Alternating method applied to edge and surface crack problems.

The alternating method, which intimately combines analytical results with numerical calculations, as applied to edge crack problems in two dimensions and surface crack problems in three dimensions, is treated. The case of a crack perpendicular to the edge of a semiinfinite material is considered. One of the crack geometries that has received continual interest in fracture mechanics is that of a semielliptical crack whose major axis lies on a stress free surface. In order to demonstrate the sensitivity of the solution to the influence of the free surface the semicircular crack problem is again treated by the alternating method.