基于双标量理论的混凝土高温损伤模型

摘要

基于双标量的各向同性损伤理论,提出了高温作用下的混凝土弹性本构模型.根据Moil-Tanaka理论,建立了适合于混凝土材料的宏观损伤变量与细观孔隙度之间的关系;基于混合物理论,推导了混凝土在荷载、温度作用下孔隙度的变化规律,得到了混凝土高温作用下的损伤演化方程;理论计算结果与试验结果对比表明,损伤演化方程可以很好的反应混凝土的高温损伤.模型通过孔隙度的变化,综合考虑了力学荷载和温度荷载对损伤的影响,为混凝土的高温损伤模型研究提供一种新的方法.%A new elastic damage model for concrete subjected to high temperatures is presented in this paper based on double scalar isotropic damage theory.The relationship between the macro-damage variables and the micro-porosity of the concrete was derived based on Mori-Tanaka method;Based on theory of mixtures,the evolution equation of porosity subjected to load and temperatures is deduced and the damage evolution equation can also be obtained.A comparison of theoretical and test results show the damage evolution equation is rational.The reflection of load and temperatures is considered through the evolution of porosity,it provides a new method to study the damage model for concrete subjected to high temperatures.