基于微-细观机理的混凝土疲劳损伤本构模型
THE FATIGUE CONSTITUTIVE MODEL OF CONCRETE BASED ON MICRO-MESO MECHANICS
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摘要: 该文致力于混凝土疲劳损伤发展机理的微细观解释. 以速率过程理论为基础,通过考虑裂纹断裂过程区中的水分子动力作用,在细观尺度上建立了具有物理机理的疲劳损伤能量耗散表达式. 结合细观随机断裂模型,以宏观损伤力学为框架,建立了疲劳损伤演化方程. 通过数值模拟,计算了单轴受拉时的疲劳损伤演化以及不同加载幅度下的疲劳寿命. 与相关试验结果的对比显示出该文模型能够很好地表现混凝土材料的疲劳损伤演化过程.Abstract: In this paper we focus on the explanation of concrete fatigue damage on micro-meso-scales. Base on the rate process theory, the physical meaningful expression of fatigue damage energy dissipation is built on meso-scale with considering the dynamic effect of water molecules in the fracture process zone. Combing with meso-stochastic fracture model, the fatigue damage evolution equation is acquired under the framework of macro-damage mechanics. The fatigue damage evolution curve and fatigue life under various loading levels in uniaxial tension are computed with numerical simulation and the comparisons with test results show that the model proposed here gives a correct description of fatigue damage evolution process of concrete.