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Japanese accident statistics show that despite the decreasing trend of the overall traffic fatalities, more than 1,000 pedestrians are still killed annually in Japan. One way to develop further understanding of real-world pedestrian accidents is to reconstruct a variety of accident scenarios dynamically using computational models. Some of the past studies done by the authors' group have used a simplified vehicle model to investigate pedestrian lower limb injuries. However, loadings to the upper body also need to be reproduced to predict damage to the full body of a pedestrian. As a step toward this goal, this study aimed to develop a simplified vehicle model capable of reproducing pedestrian full-body kinematics and pelvis and lower limb injury measures. The simplified vehicle model was comprised of four parts: windshield, hood, bumper and lower part of the bumper. Several different models were developed using different combinations of geometric and stiffness representation.

The validity of evaluating FlexPLI peak injury measures has been shown by the correlation of the peak measures between a human FE model and a FlexPLI FE model. However, comparisons of tibia bending moment time histories (BMTHs) between these models show that the FlexPLI model exhibits a higher degree of oscillatory behavior than the human model. The goal of this study was to identify potential improvements to the FlexPLI such that the legform provides more biofidelic tibia BMTHs at the normal standing height. Impact simulations using a human FE model and a FlexPLI FE model were conducted against simplified vehicle models to compare tibia BMTHs. The same series of impact simulations were conducted using the FlexPLI models that incorporated potential measures to identify measures effective for further enhancement of the biofidelity. An additional analysis was also conducted to investigate the key factor for minimizing the oscillation of the tibia BMTH.