Estimation of Pelvis Injuries and Head Impact Time using Different Pedestrian Human FE Models

A logistic regression analysis of accident cases in the NASS-PCDS (National Automotive Sampling System-Pedestrian Crash Data Study) database clearly shows that pedestrian pelvis injuries tend to be complex and 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, and the gender and age of the pedestrian. Adult female models (50^th %ile female AF50: 161 cm and 61 kg; 5^th %ile female AF05: 154 cm and 50 kg) were developed by morphing the JAMA 50^th %ile male AM50 and substituting the pelvis of the GHBMC AM50 model. The fine-meshed pelvis model thus obtained is capable of predicting pelvis fractures. Simulations conducted with these models indicate that the characteristics of pelvis injury patterns in male and female pedestrians are influenced by the hip/BLE height ratio and to some extent by the pelvis bone shape. A previously developed six-year-old (6YO) child pedestrian model and the newly developed models were used to estimate the head impact time (HIT) for a typical SUV fitted with an active pop-up hood system. The results indicate that instead of the 6YO child pedestrian, an AF05 pedestrian is the target pedestrian percentile for satisfying the Euro-NCAP test protocol requirements for SUVs. A female human body model with a pelvis fracture option showed a longer HIT than that of the pelvis model without a fracture option. The results of numerical simulations coincided well with the results of the statistical analysis.