A new legform impactor for evaluation of car aggressiveness in car-pedestrian accidents

The goal of the present study was to develop a new legform impactor that accurately represents both the impact force (i.e., force between the leg and impacting mass)and leg kinematics in lateral impacts simulating car-pedestrian accidents. In its development we utilized the knee joint of the pedestrian dummy called Polar-2 (HONDA R&D) in which the cruciate and collateral ligaments are represented by means of springs and cables, the geometry of the femoral condyles is simplified using ellipsoidal surfaces, and the tibial meniscus is represented by an elastomeric pad.

The impactor was evaluated by comparing its responses with published experimental results obtained using postmortem human subjects (PMHS). The evaluation was done under two conditions: 1)impact point near the ankle area (bending tests),and 2)impact point 84 mm below the knee joint center (shearing tests). Two impact speeds were used: 5.56 m/s and 11.11 m/s.

The responses of our impactor were reasonably close to those observed in the experiments using PMHS in terms of both impact force and leg shearing displacement (i.e., relative displacement between the leg and thigh at the knee joint level in a lateral direction). In the shearing tests, the peak values of leg shearing displacement were greater than 30 mm.