A study of the pedestrian impact kinematics using finite element dummy models: the corridors and dimensional analysis scaling of upper-body trajectories

Abstract

Pedestrian–vehicle impact experiments using cadavers have shown that factors such as vehicle shape and pedestrian anthropometry can influence pedestrian kinematics and injury mechanisms. Although a parametric study examining these factors could elucidate the complex relationships that govern pedestrian kinematics, it would be impractical with cadaver tests because of the relative expense involved in performing numerous experiments on subjects with varying anthropometry. On the other hand, finite element modelling represents a more feasible approach because numerous experiments can be conducted for a fraction of the expense. The current study examined the relationship between pedestrian anthropometry and front shape of a mid-size sedan using a PAM-CRASH model of the 50th-percentile male (50th M) Polar-II pedestrian dummy extensively validated against experimental data. To evaluate the influence of pedestrian anthropometry on response kinematics, scaled dummy models were developed on the basis of the weight and height of the 5th-percentile female (5th F), 50th-percentile female (50th F) and 95th-percentile male (95th M). Simulations of the 5th F, 50th F, 50th M, and 95th M Polar-II finite element models struck at 40 km/h by a mid-size sedan were used to generate trajectories of the head, upper thorax, mid-thorax and pelvis. In an effort to assess the validity of scaling techniques when interpreting trajectory data from vehicle–pedestrian crashes, the trajectories of the 5th F, 50th F and 95th M model were scaled to the 50th M and compared with those generated by the 50th M model. The results demonstrated non-linear behaviour of dummy kinematics that could not be accounted for with traditional dimensional analysis scaling techniques.

Keywords:

• impact
• finite element method
• pedestrian dummy
• pedestrian kinematics
• scaling