混凝土单轴受压本构模型及其应用

通过一个细观模型,从损伤的角度解释混凝土在压应力作用下应力-应变关系的非线性和应变软化,根据等效应变假设和损伤力学基本原理,建立了单轴受压混凝土的弹塑性损伤本构模型,可导出已有单轴受压本构关系,并能反映混凝土的刚度退化和卸载后的残余变形;提出一类损伤函数和塑性变形经验表达式,利用应力-应变曲线特征条件和优化算法确定模型参数;与已有受压试验结果相比较,结果吻合良好.

A Generic Constitutional Model for Concrete Materials in Axial Compression and Its Application

There are many equations for the stress-strain curve of plain concrete under axial compression.The nonlinear performance of the curve and strain softening are analyzed through a meso-damage model.Based on the hypothesis of strain equivalence and theory of damage mechanics,an elastoplastic damage constitutional model of concrete subjected to uniaxial monotonic loading is established.Existing stress-strain relations of concrete under the loading can be deduced from the model.The stiffness degradation and plastic strain can be shown in the model.The function of damage and plasticity strain is given,and the coefficients used in the model can be determined by the condition of the curve on the characteristic points and method of optimization.It is found that theoretical curve has a good agreement with the experiments.