岩土材料应变局部化的有限元分析方法

采用有限单元法分析岩土材料的应变局部化时经常会遇到单元尺寸敏感性问题和网格锁定问题。自适应网格技术能够有效地解决网格锁定问题,但仍然无法克服计算结果对单元尺寸的依赖性,尽管在一维情况下被证明是可行的。复合体理论(均匀化理论)和弱非连续有限元方法可以成功地解决岩土材料的单元尺寸敏感性问题,在一维情况下两类方法实际上是一致的。本文针对岩土材料应变局部化的有限元新技术所存在的若干问题进行了详细的讨论,并给出了有关算例。

Strain localization problems in geomaterials using finite elements

Significant difficulties in finite element simulations of strain localization problems are associated primarily with the issues of mesh-size and mesh alignment dependencies.Adaptive remeshing technique proposed by Zienkiewicz and the first author has been considered as one of effective approaches for circumventing the problem of mesh alignment dependence.The computational results obtained by adaptive remeshing are still often sensitive to mesh size,although such techniques can be proved to be effective in the one-dimensional cases.Homogenization procedure introduced by Pietruszczak and the first author and weak discontinuity approach have shown their capabilities to overcome the difficulty arising from the mesh-size dependence.It must be pointed out here that those two methods are essentially identical at least in one-dimensional problems.In this paper,detailed discussions on the aforementioned approaches used in the finite element modeling for localized deformation in geomaterials are given.Several two-dimensional applications are shown finally.