Elasto-plastic fracture modelling of 3-D metallic structure using XFEM

Abstract

ABSTRACT The structural integrity of metallic structures/components depends on their fracture behaviour. These materials respond non-linearly in nature under applied service conditions. Therefore, the prediction of accurate fracture parameters under elasto-plastic conditions is cumbersome. This work consists of an accurate and robust computational approach to predict elasto-plastic fracture parameters for a 3-D cracked domain. A mesh-independent novel computational method known as the Extended Finite Element Method (XFEM) is employed to predict elasto-plastic fracture parameters (J-integral). Both material and geometrical non-linearity have been incorporated into the computational approach. The Ramberg-Osgood material model has been incorporated to characterise the non-linear relationship of stress-strain. The material non-linearity is modelled by von-Mises yield criteria along with isotropic strain hardening. Elastic predictor plastic corrector algorithm is used for modelling non-linear stress-strain behaviour. The geometric non-linearity is modelled by an updated Lagrangian approach. Few numerical cases are presented to show the efficacy of the proposed computational approach. To incorporate the proposed approach, an inhouse MATLAB code has been developed. The obtained numerical results are displayed in the form of convergence study, J-integral, and deformation contours. Additionally, a component-based problem, i.e. surface crack in a spur gear, has been analysed to show the robustness of the proposed methodology.