A Numerical Investigation on the Variation in Hip Injury Tolerance With Occupant Posture During Frontal Collisions

Objective: More than half of occupant lower extremity (LEX) injuries during automotive frontal crashes are in the knee–thigh–hip (KTH) complex. The objective of this study is to develop a detailed and biofidelic finite element (FE) occupant LEX model that may improve current understanding of mechanisms and thresholds of KTH injuries.

Methods: Firstly, the pelvis, thigh–knee–hip, and foot models developed in our previous studies were connected into an occupant lower limb model. Further validations, including posterior cruciate ligament (PCL) stretching, thigh lateral loading, KT, and KTH impact loading were then performed to verify the injury predictability of the model under complex frontal and lateral loading corresponding to automotive impacts. Finally, a sensitivity study was performed with the whole lower limb model to investigate the effect of the hip joint angle to acetabulum injury tolerance in frontal impacts.

Results: The whole lower limb model proved to be stable under severe impacts along the knee, foot, and lateral components. In addition, the biomechanical and injury responses predicted by the model correlated well with the corresponding test data. An increase in hip joint extension angle from −30 to +20° relative to neutral posture showed an increase of 19 to 58 percent hip injury tolerance.

Conclusions: The stability and biofidelity response of the pelvis–lower limb (PLEX) model indicates its potential application in future frontal and lateral impact FE simulations.