基于断裂能的混凝土弹塑性损伤本构模型和尺寸效应研究  

Study on Elastic-plastic Damage Model and Size Effect of Concrete Based on Fracture Energy

作　　者：江婷 杜效鹄[1] 沈振中[2] 张宏伟[2] 许峙峰 JIANG Ting;DU Xiao-hu;SHEN Zhen-zhong;ZHANG Hong-wei;XU Zhi-feng(China Renewable Energy Engineering Institute,Beijing 100120,China;College of Water Conservancy and Hydropower Engineering,Hohai University,Nanjing 210098,China;School of Civil Engineering and Architecture,Wuhan Institute of Technology,Wuhan 430074,China)

机构地区：[1]水电水利规划设计总院,北京100120 [2]河海大学水利水电学院,江苏南京210098 [3]武汉工程大学土木工程与建筑学院,湖北武汉430074

出　　处：《水电能源科学》2024年第1期79-83,共5页Water Resources and Power

基　　金：国家重点研发计划(2022YFC3005403);西藏自治区科技重大专项课题(XZ202201ZD0003G)。

摘　　要：为研究混凝土断裂特性与尺寸效应,引入断裂能和等效应变表示混凝土的损伤演化规律,结合混凝土塑性变形特征,提出基于断裂能的混凝土弹塑性损伤本构模型,并建立相应的数值计算模型。为验证数值计算结果的合理性,引入改进的能量尺寸效应公式进行对比分析。通过对三点弯曲梁的有限元数值模拟和断裂参数敏感性分析发现,尺寸较小的梁失效时,断裂过程区未扩展至特征长度,限制了能量耗散,从而提高了梁的抗断裂能力,增强了梁的名义强度;随着尺寸增大,失效时的断裂过程区逐渐接近特征长度,梁的名义强度逐渐减小;当断裂过程区达到特征长度后,结构名义强度不再随梁尺寸的增大而减小。To study the fracture characteristics and size effect of concrete,this study employs fracture energy and equivalent strain to express damage evolution law.By incorporating the plastic deformation characteristics of concrete,an elastic-plastic constitutive model for damage based on fracture energy was proposed,and the corresponding finite element numerical calculation model was established.An improved energy size effect formula was introduced to validate the reasonability of numerical simulation results.By conducting finite element numerical simulations and sensitivity analyses of parameters on a three-point bending beam,it is found that when the small-size beam fails,the fracture process zone may not expand to the characteristic length,thereby limiting energy dissipation and consequently enhancing fracture resistance and nominal strength of the beam.As the size of beams increases,the FPZ at beam failing gradually approaches the characteristic length,resulting in a gradual decrease in nominal strength of the beam.Once the FPZ reaches the characteristic length,there is no further decrease in nominal strength with increasing beam size.

关 键 词：混凝土 能量准则 断裂特性 尺寸效应 结构名义强度 三点弯曲梁 

分 类 号：TV331[水利工程—水工结构工程]