Finite Element Modeling of Passenger-Side Small Overlap Crash Test with a View to Correlate the Right Foot Kinematics and Injury of the Hybrid-III Dummy

The Insurance Institute of Highway Safety (IIHS) introduced driver side small overlap test in 2012 and added the passenger side small overlap test in 2018 to the top safety pick plus ratings requirement. The injury of a passenger’s outboard right foot in the passenger-side small overlap rigid barrier (PSORB) test is of more concern compared to the driver’s outboard left foot in the driver-side small overlap rigid barrier (DSORB) test. The reason is, the passenger’s right foot is positioned just above the carpet on the toe pan, and is closer to the barrier during the PSORB impact event, unlike the driver’s outboard left foot in DSORB, which rests on a stiff foot rest. So it is often necessary to develop countermeasures to protect the passenger from lower leg injuries.

This paper describes a time efficient method to model the PSORB occupant sled model using finite element modeling and it also demonstrates the model’s application in the process of countermeasure development for the protection of a passenger from lower leg injuries. Finite element (FE) models of the Hybrid-III dummy, passenger airbag, knee airbag, seat belt system and other critical vehicle components and assemblies were modeled as required and integrated in the sled model. A detailed finite element model of the carpet assembly was also modeled. The paper also explains a quick and simple scaling method used to generate the Ls-Dyna material properties of the different grades of carpet foam, from its respective compression test data. The overall results of the base model and the countermeasure model were validated and confirmed with their respective internal small overlap rigid barrier tests. The proposed method of modeling the sled model has shown to be effective with respect to computational time and robust in predicting the passenger’s lower tibia axial force response for a given intrusion rate of the toe pan.