Research Program to Investigate Lower Extremity Injuries

Biomechanical response and injury tolerance of the lower extremities is being investigated at the University of Virginia. This paper presents the experimental and simulation work used to study the injury patterns and mechanisms of the ankle/foot complex. The simulation effort has developed a segmented lower limb and foot model for an occupant simulator program to study the interactions of the foot with intruding toepan and pedal components. The experimental procedures include static tests, pendulum impacts, and full-scale sled tests with the Advanced Anthropomorphic Test Device and human cadavers. In these tests, the response of the lower extremities is characterized with analogous dummy and cadaver instrumentation packages that include strain gauges, electrogoniometers, angular rate sensors, accelerometers, and load cells. An external apparatus is applied to the surrogate's lower extremities to simulate the effects of muscle tensing. Sled tests are performed with a toepan device that subjects the lower extremities to rotational, longitudinal, and vertical intrusion pulses typical of offset vehicle crashes. Based upon data from the component and full-scale sled tests, a risk function which correlates observed cadaver injury with dummy responses is developed.