摘要
提出了耦合细尺度上基于离散颗粒集合体模型的离散单元法(DEM)和粗尺度上基于Cosserat连续体模型的有限元法(FEM)的连接尺度方法(BSM)以研究颗粒材料的力学行为.采用Cosserat连续体模型和FEM模拟的粗尺度域覆盖全域,而采用离散颗粒集合体模型的DEM模拟的细尺度域仅限于需特别关注材料微结构演变和非连续变形行为的局部区域.对这两个区域间的界面提出了适当的界面条件及其实施方案.通过采用适当的连接尺度投影算子,空间离散的粗、细尺度耦合系统多尺度运动方程具有解耦的特点,并且允许分别求解,因而也允许分别采用不同时间步长对粗、细尺度进行计算,可极大地提高BSM的计算效率.二维地基数值算例结果说明了所陈述方法的可应用性,以及相对基于Cosserat连续体模型的FEM和基于离散颗粒集合体模型的DEM的优越性.
The bridging scale method（BSM） that couples the discrete particle assembly modeling with discrete element method（DEM） and the Cosserat continuum modeling with finite element method（FEM） in both fine and coarse scales,respectively,is proposed to study the mechanical behaviors of granular materials.The coarse scale domain,modeled with the Cosserat continuum and numerically simulated with the FEM,covers the whole medium concerned;while the fine scale one,modeled with the discrete particle assembly and numerically simulated with the DEM,is limited to a localized region,where the material microstructure,discontinuous deformation behaviors and their evolutions are needed to pay particular attentions.The interfacial condition between the two domains is present and the scheme for its numerical implementation is proposed.By using a proper bridging scale projection operator,two decouped sets of motion equations of the combined coarse-fine scale system are allowed to solve with two separate solvers and to use distinct time step sizes,which will greatly enhance the computational efficiency of the BSM.The numerical results for a 2D example problem of the soil foundation illustrate the applicability and performance of the proposed method,and its advantages as compared with the FEM based on the Cosserat continuum modeling and the DEM based on the discrete particle assembly modeling.
出处
《力学学报》
EI
CSCD
北大核心
2010年第5期889-900,共12页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然科学基金(90715011
10672033)
国家重点基础研究发展计划(973)(2010CB731502)资助项目~~
