断裂能与统一损伤加载面描述的混凝土本构模型  

Concrete constitutive model described by fracture energy and unified damage loading surface

作　　者：何伟[1] 谷钰 徐颖[1] HE Wei;GU Yu;XU Ying(School of Civil Engineering and Architecture,Anhui University of Science and Technology,Huainan 232001,China)

机构地区：[1]安徽理工大学土木建筑学院,安徽淮南232001

出　　处：《铁道科学与工程学报》2019年第4期1008-1015,共8页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51208005);安徽理工大学博士基金资助项目(11084)

摘　　要：构建一个混凝土损伤本构模型,研究目的为解决现有模型中存在的损伤演化、双轴强度与网格尺寸依赖性问题。基于试验观察,提出符合实际的压缩损伤演化方程;在不可逆热力学的框架下,利用当量转化应力状态的方法,在应变空间构造统一损伤加载面,以表达混凝土的双轴强度;借助断裂能对损伤阀值正则化的方法,以合理反映应变软化过程中的能量耗散,并达到消除网格尺寸依赖性之目的。采用编制的程序,对单轴与双轴加载、四点弯非比例加载等混凝土试验进行数值计算,验证了模型的合理性与有效性。研究结果表明:模型不仅解决了上述存在的问题,而且具备在较复杂应力路径下预测结构的承载力、变形及裂缝扩展的能力,可为混凝土结构的定量评价提供支持依据。This paper proposes a concrete damage constitutive model that aims to solve problems of damage evolution, biaxial strength and mesh-size dependency in existing models. Based on the experimental observation, a real compressive damage evolution equation was proposed. In the framework of irreversible thermodynamics, a unified damage loading surface was developed to describe the biaxial strength of concrete by the method of transforming stress states into an equivalent strain. The problem of mesh-size dependency was solved by the fracture energy regularization of damage thresholds, in which the energy dissipation can be evaluated properly during the strain softening. With the application of the user program, the rationality and validity of the model were demonstrated by the numerical calculation of concrete specimens subjected to different loadings, which include uniaxial and biaxial loadings, and the four-point bending with non-proportional loading. The results show that the model not only solves the aforementioned problems, but also has the ability to predict the structural load-carrying capacity, deformation and crack propagation under complex stress paths, and provides a support to the quantitative evaluation of concrete structures.

关 键 词：损伤演化 双轴强度 网格尺寸依赖性 当量转化 损伤加载面 断裂能 应变软化 

分 类 号：TU528[建筑科学—建筑技术科学]