Lifetime prediction of laser-precracked fused silica subjected to subsequent cyclic laser pulses

Abstract

Measurements of fatigue failure strength of laser-cracked fused silica in air at room temperature for different numbers of laser shots and laser fluences are presented. The failure-strength variability is found to be due mainly to the spectrum of crack depths. Agreement with theory suggests the incorporation of a residual term into the failure–strength equation. Due to its sign, the residual stress is of mouth-opening displacement nature at the crack. Analysis of the residual stress data shows a linear proportionality with crack depth, whereas the failure–strength is inversely proportional to the square root of the crack depth.

A New Method for Precracking Beam for Fracture Toughness Experiments

“…In general, cyclic fatigue on a notched sample is an effective approach to precrack ceramic samples, 3,4 but it is expensive and time consuming. Another widely used technique to precrack fine ceramics is the bridge‐indentation method, 5–7 which has been adopted in international standard of fracture toughness tests 8 .…”