中文摘要：

为了充分发挥有限元与颗粒离散元各自的优势,提出了一种由有限元转化为颗粒流的方法。数值模型首先用较粗的有限元网格进行离散,并在单元上引入连续介质本构模型。力学计算开始后,实时跟踪各单元的应力状态。一旦某单元的应力满足Mohr-Coulomb准则或最大拉应力准则,删除该单元,同时创建具有一定数目、随机分布且微嵌入的颗粒簇。其后,该单元所在区域的非连续变形及失稳断裂由颗粒簇演化获得。各颗粒的质量、材料参数、速度、位移、接触力等信息根据插值从有限元单元中继承。为了实现有限元与颗粒流接触面的耦合计算,引入了点-棱（二维）及点-面（三维）接触模型,通过法向及切向弹簧实现接触力的计算。颗粒球与有限元板的碰撞分析、单轴压缩、岩石切割等案例展示了上述方法的精确性及合理性。

英文摘要：

To take the advantages of both the FEM and the particle DEM methods, a procedure is proposed to transit the FEM into the DEM. In this procedure, the domain of concern is first discretized into a certain number of coarse FEM elements, and the behavior of each element is characterized by using a continuum constitutive model. During simulation, the stress state of each element is tracked for each time step. Once if the stress state of an element satisfies either the Mohr-Coulomb criteria or the maximum tensile stress criteria, the element is deleted and immediately replaced by a cluster of particles, which are randomly distributed and slightly interpenetrated. As such, the response of the deleted element is fully described by this cluster of particles. The particle properties of the cluster, including mass, material properties, velocity, displacement and contact force, are all inherited from the deleted element by using an interpolation method. To realize the simulation coupling FEM and particle DEM, the point-edge（2D） and point-face（3D） contact models are introduced, and the contact forces are calculated using normal and tangent numerical springs. Numerical examples such as the impact of a particle ball onto a slab, the uniaxial compression and rock cutting, are provided to illustrate the capability of the proposed method.