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为模拟混凝土滞回行为,在传统损伤力学模型中引入非线性卸载-线性重加载路径,然后采用累积耗散能量定义损伤因子,建立了基于能量耗散机制的各向异性受压损伤模型。应用该模型模拟混凝土受压往复加载试验,并进行损伤指数?的敏感性分析。计算结果显示,模型获得的应力-应变响应与试验结果具有良好的可比性,能够反映损伤导致的刚度退化、残余变形累积以及加卸载过程中的滞回耗能现象。同时,损伤指数?的取值对计算精度影响显著,必须完善其率定方法。数值算例表明,该模型可以应用于模拟受压往复加载作用下的混凝土非线性力学行为。
In order to simulate the hysteretic behavior of concrete, a nonlinear unloading-linear reloading path was introduced into the traditional damage mechanics model, and then the damage factor was defined by the cumulative dissipated energy. An anisotropic compression damage model based on energy dissipation mechanism was established. The model was applied to simulate the compressive loading and unloading test of concrete, and the damage index was analyzed. The calculated results show that the stress-strain response obtained by the model is in good agreement with the experimental results, which can reflect the stiffness degradation, residual deformation and hysteresis energy dissipation during loading and unloading. At the same time, the damage index has a significant impact on the calculation accuracy and must be improved. Numerical examples show that the model can be used to simulate the nonlinear behavior of concrete under compressive reciprocating loading.