Notch effect on potential fracture behaviours of a cracked solid under mixed Mode-I/II loading

Based on the energy-based fracture modelling for multiple-crack initiation, present work quantitatively explains how a blunted crack tip affects the fracture behaviours. If a crack tip is blunted, the original crack becomes a notch. When a notch under mixed Mode-I/II loading is narrow enough, the asymptotic singular stress fields are approximately true, which implies that the six energy-based driving forces distributed along the boundary of a notch tip still exist. These energy-based driving forces will drive the notch tip to fracture, including the notch kinking and branching. As the crack tip is blunted, the sifting constraints between the sub-boundaries of original crack tip are weakened. Therefore, the potential fracture configurations for an original ideal crack tip will change. The notch effect mainly cover that all energy-based driving forces parallel to the crack surface have the potential to trigger the crack tip to fracture, synthesis and decomposition of the adjacent energy-based driving forces, and the fracture toughness for notch branching and extension increases after a crack-tip blunting. Two application examples of present fracture modelling have been carried out. The predicted fracture behaviours are consistent with the fracture behaviour in the experiments, which should refresh the understanding on the notch tip kinking and branching for the notched solids under mixed Mode-I/II loading.