## Abstract

- (1)
The indeterminacy encountered when (in plane strain or stress), the direct BIE formulation of a thin ellipse is used to represent a crack when the ellipse degenerates to a line. A similar feature occurs in three-dimensional problems. We describe this degeneracy more fully later in this introduction, attempts to remove this difficulty are described in Section 3.3.

- (2)
The existence of a stress singularity at a sharp crack tip which requires accurate boundary element modelling in order to obtain reliable numerical results. Such modelling is described in detail in Section 3.4. Note however that, although a square root stress singularity occurs in the elastic analysis of a crack in a homogeneous medium, other stress singularities may be encountered (for a review see Atkinson

^{1}).

## Keywords

Stress Intensity Factor Boundary Element Method Energy Release Rate Stress Intensity Factor Boundary Integral Equation## Preview

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