Study on the Crack Initiation in Parallel Double Cracks Based on the Generalized Maximum Tangential Stress Criterion

This study proposes a simplified method for calculating the initiation stress of parallel double cracks under compression, based on the generalized maximum tangential stress (GMTS) criterion. The stress intensity factor (SIF) of parallel double cracks is derived by considering the crack interaction mechanism and the superposition method. Using discrete element software, uniaxial compression tests were performed on parallel double crack specimens with varying geometries. The predicted results of the proposed calculation method have been validated through numerical simulations and physical model experiments. The findings demonstrate that incorporating T-stress into the calculation significantly improves the prediction of initiation stress. Crack inclination angle emerges as the predominant factor of initiation stress among geometric parameters. With relatively small crack inclination angles, negative T-stress suppresses fracture initiation, while for larger angles, positive T-stress facilitates fracture initiation.