On the HDD analysis of micro crack initiation, propagation, and coalescence in brittle materials

Abstract

Micro cracks in brittle materials seem to be the main cause of their breakage under various loading conditions. In the present paper, the numerical and experimental analyses of initiation, propagation, and coalescence of micro cracks have been investigated. A higher order displacement discontinuity method with special crack tip elements is used to estimate the mixed-mode (mode I and mode II) stress intensity factors near the tips of the preexisting micro cracks. The propagation direction of micro cracks is estimated by using the maximum tensile stress criterion which is based on the linear elastic fracture mechanics concept. Some experiments are also carried out to observe the crack coalescence and crack propagation path of micro cracks. These experiments also verify the validity of the numerical results. For example, the crack initiation angles obtained numerically are compared with the corresponding experimental results showing the validity of these numerical results. Some of the numerical and experimental results are also compared with the corresponding results given in the literature.