The plane interaction problem for a circular elastic inclusion embedded into an elastic matrix which contains an arbitrarily oriented crack is considered. Using the existing solutions for the edge dislocations [6] as Green’s functions, first the general problem of a through crack in the form of an arbitrary smooth arc located in the matrix in the vicinity of the inclusion is formulated. The integral equations for the line crack are then obtained as a system of singular integral equations with simple Cauchy kernels. The singular behavior of the stresses around the crack tips is examined and the expressions for the stress-intensity factors representing the strength of the stress singularities are obtained in terms of the asymtotic values of the density functions of the integral equations. The problem is solved for various typical crack orientations and the corresponding stress-intensity factors are given.

The cylindrical shells containing a circumferential crack subjected to axial tensaon are considered. For a uniform stress away from the crack the membrane and bending components of the stress intensity factor are obtained within the confines of an eight order linear shallow shell theory. By subjecting 6061-T4 aluminum cylinders to axial fatigue, crack propagation data are collected. Using two different empirical models the shell data are analyzed along with the plate data and it is shown that the fatigue crack propagation behavior of shells can be predicted from that of flat plates with the same material and thickness. The shells are then subjected to static rupture tests. Due to the difference in the nature of plastic deformations in shells and plates, a direct comparison of the rupture results in the two cases, smailar to that of fatigue results, does not seem to be possible.

The stress distribution in plates bonded through stepped joints is analyzed. The problem is solved under the assumption of gen eralized plane stress. A series of examples are worked out on specific plate geometries and material combinations. The effect of step ends is separately studied. As a limiting case, the solution for bonded plates with a smoothly tapered joint is given, and its results are compared with that of stepped joint.

The plane strain problem of a multi-layered composite with parallel cracks in considered. The main objective of this paper is to study the interaction between parallel and collinear cracks. The problem is formulated in terms of a set of simultaneous singular integral equations which are solved numerically. The effect of material properties on the interaction between cracks is also demonstrated.

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