We tackled the question how long must a crack be to be able to apply classical fracture mechanics models. We developed a model with a large number of randomly sized, shaped and oriented grains with a crack inserted into a surface grain. We estimated the standard deviation of crack tip opening displacements (CTOD) due to the random crystallographic orientations of the grains surrounding the crack. We showed that even at crack length equivalent to 7 grains the standard deviation of the crack tip opening displacements due to the surrounding crystallographic orientations is still 7.3%.
COBISS.SI-ID: 2173827
A planar model of a polycrystalline aggregate was employed in this paper to arrive at new results. The results include the simulated mesoscopic strain fields, including the development of shear bands, and a sensitivity analysis of the equivalent macroscopic response at various sizes of polycristalls smaller than Representative Volume Element (RVE). Columnar grain structure is assumed in a planar (plane strain) finite element model. The presentation of results includes the comparison of aggregate responses obtained assuming 2-D only and full 3-D random grain orientations.
COBISS.SI-ID: 218506