Dimple fracture simulation of fracture specimen under different constraint conditions

Three kinds of fracture specimens are tested under different constraint conditions. By the SEM (Scanning Electron Microscope) observation, it is shown that the toughness of fracture Surface is different from each other largely. This is the effect of constraint condition. The dimple fracture process is Simulated by the finite element method using Gurson's constitutive equation, and the crack tip stress fields are obtained. The distibutions of stress triaxiality qualitatively agree with the experimental results. The J-R curves obtained also qualitatively agree with those of experiments, and the fracture surface roughness is well simulated.