Study effects of pre-collision factors on pedestrian kinematics and injury responses

This paper is proposed to numerically study effects of impact angle, impact position, posture, and height of pedestrian on kinematics and injury responses. A finite element human body model was employed to develop vehicle-pedestrian crash simulations. A 50th-percentile adult male (AM50) in standing and walking postures were considered. The human body model was set to impact a passenger car at its corner and at the centre of the bumper with 90° and 45° impact angles. Eight simulations were conducted. Since Asian pedestrians are usually smaller than their American counterpart, this paper also investigated the effect of pedestrian height by scaling down the AM50 model to a typical Asian height and weight. Four additional simulations were conducted. It was found that the impact position at the vehicle front-end affected the head impact location. Impacting at the corner position had high chance of head impacting the A-pillar which led to severe head injury. Impact angles also showed influence on the kinematics and injury response. Knee bending moment for the 45°impact angle was smaller than the 90°impact angle while bone bending was not much different. The 90° impact angle exhibited lower head injury criteria than the 45° impact angle. The results also revealed that different pedestrian postures led to some different kinematics with respect to the head impact location and speed. Pedestrian in walking posture exhibited more severe head and thorax injuries while the standing posture showed higher bending moment of the lower extremities. Finally, the human body model with Asian height exhibited higher risk of head injury than using AM50 data. The results of this study will be useful to vehicle manufacturers in designing a front structure of the vehicle and pedestrian protection systems.