Effect of Vehicle's Front End Profile on Pedestrian's Lower Extremity Injury Pattern in Real World and Verification by Large Male FE Human Model

Logistic regression analysis for accident cases of NASS-PCDS (National Automotive Sampling System-Pedestrian Crash Data Study) clearly shows that the extent and the degree of pedestrian's lower extremity injury depend on various factors such as the impact speed, the ratio of the pedestrian height to that of the bonnet leading edge (BLE) of the striking vehicle, bumper to knee ratio, bumper lead angle, age of the pedestrian, and posture of the pedestrian at the time of impact. The pedestrian population is divided in 3 groups, equivalent to small-shorter, medium-height and large-taller pedestrian with respect to the “pedestrian to BLE height-ratio” in order to quantify the degree of influence of lower leg injuries in each group. Large adult male finite element model (95th percentile male: 190 cm and 103 kg) was developed by morphing the Japan Automobile Manufacturers Association (JAMA) 50th percentile male. Lower extremity of developed large male was fine meshed to predict the fractures accurately. A car model was systematically morphed to create different designs having various front end profile dimensions. Large male model with fine meshed lower extremity was impacted against those series of morphed vehicle models. Effect of vehicle's front end profile on lower extremity bone injuries was evaluated by accident analysis of PCDS data and their trends are verified by FE simulation of large male HBM. The results from accident analysis had good correlation with those obtained from FE simulations.