Three-Point Bending Crack Propagation Analysis of Beam Subjected to Eccentric Impact Loading by X-FEM

When analyzing a failure or crack propagation problem by FEM, there are the following challenges to solve. (1)It’s necessary to make element boundary match to the failure surface or the crack surface. (2)The failure shape and the crack propagation direction depend on the mesh. (3)It’s necessary to express a singularity of crack tip field. (4)Both of the crack propagation path criterion and the crack propagation speed criterion are required. To overcome these challenges, Nishioka, et al. developed the moving finite element method which repeats mesh subdivision with crack propagation and [1] succeeded to analyze a dynamic crack propagation problem with a high accuracy . On the other hand, erosion technique generally is used to express the failure in fracture analysis by general-purpose FEM cord including LS-DYNA. However, it is difficult to evaluate it exactly from point of view as shown above. [2] In contrast, the extended finite element method; X-FEM is expected as technique to overcome the above problem to be able to express crack propagation by adding a function to express a discontinuity and singularity of the crack to the shape function of the finite element instead of expressing the crack explicitly. Therefore, in this study, we applied FEM with eroding technique and X-FEM for three-points bending of crack propagation problems of the beam subjected to eccentric impact loading. Then, evaluated problems and the effectiveness of each technique through the comparison with the experiment result.