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A detailed finite element model of the human pelvis and lower extremities was developed based on anatomic data from the NIH-sponsored Visible Human Project. Anatomic slices were digitized and converted through a multi-step process into a fully hexahedral element finite element mesh. A procedure was also developed to rotate the femur about the center of rotation of its head to provide various degrees of hip flexion/extension and abduction/adduction. A preliminary series of simulations was conducted using LSDYNA to investigate the effects of hip position on the contact area within the joint and the associated stress levels in the surrounding bony structures. Results suggest that the risk of femoral neck fracture increases as the amount of hip abduction increases.

A new anthropomorphic test device (ATD) is being developed by the US Army to be responsive to vertical loading during a vehicle underbody blast event. To obtain design parameters for the new ATD, a series of non-injurious tests were conducted to derive biofidelity response corridors for the foot-ankle complex under vertical loading. Isolated post mortem human surrogate (PMHS) lower leg specimens were tested with and without military boot and in different initial foot-ankle positions. Instrumentation included a six-axis load cell at the proximal end, three-axis accelerometers at proximal and distal tibia, and calcaneus, and strain gages. Average proximal tibia axial forces for a neutral-positioned foot were about 2 kN for a 4 m/s test, 4 kN for 6 m/s test and 6 kN for an 8 m/s test. The force time-to-peak values were from 3 to 5 msec and calcaneus acceleration rise times were 2 to 8 msec.