碳纤维板混凝土界面黏结性能的试验研究与有限元分析
文章编号：16742974(2014)06004309
收稿日期：20140224
基金项目：国家十二五科技支撑计划项目(2011BAJ08B02)；国家自然科学基金资助项目(51008036)；湖南省科技计划重点项目(06sk4057)
作者简介：尚守平（1953-），男，山东黄县人，湖南大学教授，博士生导师
通讯联系人，E-mail:59602151@qq.com
摘 要：碳纤维板与混凝土的界面黏结性能是碳纤维加固混凝土结构的关键性能之一，对加固结构的力学行为和破坏形态等有着重要影响.进行了4个试件的碳纤维板混凝土黏结双面剪切试验，研究了设置不同粘贴长度的试件的界面力学行为和破坏模式，分析了黏结长度对界面极限承载力和应力分布的影响.试验结果表明：加载点附近应力远大于端部应力,板端黏结界面剪应力沿板长方向大致呈指数衰减分布.在试验研究基础上，在ANSYS中采用正交弹簧单元组模拟界面黏结，建立了试件的有限元模型，并采用试验分析得到的局部黏结滑移曲线关系作为有限元模型中的界面弹簧单元刚度，计算发现有限元分析结果和试验结果比较吻合，从而验证了本文有限元模型的有效性.以本文试验得到的黏结滑移曲线关系为基础，通过拟合得到了基于几种经典黏结滑移本构形式的界面本构模型.试验及有限元分析表明：当拉伸应力超过碳纤维板强度的24%时，碳板已开始从混凝土表面剥离.为保证充分利用碳纤维板的强度，应采用可靠锚具对碳纤维板进行锚固.
关键词：碳纤维板；界面；黏结性能；剪切试验；有限元方法
中图分类号： TU318 文献标识码：A
Experimental Research and Finite Element Analysis
of the Interfacial Bonding Behavior of CFRPConcrete Interface
SHANG Shouping1,LI Zhibing1,2,PENG Hui3
(1.College of Civil Engineering, Hunan Univ, Changsha, Hunan 410082, China;
2. College of Construction Engineering and Arts, Hunan Institute of Technology, Hengyang, Hunan 421002, China;
3. School of Civil Engineering and Architecture, Changsha Univ of Science & Technology, Changsha, Hunan 410004, China)
Abstract: The bonding behavior of CFRPConcrete Interface is a key performance of concrete structure strengthened with CFRP plate, and it has a critical effect on the mechanical behavior and the failure mode of the strengthened structure. Thispaper adopted doubleshear tests on 4 concrete components strengthened with CFRP plate to investigate the mechanical behavior and the failure mode of the specimens with different bond length and to analyze the influence of different bond lengths on the ultimate capacity and the distribution of the bonding stress. According to the test results, the distribution of the CFRP strain along the bond length shows an exponential decreasing law, and the stress near the loading position is much greater than the other end. The orthotropic spring elements were adopted to simulate the adhesive layer with ANSYS software, and the finite element model of the specimen was established. The local bond slip curve obtained from the test was used as the Fd curve of spring elements. The FEA results agree with the experimental ones, confirming the correctness of the FEM. Based on the bond slip curves obtained from the test, some bondslip constitutive relationships werefitted according to several classic bondslip constitutive relations. The test and FEA results show that the CFRP plate has begun peeling from the concrete surface when the tensile stress applied to CFRP reaches 24% of the tensile strength of the material. To ensure the full utilization of CFRP strength, the anchorage for CFRP plate should be adopted.
Key words: CFRP plate; interfaces; bonding behavior; shear test; finite element method
近年来外贴碳纤维板加固在建筑及桥梁结构加固补强中应用广泛，在碳纤维板与混凝土间传递应力的界面黏结，对加固结构受力性能起着至关重要的作用.为精确预测加固结构的力学行为，需要深入把握黏结界面的受力行为.因此研究人员对加固结构的受力性能和力学行为开展了大量研究\[1-6\]，设计了各种界面黏结性能的试验测试装置并通过试验考察了界面受剪行为；推导了碳纤维板加固钢筋混凝土受弯构件界面应力的计算公式；也针对黏结界面的特点建立了平面有限元模型分析界面剪应力滑移关系.已有的单剪试验方法操作较繁琐，试验结果受试验设备和试件形状影响较大；已完成的有限元分析通常忽略黏结层的受剪滑移，直接在界面将两种材料节点耦合，或将整个结构简化成平面进行分析 \[7-9\]；现有的剪应力滑移计算理论模型较多，考虑的参数较片面且不一致.鉴于此，本文参考Yun等人\[10\]的试验设计，实施了双面粘贴碳纤维板的混凝土棱柱体组合试件的受剪试验；研究了界面受剪条件下黏结应力变化规律；得到了黏结滑移曲线，定义了适用黏结界面受力状态的弹簧单元组，建立了相应的三维有限元模型，并将分析结果和试验结果进行了对比分析；基于已有的黏结滑移本构关系进行了本文试验所得到的黏结滑移曲线值拟合，比较了不同本构模型与试验结果的吻合程度.