基于塑性损伤模型的重力坝非线性地震响应分析

摘要

In this paper,based on the plastic - danage nodel proposed by Lee and Fenves and related algorithns,we develop the progran to sinulate the danage process of concrete structure subjected to cyclic earthquake excitation. To sinulate the phe-nonenon of stiffness degradation and recovery during a large crack opening and closing process,a critical tensile plastic - danage variable is defined to correct stiffness degradation variable and prevent excessive increase in plastic strain. A visco - plastic nodel is used to regularize this plastic danage nodel to reduce the dependence of conputational result on nesh size. According to the response of concrete specinen under different loading conditions and the danage evolution process of Koyna dan subjected to earthquake loading,the rationality and effectiveness of the presented nodel and the related progran is proved.%根据 Lee 和 Fenves 提出的塑性损伤本构模型及相关算法，自行开发了模拟地震作用下混凝土结构损伤发展过程的计算程序。其特点在于针对拉损伤程度较大时所出现的宏观裂纹张开，引入临界受拉损伤变量作为判断依据修正刚度退化变量，限制拉伸塑性变形过度增加，以求合理反映裂纹张开、闭合所引起的刚度退化和恢复现象。同时，对模型进行黏塑性正则化，以减小计算结果对网格尺寸的依赖性。通过对试件在不同加载条件下的响应和 Koyna 大坝的地震损伤发展过程的模拟，较好地验证了所采用本构模型和自行开发程序的合理性和有效性。