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
江婷 1杜效鹄 1沈振中 2张宏伟 2许峙峰3
作者信息
- 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
- 折叠
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.
Abstract
To study the fracture characteristics and size effect of concrete,this study employs fracture energy and e-quivalent 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 rea-sonability 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 char-acteristic 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Key words
concrete/energy criteria/fracture characteristics/size effect/structural nominal strength/three-point-bending beam引用本文复制引用
基金项目
国家重点研发计划(2022YFC3005403)
西藏自治区科技重大专项课题(XZ202201ZD0003G)
出版年
2024
NETL
NSTL
维普
万方数据