Experimental Study on Three-Dimensional Internal Crack Propagation in Brittle Materials With Combined Defects

This study investigates the fracture behavior of brittle solids with combined defects by prefabricating internal cracks in glass materials using three-dimensional internal laser-engraved crack (3D-ILC) technology. The results of physical and numerical experiments indicate that under biaxial compression, cracks first appear on the surface of the cavity, followed by the propagation of the prefabricated cracks. During propagation, these two cracks attract each other, ultimately leading to crack coalescence. As the geometric distribution of the combined defects changes, the propagation direction of the prefabricated cracks deflects to varying degrees as is to be expected. The failure process of the specimens with combined defects was a mixed-mode I–II–III fracture. This research provides experimental and theoretical references for the study of crack propagation in rock materials containing combined defects.