
Post Test Damage Assessment:
Boot outer sole bent upward and sole/upper separation just starting. Overboot heel destroyed
with minimal damage to the upper.
Post Test Diagnostic Imaging:
A transverse tibial fracture, which is not displaced, starts 190 mm distal to the tibial plateau.
Slightly above this there is a non-displaced transverse fibular fracture. 145 mm below the initial
tibial fracture, there is a second, non-displaced transverse fracture. 20 mm below this there is a
non-displaced fibular fracture. 80 mm superior to the distal tibial articular surface, an oblique fracture begins at the medial tibial cortex and extends slightly obliquely and inferiorly down towards
the mid distal tibial articular surface. This fracture runs mainly in the sagittal plane. There is also
a non-displaced linear, interarticular fracture at the extreme distal lateral aspect of the tibia. A
few small fragments have come off this area and reside at the posterior aspect of the ankle joint.
A linear interarticular fracture is present at the junction between the posterior and middle thirds
of the talus. There is no significant displacement. A fracture is present off the extreme anterior
superior aspect of the calcaneus. A non-displaced transverse fracture is present through the mid
shaft of the fourth metatarsal. A longitudinal fracture is present at the medial basilar aspect of the
fifth metatarsal. Neither of these fractures is displaced.
Post Test Clinical Examination Notes:
a. Fore Foot:
b.
c.
d.
e.
f.
Non-displaced fracture 3,4 MT, complete forefoot dislocation
open superiorly.
Hind Foot:
Calcaneus intact, simple minimally displaced fracture talus
(not neck). Open wound on plantar surface of foot over heal
but no calcaneal #.
Ankle Joint / Plafont:
Tibia / Fibula: Non-displaced vertically oriented fracture tibia, non-displaced
horizontal closed fracture of distal 1/3 and prox. 1/3 tibia.
Soft Tissue:
Contamination:
Overall Assessment:
No amputation necessary.
Recommended Treatment of Injury:
a. Amputation:
NO
b. Level:
n/a
c. Likelihood of neurologic/vascular injury: Avascular necrosis possible.
MTS Score:
78
1A
DRDC Suffield TR 2007-070
Shot ID
703/M01071A
DRDC Suffield TR 2007-070
Load Cell
Yes
Bone Type
Hard
Boot Type
Wellco
Overboot
Wellco
Explosive
M14
79
80
DRDC Suffield TR 2007-070
DRDC Suffield TR 2007-070
81
Pre Test Notes:
M01071A leg ID #703. Mine centred under heel of overboot.
Post Test Damage Assessment:
Boot sole is bent upward slightly. Overboot heel is destroyed with minimal damage to the upper.
Post Test Diagnostic Imaging:
The proximal shaft of the tibia and fibula appear intact. Extensive comminuted fractures involving
the distal tibia extending through the tibiotalar joint surface. Oblique fracture is present through
the medial malleolus. None of the fracture fragment shows any significant displacement. There is a
fracture through the distal shaft of the fibula with only slight lateral displacement of the fragment.
The talus is fractured in several places mainly involving its mid aspect extending superiorly and
posteriorly through the joint surface. There is widening and some disruption of the talonavicular and calcaneocuboid joints with a small avulsion fracture present at the plantar aspect of the
joint probably avulsed off the anterior surface of the calcaneus. There are non-displaced fractures
through the proximal second through fifth metatarsals as well as through the distal second and
third metatarsals. Minimal, non-displaced fracture at the base of the fourth proximal phalanx and
through the mid shaft of the fifth proximal phalanx. The tarsal bones are difficult to evaluate, but
appear to be largely intact. Continuous axial images were made beginning at the knee joint and
extending inferiorly throughout the entire lower leg and foot. The proximal portions of the tibia and
fibula are intact. There are several fracture lines through the soft tissue material. In the distal tibia
there is a fracture line extending obliquely along the anteromedial aspect of the tibia with minimal
displacement. This continues distally and more laterally with an oblique fracture line through the
mid shaft of the distal tibia. Below this there is another fracture line along the medial aspect of the
tibia, which continues distally and becomes a comminuted fracture extending to the joint surface.
Associated with this is a transverse fracture through the distal tibia extending from medial to lateral
with dorsal displacement of the fragments and a small separate fragment medially. More distal, at
the ankle joint there are several bony fragments with disruption of the articular surface.
Post Test Clinical Examination Notes:
a.
b.
c.
d.
Fore Foot:
Non-displaced fractured 2,3,4,5 metatarsals.
Hind Foot:
Simple fracture of the calcaneus and severe comminution of talus.
Ankle Joint / Plafont:
Tibia / Fibula: Distal tibia very comminuted with ligamentous injury and bone loss.
Horizontal closed fracture of distal 1/3 and prox 1/3 tibia.
e. Soft Tissue:
Less fissuring of gelatine out of keeping with degree of bone injury.
f. Contamination:
Overall Assessment:
Open contaminated injury of calcaneus and hind foot with severe distal tibia injury.
Recommended Treatment of Injury:
a. Amputation:
YES
b. Level:
BKA
c. Likelihood of neurologic/vascular injury: Distal tibial vascular and nerve injury likely
82
DRDC Suffield TR 2007-070
MTS Score:
2A (Reviewer MTS assessment for this injury was 1A)
DRDC Suffield TR 2007-070
83
Shot ID
704/M01072A
84
Load Cell
No
Bone Type
Hard
Boot Type
Wellco
Overboot
Wellco
Explosive
M14
DRDC Suffield TR 2007-070
Pre Test Notes:
M01072A leg ID #704. Mine was centred under heel of overboot.
Post Test Damage Assessment:
Slight deformation of boot outer sole. Overboot heel is destroyed with minimal damage to the upper.
Post Test Diagnostic Imaging:
The proximal and mid tibia and fibula are intact. Several fracture lines are present through the distal
tibia, but without significant displacement. Non-displaced fracture distal third of the fibula. There
is a fracture present through the mid aspect of the talus with slight separation of the fragments.
There may be some small linear fractures through the calcaneus, but it is largely intact. No obvious
fracture lines are seen through the tarsal region. Non-displaced fractures are present through the
bases of the second through fifth metatarsals, mid to distal shaft of the third metatarsal and the
bases of the proximal phalanges of the fourth and fifth toes. CT Scan shows a comminuted fracture
that extends transversely in the distal third of the tibia. The anterior fragment is intact and there
are several smaller posterior fragments present. Closer to the joint surface there are four major
fragments present with minimal displacement. Minimal non-displaced fracture through the fibula.
Fracture is present through the dome of the talus and extends vertically through its length into the
subtalar joint. The calcaneus appears intact with no major fracture seen. There are fracture lines
extending through the navicular bone medially and laterally without significant displacement with
the fracture lines extending somewhat distally again, with no significant displacement. Fracture is
DRDC Suffield TR 2007-070
85
present through the distal medial corner of the cuboid bone with minimal anteromedial displacement. Oblique fracture base of the second metatarsal, Non-displaced. Fracture proximal ends of the
third, fourth and fifth metatarsals, non-displaced. Fracture at the distal end of the third metatarsal
seen on the radiographs is not visible. The phalanges appear intact.
Post Test Clinical Examination Notes:
a.
b.
c.
d.
Fore Foot:
Simple closed fractures of 2,3,4,5 MT
Hind Foot:
Hind foot relatively intact and calcaneus intact.
Ankle Joint / Plafont:
Tibia / Fibula: Severely comminuted open distal tibia and fibula fractures.
Severe open wound of distal tibia and fibula.
e. Soft Tissue:
Less fissuring of gelatine out of keeping with degree of bone injury.
f. Contamination:
Overall Assessment:
This would not need amputation but the tibia/fibula injury would be difficult to deal with.
And would need open reduction internal fixation (ORIF). High risk of infection and
avascular necrosis
Recommended Treatment of Injury:
a. Amputation:
NO
b. Level:
BKA
c. Likelihood of neurologic/vascular injury: High risk of avascular necrosis of fracture
MTS Score:
86
1A
DRDC Suffield TR 2007-070
Shot ID
705/M01071B
DRDC Suffield TR 2007-070
Load Cell
Yes
Bone Type
Soft
Boot Type
Wellco
Overboot
Wellco
Explosive
M14
87
Pre Test Notes:
M01071B leg ID #705. Mine was centred under heel of overboot.
Post Test Damage Assessment:
Boot outer sole is slightly deformed. Overboot heel is destroyed. Overboot side panels are minimally
damaged.
Post Test Diagnostic Imaging:
A force transducer has been placed in the mid tibial shaft. There are transverse fractures in the tibial shaft at the stress monitors upper and lower aspects. There is also a transverse fracture through
the fibular shaft at the lower end of the tibial stress monitor. No fractures are present above this.
60 mm below the lower level of the stress monitor, an oblique fracture begins at the medial aspect
of the tibial shaft and extends obliquely downward and laterally for a distance of 55 mm. This exits
at the lateral aspect of the tibial shaft and runs mostly in the sagittal plane. The fracture fragments
here are separated by 3 mm. There are no associated fibular fragments at this level. Below the
level of the oblique fracture, there is a series of comminuted, interarticular fractures affecting the
distal tibial shaft and articular surface. There are several fracture fragments, the largest of which
is at the posterior malleolus. These fragments are separated by up to 6 mm. Once again there are
no associated fibular fractures. The talus is fragmented into innumerable fragments. They remain
fairly contained within the talar area. There is a vertical fracture running in the coronal plane in
the calcaneus, at the junction between the anterior and middle two-thirds. A flake-like fracture is
present off the dorsal aspect of the navicular. This is not significantly displaced. No other fractures
are seen to involve the tarsal bones. There are non-displaced transverse fractures through the bases
88
DRDC Suffield TR 2007-070
of the fourth and fifth metatarsals, an oblique fracture through the base of the second metatarsal,
and a transverse fracture through the mid shaft of the first metatarsal. A transverse fracture is
present through the mid shaft of the proximal phalanx of the left little toe.
Post Test Clinical Examination Notes:
a. Fore Foot:
b.
c.
d.
e.
f.
There is a dislocation of the forefoot that is open but
only clinically apparent with forceful manipulation of the foot.
Forefoot dislocation, Non-displaced # 1,2,3,4,5 MT.
Hind Foot:
There is a small amount of fissuring of the gelatine
on the plantar surface of the hind foot. The calcaneus has
a simple. Non-displaced fracture vertically oriented pointing to
the talus, which is completely destroyed in a comminuted
fracture.
Ankle Joint/Plafont: Total comminution of plafont, distal 1/3 tibia
badly comminuted.
Tibia / Fibula: There is a badly comminuted open tibial fracture.
Severe open wound of distal tibia and fibula.
Soft Tissue:
Contamination:
Overall Assessment:
I feel this wound would need an amputation. A badly comminuted contaminated
fracture with high likelihood of vascular compromise to the fracture area.
Recommended Treatment of Injury:
a. Amputation:
YES
b. Level:
BKA
c. Likelihood of neurologic/vascular injury: strong possibility
MTS Score:
2A (Reviewer MTS assessment for this injury was 2B)
DRDC Suffield TR 2007-070
89
Shot ID
706/M01072E
90
Load Cell
Yes
Bone Type
Soft
Boot Type
Wellco
Overboot
Wellco
Explosive
M14
DRDC Suffield TR 2007-070
Pre Test Notes:
M01072E leg ID #706. Mine was centred under heel of overboot.
Post Test Damage Assessment:
Boot upper and outer sole have separated, and sole has suffered mild deformation. Overboot heel
destroyed with minimal damage to the side panels.
Post Test Diagnostic Imaging:
A stress monitor is present in the mid tibial shaft. There are no complications associated with
this. The initial tibial fracture begins 120 mm above the distal tibial articular surface. It begins at
the anterior aspect of the tibia and extends obliquely downward in the coronal plane for a distance
of 60 mm. This fracture fragment is angled slightly anteriorly. Inferior to this there is a complex,
interarticular fracture that extends through the remainder of the tibial shaft and into the distal
tibial articular surface. Most of these fractures run in the coronal plane, but there are one or two
which run in a sagittal plane at the posterior aspect. These fractures are displaced from each other
by 2-3 mm. A non-displaced transverse fracture is present in the fibular shaft, 95 mm superior to
the tip of the lateral malleolus. A comminuted, interarticular, fracture involves the talus. Most of
the fractures are present at the posterior aspect of the talus, but some run anterioinferiorly. The
fracture fragments are not significantly displaced. A minimally comminuted, vertical fracture runs
through the calcaneus at the junction between the anterior and middle two-thirds. The fragments
are separated by 5 mm. Non-displaced transverse fractures are present through the mid shaft of
DRDC Suffield TR 2007-070
91
the first metatarsal, and the proximal shafts of the second, fourth and fifth metatarsals. There
are also non-displaced transverse fractures through the proximal phalanges of the fourth and fifth
toes. There is a traumatic, non-displaced disarticulation between the talus/calcaneus and the tarsal
bones.
Post Test Clinical Examination Notes:
a. Fore Foot:
b. Hind Foot:
c.
d.
e.
f.
Simple closed fractures of metatarsals.
Comminuted fracture of the talus with a simple fracture of
the calcaneus.
The skin is open over the calcaneus.
Ankle Joint / Plafont:
Tibia / Fibula: Closed spiral fracture of distal tibia.
Soft Tissue:
Localized to open wound of calcaneus and talar area.
Contamination: Minimal.
Overall Assessment:
Comminuted spiral fracture of tibia closed and minimally displaced. I think
this limb is salvageable. It has the appearance of a foot exposed to a fall
rather than a coupled blast wave. The appearance is of a lower G force affecting
it.
Recommended Treatment of Injury:
a. Amputation:
NO
b. Level:
c. Likelihood of neurologic/vascular injury: Possible, and would determine if
an amputation would be needed.
MTS Score:
92
1A
DRDC Suffield TR 2007-070
Shot ID
707/M01072B
DRDC Suffield TR 2007-070
Load Cell
No
Bone Type
Soft
Boot Type
Wellco
Overboot
Wellco
Explosive
M14
93
Pre Test Notes:
M01072B leg ID #707. Mine was centred under heel of overboot.
Post Test Damage Assessment:
Deformation of the boot sole but no breaching of the boot. Overboot heel destroyed. Little damage
to overboot upper.
Post Test Diagnostic Imaging:
See x-ray report.
Post Test Clinical Examination Notes:
a. Fore Foot:
b. Hind Foot:
c.
d.
e.
f.
Break of the 2nd and 5th metatarsals.
Comminuted fracture calcaneus with probable bone loss,
slightly comminuted fracture talus but much less so
than calcaneus.
Ankle Joint / Plafont:
Tibia / Fibula: Distal tibia intact. Minimally displaced distal 1/3 tibia fracture.
The distal tibia tibial plateau has no fracture but there
is a fracture of distal 1/3 of tibia.
Soft Tissue:
Contamination:
Overall Assessment:
94
DRDC Suffield TR 2007-070
The calcaneus has so much destruction and bone loss that an amputation would
be needed.
Recommended Treatment of Injury:
a. Amputation:
YES
b. Level:
BKA
c. Likelihood of neurologic/vascular injury: The talus has a fracture at risk of
avascular necrosis.
MTS Score:
2A
DRDC Suffield TR 2007-070
95
Shot ID
708/M01072C
96
Load Cell
No
Bone Type
Soft
Boot Type
Wellco
Overboot
Wellco
Explosive
M14
DRDC Suffield TR 2007-070
Pre Test Notes:
M01072C leg ID #708. Mine was centered under heel of overboot.
Post Test Damage Assessment:
Boot sole deformed and partially separated from upper. Two tears in boot upper. Overboot heel
cap destroyed with minimal damage to upper.
Post Test Diagnostic Imaging:
The knee joint and the proximal and mid tibia and fibula are intact. There is transverse fracturing through the distal third of the tibia and fibula without any significant displacement. More
distally, there are several fracture lines through the distal tibia extending to the joint surface without significant displacement of the fragments. The talus and calcaneus are shattered into multiple
fragments. No obvious fractures are seen through the tarsal bones. There are some non-displaced
transverse fractures through some of the metatarsals, most notably the distal shaft of the third and
the proximal shafts of the fourth and fifth metatarsals. The phalanges are intact. CT scans show an
oblique non-displaced fracture is present through the distal third of the tibia with a similar oblique
non-displaced fracture of the adjacent distal fibula. Comminuted fracture is present through the
distal tibia extending to the articular surface with several fragments present, but without significant
displacement. There are several comminuted fracture lines extending through the articular surface
DRDC Suffield TR 2007-070
97
of the talus without significant displacement. Most of the fragments are present posteriorly with
the anterior part of the talus largely intact. Linear fracture extends through the lateral aspect of
the navicular bone. The calcaneus is shattered into multiple bony fragments. In the tarsal region
there is a fracture through the first cuneiform bone without significant displacement. There is also
a fracture through the medial corner of the cuboid bone with minimal displacement. Non-displaced
fractures are present through the base of the first, fourth and fifth metatarsals and the distal third
metatarsal. None of the phalanges are fractured.
Post Test Clinical Examination Notes:
a. Fore Foot:
b. Hind Foot:
c.
d.
e.
f.
Simple closed fractures of metatarsals 1-3.
Badly comminuted calcaneus fracture, talus fractured
and open.
Ankle Joint / Plafont:
Tibia / Fibula: Comminuted fracture distal tibia, closed transverse
fracture further up tibia at level of distal 2/3-1/3.
Soft Tissue:
Foot open with open fractures of calcaneus and tibia.
Contamination: Yes
Overall Assessment:
Below knee amputation would be needed. There is the possibility depending on
vascular injury and periosteum and degree of contamination that the injury
could be packed and debrided but this would necessitate numerous surgical
procedures and rehabilitation. Even then amputation might result.
Recommended Treatment of Injury:
a. Amputation:
YES
b. Level:
BKA
c. Likelihood of neurologic/vascular injury: High likelihood of injury
to nerves and vascular supply to foot at level of distal tibial
fracture making reconstruction impossible.
MTS Score:
98
2A
DRDC Suffield TR 2007-070
Shot ID
709/M01072F
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Load Cell
No
Bone Type
Soft
Boot Type
Combat (US)
Overboot
None
Explosive
M14
99
Pre Test Notes:
M01072F leg ID #709. Mine was centred under heel of combat boot, i.e. no protection.
Post Test Damage Assessment:
Boot is completely destroyed behind the toe tread.
Post Test Diagnostic Imaging:
AP and lateral radiographs demonstrate normal proximal tibia and fibula. The distal tibia appears
to be intact as far as I can see on the radiographs. There is a transverse fracture of the distal fibula
with lateral angulation of the fragment. The tibiotalar joint appears intact. However, there is severe
fracturing of the proximal aspect of the talus. Below the proximal talus there has been complete
disruption and shattering of the foot with multiple fragments from the tarsal region completely
shattered. Most of the metatarsals are also destroyed through their proximal ends. The phalanges
of the foot remain intact. CT scans confirm the proximal to distal tibia remains intact. There is
a fracture through the distal fibula without any significant displacement on the CT images. The
articular surface of the distal tibia appears to be essentially intact. The proximal talus shows several
fractures with very little of the bone remaining. Distal to this, the talus, calcaneus and tarsal bones
100
DRDC Suffield TR 2007-070
are completely shattered into multiple scattered fragments. Portions of the metatarsals remain intact, although there is varying degrees of fracturing through their proximal ends. The phalanges of
the foot are intact, but are better evaluated on the radiographs.
Post Test Clinical Examination Notes:
a.
b.
c.
d.
e.
f.
Fore Foot:
Amputated
Hind Foot:
Amputated
Ankle Joint / Plafont: Basically intact with some injury of joint surface
Tibia / Fibula: Intact
Soft Tissue:
Massive soft tissue wound of foot.
Contamination: Moderate
Overall Assessment:
Distal leg amputated with destruction of hind foot, severe comminution of fore
foot, which has been amputated traumatically.
Recommended Treatment of Injury:
Redo completion amputation
a. Amputation:
YES
b. Level:
BKA
c. Likelihood of neurologic/vascular injury:
MTS Score:
2B
DRDC Suffield TR 2007-070
101
Shot ID
710/M01073A
102
Load Cell
No
Bone Type
Soft
Boot Type
Combat (US)
Overboot
None
Explosive
M14
DRDC Suffield TR 2007-070
Pre Test Notes:
M01073A leg ID #710. Mine was centered under heel of combat boot, i.e., no protection.
Post Test Damage Assessment:
Boot is completely destroyed behind the toe tread.
Post Test Diagnostic Imaging:
Radiographs demonstrate horizontal fracture lines through the distal tibia without any displacement. Oblique vertical fracture lines are present through the distal tibia. At the level of the lateral
malleolus the tibia is completely fractured, and the distal tibia, as well as the bones of the foot are
shattered into multiple fragments. The distal metatarsal and phalanges remain essentially intact.
The lateral malleolus shows only minimal fracturing.
Post Test Clinical Examination Notes:
a. Fore Foot:
b. Hind Foot:
c. Ankle Joint / Plafont: Severe comminution of fracture dislocation
with spontaneous amputation.
d. Tibia / Fibula: Minimally displaced fracture distal tibia. Amputation
DRDC Suffield TR 2007-070
103
with comminution of tibia and heavy contamination of
fragments. Distal 1/3 fracture of tibia non-displaced.
e. Soft Tissue:
f. Contamination: Heavy contamination of hind foot and distal tibia.
Overall Assessment:
Spontaneous amputation from distal tibia.
Recommended Treatment of Injury:
a. Amputation:
YES
b. Level:
BKA
c. Likelihood of neurologic/vascular injury: Of distal tibia
MTS Score:
104
2B
DRDC Suffield TR 2007-070
Shot ID
711/M01073B
DRDC Suffield TR 2007-070
Load Cell
No
Bone Type
Soft
Boot Type
Wellco
Overboot
Wellco
Explosive
PMA-2
105
Pre Test Notes:
M01073B leg ID #711. Mine was centred under heel of overboot.
Post Test Damage Assessment:
Boot heel damaged and separated from upper. Upper torn open. Overboot heel destroyed and
side panels partially separated from outer sole.
Post Test Diagnostic Imaging:
Plain film and CT of the lower leg show vertical fracture through the distal tibia with some separation. There is a comminuted fracture through the distal tibia above the ankle with separation
of the foot, which is displaced distally. The proximal tarsal bones are shattered. There are some
linear fractures through some of the metatarsals and phalanges, but the distal part of the foot is
intact. Fracture is also present through distal fibula and through the lateral malleolus above the
ankle joint.
Post Test Clinical Examination Notes:
a. Fore Foot:
b. Hind Foot:
106
Fracture of the 2nd, 3rd, 4th and 5th metatarsals.
Hind foot completely destroyed with only dorsal
DRDC Suffield TR 2007-070
c.
d.
e.
f.
skin ridge holding foot on all together.
Ankle Joint / Plafont:
Tibia / Fibula: Distal tibia and fibula comminuted with amputation.
Soft Tissue:
Contamination: Spontaneous amputation foot with heavy contamination.
Overall Assessment:
There is a possibility of secondary infection resulting in Above Knee Amputation.
Recommended Treatment of Injury:
a. Amputation:
YES
b. Level:
Proximal below knee or above knee
c. Likelihood of neurologic/vascular injury:
MTS Score:
2B
DRDC Suffield TR 2007-070
107
Shot ID
712/M01073C
108
Load Cell
No
Bone Type
Soft
Boot Type
Wellco
Overboot
Wellco
Explosive
PMA-2
DRDC Suffield TR 2007-070
Pre Test Notes:
M01073C leg ID #712. Mine was centred under heel of overboot.
Post Test Damage Assessment:
Boot heel cap separated from upper. Major tears in the rear part of the upper. Overboot heel
destroyed, and side panels are half separated from the sole.
Post Test Diagnostic Imaging:
CT scans show that there is an oblique intra-articular fracture through the lateral tibial plateau.
Several horizontal fractures are present through the distal tibia and fibula. There is complete fracture
through the distal tibia and slightly more proximally through the distal fibula with disarticulation of
the foot with the bony structures shattered into multiple fragments. The metatarsals and phalanges
remain largely intact.
Post Test Clinical Examination Notes:
a. Fore Foot:
Fractures heads of MT 1-5, bases 2,3.
b. Hind Foot:
Complete destruction of hind foot.
c. Ankle Joint / Plafont:
DRDC Suffield TR 2007-070
109
d. Tibia / Fibula:
Distal 5 cm tibia and fibula destroyed, fracture
distal 1/3 tibia. Heavily contaminated wound with massive
soft tissue injury, amputation proximal tibia-fibula.
e. Soft Tissue:
f. Contamination:
Overall Assessment:
Traumatic amputation with likelihood for secondary infection and need for
further amputation.
Recommended Treatment of Injury:
a. Amputation:
YES
b. Level:
Proximal BKA
c. Likelihood of neurologic/vascular injury:
MTS Score:
110
2B (Reviewer MTS assessment for this injury was 3)
DRDC Suffield TR 2007-070
Annex C: Data Records from the Load Cells
During four of the twelve tests, a load cell was used in the mid-tibia to measure three forces Fx , Fy
and Fz and three moments, Mx , My and Mz . However, one load cell was only a five-axis load cell
and did not measure the moment Mz . The following diagram shows the coordinate system used to
define the direction of the above forces and moments.
Data was recorded at a rate of 500,000 samples per second. The raw data was then processed
digitally, after the fact. A low-pass two-pole Butterworth filter with roll off at a frequency of 10,000
Hz was used to reduce the magnitude of some spikes and remove some noise from the signal. This
was particularly relevant near time zero because the high-voltage firing pulse generated noise spikes.
These spikes died off within 20 to 50 µs, but were of such a magnitude that the low pass filter could
not remove them completely. Given that the load cell was located at the mid-tibia, approximately
300 mm from the explosion source, it would require a wave speed of 6000 m/s or greater for the
signal to reach it in 50 µs. This is physically impossible given that the FSLL materials consist of
mineralized plastic and gelatine with a wave speed closer to 300-500 m/s. Thus, any signal recorded
before 50 µs was simply ignored during the analysis. The following pages present the load cell data
recorded during the FSLL tests. Three traces are presented for each channel, the first showing the
full record (256 ms), the second showing the first 20 ms after detonation, and the third showing the
first 5 ms after detonation. This format allows the readers to make their own interpretation about
the quality of the signals.
The following pages present the load cell data recorded during the FSLL tests. Three traces are
presented for each channel, the first showing the full record (256 ms), the second showing the first
20 ms after detonation, and the third showing the first 5 ms after detonation. This format allows
the readers to make their own interpretation about the quality of the signals.
Table C.2 provides a compilation of the minimum and maximum values for each record, and the
time at which these values occurred. The red curves are the integral of the signal, which provides
a clear indication of the polarity of the signal, i.e., positive or negative relates directly to the local
slope of the integral.
Table C.1: Table of Contents Annex C
Shot ID
Leg ID
Bone Type
M01072D
M01071A
M01071B
M01072E
701
703
705
706
Hard
Hard
Soft
Soft
DRDC Suffield TR 2007-070
Boot Type
Blast
Blast
Blast
Blast
R
(Wellco
)
R
(Wellco
)
R
(Wellco
)
R
(Wellco
)
Overboot
Mine
Page
R
Wellco
R
Wellco
R
Wellco
R
Wellco
M14
M14
M14
M14
114
120
125
131
111
points out of the paper
Figure C.1: Coordinate system for the load cell measurements.
Table C.2: Summary of minimum and maximum values of the records
FSLL 701
FSLL 703
FSLL 705
FSLL 706
Channel
Fx
Fy
Fz
Mx
My
Mz
112
Minimum
Maximum
Minimum
Maximum
Minimum
Maximum
Minimum
Maximum
Minimum
Maximum
Minimum
Maximum
Value
Time
Value
Time
Value
Time
Value
Time
-519
323
-315
132
-4321
52
-263
1632
-365
1683
-16
68
0.79
1.84
0.81
1.18
1.14
0.26
0.72
0.81
0.50
0.76
1.97
0.78
-133
174
-4515
1246
-45
1450
-
0.57
1.03
1.10
0.69
0.74
0.68
-
-280
158
-389
159
-4312
54
-469
1186
-311
1112
-41
122
0.77
1.00
1.82
1.01
1.13
0.35
2.51
0.79
1.14
0.69
1.99
0.77
-202
208
-232
110
-5523
-947
1676
-503
1890
-
0.67
1.82
2.03
0.98
0.99
0.91
0.68
0.84
0.61
-
DRDC Suffield TR 2007-070
Table C.3: Key parameters for the normal force and its integrated values at different times
Tarrival
Tpeak
Min. Fz
Iz |1.5ms
Iz |2ms
Iz |5ms
Iz |10ms
FSLL 701
FSLL 703
FSLL 705
FSLL 706
Average
Std Dev
0.38
1.14
4321
3034
3741
6121
7164
0.45
1.10
4515
3000
3612
4612
4834
0.38
1.13
4312
2939
3354
4893
6865
0.41
0.99
5523
3790
4419
6613
7681
0.41
1.09
4668
3191
3782
5560
6636
0.04
0.07
578
401
454
960
1248
DRDC Suffield TR 2007-070
113
Figure C.2: Fx record for FSLL ID 701 fitted with a blast boot with overboot against an M14 mine
114
DRDC Suffield TR 2007-070
Figure C.3: Fy record for FSLL ID 701 fitted with a blast boot with overboot against an M14 mine
DRDC Suffield TR 2007-070
115
Figure C.4: Fz record for FSLL ID 701 fitted with a blast boot with overboot against an M14 mine
116
DRDC Suffield TR 2007-070
Figure C.5: Mx record for FSLL ID 701 fitted with a blast boot with overboot against an M14
mine
DRDC Suffield TR 2007-070
117
Figure C.6: My record for FSLL ID 701 fitted with a blast boot with overboot against an M14
mine
118
DRDC Suffield TR 2007-070
Figure C.7: Mz record for FSLL ID 701 fitted with a blast boot with overboot against an M14
mine
DRDC Suffield TR 2007-070
119
Figure C.8: Fx record for FSLL ID 703 fitted with a blast boot with overboot against an M14 mine
120
DRDC Suffield TR 2007-070
Figure C.9: Fy record for FSLL ID 703 fitted with a blast boot with overboot against an M14 mine
DRDC Suffield TR 2007-070
121
Figure C.10: Fz record for FSLL ID 703 fitted with a blast boot with overboot against an M14
mine
122
DRDC Suffield TR 2007-070
Figure C.11: Mx record for FSLL ID 703 fitted with a blast boot with overboot against an M14
mine
DRDC Suffield TR 2007-070
123
Figure C.12: My record for FSLL ID 703 fitted with a blast boot with overboot against an M14
mine
124
DRDC Suffield TR 2007-070
Figure C.13: Fx record for FSLL ID 705 fitted with a blast boot with overboot against an M14
mine
DRDC Suffield TR 2007-070
125
Figure C.14: Fy record for FSLL ID 705 fitted with a blast boot with overboot against an M14
mine
126
DRDC Suffield TR 2007-070
Figure C.15: Fz record for FSLL ID 705 fitted with a blast boot with overboot against an M14
mine
DRDC Suffield TR 2007-070
127
Figure C.16: Mx record for FSLL ID 705 fitted with a blast boot with overboot against an M14
mine
128
DRDC Suffield TR 2007-070
Figure C.17: My record for FSLL ID 705 fitted with a blast boot with overboot against an M14
mine
DRDC Suffield TR 2007-070
129
Figure C.18: Mz record for FSLL ID 705 fitted with a blast boot with overboot against an M14
mine
130
DRDC Suffield TR 2007-070
Figure C.19: Fx record for FSLL ID 706 fitted with a blast boot with overboot against an M14
mine
DRDC Suffield TR 2007-070
131
Figure C.20: Fy record for FSLL ID 706 fitted with a blast boot with overboot against an M14
mine
132
DRDC Suffield TR 2007-070
Figure C.21: Fz record for FSLL ID 706 fitted with a blast boot with overboot against an M14
mine
DRDC Suffield TR 2007-070
133
Figure C.22: Mx record for FSLL ID 706 fitted with a blast boot with overboot against an M14
mine
134
DRDC Suffield TR 2007-070
Figure C.23: My record for FSLL ID 706 fitted with a blast boot with overboot against an M14
mine
DRDC Suffield TR 2007-070
135
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136
DRDC Suffield TR 2007-070
DOCUMENT CONTROL DATA
(Security classification of title, body of abstract and indexing annotation must be entered when document is classified)
1.
ORIGINATOR (the name and address of the organization preparing the
document. Organizations for whom the document was prepared, e.g. Centre
sponsoring a contractor’s report, or tasking agency, are entered in section 8.)
Defence R&D Canada – Suffield
Box 4000, Station Main, Medicine Hat, Alberta,
Canada T1A 8K6
3.
2.
SECURITY CLASSIFICATION
(overall security classification of the
document including special warning terms if
applicable).
UNCLASSIFIED
TITLE (the complete document title as indicated on the title page. Its classification should be indicated by the appropriate
abbreviation (S,C,R or U) in parentheses after the title).
Assessment of Lower Leg Injury from Land Mine Blast - Phase 2
4.
AUTHORS (last name, first name, middle initial)
Bergeron, D.M.; Anderson, I.B.; Coley, G.G.; Fall, R.W.
5.
DATE OF PUBLICATION (month and year of publication of
document)
6a.
152
March 2007
7.
NO. OF PAGES (total
containing information.
Include Annexes,
Appendices, etc).
6b.
NO. OF REFS (total
cited in document)
3
DESCRIPTIVE NOTES (the category of the document, e.g. technical report, technical note or memorandum. If appropriate, enter the
type of report, e.g. interim, progress, summary, annual or final. Give the inclusive dates when a specific reporting period is covered).
Technical Report
8.
SPONSORING ACTIVITY (the name of the department project office or laboratory sponsoring the research and development.
Include address).
Defence R&D Canada – Suffield
Box 4000, Station Main, Medicine Hat, Alberta, Canada T1A 8K6
9a.
PROJECT NO. (the applicable research and development
project number under which the document was written.
Specify whether project).
9b.
GRANT OR CONTRACT NO. (if appropriate, the applicable
number under which the document was written).
CCMAT
10a. ORIGINATOR’S DOCUMENT NUMBER (the official
document number by which the document is identified by the
originating activity. This number must be unique.)
10b. OTHER DOCUMENT NOs. (Any other numbers which may
be assigned this document either by the originator or by the
sponsor.)
DRDC Suffield TR 2007-070
11.
DOCUMENT AVAILABILITY (any limitations on further dissemination of the document, other than those imposed by security
classification)
( X ) Unlimited distribution
( ) Defence departments and defence contractors; further distribution only as approved
( ) Defence departments and Canadian defence contractors; further distribution only as approved
( ) Government departments and agencies; further distribution only as approved
( ) Defence departments; further distribution only as approved
( ) Other (please specify):
12.
DOCUMENT ANNOUNCEMENT (any limitation to the bibliographic announcement of this document. This will normally correspond
to the Document Availability (11). However, where further distribution beyond the audience specified in (11) is possible, a wider
announcement audience may be selected).
Unlimited
13.
ABSTRACT (a brief and factual summary of the document. It may also appear elsewhere in the body of the document itself. It is highly
desirable that the abstract of classified documents be unclassified. Each paragraph of the abstract shall begin with an indication of the
security classification of the information in the paragraph (unless the document itself is unclassified) represented as (S), (C), (R), or (U).
It is not necessary to include here abstracts in both official languages unless the text is bilingual).
In 1999, the Canadian Centre for Mine Action Technologies (CCMAT) evaluated the suitability of
a frangible leg model to assess the performance of mine-protective footwear. The model performance was satisfactory, but the strength of some bones needed to be adjusted. Furthermore,
M14 mines could not be obtained in time for these tests which made it difficult to compare the
results against those from cadaver tests done in the United States. In 2001, the same frangible
leg model, now having improved bones, was evaluated in a second test series using M14 mines.
This report presents the results from the 2001 test series. The improved model performed notably better than the previous model. The results compared well against the cadaver test results, although some further improvements could be made to increase its realism. However,
the frangible leg model can be used, as is, to assess the performance of protective footwear
against anti-personnel mines, provided the user accounts for the strengths and weaknesses of
the model.
14.
KEYWORDS, DESCRIPTORS or IDENTIFIERS (technically meaningful terms or short phrases that characterize a document and could
be helpful in cataloguing the document. They should be selected so that no security classification is required. Identifiers, such as
equipment model designation, trade name, military project code name, geographic location may also be included. If possible keywords
should be selected from a published thesaurus. e.g. Thesaurus of Engineering and Scientific Terms (TEST) and that thesaurus-identified.
If it not possible to select indexing terms which are Unclassified, the classification of each should be indicated as with the title).
frangible leg model
anti-personnel landmines
protective footwear
protective equipment
blast effects
blast physics
mine blast injury database
human cadavers