Side impact occupant response with varying positions

Injuries in side impact collisions, particularly to the thorax, are one of the leading causes of fatalities and severe injury in automotive collisions. Current side impact crash testing standards stipulate an initial position of the anthropometric test device (ATD) before impact; however, there is limited data regarding the relationship between initial ATD position, response and predicted injury. In this study, a finite element model of a full-scale side impact test was developed integrating full-vehicle, barrier and ATD models. The individual models were verified and validated, followed by validation of the fully integrated model using vehicle-specific crash tests and a broader study of late model sedan crash tests. The model predicted that the velocity profile of the impacted door was dominated by occupant interaction during contact and by the vehicle structure before and after contact with the occupant. Generally, the predicted level of injury increased when the ATD model was positioned closer to the intruding door or moved further rearwards due to interaction with the B pillar. Additionally, the door interior geometry was found to have a significant effect on the results due to the timing and location of interaction with the thorax. The thorax deflection was found to be much less sensitive to changes in position than the viscous criterion, which incorporated a velocity term in addition to a deflection. This study demonstrates the importance of occupant position on response and the possibility to enhance safety through interior door design and standoff distance.