立方体劈裂抗拉试验数值模拟与强度计算分析  

Numerical simulation and strength calculation analysis of cubic splitting test

作　　者：魏杉 程炯 黎冰[1] Wei Shan;Cheng Jiong;Li Bing(College of Civil Engineering,Southeast University,Nanjing 210096,China;Energy China Zhejiang Electric Power Design Institute Co.Ltd,Hangzhou 310000,China)

机构地区：[1]东南大学土木工程学院,江苏南京210096 [2]中国能源建设集团浙江省电力设计院有限公司,浙江杭州310000

出　　处：《建筑科学》2023年第7期17-27,共11页Building Science

基　　金：国家自然科学基金项目(51578145)。

摘　　要：我国现行相关规范对于立方体试件劈裂抗拉强度的计算采用的是传统圆盘劈裂抗拉强度计算公式,而未考虑试件形状和木质垫条的影响。通过ABAQUS软件对立方体试件劈裂抗拉试验开展了二维和三维数值模拟,研究了试件的应力状态以及垫条宽度的影响,并结合Griffith强度准则分析了试件的起裂点位置。结果表明,集中力作用下立方体试件劈裂面上的拉应力最大值并不是位于试件中心,而是位于加载面附近;设置木质垫条进行试验加载能够有效缓解加载面上的应力集中现象,木质垫条传递荷载的有效宽度不超过30mm;采用规范规定的宽度为15mm~20mm的木质垫条时,立方体试件不满足中心点起裂的要求。基于二维数值模拟结果,引入修正系数k对规范中的劈裂抗拉强度公式进行修正,以考虑垫条宽度对试验结果的影响。该修正公式可为立方体劈裂抗拉试验确定材料抗拉强度所用。The formula for calculating the splitting tensile strength of the cubes is obtained from the formula of the disc specimen,and the current numerical simulation studies of the cube specimen ignore the influence of the load distribution on the loading surface and the shape of specimen.In order to ensure the validity of the test and obtain a more accurate tensile strength correction formula,the splitting tension test is carried out by the two⁃dimensional and three⁃dimensional numerical simulation using ABAQUS,and the stress state is analyzed in combination with the Griffith criterion.Also the influence of the width of the strip is studied.The results indicate that,under the concentrated force,the maximum tensile stress on the splitting surface of the cube specimen is not located at the center of the specimen but near the loading surface.Using a wood strip for loading can effectively eliminate the stress concentration on the loading surface,and the effective width of the wood strip is within 30mm.When the width of the strip is 15mm~20mm as required by the specification,the cube specimen fails to meet the requirements of the crack initiation at the center.A correction coefficient k is introduced to modify the standard formula based on the two⁃dimensional numerical simulation results,which takes into account the influence of the width of the strip in the strength result of cube splitting tension test.The revised formula can be used to accurately determine the tensile strength of the material by cube splitting tension test.

关 键 词：劈裂抗拉试验 劈裂抗拉强度 数值模拟 立方体试件 垫条 

分 类 号：TU311.4[建筑科学—结构工程]