Study on Finite Element Analysis Considering Coupling of Material Failure and Structural Collapse

基于连续介质损伤力学本构方程的有限元分析，虽然还存在一些问题，但也为考虑材料破坏和结构破坏耦合的非线性分析提供了可能。本研究的目的是在已有的断裂局部分析方法研究成果的基础上，开发一个材料破坏与结构倒塌耦合分析的原型程序，建立局部耦合分析程序。在已有结果的基础上，编制了基于ASI和三维有限元的弹粘塑性分析程序。该程序通过忽略损伤的分析，给出了位移和应变历史，并确定了损伤部位。在此基础上，建立了考虑延性、脆性、蠕变、疲劳和环境损伤的弹粘塑性损伤本构方程及其积分程序。该积分器给出了损伤点的损伤历史，在此基础上可以确定蠕变和疲劳寿命。其次，建立了完全耦合方法的程序。编制了基于ASI和三维有限元的弹粘塑性损伤分析程序，建立了弹粘塑性损伤本构方程。根据计算的应力、应变、位移和损伤历史，判断材料破坏和结构倒塌。全球系统已经通过合并并行处理求解器来完成，以进行大规模分析。所开发的程序已应用于部分结构和构件的完全或局部耦合分析。通过将计算结果与相应的实验结果进行比较，验证了程序的有效性。

The finite element analysis using constitutive equations based on continuum damage mechanics has made possible nonlinear analysis considering coupling of material failure and structural collapse, although there still remain some problems. The purpose of the present study is to develop a prototype program for coupled analysis of material failure and structural collapse, based on the research results concerning local approach to fracture.The following has been done to establish the procedure of locally-coupled approach. A program for elasto-viscoplastic analysis by ASI and 3-d finite element method has been completed, based on the existing results. This program gives the displacement and strain history by the analysis neglecting damage and determines the spot to be damaged. Then, an elasto-viscoplastic damage constitutive equation and its integrator program have been developed, considering ductile, brittle, creep, fatigue and environmental damage. This integrator gives the damage history of the damaged spot, based on which the creep and fatigue life can be determined.Next, the following has been done to establish the procedure of fully-coupled approach. A program for elasto-viscoplastic damage analysis by ASI and 3-d finite element method has been completed, introducing the established elasto-viscoplastic damage constitutive equation. The material failure and structural collapse are judged, based on the calculated history of stress, strain, displacement and damage. The global system has been completed by incorporating the parallel processing solver for large-scale analysis. The developed program has been applied to the fully or locally-coupled analysis of some structures and structural members. The validity of the program has been demonstrated by comparing the calculated results with the corresponding experimental results.