考虑累积损伤退化的钢材等效本构模型研究

在结构抗震分析中，钢材在循环荷载作用下的一维本构关系是利用杆系模型进行结构弹塑性地震响应分析的基础。为了更准确地模拟结构在强震作用下的反应，提出能够考虑累积损伤、刚度和强度退化的钢材等效本构模型，包括骨架曲线、滞回准则以及退化特征，利用损伤控制因子数学模型对钢构件、节点及结构的损伤退化全程进行描述。根据提出的等效本构模型并利用有限元软件ABAQUS提供的用户材料子程序UMAT，采用Fortran语言开发能够进行钢框架强震作用分析的损伤退化过程计算程序。采用等效本构模型对典型试验进行模拟分析，其结果与试验结果吻合良好，充分证明钢材等效本构模型用于钢构件在强震作用下弹塑性分析的准确性及可行性。

Study on equivalent constitutive model of steel with cumulative degradation and damage

In seismic analysis of structures, one-dimensional constitutive model of structural steel subjected to cyclic loading is the basis for seismic response study. In order to simulate the seismic response more accurately, a uniaxial equivalent constitutive model of structural steel under cyclic loading was proposed, which considered cumulative damage and degradation of strength and stiffness. The model consisted of hysteretic skeleton curves, hysteretic criterion and degradation characteristic. The mathematical expressions of damage control factors were defined to describe the degradation behavior of steel members, connections and structures. According to the user subroutine interfaces UMAT provided by ABAQUS and proposed model, the program was implemented with Fortran language for simulating the damage and degradation process of the seismic analysis under strong earthquake. The simulative results of equivalent constitutive model were consistent with test curves. The proposed model was proved correct and applicable for elastic-plastic analysis of structures under strong earthquake. 