Experimental and Numerical Simulation of Crack Propagation in Sandstone by Semi Circular Bend Test

Fracture toughness investigation provides a perception of required minimum stress to commence the existing crack in material. Over the years, many approaches are developed for estimation of fracture toughness of rock in Mode I. Among them, semi-circular bend (SCB) test is most popular due to easier sample preparation. In this study, sandstone rock was collected from two locations (Jhanjra and Kusunda mines) for conducting SCB test. This test is conducted by varying the notch length (16, 18, 20, 22mm) and fracture toughness and fracture energy are determined. Further, fracture toughness is determined with different models based on tensile strength of rock. In ABAQUS, XFEM approach with cohesive zone model is applied to investigate the crack growth in rock by SCB test. The results of the numerical analysis are compared with the laboratory results and it was found that fracture toughness decreases with increase in notch length as the applied load has to travel less distance to reach the tip of the notch.