Prediction of crack propagation and fracture in residually stressed glass as a function of the stress profile and flaw size distribution

Engineered stress profile (ESP) glasses are noted for narrow strength distributions and the potential for stable growth of multiple surface cracks under applied tensile stress. This behavior depends on the interaction of the surface flaw size distribution with the residual stress profile in the material. In this work, several surface preparation methods were used to produce a range of flaw size distributions in soda lime silica glass specimens. Two ion exchange processes were then performed on these specimens to produce ESP glass. For each condition, crack growth behavior and fracture strength were experimentally observed. Residual stress profiles resulting from each ion exchange process were measured with an optical technique. These stress profiles were used to calculate stress intensity factors as a function of crack geometry, using a weight function method. Crack growth and fracture strength predictions based on these stress intensity factors were compared to experimental data, resulting in good agreement in most cases.