Evaluation of lower limb injury mitigation from inflatable carpet in sled tests with intrusion using the Thor Lx 2001-06-0092
Real-world crash investigations have suggested that lower limb
injury risk is increased with the occurrence of toepan intrusion in
a frontal collision. In order to more closely evaluate the effects
of different modes of toepan intrusion, a rotational and
translational intrusion device was built for the test sled at the
University of Virginia. Sled tests were performed at a velocity of
56 km/h with a belted Hybrid III occupant and a simulated knee
bolster and steering wheel air bag. Lower limb injury risk measures
were obtained with Hybrid III and Thor Lx dummy lower
extremities.
Dummy response variables of interest included tibia axial and
shear loads, tibia bending moments, ankle rotations and foot and
tibia accelerations. The tests were conducted with no intrusion and
with a translational intrusion with a peak deceleration of
approximately 175 g's with 14 cm of translation. A lower limb
injury mitigation device, the Inflatable Carpet (InCa), was used in
comparison tests to evaluate its efficacy in reducing loads
imparted to the lower limb for varying initial foot positions.
Results from the tests indicate that intrusion causes an increase
in tibia axial load mainly due to acceleration, and ankle
dorsiflexion mainly due to translation, both potentially increasing
injury risk. The InCa resulted in large load reductions in the
clearance position, and also reduced dorsiflexion angles. The
design of the air bag used in this study was optimized for use in
settings with toepan rotation in addition to translation. Occupant
response was sensitive to a number of factors, such as knee bolster
design and Inflatable Carpet geometry, which have to be taken into
account in the tuning of the InCa design. Additional tests were
conducted in a static setting, with various out-of- position lower
limb configurations. These tests did not identify any potential
harmful effects of accidental InCa deployment.
Author(s):
Rodney W. Rudd, Jeff R. Crandall, Erik Hjerpe, Yngve Håland
Affiliated:
University of Virginia Automobile Safety Laboratory, Autoliv Research
Pages: 16
Event:
International Technical Conference on Enhanced Safety of Vehicles
Related Topics:
Impact tests
Frontal collisions
Airbag systems
Foot
Injuries
Crashes
Vehicle occupants
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