عنوان مقاله [English]
Numerical crack modeling is an important and basic problem for researchers. Also, Finite element has good availability in crack modeling, but there are a few problems in using standard shape functions. Meshless methods shape functions, so Discrete least square, which is used in this research, makes them more efficient with Finite element, especially in high-gradient problems. In this study, the cohesive crack theory leaving the usual numerical methods for crack behavior is investigated. In this way, doing the model conditions that do not occur crack with force out on the edges crack, and gradually become more open crack, and decrease the cohesive tension, that done zero, it means the whole crack is opening. Therefore, meshless methods use some techniques, such as visibility criterion and diffraction method, to encounter this problem. This technique is the simplest method for discontinuity modeling in meshless methods and has more compatibility with general domain discretization in meshless methods. Through engineering problems, the domain of the problem may contain nonconvex boundaries, particularly the fractured ones having discontinuous displacement fields. In such conditions, the shape functions associated with particles, whose supports intersect with the discontinuity, should be modified. One of these criteria is the visibility. In this approach, if the assumed light beam meets the discontinuity line, the shape function after the barrier will be cut. Therefore, discontinuity is applied to the geometry. In other words, the shape function of the particles, which prevents the crack or discontinuity from reaching the light beam, will be modified to amount to a zero.In this study, Cohesive Crack Theory is investigated for modeling and simulating crack behavior in DLS meshless method. This method gradually decreases the resistance of the cracked area to simulate splitting of the material. Finally, the high efficiency and accuracy of DLSM is given by comparing the DLSM results with experimental or FEM ones.