LAUSR

The main failure mechanism of brittle materials occurs through the initiation and propagation of cracks. Researches involved with various loading modes and material defects have been widely investigated to control the stability of subsurface crack. However, no detailed fracture mechanics analysis has been published to understand the direct effect of process parameters on crack growth. In this paper, taking the plastic deformation below the tool and the intrinsic line defect located at the plastic zone boundary into account, a mechanical and numerical study of the fracture mechanics is proposed from the perspective of process parameters in grinding of brittle materials. The stress intensity factors are computed in detail to analyze the various impacts of process parameters and tool geometry on the subsurface crack propagation. Results indicate that the main fracture mode for median crack induced in brittle material grinding is opening rather than shear. Although the residual stress caused by plastic zone plays an important role in fracture behavior, the effect of dislocations cannot be ignored as well. In addition, the starting point of opening fracture is also affected by grinding parameters and tool geometry. A small grinding speed, a sharp large tool, a large table speed and grinding depth will lead to strong anti-shielding effect on mode I crack propagation and strong shielding effect on mode II crack propagation. The results can be used to provide guidance for the development of controlled spalling technology which enables the reuse of cracking substrate.