Characterizing the flexural/damage behavior of Aluminosilicate glass at low/high loading rates: Application of SHPB for mode-1 loading of laminated glass

Understanding the flexural response of monolithic and laminated glass is essential for making informed choices while selecting glass for varying applications. That is because the behavior of monolithic and laminated glass may not necessarily be the same under certain loading conditions and assessing their performance differences helps in determining their suitability for specific applications. The presented work is aimed at quantifying the flexural/damage behavior of monolithic and laminated glass. Quasi-static and dynamic flexural tests were conducted on monolithic and laminated glass in mode-1 loading while maintaining identical loading and support interfaces. In the first phase, quasi-static flexural tests were performed, and results were quantitatively compared by two approaches: Effective Thickness Approximation (ETA) and the theory of Thick Sandwiched Beams (TSB). Experimentally observed deflection corroborated with both the analytical methods; the absolute error remained less than 2.5 % and 0.5 % for ETA and TSB, respectively. Importantly, failure of the laminate was witnessed at approximately 50 % lower force compared to its monolithic counterpart, which was attributed to the span length of the specimen and the interlayer's shear stiffness. Fractography was performed to elicit Aluminosilicate glass's mirror constant and fracture surface energy, as 1.86 MN/m^3/2 and 3.95 J/m², respectively. In Phase-2, Dynamic flexural tests were conducted on a novel Electromagnetic Split Hopkinson Pressure Bar (ESHPB), and an experimental–numerical coupled approach was introduced to analyze the results. The results established that the adverse effects of shorter span length on the flexural strength of laminated glass are mitigated, primarily due to the viscoelastic response of the interlayer. The reprographic images attributed the fracture of monolithic and laminated glass specimens solely to the bending-induced stresses.