混凝土弹塑性随机损伤本构关系研究

Elastoplastic stochastic damage constitutive law for concrete

结合混凝土组成特点和破坏特性分析,从细观层次上定义了受拉损伤变量和受剪损伤变量。以材料细观极限破坏应变为基本随机变量,通过引入能量等效应变,得到多轴受力时的随机损伤演化规律。结合作者提出的混凝土确定性多轴弹塑性损伤本构关系,发展了混凝土弹塑性随机损伤本构关系模型,推导给出主方向应力的均值和方差。建议模型中的参数可根据混凝土单轴受力时的应力-应变曲线试验结果,结合随机建模原理和优化算法确定。将分析得出的应力-应变关系与试验结果比较,符合良好。

Based on the composition and failure mechanism of concrete, two types of damage variables, named tensile damage variable and shear damage variable, are defined at the mesoscopic scale. Based on a previously established elatoplastic damage constitutive law and the principle of damage mechanics, a new elastoplastic stochastic damage constitutive law is proposed. By introducing the concept of energy equivalent stain, it is demonstrated that the multi-axial damage evaluation is the same as those in uniaxial stress state. The mean value and variance of stress under biaxial loading are derived. The analytical results are in good agreement with those from experiments.