Isogeometric analysis of stress intensity factors for curved crack problems

Abstract

Abstract An isogeometric analysis method is developed for the stress intensity factors in curved crack problems. In the isogeometric approach, NURBS (Non-Uniform Rational B-Spline) basis functions in CAD system is directly utilized in the response analysis, which enables the seamless incorporation of the higher continuity and the exact geometry such as curvature and normal vector into the computational framework. In mixed-mode curved crack problems, the precise evaluation of crack-face integral is essential to compute the precise stress intensity factors, especially for the path-independency of interaction integral. The CAD-based exact representation of tangential and normal vectors facilitates to exactly define a local coordinate system at the crack-tip, and accurately evaluate the crack-face integral. Compared with the standard finite element approach, a higher continuity of stress and strain fields are expected in the interaction integral domain. Various numerical examples of curved crack problems are presented to demonstrate the accuracy of developed isogeometric method through the comparison of both exact and finite element solutions.