Effect of muscle contraction on the lower limb response in low speed car-pedestrian lateral impact: simulations for a walking pedestrian

This paper investigates the effect of muscle contraction on lower extremity injuries for pedestrian walking posture in a car-pedestrian lateral impact at low speed. The full body model, pedestrian model with active lower extremities (PMALE), which was configured in a symmetric standing posture, has been repositioned in the walking posture. Finite-element simulations have then been performed using the PMALE in walking posture and front structures of a car. Two impact configurations, i.e. impact on the right and left legs, have been simulated. Two pre-impact conditions, that of a symmetrically standing pedestrian representing a cadaver and an unaware pedestrian, have been simulated for both the impact configurations. Stretch-based reflexive action was included in the simulations for an unaware pedestrian. It is concluded that (1) with muscle contraction, the risk of ligament failure decreases whereas the risk of bone fracture increases; (2) in lateral impacts, Medial Collateral Ligament (MCL) could be considered as the most vulnerable and Lateral Collateral Ligament (LCL) as the safest ligament; and (3) for a walking pedestrian, Posterior Cruciate Ligament (PCL) would be at a higher risk in the case of impact on the rear leg, whereas Anterior Cruciate Ligament (ACL) would be at a higher risk if car strikes the front leg.