SIFs evaluation of sharp V-notched fracture by XFEM and strain energy approach

Abstract

Numerical estimation of stress intensity factors (SIFs), an important fracture mechanics parameter, for sharp V-notched structures is presented by using a new effective approach based on strain energy method associated with extended finite element method (XFEM). This approach takes advantages of both enrichments and the strain energy method. While enrichments allow the representation of notch-faces independent of the mesh, the strain energy approach is however used for the evaluation of fracture parameters as its formulation is simple and easy to implement. The present approach also avoids the use of high-order stress terms in the framework of existing least-squares method (LSM) based approach. In addition, the dependence on the position and the number of selected stress points in the sense of the LSM based approach is no longer required in the present approach. In this work, a jump enrichment function is taken for describing the intersection of notch-faces, whereas eight branch functions are employed for capturing nodes surrounding the notch-tip. Furthermore, high accurate results can be obtained by only using the first term of asymptotic stress field. Our results also show the SIFs calculated by the present method that are independent of integral paths. Several V-notched numerical examples for pure modes and mixed-mode fractures are analyzed to demonstrate the accuracy of the developed method.