应变局部化数值模拟中的网格依赖性问题研究

Research on Grid Dependence in Numerical Simulation of Strain Localization

应变局部化现象是岩土材料在工程应用中的普遍现象,当达到承载力极限状态之后岩土材料会发软化行为,由于软化行为的发生,以经典连续体理论研究局部化问题会产生网格依赖性。为了解决这一问题,本文以ABAQUS有限元分析软件为有限元分析基础平台,通过接入子程序UMAT建立模型模拟应变局部化现象。结果发现在UMAT接口下得到不同尺寸的网格划分等效塑性应变图的剪切带会随着网格密度的增加而变宽,这样我们就可以证明应用微极理论可以有效地解决网格依赖性问题,从而避免经典连续体划分网格尺寸对数据的影响。

The problem of strain localization is ubiquitous in use of geotechnical material and the geotechnical material will become soft when in state of ultimate bearing capacity. In this condition,the problem of strain localization based on classical continuum theory can cause grid dependence. To solve this problem,the ABAQUS finite element analysis software was introduced which is used to build the model of strain localization by access to the subroutine UMAT. The result shows that the shear band will be widen with the increase of grid density which indicates the micropolar theory can solve the problem of strain localization to avoid the effect of the classical continuum body grid size.