混凝土二轴受拉应力—应变关系

Relation of stress-strain for concrete material subjected to biaxial tensile stress

在分析混凝土二轴受拉破坏机制的基础上,通过选取合理的损伤变量和自由能势函数,基于不可逆力学原理,建立二轴受拉的损伤本构模型;利用损伤能释放率确定损伤演化规律,导出混凝土二轴受拉应力—应变关系的显式表达式,其参数可通过单轴拉伸试验确定;利用二轴拉伸曲线特征点条件,得到峰值应变的变化规律;与已有试验结果相比较,效果良好。

Based on the analysis of the failure feature of concrete material subjected to biaxial tensile loading from mesoscopic fracture, a rational damage variable and function of free energy are introduced. With the help of irreversible mechanics theory, a damage constitutional model of concrete under biaxial tensile loadings is put forward. Damage can be determined by damage energy release ratio and the coefficients used in the model can be uniquely determined by the experiments on the concrete subjected to monotonic axial tensile loading, the relationship of stress and strain is established. The trail and repeated are evaded. The strain at the peak under different stress ratio are also gotten by the condition of the stress-strain curve on the characteristic points. It is found that theoretical results have a good agreement with experiments＇.