Laminated glass plates: revealing of nonlinear behavior

A laminated glass unit which consists of two glass plies and an interlayer polyvinyl butyral (PVB) shows very complex behavior in the range of service loads. Complex behavior is due to the effect of geometry that undergoes large deflection and order difference in modulus of elasticity of glass and PVB. The nonlinear behavior of laminated glass plate is represented by five coupled nonlinear partial differential equations for lateral and in-plane displacements obtained through the variational approach. Linear algebraic equations are obtained by writing the differential equations at discrete points of glass plates by using finite difference method with central differences. Since the algebraic equations are nonlinear, the iterative technique is employed to predict the displacements through the banded matrix solver for lateral displacement and strongly implicit method for in-plane displacements. Solution will only be reached when variable underrelaxation parameter is used; otherwise solution diverges. Results denote that complex stress fields develop, and maximum stress is traveling; starting at the center, following x-axis, then moving on the diagonal and settling at the region closer to the corner at high nonlinearity level. (C) 2003 Elsevier Ltd. All rights reserved.