一种裂纹扩展的通用离散元程序分析模型及其含预制双裂纹试样的模拟

An Analysis Model of UDEC for Crack Propagation and Numerical Simulations for Specimens with Double Pre-Existing Cracks

针对通用离散元程序(UDEC)提出一种新的预制裂纹扩展三角形块体分析模型,首先采用有限元商业软件将关注区域剖分成由三角形单元组成的有限元网格,再用转换程序转换成UDEC分析模型,UDEC分析模型由三角形块体和模拟块体边界的节理组成,节理包括真实的节理和虚拟节理,裂纹扩展沿虚拟节理进行,虚拟节理破裂准则采用UDEC的SS节理模型,用于模拟岩石裂纹萌生、扩展、贯通。编制了转换程序,并采用预制裂纹扩展UDEC三角形块体分析模型计算三个单轴压缩应力作用下含预制双裂纹试样的裂纹扩展算例,并对模拟结果与试验结果进行对比,模拟结果的裂纹扩展规律与已有的物理试验结果基本一致,表明该算法正确有效。

An UDEC analysis model composed of triangular blocks for crack propagation was proposed.In the proposed model,a FEM mesh of triangular elements was generated in the interesting area by a finite element software first.Then the FEM mesh was converted into an UDEC mesh by a transformation program.The UDEC mesh was composed of triangular blocks and joints on the boundary of simulated blocks.The joints included virtual joints and real joints.These virtual joint interfaces provided paths along which cracks could generate and propagate.Its failure was controlled by the model of Joint model SS which was provide by UDEC.The proposed analysis model of UDEC was used for simulating the generation,propagation and coalescence of rock cracks.The transformation program of the proposed model was developed.To verify the correctness of the algorithm,three numerical examples of test samples with double parallel pre-existing cracks under uniaxial compression were computed.The simulated results were compared with the ones of existing tests.The simulated laws of crack propagation were in accordance with the phenomena observed in the tests.Those indicated that the proposed UDEC analysis model for cracks propagation was correct and effective.