Abstract：It is difficult to describe the thickness of joint with a constant in practical engineering. In order to model the mechanical behaviors of joints conveniently，a non-thickness three-node joint element is proposed on the basis of the existed three-node joint element；and the stiffness matrix of non-thickness three-node element is deduced. For it shares the same nodes with original three-node triangle element，the non-thickness three-node joint element is adopted to model crack propagation without remeshing or adjustment of the original mesh. Another advantage is that the cracked body is meshed without considering its geometry integrity and the existence of joints or pre-existed crack in the procedure of mesh generation；and then the triangular element intersected by crack or joint is automatically transformed into the three-node joint element to represent pre-existed cracks. These make the numerical simulation of crack propagation highly convenient and efficient. After the maximum strain failure criterion is chosen to determine whether the element is intersected by the extended crack or not，the extended crack is located in the model based on hypothesis of the direction of crack propagation perpendicular to the direction of the extended crack passing through the centroid of the triangle element. By simulating the marble plates with double parallel cracks subjected to uniaxial compressive loads，it is shown that the simulated results are in good agreement with the experimental results，so as to show that the present method is valid and feasible in rock crack propagation simulation.
2010, Vol. 29 
