岩石、混凝土类材料断裂破坏有限元数值模拟中的有效方法

A method in finite element simulation for fracture process of rock-concrete materials

岩石、混凝土类材料断裂破坏有限元数值模拟中的网格重划,依据单元畸变和裂缝介质间的单元干涉作为网格重划判据,采用几何体重构技术把几何实体分解成能在ANSYS上实现六面体网格划分的几个部分,利用体积判断法确定新结点在旧单元的单元编号,在场量传递上采用基于解析性质的等参有限元逆变换,把旧网格场量信息传递到新网格中。本文对ANSYS进行二次开发,实现了三维网格重划,网格重划采用单元畸变和界面干涉两个判据,在网格再划分前进行几何体重构,提取变形后的点线面信息重新生成实体,充分利用AN-SYS的函数和体积判断法找到新结点在旧网格中的位置,在新旧网格间的场量传递中采用基于解析逆等参单元法。在平台上实现了三维有限元网格重划技术,最后利用方料的单轴压缩断裂模拟计算检验了传递前后等效塑性应变分布用载荷信息的变化,证明了所开发系统的正确性。

Grid remeshing in the finite element numerical simulation of the fracture and damage of rock and concrete materials is based on the unit inference between the unit distortion and fracture media as the base for the grid remeshing. The geometry body restructure technology is adopted to decompose the geometry into several parts to realize the hexahedron grid remeshing in ANSYS. Also ,the volume judgement method is used to determine the new structural nodes in the unit coding of the old units. In the field quantity transformation, the equal-parametric finite element inverse transformation based on the analytical characters is adopted to transform the field quantity information in the old grids into the new grids. This paper deals with the second development of ANSYS and the realization of 3D grid remeshing. Two judgement evidences such as the unit distortion ,and boundary surface interference are used to remesh grid. Before the grids are remeshed,the geometry body should be reconstructed; and node ,line and surface information after the deformation can be extracted to generate new entities. Accordingly,ANSYS function and volume judgement method can be fully used to find the positions of new nodes in the old grids. And at same time, the equal-parametric unit method based on the analytical inversion ean be used in the field quantity transformation between the new and old grids. Therefore, 3D finite element grid remeshing technology can be realized on the platform. Finally, the single axis compression fracture simulation computation with square materials is used to test the variation in loading information of equalplastic strain distribution, whereby proving the correctness of the developed system