Finite Element Analysis Of Bone Fracture Of Lower Extremity In Car-Pedestrian Accidents

In car-to-pedestrian accident, pedestrian have a high injury risk due to lack of protection from car impacts. The lower extremities of pedestrian are the most frequently injured parts of human body. In this paper, finite element method (FEM)was used to study the biomechanical responses and injury mechanism of pedestrian lower extremities in traffic accidents. The FEM model was used also to predict the risk of bone fracture of the lower extremities. The results from this study can forms a background knowledge to improve the safety performance of passenger car bumper system for protection of pedestrian lower extremities in traffic collisions.An existing FE model of lower extremity (HBM-lower limb) was improved and used in this study. The FE model of pedestrian lower extremity is based on the anatomy of human lower extremity. This model composes of skeleton system and ligament system. In this model, femur and tibia and fibula are modeled by using solid elements. The rest parts are modeled by using shell elements and linear spring-dumper elements.In this paper, the program LS-DYNA was used. The model was validated by simulating the tibia three-point bending test and lower extremity sheering and bending tests. The results from simulations were compared with the results from the biomechanical tests. By using this model, lower extremity impact in different loads was simulated. The influence of impact location to lower extremity injuries was analyzed and discussed.The results indicated that the risk of lower extremity injury could be reduced by lowering bumper height. This model enabled to study the biomechanical responses and injury mechanism of the lower extremities. It was suggested for further improvement of this model in terms of the soft tissue and better rupture mechanism. This model has good bio-fidelity and will contribute to the research on lower extremity injury mechanisms and development of injury protection device.