Study of damage in windshield glazing subject to impact by a pedestrian’s head

The windshield is one of the major components in a vehicle that determines the injury to a pedestrian’s head. Therefore, it is critical to study the damage to windshield glazing so as to promote the protection structure for pedestrians. In this paper, classical plate theory in combination with the Green strain and the von Karman assumption is used to develop constitutive relations to describe the large-deformation behaviour of composite poly(vinyl butyral) (PVB) windshield glazing. Previous test data are used to verify the constitutive relations model. A three-dimensional finite element model describing the impact between the head of a pedestrian and the windshield is constructed to investigate the mechanism underlying the damage to the windshield. Three main crack patterns of composite PVB glazing are proved to exist: a circumferential crack, a spider-web crack, and a plastic crack. Therefore, this paper studies the effect of different impact conditions and windshield structures on the damage to the windshield glazing and on the head injury. The results show that a high speed will cause not only a high initial impact speed but also the equivalent impact weight which can increase both the probability and extent of head injury. Furthermore, the study proves that the PVB film greatly improves the protection for a pedestrian in a traffic accident and it is advised that more layers of PVB film are introduced into the windshield to protect pedestrians better.