Experimental Investigation of Prescribed Crack Patterns and Post-Fracture Behaviour in Laminated Safety Glass

Abstract

Laminated safety glass (LSG) maintains structural integrity after fracture due to the adhesion of glass fragments to the polymer interlayer, providing a residual load-bearing capacity that is crucial for safety in architectural and vehicular applications. Understanding this post-fracture behaviour is essential for ensuring structural safety, yet the influence of crack geometry on the mechanical response of fractured LSG has not been systematically investigated so far. This study investigates the influence of distinct crack constellations on the residual stiffness of fractured LSG using pre-fractured small-scale specimens tested under controlled tensile loading. To this end, a methodology is introduced that enables the controlled generation of prescribed crack patterns in thin laminated glass (2 mm + 0.76 mm + 2 mm). Based on this approach, the role of cracks oriented parallel to the principal tensile loading direction is systematically examined. In addition, stochastically generated Voronoi-type fractured crack configurations are investigated and compared with regular patterns by matching the cumulative crack lengths projected onto the loading direction. The experimental results indicate that the common assumption that cracks running parallel to the tensile loading direction do not contribute to a reduction in tensile stiffness must be critically reconsidered. Furthermore, the chaotically fractured specimens exhibit a high degree of reproducibility. The results establish a fundamental understanding of how geometric parameters of fracture patterns govern global stiffness and load transfer in fractured laminates subjected to tensile load, thereby supporting the reliable prediction of LSG residual performance in safety-critical applications.