Optimal Specifications for the Advanced Pedestrian Legform Impactor.

This study addresses the virtual optimization of the technical specifications for a recently developed Advanced Pedestrian Legform Impactor (aPLI). The aPLI incorporates a number of enhancements for improved lower limb injury predictability with respect to its predecessor, the FlexPLI. It also incorporates an attached Simplified Upper Body Part (SUBP) that enables the impactor's applicability to evaluate pedestrian's lower limb injury risk also with high-bumper cars. The response surface methodology was applied to optimize both the aPLI's lower limb and SUBP specifications, while imposing a total mass upper limit of 25 kg that complies with international standards for maximum weight lifting allowed for a single operator in the laboratory setting. All parameters were virtually optimized considering variable interaction, which proved critical to avoid misleading specifications. The results from this study can be used to construct physical aPLIs that are expected to be used in future car-to-pedestrian crash safety testing programs worldwide.

Development of a biofidelic flexible pedestrian legform impactor.

The European Enhanced Vehicle-Safety Committee (EEVC) has proposed a test procedure to assess the protection vehicles provide to the lower extremity of pedestrians during a collision. This procedure utilizes a legform impactor developed by the Transport Research Laboratory (TRL). However, the TRL Pedestrian Legform Impactor (TRL-PLI) is composed of rigid long bones (cannot simulate the bone flexibility of the human) and rather stiff knee joint. The differences lead to a lack of biofidelity of the TRL-PLI, i.e. unnaturally stiff responses are observed. This study develops a biofidelic Flexible Pedestrian Legform Impactor (Flex-PLI) that can simulate human bone flexibility and human knee joint stiffness properly. The Flex-PLI can also measure many of the injury parameters, long bone strains at multiple locations, knee ligament elongations, and the compression forces between the femoral condyles and tibial plateau in comparison to the TRL-PLI. This paper presents the detailed specifications and measurement systems of the Flex-PLI, and also describes the results of biofidelity evaluation for the thigh, leg, and knee joint of the Flex-PLI in component level.