Post-failure behavior of laminated glass beams using different interlayers

An experimental investigation is presented on the mechanical response of progressively damaged Laminated Glass (LG) beams assembled with modified polyvinyl butyral (PVB)-based interlayers (DG41). While it is known that ionoplast interlayers significantly improve the load-bearing capacity and residual strength of damaged LG elements, limited experimental data are available on recently developed compounds such as DG41. The role of interlayers increases with the damage level within LG elements: when glass plies break, LG stiffness and strength depend on the ability of the interlayer to couple intact glass plies and fragments of shattered ones. For damaged LG beams, the consequences of the increases in volume of a broken tempered glass plies are discussed. In particular, the interlayer activates two competing effects on the undamaged glass plies affecting the residual carrying capacity: a positive “tension-stiffening” over time and the tendency of tempered glass to expand when fractured that triggers “negative” stress/strain fields in undamaged glass plies.