Modeling of the Failure Behaviour of Windscreens and Component Tests

Windscreens from laminated safety glass (glass/PVB interlayer/glass) are widely used in automotive structures and have an important contribution to the stiffness of the vehicle. The stiffness of the laminated safety glass is dominantly given by the two layers of glass while the PVB interlayer serves to fix glass splinters to avoid serious injuries of the passengers in a collision. A finite element model for modelling the failure behaviour of laminated glass windscreens is presented. A special element structure with three layers (shell/volume/shell) has been used to model the laminated glass windscreen. A fracture criterion for brittle fracture based on the maximum principal stress (σI ≥ σc) was applied to model the fracture behaviour of glass. The PVB interlayer was modelled with both a linear elastic and a hyperelastic material law without damage. The critical fracture stress of glass was determined by fitting the failure force measured from static bending tests on laminated glass windscreens. The transferability of the fracture criterion and the corresponding parameter was checked by simulating two different loading cases of the component tests.