Propagation and interaction of two parallel internal cracks under tensile stress in cuboid glass

The behavioral characteristics of multiple cracks are important factors leading to material failures. However, to date, the fracturing and interactions of internal cracks have received minimal research due to the challenges in creating real internal cracks in brittle solids without incurring any damages to the surfaces. Therefore, this study investigated the fracturing processes and interactions between two parallel penny-shaped internal cracks under tensile stress conditions using both experimental and numerical simulation methods. Glass was used as the experimental material in this study. The results showed that the vertical spacing d between the two cracks was an important factor which affected both the crack interactions and the failure loads. When the d was small, attraction and coalescence occurred between the two cracks. However, when the d was large, the fracturing was observed to occur in the plane where one crack was located. A crack propagation arc appeared in all of the examined specimens. The loads of the crack initiation and the strength levels of the specimens were determined to be positively related to the crack spacing d. It was found that the larger the d was, the larger the crack initiation load and tensile strength values would be. In the present study, the crack paths in the numerical simulations based on the MTS criterion were determined to be consistent with the experiment results.