循环荷载作用下的混凝土弹塑性损伤本构模型及数值实现

AN ELASTIC-PLASTIC DAMAGE CONSTITUTIVE MODEL OF CONCRETE UNDER CYCLIC LOADING AND ITS NUMERICAL IMPLEMENTATION

该文建立了一种描述混凝土在循环荷载作用下复杂力学行为的弹塑性损伤模型。该模型借助四参数等效应变将复杂的多轴问题转换至单轴等效应变空间中求解,考虑了混凝土卸载过程中的刚度退化现象及不可逆变形。同时针对等效应变的非负特性,提出了拉压转换处理方法,从而在求解损伤变量时无需区分拉损伤和压损伤。该文提出的弹塑性损伤模型数学形式简洁,且实现过程不依赖于四参数模型,实现方法普遍适用于各类混凝土等效应变模型,通过模拟单轴循环荷载试验和Koyna大坝动态损伤过程,验证了该文模型的正确性与可靠性。

An elastic-plastic damage model describing the complex mechanical behavior of concrete under cyclic loading is established.The model uses the four-parameter equivalent strain to convert the complex multi-axis problem into the uniaxial equivalent strain space,and considers the stiffness degradation and irreversible deformation during concrete unloading.In view of the non-negative characteristics of equivalent strain,a tension-compression conversion processing method is proposed,so that distinguishing between tension and compression damage is no longer necessary when solving damage variables,and the mathematical form of the model is concise as a result.Meanwhile,the realization process does not depend on the four-parameter model,and the realization method is applicable to various concrete equivalent strain models.By simulating the uniaxial cyclic load test and the dynamic damage process of the Koyna dam,the correctness and reliability of the model in this paper are verified.