Abstract: The stress intensity factor is an important mechanical parameter for controlling the behaviour of the brittle fracture toughness and fatigue crack growth. In the past researches, methods and formulas for solving K-factor of various cracked components are complicated. The expressions of K_Ⅰ and K_Ⅱ are both different fitting expressions, which have a limited application. A semi-analytical model with a simple form and general applications to predict K-factor for components with mode Ⅰ-Ⅱ crack is proposed based on energy density equivalence principle, and parameters can be calculated by a few FEA calculation. The result shows that K-factor predicted by the semi-analytical model agrees well with the literature result and the FEA result, and the model provides important theoretical foundation to studies on the brittle fracture toughness and fatigue crack growth.

Key words: energy density equivalence principle, stress intensity factor, semi-analytical model, modeⅠ-Ⅱcrack