摘要
基于非线性几何场论，探讨了有限变形稳定分析中二阶变分的重要性，考虑Ｍｏｈｒ－Ｃｏｕｌｏｍｂ退化屈服限及正交流动法则，假定屈服限取决于非局部塑性应变以模拟应变软化，弹性量仍由经典局部场确定，计算了砼材料剪切带演化导致的不同破坏型式．结果表明，计算模型对单元网格数具有不敏感性．正确加载路径和Ｈｉｌ的稳定性二阶能量准则相一致．稳定路径同网格、荷载的对称性关系不大．
Based on the nonlinear geometry field theory, the second order work of finite deformation is studied and compression failure subjected to propagation of shear bands is analysed by finite elements, using Mohr Coulomb′s plasticity with a degrading yield limit and normality, strain softening is simulated through a negative value of the plastic hardening modules. To serve as a localization limiter, the yield limit is assumed to depend on a nonlocal plastic strain which is related with microcracks or microdefects of material, while the elastic response is local. Numerical experiments show that the model is independent to the element size. The correct path is identified on the basis of Hill′s second order energy criterion for path stability, and it is found that stable response path does not correspond to symmetry mesh or loads. The results indicate the need to include checks for path stability in finite element programs for strain softening.
出处
《大连理工大学学报》
EI
CAS
CSCD
北大核心
1996年第4期483-487,共5页
Journal of Dalian University of Technology
