Numerical representation of fracture patterns and post-fracture load-bearing performance of thermally prestressed glass with polymer foil

Abstract

Glass can be thermally prestressed to enhance its load-bearing performance and tensile strength for civil engineering constructions. In such applications, the glass is thermally treated (internal stress state) and polymer foils/interlayers are applied to generate a laminate with a higher resistance to bending (out-of-plane loading) in case of fracture. In this contribution, a thermally prestressed glass panel with polymer foil as a backsheet is investigated as a special configuration of safety glass. In its post-fracture state, the polymer foil still provides a minimum structural integrity. Commonly, the post-fracture load-bearing performance of such polymer-glass assemblies is experimentally assessed by large scale tests related to high costs and testing time. In this research, an approach is presented to numerically assess the post-fracture load-bearing performance (bending) of such a fractured glass panel. The approach is based on A) digital image processing of the fracture pattern of three glass samples, B) the generation of a quadtree finite element (FE) mesh, C) the use of prismatic polyhedral FE to efficiently represent glass fragments in the quadtree FE mesh and D) cohesive elements with a nonlinear traction-separation law (TSL) for finite separation to represent the structural effect of the polymer foil during the post-fracture state.