应变局部化弹黏塑性分析的内嵌局部软化带模型

Elasto-viscoplastic finite element analysis for strain localization problems with embedded localized softening bands

针对岩土介质结构在破坏过程中局部化变形的问题,结合位移不连续的思想,提出内嵌局部软化带模型来捕捉结构中的局部化带。通过虚功原理建立了含局部化带影响的弹黏塑性的有限元计算模式,其中分叉理论作为局部化判断条件。模型将局部化带的形成视为一个黏塑性屈服流动过程,从而能够连续地描述局部化变形前后的力学性质。特点是计算量小、物理意义明确,可以方便地整合到传统有限元分析程序中。算例表明,计算模型是合理和有效的。

To simulate the strain localization in the failure process of geomaterials, a model with embedded localized softening bands incorporating into the idea of strong discontinuities is presented. Based on the virtual work principle, the equilibrium equations of FEM considering the effect of localization deformation are established; and the bifurcation theory is adopted as the criterion of onset of strain localization. The model can describe the mechanism of pre-localization and post-localization continuously by regarding localization as a viscoplastic flow procedure. The main advantages of this algorithm are that the model needs little amount of computation, and it has exact physical meaning compared with other methods. Furthermore, it can be incorporated into the conventional finite element analysis procedure. Numerical results have been carried out to show the validity of the model.