A fast approach for predicting stress intensity factors in tortuous cracks under mixed-mode loading

Realistic crack morphologies are generally sinuous rather than straight, which brings a great challenge to capture accurately the stress intensity factors at the crack tip. In this paper, a fast approximation method for predicting stress intensity factors in tortuous cracks under mixedmode loading is proposed in terms of geometry simplification and semi -theoretical calculation. First, the finite element results show that the main and branch two -segment crack geometry approximation possesses a good capability of predicting the stress intensity factors of tortuous cracks under mixed -mode loading, whereas the simplification strategy of one straight crack cannot characterize the crack tip field of sinuous cracks. Then, an efficient semi -theoretical estimation approach is proposed to obtain the stress intensity factors of the branch crack from those of the main crack, which is validated to further reduce the computational time, resulting in a two-step accelerated operation. Moreover, the effect of main crack offset is also discussed and some recommendations are given to ensure accurate predictions within an acceptable margin of error for microstructural design or other application purposes.