混凝土单轴应力—应变关系的平行杆系模型

Model of Uniaxial Stress-Strain Relation of Concreteby Multi-Parallel-Bars System

从断裂力学角度对混凝土在单轴受压时的破损机理和软化特性进行了分析,指出劈裂裂纹面的失稳弯折是其主要原因.建立了一种平行杆系模型用以描述上述机制,并据此提出了损伤指标.针对几种普通强度等级的素混凝土和相应的约束混凝土确定了平行杆系模型的具体参数,并对比分析了不同混凝土的杆系分布特征及产生机理.

The mechanism of damage and softening of concrete under uniaxial compression is analyzed in the light of fracture mechanics; it is found that the bending and breaking due to the buckling of the cleaving crack surfaces are the major causes. A multiparallelbars model is developed to describe the above mechanism and a related damage index is initiated based on this model. The model parameters of some prime and confined concrete of ordinary strength grades are determined. Comparison of bars distribution features and their causes are made among different kinds of concrete.