Search Results

Laminated glass consisting of two soda lime glass plies adhered by a polyvinyl butyral interlayer (PVB) is used for automotive glazing. This paper describes the application of a dynamic, nonlinear finite element method to investigate the failure modes of a laminated glass subjected to low-velocity impact with a spherical headform. Crack type, crack location and crack initiation time are evaluated using the maximum principal stress and J-integral criterion. Failure occurred due to flexural stresses and not bearing stresses. The first crack always initiated at the center of the outer impacted ply and PVB interface, and later on the exterior surface of the inner ply. The PVB thickness and velocity of impact had little or no effect on the first crack initiation.

Various foam models are developed using LS-DYNA3D and the model predictions were validated against experiments. Dynamic and static stress-strain relations are obtained experimentally for crushable and resilient foam materials and used as inputs to the finite element analyses. Numerous simulations were carried out for foams subjected to different loading conditions including static compression and indentation, and dynamic impacts with a rigid featureless and a rigid spherical headform. Comparisons of the results obtained from different foam models with test data show appropriate correlations for all the cases studied. Parametric studies of the effects of tensile properties of foam material and the interface parameters on foam performance are also presented.