Elastic and residual stresses around ball indentations on glasses using a micro-photoelastic technique

In this study, elastic and residual stresses around ball indentations on soda-lime silicate and silica glasses were measured using a micro-photoelastic imaging system and diamond indenters with different tip radii. Elastic stresses during ball indentation can be compared with classical Hertzian analytical solutions. As a result, it is found that the elastic stresses obtained from birefringence data are in good agreement with the analytical solutions calculated only from elastic moduli and Poissonʹs ratio of glass and of diamond. The residual stresses have been estimated assuming that the residual stresses satisfy the linear elastic constitutive law. These residual stresses around the indentation imprint without any cracks are compared with the estimated stresses using Yoffeʹs model and the morphology of subsequent cracks.