A Comparative Study on the Fracture Prediction Capability of XFEM and FEM for Tensile Specimens

This paper aims to evaluate the capabilities of the eXtended finite element method (XFEM) against the finite element method (FEM) of damage modeling in predicting damage initiation and evolution in a tensile specimen. Although the comparison of the two mentioned techniques can be made for various specimens such as SENB, SENT, CT, and standard dog-bone specimens, a rectangular cuboid specimen made of API X65 pipeline steel with a through-thickness crack is modeled in the Abaqus finite element software in this work as a basic study. The maximum principal strain and fracture energy are respectively used as the damage initiation and evolution criteria in the initial stage of creating the XFEM model. The specimen then goes through a displacement-control loading at one end, while the other end is fixed until it fails. A similar procedure is followed for the FEM models working with either of the considered damage models in this study, namely the ductile damage model and the Johnson–Cook damage model, but with a contour integral crack so that the results of FEM could be compared with those of the XFEM. Mesh sensitivity analysis is also performed by considering different mesh types and sizes for the XFEM and FEM models.