CALCULATION OF STRESS INTENSITY FACTORS BY SENSITIVITY ANALYSIS WITH RESPECT TO CHANGE OF BOUNDARY-CONDITIONS

A boundary integral equation formulation for design sensitivity with changing boundary conditions is developed using the material derivative concept and the direct differentiation method. The change of boundary conditions is described using the tangential component of the velocity field. An arbitrary rigid body motion is considered to remove singularities that occur from differentiation of the fundamental solutions, thus avoiding the difficulties associated with their numerical integrals. The formulation is then applied to calculate stress intensity factors as a new method of computational fracture mechanics. As a check on the accuracy of the formulation, numerical examples are given including various cracks in a plate under uniform tension. Excellent accuracy is observed as compared with analytic results.