AIRBAG TEST CONDITIONS BASED ON
REAL-WORLD CRASH EXPERIENCE
J. W. M e l v i n
Highway S a f e t y Research I n s t i t u t e
The U n i v e r s i t y o f Michigan
Ann Arbor, Michigan 48109
FINAL REPORT
June 1982
Prepared f o r
Honda Research and Development Company, L t d .
Wako Center
1-4-1 Chuo, Wako-Shi
Sa i tama, 3 5 1 , Japan
Tubricol Report Docrmtuti" Pogo
1. R-rt
2. Go-m
Mo.
3. Ruipimt's Cetoly No.
Accession No.
UM-HSRI -82-25
5. Rapoft Dot*
4. Title d Subtitle
June 1982
AlRBAG TEST CONDITIONS BASED ON
REAL-WORLD CRASH EXPERIENCE
6. P u k i n g 0fp.nixotia Cod.
I.P & n * y
7. Auko6s)
UM-HSR 1-82-25
J. W. M e l v i n
10. WorC Unit No. (TRAIS)
9. P u b m i n e Orgmizotior, N r e d Ad&*ss
Highway S a f e t y Research I n s t i t u t e
The U n i v e r s i t y o f Michigan
Ann A r b o r , Michigan 48109
NH
12. * w i n g
O r g m i x d o n R.port No.
11. Conooct or Gronc No.
Honda Research and Development Co.,
Wako Center
1-4-'1 C ~ U O , Wake-Shi
Saitarna. 351, Japan
TYP
13.
a d Address
of R-o*
ond Period ~overod
FINAL REPORT
A p r i l 1982-June 1982
Ltd.
14. +enswing Agency Code
IS. S u p p l m t w y Noto.
1'6. Abatrwt
To e s t a b l i s h a c r a s h t e s t m a t r i x f o r d e v e l o p i n g and e v a l u a t i n g an
a i rbag r e s t r a i n t system, an a n a l y s i s was made o f e x i s t i n g i n f o r m a t i o n
on motor v e h i c l e a c c i d e n t s , biomechanical p r i n c i p l e s o f occupant
p r o t e c t i o n , and p r i n c i p l e s o f occupant r e s t r a i n t systems. Eva1 u a t ions
o f a i r b a g r e s t r a i n t systems by means o f c r a s h t e s t s u s u a l l y c e n t e r
upon t h e t e s t c o n d i t i o n s o f FMVSS 208 ( f l a t b a r r i e r c r a s h t e s t i n g o f
P a r t 572 t e s t dummies a t 30 mph w i t h impact angles from 0' t o 30').
But those c o n d i t i o n s s p e c i f i e d i n FMVSS 208 may n o t adequately r e p r e s e n t
t h e p o s s i b l e r e a l - w o r l d c r a s h exposure t h a t a p r o d u c t i o n a i rbag m i g h t
face on U.S. highways. T h i s r e p o r t suggests a supplemental c r a s h t e s t
m a t r i x t o r e p r e s e n t more c o m p l e t e l y t h e r e a l - w o r l d c o n d i t i o n s an a i r b a g
r e s t r a i n t system e v a l u a t i o n program must c o n s i d e r .
17. Koy Wwds
18. Disnibunor, S t o t n r r t
Airbag Restraint Testing
A c c i d e n t Data A n a l y s i s
It. kcurity C l r u f . (of this
None
i
Unl imi t e d
3. kcurity CIassil. (
.
I
this pogo)
None
21.No.efPoges
25
n
Price
TABLE OF CONTENTS
LIST O F TABLES
.........................
l NTRODUCT l ON
2.0
............
Impact D i r e c t i o n . . . . . . . . . . . . . . . . . . .
Type o f O b j e c t S t r u c k . . . . . . . . . . . . . . . .
V e h i c l e V e l o c i t y Change ( D e l t a V)
..........
D i s t r i b u t i o n o f NCSS I n j u r i e s . . . . . . . . . . . .
REVIEW OF REAL-WORLD ACCIDENT DATA
2.1
2.2
2.3
2.4
3.0
DISCUSSION OF FACTORS INFLUENCING AIRBAG DESIGN
AND PERFORMANCE
4:O
DISCUSSION OF
5.0
D l SCUSS l ON OF CRASH TEST l NG FACTORS
AND SUGGESTED CRASH TEST MATRIX
6.0
REFERENCES
......................
BIOHECHANICAL FACTORS . . . . . . . . . . . .
..............
........................
LIST O F TABLES
1
2
3
4
.
.
.
.
D i s t r i b u t i o n o f Impact
I n j u r y Groupings
Direction
for
Various
Occupant
.....................
D i s t r i b u t i o n o f Accident Type f o r V a r i o u s Occupant
I n j u r y Groupings
.....................
D i s t r i b u t i o n of Vehicle
Occupant I n j u r y Groupings
Velocity
Changes
for
4
Various
................
...
..............
D i s t r i b u t i o n o f AlSn3.4.5. 6 I n j u r i e s by Body Region
5 . Honda A i r b a g Crash Test M a t r i x
3
5
7
15
1.0
INTRODUCTION
An a n a l y s i s was conducted t o assess e x i s t i n g i n f o r m a t i o n
vehicle
accidents,
biomechanics
of
occupant
protection,
p r i n c i p l e s o f occupant r e s t r a i n t systems i n order t o e s t a b l i s h
test
matrix
on
motor
and
a
the
crash
t h e development and e v a l u a t i o n o f an a i r b a g r e s t r a i n t
for
system.
The c r a s h t e s t
centers
upon
the
evaluation
test
of
conditions
airbag
of
restraint
FMVSS 208.
systems
usually
This involves f l a t
b a r r i e r c r a s h t e s t i n g a t 30 mph w i t h impact angles from 0 " t o 30°, u s i n g
50th p e r c e n t i l e
cond i t i ons
male
speci f i ed
test
in
dummies
FMVSS
(Part
572).
The
limited
crash
208 may n o t be adequate t o r e f 1 e c t t h e
p o s s i b l e r e a l - w o r l d c r a s h exposure t h a t a p r o d u c t i o n a i r b a g system m i g h t
f a c e on t h e highways o f t h e U n i t e d S t a t e s .
report
to
suggest
more c o m p l e t e l y t h e
I t is
the
intent
of
this
a supplemental c r a s h t e s t m a t r i x t h a t would r e f l e c t
real-world
conditions
system e v a l u a t i o n program must c o n s i d e r .
that
an
airbag
restraint
REVIEW OF REAL-WORLD ACCIDENT DATA
2.0
The d a t a base chosen t o p r o v i d e t h e i n f o r m a t i o n f o r
real-world
crash
d a t a c o l l e c t i o n program
(NHTSA)
.
March 31,
In
(NCSA)
the
exposure o f an a i r b a g system i s t h e d a t a c o l l e c t e d by
t h e N a t i o n a l Crash S e v e r i t y Study (NCSS).
Analysis
analyzing
of
of
the
The NCSS was a major a c c i d e n t
National
Center
for
Statistics
and
t h e N a t i o n a l Highway T r a f f i c S a f e t y A d m i n i s t r a t i o n
1977,
Data c o l l e c t i o n began on January 1 ,
and
t e r m i nated
on
1979.
t h e NCSS study, a c c i d e n t s were i n v e s t i g a t e d i n seven geographic
areas w i t h i n
aggregate
the
of
continental
United
States,
selected
so
that
the
t h e areas c l o s e l y resembles t h e u r b a n i z a t i o n d i s t r i b u t i o n
of the e n t i r e country.
W i t h i n each area, a s t r a t i f i e d sampling p l a n was
used t o gather d e t a i l e d i n f o r m a t i o n on passenger cars, l i g h t t r u c k s , and
vans, as w e l l as t h e i r occupants, i n a c c i d e n t s severe enough t o
that
t h e v e h i c l e s be towed from t h e scene.
(weighted total=54,318)
tota1=67,281)
,
A t o t a l o f 11,386 a c c i d e n t s
i n v o l v i n g 14,805 towed passenger c a r s
24,976
vehicle
require
(weighted
occupants (weighted tota1=106,121),
917 f a t a l i t i e s (weighted t o t a l = 9 1 7 ) were c o l l e c t e d i n t h e NCSS study.
more complete d e s c r i p t i o n o f t h e NCSS
ed.
(1)
study
can
be
found
in
and
A
Ricci,
.*
For
this
analysis,
reviewed f r o m
the
instantaneous
change
types f o r
crashes
restraint
systems.
the
summary d a t a on passengers c a r s ( 1 ) were
standpoints
in
that
of
impact
direction,
object
v e h i c l e v e l o c i t y ( c a l l e d d e l t a V)
would
Airbag
be
of
systems
relevance
are
to
generally
,
and i n j u r y
airbag
felt
struck,
to
occupant
be most
e f f e c t i v e i n crashes t h a t a r e o f t h e f r o n t a l t y p e and whose s e v e r i t y
sufficiently
great
that
system were n o t a c t i v a t e d .
serious
injuries
W i t h t h a t i n mind,
would
the
is
l i k e l y occur i f t h e
following
analyses
were conducted t o o b t a i n an overview o f t h e r e l e v a n t c r a s h d a t a .
*Numbers
t h i s report.
in
parentheses
denote
r e f e r e n c e s l i s t e d a t t h e end o f
2.1
-
Impact D i r e c t i o n
The p r i n c i p a l d i r e c t i o n o f f o r c e (PDOF) t o an impacted
broken down i n t o " c l o c k d i r e c t i o n s " o r 30'
necessarily
the
same as t h e a r e a o f t h e v e h i c l e damaged.
into
the
side
the f r o n t of the car.
the
left)
occupant
If
compartment.
d i r e c t i o n s o t h e r than 12 o ' c l o c k
impact
directions,
we
combine
(0°),
For example,
impact
vector
The PDOF does, however, g i v e a
general p i c t u r e o f t h e v e c t o r o r i e n t a t i o n o f t h e major
the
is
T h i s PDOF i s n o t
increments.
i t i s p o s s i b l e t o have an 1 1 o ' c l o c k (30' t o
vehicle
we
the
find
deceleration
of
l e f t and r i g h t c l o c k
the
distribution
of
p r e s e n t e d i n T a b l e 1 , grouped a c c o r d i n g t o occupant
injury levels.
TABLE 1
DISTRIBUTION OF IMPACT DIRECTION FOR
VARIOUS OCCUPANT INJURY GROUPINGS
Impact D i r e c t i o n (PDOF)
A l l Occupants
12 O'Clock (0')
1 & 1 1 O ' c l o c k (f30°)
2 & 10 o l c l o c k (+60°)
3 & 9 O ' c l o c k (*go0)
27.3%
22.5%
14.8%
2.4%
3+
Fatal
17.0%
32.7%
20.0%
20.2%
3.2%
3.6%
34.4%
16.6%
19.2%
6.1%
A I S 2+
34.1%
21.0%
AIS
The d a t a i n T a b l e 1 i n d i c a t e t h a t t h e +30° t e s t cond i t i ons o f FMVSS
208 would c u m u l a t i v e l y i n c l u d e 50% t o
a1 1
the
NCSS
crashes.
55% o f t h e occupants
include
addressed
in
the
The r e v i s i o n proposed by NHTSA t o FMVSS 214 f o r s i d e impact
a +60° impact P D O F .
Thus, one m i g h t conclude t h a t t h e d i v i s i o n
between f r o n t a l impact and s i d e impact should occur when t h e PDOF i s
245".
in
The quest i o n o f when t h e PDOF p e r t a i n s more t o
s i d e impact than t o f r o n t impact has n o t r e a l l y been
literature.
involved
This
impact v e c t o r .
would
give
equal
Interpolation of
frontal
the
at
and l a t e r a l components t o t h e
cumulative
frequency
data
from
T a b l e 1 i n d i c a t e s t h a t a p p r o x i m a t e l y 63% o f t h e occupants i n j u r e d a t t h e
level
+ 4 5 O .
o f AIS 3 o r g r e a t e r would be i n c l u d e d f o r PDOF d i r e c t i o n s between
Thus, i t i s reasonable t o extend t h e range o f t h e PDOF f o r a i r b a g
crash testing to include direct ions up to k45' in order to increase
the
coverage of real-world accident victims.
2.2
-
Of Object Struck
Table
2
shows the distribution of NCSS accidents by accident type
for the same injury groups.
TABLE 2
DISTRIBUTION OF ACCIDENT TYPE F O R
VARIOUS OCCUPANT INJURY GROUPINGS
Accident Type
A l 1 Occupants
A I S 2+
AIS 3+
Fatal
Single Vehicle/Fixed Object
Two Vehicles/Head-On
Two Vehicles/Side
Three or More Vehicles
19.5%
10.8%
36 7%
11.7%
31.6%
31.8%
17.8%
29.4%
20.8%
25.2%
7.2%
16.2%
27.6%
9.5%
27.2%
8.5%
A few comments need to be made about this breakdown of
The
two-vehicle/side-impact
data
of
the
data
pertain
data.
invariably include one side-impacted
vehicle and one frontally-impacted vehicle in each
half
the
to frontal impacts.
crash.
Thus,
only
These frontal impacts
would most likely be different than those occurring in two-vehicle/headon crashes, in terms of both the vehicle-to-vehicle interaction and
V of the frontally-impacted vehicle.
delta
the
An estimate of the relative
frequency of frontal impact for occupants in these crashes, obtained
simply
dividing
all
by
"side" data by two, produces numbers of occupants
injured at the AIS2+, AIS 3+, and fatal levels that are
somewhat
lower
than those in two-vehicle/head-on crashes.
Similarly,
directions.
the single-vehicle/fixed-object data include all impact
An estimate of the relative frequency of frontal impact for
occupants in these crashes can be made by
vehi cl e/f i xed-object
given in section 2.1.
data
taking
63% of the single-
based on the re1 at ive frequency of k45' PDOF
This would produce relative frequencies for
each
18% t o 20%, which w o u l d be s i m i l a r t o t h e r e l a t i v e
i n j u r y group o f about
f r e q u e n c i e s o f t h e two-vehicle/head-on
category.
As a r e s u l t o f t h e above c o n s i d e r a t i o n s , i t appears
in
frontal
i n vehicle-to-fixed
o b j e c t , head-on v e h i c l e - t o - v e h i c l e ,
types.
The
implications
for
crash
a i r b a g r e s t r a i n t systems a r e t h a t equal emphasis
vehicle-to-fixed
tests.
occur
object
tests
vehicle-to-
test evaluation of
should
type
be
placed
on
frontal
crashes
s i m i l a r frequency t o t h e o t h e r two types o f f r o n t a l crashes
should be c o n s i d e r e d i n s e t t i n g t h e t h r e s h o l d l e v e l
airbag
and
and t o b o t h types o f v e h i c l e - t o - v e h i c l e
Also, t h e f a c t t h a t f r o n t - t o - s i d e - v e h i c l e
with
injuries
crashes occur w i t h s i m i l a r frequency i n t h e NCSS d a t a
(+45')
side-vehicle
that
deployment,
because
h i v e 1 ower d e l t a V l s and
these
for
initiation
of
f r o n t - t o - s i d e crashes would tend t o
decelerations
than
head-on
f i xed-obj e c t
or
crashes.
2.3
V e h i c l e V e l o c i t y Change ( D e l t a V l
The
NCSS
study
contains
20,279
(weighted t o t a l ) frontal-damage
Table 3 g i v e s i n f o r m a t i o n on occupants
passenger cases.
injured
t h e 31,431 occupants i n these crashes i n two d i f f e r e n t ways.
to
among
One way i s
g i v e t h e percentage of a l l occupants i n j u r e d f o r v e l o c i t y changes up
t o 35 mph and 40 mph, r e s p e c t i v e l y ( c u m u l a t i v e
frequency)
.
The
other
way i s t o g i v e t h e percentage o f occupants i n j u r e d i n t h e v a r i o u s i n j u r y
groupings
among
specif i c a l l y o f
those
involved
in
crashes
35 mph and 40 mph ( i n j u r y r a t e )
with
velocity
.
TABLE 3
D l STR l BUT l ON OF VEH l CLE VELOC l TY CHANGES FOR
VAR l OUS OCCUPANT l NJURY GROUP l NGS
AIS 2+
AIS
3+
Fatal
Cum.
Freq.
Injury
Rate
Cum.
Freq.
Injury
Rate
Cum.
Freq.
lnjury
Rate
35 MPH
87%
50%
78%
3 3%
50%
11%
40 MPH
92%
58%
85%
43%
60%
20%
Delta V
changes
These d a t a i n d i c a t e t h a t a c r a s h v e l o c i t y change o f 40 mph
of
instead
35 mph n e a r l y doubles t h e f a t a l i n j u r y r a t e as w e l l as p r o d u c i n g a
10% increase
fatalities.
in
the
cumulative
Significant
injury rates f o r
the
AIS
frequency
increases
2+
and
in
of
the
occurrence
of
t h e c u m u l a t i v e f r e q u e n c i e s and
3+
AIS
levels
also
result
when
c o n s i d e r i n g t h e 40 mph l e v e l i n s t e a d o f t h e 35 mph l e v e l .
a crash t e s t v e h i c l e d e l t a V o f 40 mph would appear t o be
Choosing
a s u i t a b l e goal f o r i n c r e a s i n g t h e p r o t e c t i v e c a p a b i l i t i e s o f a v e h i c l e .
However, i t must be k e p t i n mind t h a t t h e d e l t a V
data
are
not
equivalent
values
t o b a r r i e r crash d e l t a Vs.
in
the
NCSS
The a c c e l e r a t i o n
l e v e l s a s s o c i a t i o n w i t h b a r r i e r crashes tend t o be higher t h a n those f o r
car-to-car
complet;
crashes a t t h e same d e l t a Vs.
This
is
attributed
to
the
and u n i f o r m c o n t a c t t h a t t h e f l a t b a r r i e r produces a g a i n s t t h e
f r o n t o f the t e s t vehicle.
real-world
crash
severity
Thus, a 40 mph d e l t a
V
level
in
terms
of
may be r e p r e s e n t e d by a lower d e l t a V i n an
e q u i v a l e n t b a r r i e r crash t e s t .
The
35 mph b a r r i e r crash v e l o c i t y
used
by Honda i n p r e v i o u s t e s t i n g may be near t h i s equivalence l e v e l .
2.4
-
D i s t r i b u t i o n o f NCSS I n j u r i e s
The
goal
of
any r e s t r a i n t system i s t o p r e v e n t s e r i o u s and f a t a l
I n meeting t h i s goal i t i s p o s s i b l e t h a t some i n j u r i e s may be
injuries.
produced by t h e r e s t r a i n t
injuries
system
may n o t be prevented.
itself
and
that
many
lower
Choosing t h e c r a s h t e s t s e v e r i t y l e v e l s
f o r e v a l u a t i n g a r e s t r a i n t system r e q u i r e s a d e c i s i o n as t o
of
level
what
level
i n j u r y w i l l be judged a c c e p t a b l e and what l e v e l s o f i n j u r y a r e t o be
prevented.
Currently, i t i s generally f e l t t h a t the A I S 3 level
acceptable
injury
level
for
the
upper
crash
is
an
severity l i m i t o f the
vehicle.
I n view o f t h i s , t h e NCSS d a t a on t h e most f r e q u e n t i n j u r i e s common
a t A I S levels of 4,
5, and 6 can p r o v i d e
i n j u r i e s t h a t a r e t o be prevented.
injuries
to
the
insight
into
the
types
of
Table 4 p r e s e n t s t h e d i s t r i b u t i o n o f
major body r e g i o n s f o r A I S 3 and t h e h i g h e r t h r e e A I S
levels.
The t h r e e most f r e q u e n t l y i n v o l v e d body r e g i o n s a t A I S 4,
are
the
head,
abdomen,
and
thorax.
5, and 6
These would most l i k e l y be w e l l
TABLE 4
DISTRIBUTION OF ~ 1 5 = 3 , 4 , 5 , 6 INJURIES
BY BODY REGION
5
Body Region
AIS 3
AIS 4
AIS
Head
Abdomen
Thorax
Leg
Neck
Arm
Back
10.2%
8.3%
36.6%
26.1%
4.2%
12.8%
1 .g%
24.7%
29.9%
19.2%
16.5%
1.3%
38 3%
30 7%
25 -4%
0.2%
4 .O%
0.0%
1.1%
.
6
7 3%
1.0%
p r o t e c t e d by an e f f e c t i v e a i r b a g system.
AIS 6
A I S 4,5,6
30.1%
26.3%
21 .9%
8.6%
7.9%
3.8%
1 .O%
29.7%
1.4%
23.1%
o .o%
43.4%
0.0%
0.9%
Note t h a t a t t h e AIS
3
level
t h e l e g r e p r e s e n t s a s i g n i f i c a n t p o r t i o n o f t h e i n j u r i e s , second o n l y t o
the thorax.
the
I t would be v a l u a b l e f o r a r e s t r a i n t system t h a t d i m i n i s h e d
occurrence
of
head,
thoracic,
and
abdominal
injuries
t o also
m i n i m i z e l e g i n j u r i e s , even though they a r e u s u a l l y c l a s s i f i e d as AIS
and be 1 ow.
4
DlSCUSSlON OF FACTORS INFLUENCING
AIRBAG DESIGN AND PERFORMANCE
3.0
The r o l e o f an occupant r e s t r a i n t system i s t o c o u p l e t h e
tightly
to
vehicle's
the
vehicle
energy
preventing,
so
as
body.
the
or
limit
capabilities
possible,
while
at
of
the
contact
the
same
time
occupant w i t h t h e
A t h i r d f u n c t i o n o f a r e s t r a i n t system
i n t e r i o r of the vehicle.
distribute
t h a t he can r i d e down t h e c r a s h u s i n g t h e
absorbing
insofar
occupant
is
to
t h e loads produced by t h e crash on t h e o c c u p a n t ' s
W h i l e a l l o f these f u n c t i o n s can be p r o v i d e d
for
in
principle,
c r i t i c a l f a c t o r s t h a t come i n t o p l a y i n t h e a c t u a l s p e c i f i c a t i o n o f
r e s t r a i n t performance l e v e l s a r e t h e mechanical response c h a r a c t e r i s t i c s
o f t h e human body under
mechanical
Ioad i ng
such
and
1 imit s
the
of
l o a d i n g t h a t can be r e l i a b l y a p p l i e d w i t h o u t s e r i o u s i n j u r y .
Such i n f o r m a t i o n i s known
as
tolerance
body.
factors
cond i t i ons
of
the
has
human
impeded
particular 1y
with
the
the
To p u t i t
in
mechanical
characteristics
impact
response
and
The l a c k o f adequate knowledge o f such
progress
respect
restraint.
biomechanical
to
simple
of
restraint
i nnovat i v e
terms,
an
system
approaches
engineer
to
must
design,
occupant
know
the
and f a i l u r e modes o f t h e s u b j e c t t h a t i s t o
be p r o t e c t e d j u s t as much as those o f t h e s t r u c t u r e s or systems t h a t a r e
b e i n g designed t o do
the
protecting.
Given
a
desired
upper
crash
v e l o c i t y l e v e l , i t i s t h e l i m i t s o f t h e human body t o w i t h s t a n d t h e t y p e
and
magnitude
o f t h e loads produced on i t by t h e r e s t r a i n t system t h a t
d i c t a t e t h e a c t u a l performance l e v e l s
of
the
vehicle
crashworthiness
structures.
In
a
frontal
crash,
t h e o r e t i c a l advantages over
First,
an
airbag
the
lap/shoulder
system
belt
has
several
restraint
system.
a i r b a g p r o v i d e s a much l a r g e r area t o r e s t r a i n t h e occupant
the
and thus can a p p l y l a r g e r t o t a l loads t o
loading.
restraint
Second,
the
the
body
for
a
given
unit
a i r b a g can l o a d t h e head as w e l l as t h e r e s t o f
t h e body and can thereby c o n t r o l t h e m o t i o n o f t h e head i n a manner t h a t
be1 t systems cannot.
increase
the
A third
possible
advantage
is
the
abi l i t y
to
s t o p p i n g d i s t a n c e o f t h e occupant by p r o v i d i n g c o n t r o l l e d
forward m o t i o n w i t h i n t h e occupant compartment d u r i n g t h e
crash.
This
f e a t u r e can be designed i n t o b e l t systems a l s o .
The
above
advantages
were r e f e r r e d t o as t h e o r e t i c a l advantages because i t depends t o a g r e a t
extent
upon
the
s e v e r i t y o f t h e c r a s h v e l o c i t y l e v e l as t o whether o r
n o t such f e a t u r e s a r e a c t u a l l y necessary
injury
to
the
v e h i c l e occupants.
prevent
severe
or
fatal
The c r a s h w o r t h i n e s s f e a t u r e s o f t h e
v e h i c l e s t r u c t u r e s must be capable o f
managing
to
adequately
doing
their
job
of
t h e c r a s h energy and p r e v e n t i n g occupant compartment i n t r u s i o n
a t a p a r t i c u l a r d e s i g n c r a s h v e l o c i t y b e f o r e such a d d i t i o n a l f e a t u r e s as
l o a d d i s t r i b u t i o n on t h e body, c o n t r o l o f
stopping
distance
are
needed.
system i s s t i l l t o p r o v i d e
uncontrolled
has found
ride
down
i n t e r i o r contacts.
that,
structures
The
have
for
crashes
remained
head
basic
of
levels
appear
and
increased
function of the r e s t r a i n t
the
crash
and
to
prevent
Real-world accident i n v e s t i g a t i o n data
in
which
the
vehicle
crashworthiness
t h e p r o p e r use o f a l a p / s h o u l d e r
effective,
b e l t poses no s e r i o u s t h r e a t o f i n j u r y t o
severity
motion,
the
occupant.
These
crash
t o i n c l u d e t h e c o n d i t i o n s o f t h e p r e s e n t FMVSS
208.
Thus,
are
not
i t appears t h a t t h e biomechanical advantages
strictly
airbag
of
crashworthiness
in
today's
Only as t h e c r a s h w o r t h i n e s s l e v e l ( t h a t i s , t h e s u r v i v a b l e crash
velocity)
it
the
necessary f o r s a f e occupant p r o t e c t i o n i n s u r v i v a b l e
v e h i c l e crashes w i t h t h e p r e s e n t l e v e l
cars.
of
i s raised t o higher l e v e l s w i t h f u t u r e v e h i c l e
become
designs
might
necessary t o p r o v i d e t h e a d d i t i o n a l f r o n t a l c r a s h p r o t e c t i v e
features o f the airbag.
A t j u s t what l e v e l t h i s
occurs
depends
to
a
g r e a t degree upon a good knowledge o f t h e biomechanical f a c t o r s i n v o l v e d
i n human t o l e r a n c e t o impact i n j u r y .
The
airbag
is
a
p a r t i c u l a r j o b very w e l l .
restraint
system
that
is
designed t o do one
That j o b i s t o p r o v i d e p a s s i v e p r o t e c t i o n f o r
a we1 l - p l a c e d ( t h a t i s , seated, f o r w a r d - f a c i ng, centered,
and
back
in
t h e v e h i c l e seat) v e h i c l e occupant i n a p r i m a r i l y f r o n t a l f o r c e c r a s h i n
which
the
inflated.
major
crash
events
take
place
forward
passenger
t h e a i r b a g remains
The a i r b a g i s mounted i n t h e forward s t r u c t u r e o f t h e v e h i c l e
and t h e r e f o r e depends t o some e x t e n t upon t h e
the
while
structure,
airbag.
including
Windshield
the
structural
windshield,
retention
in
integrity
of
i n t h e case o f t h e
vehicle
crashes
is
an
i m p o r t a n t f a c t o r i n keeping u n r e s t r a i n e d occupants i n s i d e t h e car and i s
covered
FMVSS
by
windshield
212.
integrity
performance o f
Performance
a
and
However,
during
passenger
Injury
of
and
objects
and
An
thus
disrupt
the
m i g h t compromise t h e
anal ys i s
10
and
2
of
o'clock
which 991 broken w i n d s h i e l d s o c c u r r e d .
were
broken
221 were o f unknown cause.
o f t h e crashes may have
can
Col 1 i s i o n
the
(CP I R) a c c i d e n t d a t a f i 1 es f o r f r o n t a l
between
caused by occupant c o n t a c t , 358
contact,
crash
a i rbag.
Report
crashes w i t h impact f o r c e s
vehicles
a
outside
represented
a
by
yielded
5,705
O f these, 412 were
other
than
occupant
T h i s means t h a t 6.3% t o 10.1%
problem
for
passenger
airbag
performance.
The
out-of-position
occupant
presents
another
factor
for
c o n s i d e i a t i o n i n the d e s i g n and performance o f a i r b a g r e s t r a i n t systems.
Thi s s i t u a t i o n can occur f o r b o t h t h e d r i v e r (2) and f o r
(3,4).
P r e v e n t i o n o f dangerous o u t - o f - p l a c e
the r a p i d l y i n f l a t i n g a i r b a g has
characteristics,
of-position
child
bag
significant
the
occupant i n t e r a c t i o n s w i t h
influences
on
f o l d i n g p a t t e r n s , and system placement.
occupant
generally
r e s t r i c t i o n on d e s i g n parameters.
passenger
presents
the
most
inflation
The o u t severe
4$ 0
The
problem
mechanisms,
and
D l SCUSS l ON OF B l OMECHAN l CAL FACTORS
of
describing
tolerance
r e s t r a i n t system design.
the
performance
of
restraint
knowledge
d e s i g n and e v a l u a t i o n .
criteria
for
mechanical
response,
on
systems,
the
of
,
the
biomechanics
optimize
of
the
human
body.
can be u s e f u l i n many ways i n r e s t r a i n t system
The
information
can
be
used
to
set
design
l o a d l i m i t s produced by t h e r e s t r a i n t system, such as t h e
or
the
breaking
HPR w i n d s h i e l d , w h i l e i t can a l s o be u s e f u l i n s p e c i f y i n g
t h e response o f a human s u r r o g a t e , such as a
model,
and
t h e g r e a t e r t h e need f o r more
c o l l a p s e l o a d o f t h e energy-absorbing s t e e r i n g column
load
injury
f o r c e o f t h e human body i s paramount i n
As a t t e m p t s a r e made t o upgrade
complete and a c c u r a t e d a t a
Biomechanical
to
the
Finally,
it
can
be
dummy
or
a
mathematical
used t o assess t h e i n j u r y p o t e n t i a l o f a
p a r t i c u l a r r e s t r a i n t system t h r o u g h t h e use o f i n j u r y c r i t e r i a .
There a r e s e v e r a l problems r e l a t e d t o t h e biomechanical use o f
present
type
of
test
c a l l e d P a r t 572 dummy).
that
were
intended
dummies s p e c i f i e d f o r use i n FMVSS 208 ( t h e soSuch t e s t dummies had t h e i r o r i g i n s i n
were
only
crudely
t h e r e was no a t t e m p t a t
critical
dummies
t o s i m u l a t e t h e shape and mass d i s t r i b u t i o n o f t h e
average (50th p e r c e n t i l e ) male human body.
dummies
the
The a r t i c u l a t i o n s
representative
simulating
the
of
these
o f t h e human l i n k a g e s , and
mechanical
s t r u c t u r e s as t h e head, neck, and c h e s t .
o f t h e P a r t 572 dummy were developed t o improve
the
response
of
Most o f t h e f e a t u r e s
repeatabi 1 i t y
r e p r o d u c i b i l i t y o f t h e dummy, t h e f i r s t p r i o r i t y o f any t e s t d e v i c e .
a
result,
r e s t r a i n t systems t e s t i n g .
the
impact
As
f a c t o r i s t h a t t h e i n j u r y c r i t e r i a used
biomechanical
impact
data
typical
of
in
An a d d i t i o n a l c o m p l i c a t i n g
FMVSS
208
were
o b t a i n e d w i t h human cadavers.
t h e 1 i m i t e d i n j u r y c r i t e r i a p u t f o r t h i n FMVSS
injury
situations
These d i s c r e p a n c i e s a r e t h e r e s u l t o f a l a c k
what i s known as biomechanical f i d e l i t y .
femur
and
t h e P a r t 572 dummy g i v e s exaggerated v a l u e s o f a c c e l e r a t i o n s
and f o r c e s generated under some o f
of
such
208
(head,
based
on
As a r e s u l t ,
chest,
and
c r i t e r i a ) were o b t a i n e d w i t h t h e b e s t avai l a b l e s u r r o g a t e
o f t h e human body b u t a r e i n t e r p r e t e d w i t h a s u r r o g a t e ( P a r t
5 7 2 dummy)
t h a t does n o t n e c e s s a r i l y respond i n t h e same manner as t h e human body.
The human body i s a v e r y c o m p l i c a t e d biomechanical s t r u c t u r e .
critical
structures
understood.
and
their
injury
1imits
are
not
completely
C u r r e n t research work i s aimed a t improving t h i s s i t u a t i o n ,
b u t i n some r e g i o n s , such as b r a i n i n j u r y , i t may be many
an
Its
years
before
adequate u n d e r s t a n d i n g o f a l l t h e p o s s i b l e modes o f i n j u r y and t h e i r
causes a r e achieved.
The
simplified
The same i s t r u e t o a l e s s e r e x t e n t i n t h e
injury
criteria
FMVSS
of
208
represented
a v a i l a b l e information a t the time o f i t s formulation,
other
possible
it
the best
neglects
forms o f i n j u r y , such as neck i n j u r y , because l i t t l e i s
known q u a n t i t a t i v e l y about the s u b j e c t .
Such
of
restraint
potential
but
chest.
types
of
injury
in
a
incomplete
specification
system's performance
standard r e q u i r e s t h a t r e s t r a i n t system development be approached
very
cgnservative
basis
to
ensure
that
a
system
p r e v e n t i n g one t y p e o f i n j u r y does n o t produce
on
a
t h a t i s aimed a t
another,
possibly
more
serious, type o f i n j u r y .
The
GM
Hybr i d
III
dummy
(5)
biomechanical f i d e l i t y over t h e P a r t
has
572
s i gni f icant
dummy.
I n addition, the Hybrid
I l l dummy has p r o v i s i o n s f o r advanced transducers i n
and
legs
regions
that
not
can
aid
possible
improvements i n
the
neck,
chest,
i n t h e assessment o f i n j u r y p o t e n t i a l i n body
with
the
Part
572
dummy.
The
problem
of
understanding t h e i n j u r y l i m i t s remains, however.
General
Motors
has a l s o developed a m o d i f i e d t h r e e - y e a r - o l d c h i l d
dummy w i t h improved i n s t r u m e n t a t i o n i n t h e form o f neck and
cells.
This
dummy
was
intended
e v a l u a t i o n o f a i r b a g systems.
primarily
chest
load
for out-of-position test
The dummy may n o t have good biomechanical
f i d e l i t y , s i n c e such d a t a on c h i l d r e n a r e l a c k i n g .
5.0
DISCUSSION OF CRASH TESTING FACTORS
AND SUGGESTED CRASH TEST MATRIX
To t e s t t h e p r o t e c t i v e performance o f an occupant r e s t r a i n t system,
i t i s most o f t e n necessary t o s i m u l a t e a v e h i c l e c r a s h t o
and
to
i n c l u d e a s i m u l a t i o n o f t h e v e h i c l e occupants.
can be s i m u l a t e d by a v a r i e t y o f
techniques,
component
full-scale
impact
testing,
and
techniques,
actual
sled
crash
t e c h n i q u e has v a r i o u s advantages and d i s a d v a n t a g e s .
experiments
The most
Each
realistic
crashing of cars i n t o r e a l i s t i c o b j e c t s (other car,
and
can
result
riproducib i 1 i t y of test resul ts.
in
problems
of
control
repeatability
of
and
Techniques t h a t o f f e r more c o n t r o l can
compromise t h e r e a l i s m o f t h e c r a s h e n v i r o n m e n t by
crash
testing,
testing.
tree, o r roadside s t r u c t u r e ) , s u f f e r from a lack of p r e c i s e
the
degree,
V e h i c l e crashes
including
car
some
eliminating
vehicle
m o t i o n s , such as p i t c h i n g and yawing, and t h e i r subsequent e f f e c t
on occupant k i n e m a t i c s .
Any t e s t program w i l l ,
of
necessity,
involve
compromises between r e a l i s m and r e p e a t a b i l i t y .
The
goals
of
a i r b a g r e s t r a i n t system development program can
an
b e s t be met by a combined approach u s i n g f u l l - s c a l e c a r c r a s h t e s t s
major
system e v a l u a t i o n and supplementing them w i t h s e l e c t e d s l e d t e s t s
f o r e v a l u a t i o n o f s p e c i a l cases.
test
for
program
(5)
criteria
for
included
selecting
The General Motors a i r
used such an approach.
selecting
test
conditions
cushion
crash
The GM s t u d y had a number o f
and
configurations.
These
simulations of high-occurrence r e a l - w o r l d accidents
based on a c c i d e n t d a t a , m i l e a g e and e n v i r o n m e n t a l e f f e c t s , occupant s i z e
and p o s i t i o n mix, and d u p l i c a t i o n o f p a r t i c u l a r a c c i d e n t s i n w h i c h t h e i r
a i r b a g - e q u i p p e d v e h i c l e s had been i n v o l v e d .
I n comparison t o t h e GM
necessarily
differ
in
two
study,
the
aspects.
proposed
First,
Honda
study
t h e r e a r e no r e a l - w o r l d
a c c i d e n t s t o r e c r e a t e i n v o l v i n g a i r b a g - e q u i p p e d Honda c a r s , and
the
would
second,
Honda system has been developed t o exceed t h e r e q u i r e m e n t s o f FMVSS
208 by m e e t i n g t h e i n j u r y c r i t e r i a a t a
additional
factor,
which
a v a i l a b i l i t y o f advanced a d u l t
system p e r f ormance.
can
and
crash
enhance
child
the
speed
of
Honda
dummies
for
35
study,
mph.
An
is
the
evaluation
of
The suggested t e s t c o n d i t i o n s
study
and
configurations
for
the
Honda
a r e based on t h e i n f o r m a t i o n p r o v i d e d i n t h e p r e v i o u s s e c t i o n s o f
t h i s r e p o r t and a r e intended t o r e f l e c t r e a l - w o r l d a c c i d e n t experience.
The
suggested
test
matrix
(shown
in
5)
Table
considers
the
following factors:
a.
b.
c.
d.
e.
The
Type o f crash t e s t ( b a r r i e r , c a r - c a r ,
lmpact angle (0°, 30°, 45')
Impact v e l o c i t y change ( D e l t a V)
Occupant s i z e
Occupant p o s i t i o n
various
combinations
of
been r a t e d a c c o r d i n g t o t h e i r
car-pole, o r sled)
these c o n d i t i o n s and c o n f i g u r a t i o n s have
relative
o v e r a l l performance o f t h e system.
I
importance
in
evaluating
the
The r a t i n g used t h e f o l l o w i n g code:
= E s s e n t i a l Test
A
B
C
D
= Important T e s t
= U s e f u l Test
= Can O m i t
General comments on t h e f e a t u r e s o f t h e t e s t m a t r i x f o l l o w .
A:
Essential
Tests.
Although
barrier
tests
are
n o t as
r e a l i s t i c as c a r - c a r o r c a r - p o l e t e s t s i n terms o f r e a l - w o r l d frequency,
they do r e p r e s e n t a r e p e a t a b l e and h i g h l y s t a n d a r d i z e d
The
0 ° / 35-mph
barrier
test
condition.
t e s t s w i t h t h e 5 0 t h p e r c e n t i l e male H y b r i d I I I
dummy and t h e 5 t h p e r c e n t i l e female and
95th
percentile
male
dummies
have been g i v e n a r a t i n g o f A due t o t h e combined importance o f range o f
occupant
size
and
increased
biomechanical d a t a needed f o r a complete
e v a l u a t i o n o f t h e system performance.
40-mph
30' / 40-mph
and
have
been
S i m i l a r l y , car-car
given
r a t i ngs
A
r e p e a t a b i l i t y and t e s t c o n t r o l s t a n d p o i n t o n l y one o f
the
car-car
t e s t s should be moving, i f p o s s i b l e .
j0°/35-mph
has been added
localized
vehicle
to
evaluate
deformations.
the
tests
a1 so.
the
at
oO/
From
a
vehicles
One c a r - p o l e t e s t a t
system
performance
under
The A-rated s l e d t e s t s a r e r e l a t e d t o
o u t - o f - p o s i t i o n occupants f o r t h e 5 0 t h p e r c e n t i l e
male
and
3-year-old
c h i l d dummies and a passenger-positioned 9 5 t h p e r c e n t i l e male dummy.
is
suggested t h a t t h e o u t - o f - p o s i t i o n
based on s u i t a b l e performance
in
in
It
occupant t e s t s be r u n f i r s t , and,
those
tests,
the
resulting
system
TABLE
5
HONDA A I R B A G C R A S H T E S T M A T R I X
-
T y p e of
Crash
B a r r i e r
Car-Car
Impact
Angle
D r i v e r
Pos.
O u t of
Pos.
Driver
POS.
Pass.
Pos.
O u t of
Pos.
Driver
Pos.
Pass.
Pos.
O u t of
Pos
.
Pass.
Pos.
O u t of
Pos.
C
A
B
C
B
C
C
D
D
D
C
C
A
C
C
D
D
D
C
C
D
C
D
D
25
C
C
C
C
C
C
D
D
D
C
C
C
C
C
C
D
D
D
C
C
C
C
C
C
D
D
D
D
D
D
D
D
D
A
A
B
A
A
B
D
D
D
B
A
B
A
6
45'
40
4 0
35
B
D
D
D
A
B
B
B
A
B
D
D
D
C
C
D
C
D
D
0‘
30'
30
30
45'
25
C
C
C
C
C
C
D
D
D
C
C
C
C
C
C
D
D
D
C
C
C
C
C
C
D
D
D
D
D
D
D
D
D
0'
3045'
35
35
30
B
B
C
C
A
C
D
D
D
C
A
C
C
C
C
D
D
D
C
C
C
C
C
C
D
D
D
C
C
0
C
D
D
0'
30'
30
30
25
D
D
D
D
D
D
C
C
C
C
C
C
D
0
D
C
C
C
C
C
C
D
45-
D
D
D
D
D
D
D
D
D
20* *
20* *
20**
C
D
D
C
D
D
A
B
C
D
0
0
D
D
0
B
D
D
0
0
D
D
B
D
D
D
D
C
B
B
8
C
35
35
B
B
C
B
A
B
C
B
B
B
6
A
B
C
B
B
D
D
B
6
C
B
B
D
D
C
B
B
A
B
C
0'
30'
30
30
45'
0'
30'
45'
0'
30'
45'
35
A
6
,
+ S p e c i a l l y m o d i f i e d w i t h neck and chest
**Or
Pass.
Pos.
0
D
D
35
35
30
0-
0'
Sled
.
3-YEAR-OLD
C H I L D DUMMY*
5 T H PERCENTILE
F E M A L E DUMMY
9 5 T H PERCENTILE
M A L E DUMMY
5 0 T H PERCENTILE
M A L E H Y B R I D 111 DUMMY
A
B
C
30'
45'
30'
Car-Pole
Impact
Velocity
Change. A V
(mph
t h r e s h o l d bag f i r i n g d e l t a V .
A=Essential Test
B=Important Test
C=Useful Test
D=Can O m i t
C
load c e l l s .
C
6
D
D
A
s h o u l d then be e v a l u a t e d w i t h t h e 9 5 t h p e r c e n t i l e male dummy
sled
test
t o ensure p r o p e r performance o f t h e system.
Impact
Angle.
The
impact angles have been chosen t o r e f l e c t t h e
information discussed i n Section 2.1.
Impact V e l o c i t y Change,
have been suggested.
I n a l l cases two d i f f e r e n t v e l o c i t y l e v e l s
T h i s was done t o a l l o w f o r
the
establishment
of
system performance over a range o f c r a s h v e l o c i t i e s r a t h e r t h a n " t u n i n g "
a system f o r a p a r t i c u l a r v e l o c i t y .
Occupant
Size.
chosen f o r
two
percentile
female
The
basic
dummies suggested f o r use i n t h i s s t u d y were
reasons.
dummies
The
95th
percentile
male
and
5th
were chosen t o r e p r e s e n t t h e range o f a d u l t
occupants t o be p r o t e c t e d by t h e system.
The 5 0 t h p e r c e n t i l e H y b r i d I l l
male and t h e 3 - y e a r - o l d c h i l d dummies were chosen t o p r o v i d e
additional
biomechanical d a t a on t h e system performance f o r t h e p r o p e r l y p o s i t i o n e d
adult
and
out-of-position
adult
dummies a r e c o m m e r c i a l l y a v a i l a b l e
driver
and
and
c h i l d passenger.
represent
the
best
These
available
d e v i c e s f o r e v a l u a t i n g a i r b a g performance.
Occupant
Position.
The l o n g i t u d i n a l s e a t l o c a t i o n o f t h e dummies
i n t h e d r i v e r p o s i t i o n s s h o u l d correspond t o dummy s i z e , e x c e p t f o r
out-of-position
driver
p o s i t i o n may be chosen.
mid-
t o far-back
c h i l d dummies.
where
a
closer
the
s e a t i n g p o s i t i o n o r a slumped
Passenger-position
dummies
should
be
in
a
seated l o c a t i o n even f o r t h e 5 t h p e r c e n t i l e female and
The o u t - o f - p o s i t i o n c h i l d dummy should
kneeling c l o s e t o the instrument panel.
be
standing
or
6.0 REFERENCES
Ricci, L.L., ed. NCSS Statistics: Passenqer Cars. Highway Safety
Research Institute, T h e University of Michigan, Ann Arbor, June
1980. Report No. UM-HSR I -80-36.
Horsch, J.D. and Culver, C.C. "A Study of Driver Interactions with
an l nf lati ng Air Cushion." Proceedings of the Twenty-Thi rd Stapp
Car Crash Conference, 17-19 October 1979, San Diego, California.
SAE Paper No. 791029.
--
Biss, D.J. and F i tzpatrick, M.U.
"A
Systems
Approach
to
Quantifying Air Bag-Thoracic Interaction.''
Proceedinqs of the
Twenty-Fifth Conference of the American Association for Automotive
Medicine, 1-3 October 1981, San Francisco, California.
Takeda, H. and Kobayashi, S. "Injuries to Chi ldren from Airbag
Deployment.''
Eighth
International
Technical
Conference 2
Experimental Safety Vehicles, 21-24 October, Wolfsburg, Germany.
Foster, J.K., Kortge, J.D., and Wolanin, M.J. "Hybrid Ill--A
Biomechanical 1y-Based Crash Test Dummy."
Proceedi nss of
the
Twenty-F i rst Stapp Car Crash Conference, 19-2 1 October 1977, New
Orleans, Louisiana. S A E Paper No. 770938.
Wilson, R.A. and Piepho, L.L. "Crash Testing the General Motors
Ai r
Cushion."
F i fth
International ~ e c h n ical Conference 2
Exper imental Safety Veh i cl es, 4-7 June 1974, London, Engl and.
-