Dynamic assessment of through-cracked laminated glass elements under repeated impacts

Assessing the post-breakage performance of fractured laminated glass (LG) is challenging due to the complexity of damage progression. This study investigates the dynamic behavior of small-scale, through-cracked LG elements composed of two layers of annealed glass, bonded with different interlayers. Using a three-point-bending setup, the specimens were subjected to ten repeated hard-body impacts. To quantify the residual bending stiffness as a function of damage severity, experimental modal analyses were conducted via roving hammer tests, prior to and following each impact. The fundamental vibration frequency was utilized as preliminary diagnostic parameter. Experimental frequency estimates, supported by simplified finite element (FE) numerical modelling, reveal markedly distinct degradation patterns for the tested configurations.