The influence of grains’ crystallographic orientations on advancing short crack

A model of microstructurally short cracks that accounts for random grain geometry and crystallographic orientations is coupled with crystal plasticity constitutive model. A short crack is then inserted in the slip plane in one of the grains at the model top boundary and extended into one of the available slip planes of the neighboring grain at monotonic remote load of 0.96Rp0.2. Crack tip opening (CTOD) and sliding (CTSD) displacements are then calculated for several different crystallographic orientations and crack lengths. As the crack is contained in a single grain the crystallographic orientation of the neighboring grain can change the crack tip displacements by up to 26%, however, the displacements change by up to a factor of 10, once the crack is extended beyond the grain boundary into the next grain. Significant CTSD values were observed in all the analyzed cases pointing to mixed mode loading. Another important observation is that the random crystallographic orientations of grains beyond the first two crack-containing grains affect the CTOD by a factor of up to 4.4. This effect decreases slightly with increased crack length.