According to the calculated stress intensity factors, the results of stress intensity factor analysis show that ki is the largest, much larger than type II and type III stress intensity factors. Therefore, the crack is mainly mode I crack, and serious opening displacement occurs at the beginning of crack propagation, but there is also a little sliding displacement. According to the stress intensity factor, the main mode of crack is mode I, supplemented by mode II and III.
After the crack judgment is completed, the crack propagation analysis is started. The first step of crack propagation is to set the maximum circumferential stress criterion, and the second step is to add material related Paris parameters. In the third step, the increment of crack propagation is set to be 0.2mm, and finally the crack propagation is carried out.
After the crack begins to propagate for the first time, FRANC3D will automatically identify the crack in the sub model and mesh the crack sub model; The second crack propagation is performed and the stress intensity factor at the crack tip is obtained; After the second crack propagation, FRANC3D will mesh automatically, and then carry out the third crack propagation. Such a process is repeated until the fracture state is reached, or the automatic expansion is set until the set termination condition is reached.