Impact-induced failure waves in glass bars and plates

Abstract

Glass bars and plates were subjected to impact loading. Failure waves were observed to propagate behind the compression waves. Material traversed by the failure wave suffers total loss of tensile strength and substantial drop in shear strength. Failure wave propagation velocities exceed the maximum crack propagation speed, but are not constant. In bars, failure wave speed range from 2.3 to 5.2 mm/μs, increasing with increasing impact velocity; in plates, the wave speed is about 2 mm/μs. The failure is ‘‘explosive’’ in nature, leading to radial expansion in bars and an increase in mean stress in plates.

Dynamic properties of ceramic materials

“…(1994) investigated surface roughness effects at the impact as a source for initiation of the faUure wave but found no influence. Spall experiments on alumina-silicate glass before and behind the failure wave were also in agreement with the results of Brar et al (1991).…”

“…In the former work, transverse stress gages provided definitive evidence for substantial increase in the transverse stress component a upon passage of the faUure wave, thus significantly reducing the shear stress T = (CT^-<7 ) /2. Brar et al (1991) also tested the tensUe strength of glass behind the initial elastic shock wave both before and behind the failure wave through the appropriate design of the spall experiments. These tests indicated a tensile strength in excess of 3 GPa for glass in front of the failure wave and nearly zero strength behind, suggesting a transition to fully comminuted material following passage of the failure wave.…”

Effects of Surface Treatment and Interfacial Strength on the Damage Propagation in Layered Transparent Armor under Impact

“…In many studies, the impacts to initiate the crack were at relatively low speeds (as low as 10 m/s) (Theocaris and Milios, 1981;Xu and Rosakis, 2003;Ravi-Chandar, 2004). However, the failure waves in glass are typically initiated by much higher impact speeds (Brar, et al, 1991;Kanel et al, 2004;Willmot and Radford, 2005). In this study, to observe crack behavior in glass, which is initiated by impact conditions more consistent to failure waves, we aim at impact velocities beyond one tenth of the crack speed.…”

Spring-block approach for crack patterns in glass

“…Understanding such fracture or fragmentation patterns and modelling them is a challenge for modern computational material science and physics [4][5][6][7][8][9][10]. Fracture and elasticity of soda-lime glass has been studied and modelled for a long time [11][12][13][14][15][16][17]. Recently it has been experimentally proven that fracture in glass is brittle [18].…”