Stress intensity factors for four interface-close cracks between a nonhomogeneous bonding layer and one of two dissimilar elastic half-planes

Stress intensity factors are estimated for four collinear interface cracks that are situated at the interface. between a nonhomogeneous elastic bonding layer and one of two dissimilar elastic half-planes. Tensile stress is applied normal to the cracks. The material properties of the bonding layer vary continuously from those of the lower half-plane to those of the upper half-plane. To solve this problem, two solutions are combined: the solution for two inner collinear cracks and the solution for two outer collinear cracks. To satisfy the boundary conditions for the combined solution, the differences in the crack surface displacements are expanded as a series of functions that are zero outside the cracks. The unknown coefficients in the series are solved using the Schmidt method so they satisfy the conditions inside the four cracks. The stress intensity factors are calculated numerically for the selected crack configurations. (C) 2016 Elsevier Masson SAS. All rights reserved.