平面应力状态下混凝土的本构模型

在混凝土的非线性有限元分析中,需要模拟混凝土的应力-应变关系,根据混凝土单轴受压典型曲线特征,采用Hermite插值给出了混凝土单轴受压条件下具有明显几何意义的σ-ε关系,以给定的混凝土强度准则为基础,给出了混凝土平面应力状态下的增量本构关系,利用特征屈服半径的概念将初始屈服面、后续屈服面以及破坏面表达为一个统一的形式;特征屈服半径的概念将平面应力状态下混凝土的本构关系与单轴受压状态统一起来,使问题的处理一体化,计算结果与试验结果的比较,验证了本构模型的可靠性。

Constitutive model for concrete under plane stress

The constitutive relations of the concrete are required for the nonlinear finite element analysis. According to the characteristics shown in the typical experimental curve , the stress|strain relation of the concrete under the uniaxial compression is obtained by means of Hermite interpolation . It is of an obvious geometrical meaning. Based on the strength criterion given, incremental constitutive equations for the concrete under the biaxial stresses have been established. By introducing the concept of the characteristic yielding radius, the initial subsequent yielding surface and the failure surface are expressed in a unified formula, furthermore the states of the concrete under the uniaxial and the biaxial stresses are also unified, which makes the problems into a whole. Finally its theoretical predictions are compared with the experimental results, which demonstrates a good conformity.