Characterization of Occupant Lower Extremity Behavior During Moderate-to-High Speed Rear Impacts 2013-01-0222
Injury potential to the neck has been studied extensively for
rear-end impacts. The capacity for injury to other body regions,
such as the lower extremities, has not been previously explored.
The objective of the current study was to characterize the forces
and motions experienced in the lower extremities during
moderate-to-high speed rear-end impacts.
The current study utilized publicly available rear-end crash
tests. Forty-two 50 km/hour, 20% offset, 180° barrier rear-end
impacts were used. The occupant lower extremity behavior was
analyzed for 63 ATDs, and included 42 driver's seats, 8 front
passenger seats, and 13 right-rear seat scenarios.
Three consistent events were identified during each test, in the
following sequence; 1. initial compressive femur force, 2.
secondary tensile femur force, and 3. rearward pelvis acceleration
peak. In addition to pelvic contact with the seatback, in some
cases the loading in the femur was influenced by contact between
the seat pan and the back of the tibia just below the knee. The
larger, male occupants experienced higher magnitudes of femur
compression as the vehicle was impacted from the rear. The smaller,
female occupants experienced predominately femur tension. Pelvic
acceleration data corroborated these findings. Femur forces were
consistent between both legs, indicating that there was little
torsion applied to ATDs during the rear-end crash tests.
The current study indicates that occupant anthropometry and seat
pan geometry play a significant role in loading of the lower
extremity in a rear-end impact.