Interfacial cracking from the free-edge of a long bi-material strip

A singular stress field develops at the corner where an interface between two bonded materials intersects a traction-free edge. Depending upon the geometry of the interface-corner, the free-edge stress singularity may be of the form Hr(lambda-1) , where r is the radial distance from the corner, lambda-1 is the order of the stress singularity and H is the intensity of the singularity. The intensity H of the singularity developed at the free-edge of a long bi-material strip subjected to uniform tension is evaluated for various combinations of materials, using the finite element method. The role of the intensity H in controlling the initial growth of an interfacial edge crack embedded within the singularity zone is examined. The implications of the results for the initiation of free-edge cracks are discussed. (C) 1997 Elsevier Science Ltd. All rights reserved.