摘要
基于有限元自动生成系统(FEPG),开发使用梯度塑性理论的有限元程序,用于解决应变软化后的网格依赖性问题。提出带阻尼因子的u-λ算法,联立求解位移方程和屈服面方程,既可同时解得位移和塑性乘子,又避免了广泛使用的应力返回算法中的应力拉回运算。在D-P准则中引入软化模量和材料内部特征长度,使本构模型能够考虑软化和梯度效应。在软化问题求解上使用阻尼牛顿法,算例结果表明,带阻尼因子的u-λ算法能够计算应变软化问题,以有限元弱形式表达的梯度塑性理论,使用一阶单元就能够得到合理的结果,在一定网格范围能够得到稳定的应力应变曲线。
Based on the FEPG platform, the finite element program using gradient plastic theory is developed to solve mesh dependence after strain softening. A μ-λ algorithm with damp factor is proposed, which can solve the equation of displacement and yield surface simultaneously. The algorithm can not only get displacement and plastic multiplier together, but also avoid the stress haul back calculation in stress return algorithm widely used in finite element solution procedures. The softening modulus and the internal character length are introduced into D-P yield function, and the constitutive model can consider strain softening and gradient effect. The damp Newton algorithm is used to calculate softening problems. The results of a case study show that the μ-λ algorithm with damp factor can be used to solve softening problems, the gradient plastic theory described by finite element weak form has no requirement of continuity, and appropriate outcome can be obtained by the first-order element, thus the mesh dependence of simulation is basically solved.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2012年第6期1094-1101,共8页
Chinese Journal of Geotechnical Engineering
基金
国家重点基础研究发展计划(973计划)项目(2011CB013600)
教育部博士点基金项目(20101103110011)
国家高技术研究发展计划(863计划)(2009AA044501)
