2种Ⅱ型混凝土试件断裂韧度K_(ⅡC)值的比较研究  

Comparative Research on Fracture Toughness K_(ⅡC) of Two Types of Mode-Ⅱ Concrete Specimens

作　　者：邓爱民[1] 苟联盟[2] 徐道远[1] 

机构地区：[1]河海大学力学与材料学院,南京210098 [2]江苏省交通规划设计院,南京210005

出　　处：《防灾减灾工程学报》2013年第2期190-194,共5页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金项目(10972072;50878077);中央高校业务经费课题(B103073)资助

摘　　要：根据混凝土四点剪切加载和两端切口半边对称加载这2种Ⅱ型混凝土试件断裂试验的结果,计算分析了它们的断裂韧度KⅡC及其相互关系。采用有限元方法,基于数值模拟,利用ANSYS软件计算分析了2种Ⅱ型混凝土试件断裂试验加载阶段各荷载步的应力场和应变场,用位移外推法分别计算了四点剪切加载和两端切口半边对称加载Ⅱ型断裂数值模拟试验的断裂韧度,并与试验结果进行了比较。由于两端切口半边对称加载条件下试件受力均匀,容易保证整个试验过程中试件断裂过程区切应力占据主导地位,而四点剪切加载条件下则不可避免出现张拉和扭转等现象,从而导致试件断裂破坏过程中并不总是纯剪切的Ⅱ型断裂,这可能是这2种Ⅱ型混凝土试件断裂韧度KⅡC值有所不同的原因所在。According to the Mode II fracture test results of concrete of the double edge notched specimens with fourpoint shear loading and half symmetrical loading, the relationship of the Mode II fracture toughness between two type of concrete specimens was analyzed. Based on the numerical simulation, the stress field near the crack tip was analyzed by use of the finite element method, and the Mode II fracture toughness of the two types of concrete specimens was calculat ed with the displacement extrapolation method, and the difference with the experimental results was studied. Because there is the uniform stress in the specimen with half symmetric loading, and the shear stress in the fracture process zone is much larger than the first principal stress dur ing the entire test process, while the phenomenon of opening and torsion of the surface of cracks may appear at the four point shear loading conditions, these factors lead to that the fracture process of the specimen is not always the Mode II fracture of pure shear.

关 键 词：混凝土试件 Ⅱ型断裂试验 断裂韧度 数值模拟 

分 类 号：TV148[水利工程—水力学及河流动力学]