Crack growth simulation of multiple cracks systems applying remote contour interaction integrals

The paper presents a numerical procedure for the calculation of crack loading quantities related to multiple cracks systems in plane structures based on the theory of linear elastic fracture mechanics. Path-independent interaction integrals (I-integrals) are used to avoid special requirements concerning crack tip meshing and contour size. A straightforward implementation of the I-integral enables the accurate calculation of stress intensity factors considering multiple cracks and strongly curved crack faces. In contrast to the classical application, loading quantities are calculated efficiently by choosing large integration paths including all crack tips. A separation of the total interaction energy with respect to stress intensity factors allocated to specific crack tips is achieved by appropriately choosing the auxiliary fields. Numerical examples of crack propagation simulations under critical and subcritical conditions are presented and the resulting crack paths are verified by comparison with those obtained from conventional methods.