Exploratory investigation into the post-fracture model of laminated tempered glass using combined Voronoi-FDEM approach

Abstract

It is reported that the fractured glass panels can contribute to the residual load-bearing capability of laminated glass (LG) after cracking. In order to investigate the stiffness and failure characteristics of LG at the post-fracture stage, a combined Voronoi and finite-discrete element method (FDEM) approach was proposed, which includes reconstructing the post-fracture patterns and carrying out the structural simulation of the post-fracture behaviour. The fracture morphology was determined by introducing Voronoi tessellation defined with statistical parameters such as the fragment face numbers, volume and sphericity. The interaction between glass fragments was captured with the cohesive zone model. One fractured LG block under uniaxial tension, which was taken from a triple layered LG beam with ionoplast interlayers, was modelled and validated with experimentally recorded data. Through iteration analysis, the key cohesive parameters were selected. It was then followed by investigating the influence of the fragment interaction property, the bond level and fracture morphology on the post-fracture behaviour of laminated tempered glass. Results show that the combined cohesion and frictional properties can well represent the residual interaction behaviour between fragments. The frictional property has a significant effect on the post-fracture resistance, and whereas the effect on the stiffness is not that evident. Compared to other cohesive parameters, the cohesive stiffness factors have a predominant effect on both the post-fracture stiffness and resistance. The tension stiffening effect is found to be able to provide a clear increase in post-fracture resistance, which can be up to ten times the original resistance, if the glass-interlayer interface is perfectly bonded. The progressive debonding at glass-interlayer interfaces will lead to the degradation in the loading resistance of fractured LG. A higher bond level can promote the coupling effect between interlayers and mid glass layer for providing increased load resistance after the significant debonding has occurred at the outmost glass-interlayer interface. The effect of fracture morphology on post-fracture performance is not evident in most cases except that the increase in fragment size will lead to a great stiffness growth.