DETERMINATION OF 3-DIMENSIONAL STRESS INTENSITY FACTOR USING VIRTUAL CRACK EXTENSION TECHNIQUE BASED ON SINGULAR INTEGRAL-EQUATIONS

Abstract

A numerical procedure is presented for the virtual crack extension technique based on singular integral equations of the finite-part integral to determine three-dimensional stress intensity factors for arbitrarily shaped crack problems. Basic formulation is derived for the potential energy release rate. Numerical calculations are implemented through obtaining related coefficient matrices and their derivatives with respect to the crack front nodal coordinates. Numerical results are obtained for the penny-shaped crack and the elliptical crack under uniform and linearly varying normal tractions in an infinite body, and show satisfactory agreement with exact solutions. The method presented here can be used to obtain auxilliary solutions for the Schwarz alternating method to solve more general three-dimensional crack problems of the finite body.