Breakage Prediction of Laminated Glass Using the "Sacrificial Ply" Design Concept

Laminated architectural glass has proven to be well suited for use in glazing systems that must resist wind-borne debris impacts. When the inner glass ply in a laminated window unit remains unbroken after wind-borne debris impacts on the outer glass ply, the integrity of the building envelope is preserved. A mechanics-based analytical model is developed to predict the cumulative probability of inner glass ply breakage in laminated architectural glass subjected to simulated wind-borne debris impacts on the outer glass ply. A nonlinear dynamic finite-element analysis is employed to compute stresses in each layer of the laminate due to impact. Based on the cumulative damage theory, the two-parameter Weibull distribution is used to characterize the cumulative probability of inner glass ply breakage. The analytical predictive model is calibrated using available experimental data on material parameters. Cumulative probabilities of inner glass ply breakage predicted by the analytical model are in agreement with the corresponding experimental data.