Thoracic Injury Assessment
for Improved Vehicle Safety
Introduction and Status per January 2012
SAE 2012 Government/Industry Meeting
Paul Lemmen, Bernard Been
David Hynd, Jolyon Carroll
Johan Davidsson
Boris Steeger
(Humanetics)
(TRL)
(Chalmers)
(Continental)
European Framework Project
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Background
 The trend of increasing performance of vehicles in consumer
rating programs is in contradiction with observations from
accident data
UK Safety Rating vs. Overall Star Rating
 This is due to several reasons among which the usage of
Hybrid III dummies developed in the late 70ties
 HIII thorax was designed to assess injury risk related to
localized hub type loading of an adult male
 State of the art restraints use load limiter belts in combination
with multi stage bags which result in a different load case and
sensitivity range
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Objectives
The aim of the THORAX project is to develop numerical and experimental
tools for the optimisation and asessment of frontal restraints for a wide
variety of car occupants (age, gender, size)
 Identification of the two most relevant thoracic injury types from
real world accident data
 Characterization of injury mechanisms and governing parameters for
these injury types, quantifying effects of user diversities like age
 Using PMHS test data and HBM simulations
 Development of hardware demonstrator consisting of a new
thorax / shoulder design implemented in THOR NT dummy
 Development of injury risk functions
 Assessment of the sensitivity of the hardware demonstrator to modern
vehicle safety systems and usability in safety system optimization
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• Benefit
estimation
• Volunteer testing
• Injury mechanisms
& assessment crit.
• PMHS testing
• Injury risk curves
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• Requirements
• Dummy concepts
• Design and
prototype
development
• Validation of
biomechanical
performance
WP4: Assessment for restraint optimization
• Real world
accident outcome
versus crash test
results
• Biomechanical
requirements
WP3: Demonstrator design
• Prioritisation of
thoracic injuries
WP2: Biomechanics
WP1: Accident Analysis
Project Structure
• Load cases and
evaluation criteria
• Testing
• Data analysis
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Timeline
2009
2010
2011
2012
2013
Accident surveys
PMHS and Volunteer Testing
NHTSA
Biom.
Workshop
Requirements shoulder / thorax complex
Injury risk curves
Dummy design &
prototyping
Includes occupant
diversity aspects
like young / old
Certification
procedures
Performance tuning
Anthr. & Biomechanical Eval.
Evaluation Restraint & loading sensitivity,
durability, R&R, handling
April 2013
end of
project
WP1 Accident surveys
4.8
Upper abdomen
9.1
6.2
18.3
AIS 2+
6.2
Lower abdomen
Other abdomen
3.5
Heart
21.6
Lung
17.5
Shoulder
Ribs
12.8
Sternum
Other thorax
0.0
7.5
6.3
Upper abdomen
3.1
7.5
Lower abdomen
6.3
30.6
Other abdomen
Heart
Lung
Shoulder
38.7
AIS 3+
Ribs
Sternum
0.0
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Other thorax
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WP1 Comparison accident cases / EuroNCAP test
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WP2 Biomechanical requirements
Summary of stifness trends (Kent et. al.)
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WP2 Injury mechanism and assessment criteria
PMHS
4kN+AB
6kN belt only
Frontal sled with belt
AB only
Static impactor
Number of Fractured Ribs
Deflection Combine
NFR
Dc
Combined deflection Dc:
ΔD
Dc = Ds + cf [(ΔD – Lc)+| ΔD – Lc|]
Ds
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Ds
ΔD
Lc
cf
= Mid sternal deflection
= Lower thorax differentail deflection
= Characteristic length
= correction factor
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WP2 Influence of rib cage geometry
Influence of rib initial angle on the deflection mechanism (adapted from Kent et al. 2005a)
a) Vertical rib cage b) Horizontal rib cage;
Thorax
Spine
fixture
Loading
direction
Marker
triplets
Cam n°4
Cam n°1
Cam n°2
Cam n°3
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WP3 Dummy concept design





Base design 2010 THOR NT with updated pelvis, femur, knee, neck installed
Include instrumentation to study proposed & existing assessment criteria
Minor updates in chest stiffness
Using updated SD2 shoulder and adjusted arms
In dummy DAS
Dc
N
F
R
ΔD
Ds
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Dummy updates
Clavicle load cell
Modified SD2
Upper arm redesign
matching UMTRI data
strain gages
WorldSID arm load cell
Biofidelity response tuning
In dummy DAS
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SD2 changes
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Chest response tuning NHSTA Corridor
 Based on NHTSA 2005 Biofidelity 4.3m/s
pendulum test corridor without muscle
tension
 Changes include
 Reduction of damping material thickness
 Ensolite foam ¼” inside jacket
 Mean upper CRUX X displacement
 3 repeats on 3 rib sets
Rib set 3 Average 54.3mm 2.88kN
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Rib set 1 Average 52.2mm, 2.86kN
Rib set 2 Average 51.4mm, 2.81kN
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Chest response in Lebarbe 2010 corridors
 Lebarbe frontal Biofidelity corridors 4.3m/s
pendulum test corridor without muscle tension,
based on external chest deflection
 (includes soft tissue compression outside
the ribs)
 Summation of CRUX X displacement and
calculated jacket compression
 3 repeats on 3 rib sets
Rib set 3 Average 58.1mm 2.88kN
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Rib Set1 Average 56.0mm, 2.86kN
Rib set 2 Average 55.3mm, 2.81kN
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Outlook
Key work items for next period
 Deliver 2 or 3 prototype dummies to partners for testing of biomechanical performance in Feb
– March 2012
 Evaluation biomechanical performance Feb – June 2012
 Development of Injury Risk curves by July 2012
 Risk functions of humans considering diversities
 Risk functions of hardware demonstrator
 Sled testing to assess dummy performance for
restraint optimisation June 2012 – Jan 2013
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Please visit www.thorax-project.eu for more information
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