Experimental and analytical study on the pre-crack impact response of thick multi-layered laminated glass under hard body impact

Abstract

This study presents a combined experimental and analytical study on the impact response of multi-layered laminated glass (MLG) under low-velocity hard body impact before glass breakage. The drop weight impact tests using repeated attempts with increasing impact velocities were firstly performed on 12 MLG panels with double PVB or SG interlayers to record the impact response, high speed fracture process. The experimental results identify that: (1) the indentation is the predominant factor for glass fracture in the examined impact scenarios; (2) the key time interval of the pre-crack impact response is within 0.6 ms. The indentation which hasn't been considered in the existing analytical works was hence introduced into the proposed nonlinear analytical model, which employed third order shear deformation theory and obtained the solutions of motion equations by a two-step perturbation method, according to the former finding. The calculated impact response based on the proposed model was validated with the experimental results within 0.6 ms based on the latter finding and showed satisfactory agreement.A parametric study was subsequently conducted to investigate the influence of factors such as the number of glass layers, glass thickness and ratio, panel size on the pre-crack impact response. The results show the increase of peak force and indentation is more sensitive to the increase of total glass thickness after the thickness reaches 24 mm and presents less sensitivity when the thickness approaches 57 mm. The variation of the glass thickness ratio has no influence on the pre-crack behavior once the total glass thickness is fixed.