一种新的用于各向同性损伤模型的四参数等效应变

A NEW FOUR-PARAMETER EQUIVALENT STRAIN FOR ISOTROPIC DAMAGE MODEL

基于Hsieh-Ting-Chen强度破坏准则的思想,提出由于求解混凝土各向同性损伤模量的等效应变。首先通过混凝土试件材料特性以及强度试验资料来确定四参数,然后求解出由多轴应力状态下的应变退化得到的等效应变以及相应的损伤模量。对一混凝土立方体试件进行有限元分析,计算结果表明:采用该等效应变计算所得的应力应变曲线与试验曲线吻合性较好,从而说明了该等效应变的合理性,并且可说明利用该等效应变的损伤模型不但可以描述单轴应力状态下混凝土破坏的全过程曲线,而且能描述多轴应力状态下混凝土破坏的全过程曲线。该等效应变形式单一,计算简单。

On the basis of Hsieh-Ting-Chen failure criterion, a four-parameter equivalent strain for isotropic damage modulus is presented. The four parameters are determined in terms of the material characteristic of the concrete sample and the available experimental strength data. The equivalent strain transformed from strains of different stress states is calculated. The corresponding damage modulus is then obtained. A cubic concrete sample is analyzed with finite element method. Results show that the computed stress-strain curves agree with the experimental stress-strain curves and the rationality of the equivalent strain is verified. It is also showed that the damage model with the four-parameter equivalent strain can describe the compelte failure curve under uniaxial stress state and multi-axial stresses state. The equivalent strain is simple and easily obtainable.