Digital Gradient Sensing Method to Visualize and Quantify Crack-Tip Deformations in Soda-Lime Glass Under Static and Dynamic Loading

Abstract

Transparent ceramic materials such as soda-lime glass pose unique challenges for visualizing and quantifying deformations to characterize fracture and failure. The relatively low fracture toughness coupled with high stiffness and elastic wave speeds create spatio-temporal challenges as deformations tend to be confined to a very small region around an almost mathematically sharp crack that tends to propagate at ∼1500 m/s. Soda-lime glass show weak birefringence to be able to use conventional photoelasticity. Interferometric methods often need elaborate coherent optics and are less attractive in terms of experimental simplicity. Digital image correlation (DIC) techniques, on the other hand, require creating speckles on the specimen surface which makes it difficult to locate a propagating crack-tip for evaluating fracture parameters precisely. Also, achieving a good measurement resolution at conventional magnifications using currently fielded high-speed cameras is difficult. Motivated by these overlapping factors, the feasibility of Digital Gradient Sensing (DGS) method to measure crack-tip deformations near stationary and growing cracks in soda-lime glass is investigated in this work. Both quasi-static and dynamic problems associated with crack initiation and growth are successfully demonstrated.