Three-Dimensional Cracks: An Introduction

Abstract

In the previous chapters the solution of two-dimensional and axi-symmetric crack problems have been examined in detail by employing the technique of distributing strain nuclei (in the form of dislocations or dislocation dipoles). Although the two-dimensional crack models give a good approximation to crack geometries encountered, most defects or cracks existing in engineering materials and structural components are three-dimensional in character. This chapter will therefore be devoted to the analysis of three-dimensional crack problems. Basically the same strategies developed in the previous chapters will be followed, by distributing strain nuclei over the crack faces. As will transpire, the strain nucleus which will be employed here to formulate the solution to three-dimensional crack problems is an infinitesimal dislocation loop, instead of a straight line dislocation or a dislocation dipole used for two-dimensional and axi-symmetric crack problems, though a close relation between them can be established.