Biomechanical analysis of thorax-abdomen response of vehicle occupant under seat belt load considering different frontal crash pulses

Purpose: The purpose of this work was to understand the biomechanical response and injury risk of thorax and abdomen of vehicle front seat occupants caused by seat belt load under different frontal crash pulses. Methods: A vehicle-seat-occupant subsystem finite element (FE) model was developed using the a assembly of vehicle front seat and seat belt together with the THUMS (Total Human body Model for Safety) AM50 (50th% Adult Male) occupant model. Then the typical vehicle frontal crash pulses from different impact scenarios were applied to the vehicle-seat-occupant subsystem FE model, and the predictions from the occupant model were analyzed. Results: The modeling results indicate that the maximum sternal compression of the occupant caused by seat belt load is not sensitive to the peek of the crash pulse but sensitive to the energy contained by the crash pulse in the phrase before seat belt load reaching its limit. Injury risk analysis implies that seat belt load of the four crash scenarios considered in the current work could induce a high thorax AIS2+ injury risk (>80%) to the occupants older than 70 years, and a potential injury risk to the spleen. Conclusions: The findings suggest that control of the energy in the first 75 ms of the crash pulse is crucial for vehicle safety design, and thorax tolerance of the older population and spleen injury prevention are the key considerations in developing of seat belt system.