Crack Branching in Soda-Lime Glass: Optical Measurement of Precursors Using Digital Gradient Sensing

Abstract

AbstractThe dynamic fracture of soda-lime glass (SLG) involves crack branching, underlying mechanics of which is not yet fully understood. Addressing this issue using full-field optical techniques is challenging due to severe spatio-temporal requirements as crack speeds in this material reach 1500 m/s or more and is accompanied by highly localized nanoscale deformations. Recent work by the authors have shown that transmission-mode Digital Gradient Sensing (DGS) method is capable of overcoming these challenges to visualize crack-tip fields over large regions of interest and quantify fracture parameters associated with each of the phases of crack growth event in SLG plates. In this work, time-resolved stress gradient measurements of two different SLG geometries subjected to dynamic wedge-loading are performed to quantitatively visualize single and cascading branch formations. The precursors of crack branching event are identified from the optical measurements leading up to the first and/or successive branch formations. These precursors are based on crack velocity, stress intensity factors, higher order coefficients of the asymptotic crack tip fields, and a non-dimensional parameter involving a combination of these measured quantities.Key wordsDynamic fractureSoda-lime glassCrack branchingDigital gradient sensingTransparent structures