Three-dimensional simulation of crack extension in brittle polycrystallinematerials

Crack extension resistance in brittle polycrystals was investigated from th e viewpoint of three-dimensional microcrack evolution. Even in the case of macroscopically two-dimensional cracks, inhomogeneous distribution of micro scopic stress along the crack front gives rise to three-dimensional structu res of extended crack surfaces. Numerical simulations of macroscopic crack extension were carried out, which showed that three-dimensional distributio n of grain-by-grain thermal stress leads to a significant increase in the c rack extension resistance. It was concluded that three-dimensional interpre tation on the microscopic inhomogeneity is necessary for the correct compre hension of macroscopic crack extension behavior in brittle polycrystals. (C ) 2000 Elsevier Science Ltd. All rights reserved.