Abstract

This paper considers an anti-plane moving crack between a functionally graded coating and a homogeneous substrate. The shear modulus and the mass density of the FGM coating are considered for a class of functional forms for which the equilibrium equation has an analytical solution. The problem is solved by means of singular integral equation technique. Results are plotted to show the effect of material nonhomogeneity and crack moving velocity on the crack tip field. The angular variation of the near-tip stress field is of particular interest, and the crack bifurcation behaviour is also discussed. It is shown that choice of an appropriate fracture criterion is essential for studying the stability of a moving crack in FGMs. Different fracture criteria could give opposite predictions for crack stability. It seems that the maximum cleavage stress near the crack tips is a reasonable failure criterion for a moving crack in FGMs.

Keywords

functionally graded materials, coatings, fracture mechanics, moving crack

Authors