Special criterion for crack path prediction at micro-structural scale based on dominate slip system and grain boundary

This study develops a new method for the analysis of fatigue crack growth at micro-structural scale. Proposed model was constructed based on material anisotropic properties and crystallographic planes. In this research, it has been attempted to suggest an accurate and precise criterion for the prediction of crack growth path at micro-structural scales by the study of various criteria for crack growth. For this purpose, considering fracture energy for trans-granular and inter-granular fracture as well as dominant slip planes, a criterion was proposed to predict crack growth. In the current research, fatigue tests were performed on two different alloys and the real path of the crack growth was obtained. Next, by the simulation of tested pieces through finite element software (ABAQUS) and using extended finite element method, various criteria to predict crack growth path were studied. The microstructures of both specimens tested in considered areas were modelled with an anisotropic behaviour and their crystal orientations were gained using electron-back-scattering-diffraction-pattern (EBSP) method. The results suggest the accuracy and precision of proposed criterion with minor error in single-phase alloys and major difference in two-phase alloys.

► The proposed algorithm can predict crack path at micro-structure scale.
► This algorithm is based released energy and dominate slip plane in crystals.
► Anisotropy properties of grain crystals are incorporated during crack propagation.
► The proposed algorithm is able to use different R-values for multiple phase alloys.