考虑垫条和塑性损伤影响的立方体劈裂抗拉试验分析  

Analysis of cubic splitting test considering effects of wood strip and plastic damage

作　　者：崔冠鹏 程炯 黎冰[1] Cui Guanpeng;Cheng Jiong;Li Bing(College of Civil Engineering,Southeast University,Nanjing 210096,China;China Energy Engineering Group 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5期11-22,共12页Building Science

基　　金：国家自然科学基金项目(51578145)。

摘　　要：现行相关规范采用的立方体劈裂抗拉强度计算公式未考虑试件形状和加载条件的影响。分别建立立方体试件劈裂抗拉试验的三维弹性模型和考虑材料塑性损伤属性的数值模型,模拟研究了立方体试件的应力状态,结合Griffith强度准则分析了木质垫条宽度和材料弹塑性的影响。结果表明,随着垫条宽度的增大,试件劈裂面上的等效应力最大值逐渐减小,起裂点的位置逐渐向试件端面中心移动。考虑材料的塑性损伤属性后,试件的初始起裂点位置与材料强度无关,且皆不位于试件端面中心。由于试件初始起裂点对应的竖向荷载并不是试件破坏时的峰值荷载,所以采用基于三维弹性数值模拟结果确定试件劈裂抗拉强度是不准确的,而采用规范公式计算出的劈裂抗拉强度值则偏小。建议垫条宽度宜在25mm左右。The formulas for calculating the splitting tensile strength of cubes adopted in the current relevant standards ignore the influence of the shape of the specimen and the loading conditions.The three⁃dimensional elastic model of the splitting tension test for the cubic specimen and the numerical model considering the plastic damage properties of the material are established,respectively.The stress state of the cubic specimen is simulated and analyzed,and the influence of the width of the wood strip and the elastic⁃plasticity of the material is analyzed based on the Griffith strength criterion.The results indicate that with the increase of the width of the wood strip,the maximum value of the equivalent stress on the splitting surface of the specimen gradually decreases,and the position of the crack initiation point gradually moves to the center of the end surface of the specimen.When considering the plastic damage properties of the material,the location of the initial crack of the specimen is independent of the material strength,and the initial crack is not developed at the center of the specimen.Since the vertical load corresponding to the initial crack of the specimen is not the peak load when the specimen is damaged,it is inaccurate to calculate the splitting tensile strength of the specimen using the formula obtained by the three⁃dimensional elastic numerical simulation.Besides,the splitting tensile strength calculated by the standard formula is relatively small.It is recommended that the width of the wood strip should be about 25mm.

关 键 词：劈裂抗拉试验 立方体试件 数值模拟 垫条宽度 塑性损伤 

分 类 号：TU317[建筑科学—结构工程]