关键词: 有限元法/离散元法(FEM/DEM), 单元劈裂法, 自适应技术, 裂纹扩展

Abstract: In order to simulate initiation and propagation of rock crack, Munjiza proposed FEM/DEM coupling analysis method. Because the cracks extend along the cell boundary, i.e. the propagation of crack has mesh-dependency problems. For the purpose of a better crack propagation shape, dense initial mesh is needed. To solve the above problems, the FEM/DEM adaptive analysis methods of local unit dynamic splitting is proposed to overcome mesh-dependency problems of crack morphology based on FEM/DEM coupling analysis method. However, very fine elements will not be necessary in this procedure; and dynamic splitting can take place in the local elements containing crack tips with increasing loading, which provides more possible expansion direction for subsequent expansion of the crack. Cracks are not confined along edges of elements. Cracks can grow in more natural way, which can be extended inside the element and more smoother. While original FEM/DEM coupling method divides very dense mesh, the proposed method can divide initial mesh relatively sparsely; so the cost of calculation is low. Finally, the numerical example of Brazilian disc indicates that the proposed method overcomes the dependence of crack morphology on the initial grid.

Key words: finite element method/discrete element method (FEM/DEM), method of element splitting, procedure of adaptive elements, crack growth