Head protection characteristics of windshield during pedestrian-vehicle accident

The windshield is one of the most critical vehicle components in terms of pedestrian safety; however, it has not been thoroughly and systematically investigated through combined experimental and theoretical analysis. Firstly, this paper carries out quasi-static experiments on Material Testing System (MTS) and dynamic experiments on Split Hopkinson Pressure Bar(SHPB) and new tests data are obtained. Results indicate that Polyvinyl butyral (PVB) laminated glass behaves nonlinearly and rate-dependently under various strain rates, from 1 × 10^-5s^-1∼6 × 10³ s ^-1. Thus, a constitutive model covering all strain rates is proposed to describe the constitutive behavior of PVB laminated glass and it fits well with the experimental data. Further, the constitutive relation is embedded into the 3D finite element model of windshield. With the definition of four governing factors and two evaluation indicators, the head protection characteristics of windshield are numerically studied. It is noticeable that current windshield may fail to provide sufficient protection to pedestrian's head during pedestrian-vehicle accidents and necessary countermeasures should be taken to enhance the pedestrian protection ability. Besides, explicit quantitative expressions are established to give designers quick safety design guidance. Results may shed lights on the windshield safety design and pedestrian protection research.