Experimental study on the gradual fracture of layers in multi-layer laminated glass plates under low-velocity impact

TL;DR

This study investigates how multi-layer laminated glass plates respond to low-velocity impacts, revealing fracture patterns, impact energy thresholds, and the role of interlayers, providing valuable data for model validation.

Contribution

It offers new experimental insights into the impact behavior of multi-layer laminated glass, focusing on fracture initiation, energy thresholds, and the effects of interlayer stiffness.

Findings

Fracture initiates in outer glass layers around impact point.

Partially fractured samples can withstand higher forces than initial fracture forces.

PVB interlayers act as stiff shear connectors across impact heights.

Abstract

Through pendulum impact testing on suspended samples, we demonstrate the effect of the multi-layer layout on the low-velocity impact response of laminated glass plates consisting of three or four glass layers and PVB interlayers. Non-destructive tests proved the repeatability and the consistency of performed experiments. Destructive tests revealed significant differences in impact energies and breakage forces leading to glass fracture for individual specimens under impacts of increasing height. Nevertheless, the fracture consistently initiated in outer glass layers around the impact point and vibrations of partially fractured samples exhibited similar first natural frequencies. Partially fractured samples also withstood in many cases higher contact forces than those leading to the fracture of the previous glass layer, and PVB interlayers provided a stiff shear connection between glass layers for all impact heights. Altogether, our experimental results provide comprehensive information on the pre-fracture, fracture, and post-fracture response of laminated glass, suitable particularly for validating computational models for multi-layer glass samples under low-velocity impact.