Experimental observation and numerical analysis of cracking phenomena in adjoining Vickers indentations on glass surface

Generation and propagation of radial cracks around two adjoining Vickers indentations on soda-lime glass were dynamically observed by means of a newly developed apparatus. In particular, it was remarked how the separation distance between two indentations influenced the probability of crack nucleation and propagation. The stress distribution in the region surrounding the adjoining indentations was analyzed with a three-dimensional finite element analysis. It is shown that the induced stress is strongly influenced by the preexisting stress made by the neighboring indentation. These stress field interactions results in change of the severity of the stress value especially in the region between the adjoining indentations. The interacted stress value changes with the separation distance. The analytical result is able to explain the experimental observations.