A high-fidelity numerical approach for dummy head-windshield contact interactions

In a frontal pedestrian-vehicle collision, the head of an adult pedestrian normally impacts the windshield region of a vehicle, which is the main source of severe head injury. The contact interactions between a dummy head and a windshield have been regarded as a component test in various New Car Assessment Programmes (NCAPs). Currently, it remains a challenging task to accurately simulate such complex contact interactions. In sharp contrast to the common method using a dummy head-only model, this work presents a high-fidelity numerical approach simulating the full process of dummy pedestrian-vehicle collision to consider the influence of other body parts on head kinematics. In doing so, the impact contact interactions between a dummy head and a windshield can be simulated in a more realistic way. Towards this end, a pedestrian-vehicle finite element model is established, where a Hybrid-III dummy model and a cutoff vehicle model are considered. An intrinsic cohesive zone model (CZM) is advocated to account for both of the two main failure patterns, i.e., glass fracture and glass/polyvinyl butyral (PVB) debonding, arising in the windshield under impact. A simulation procedure, that switches a simplified windshield model to an enriched one with cohesive elements (CEs) when the pedestrian head contacts the windshield, is introduced, so as to reduce computational cost. The effectiveness of the pedestrian-vehicle model and the simulation procedure is demonstrated by comparing numerical results with those in literature and those computed via LS-DYNA. Finally, parametric studies are carried out to numerically investigate the effects of vehicle speed, pedestrian standing angle, pedestrian standing position, and pedestrian gait on pedestrian kinematic behavior and head injury.