GFRP桥面板黏结界面力学分析与试验研究

发布时间：2018-05-15 22:29

本文选题：GFRP桥面板 + 黏结界面破坏　；参考：《东南大学》2015年博士论文

【摘要】：GFRP桥面板以其轻质、高强、耐腐蚀等优点,近年来已在桥梁工程中得到越来越广泛地应用。GFRP构件黏结界面是GFRP桥面板的一个重要组成部分,它决定各构件能否有效协同承载和承受温度变化引起的变形。黏结界面性能的好坏对结构性能产生重要的影响,在实际工程中经常发生因为黏结界面首先破坏而危及整个结构的现象,结构的整体承载能力往往不是桥面板本身的材料强度决定,而是取决于界面的黏结强度和断裂韧性。本论文在国家自然科学基金(50878048、50978055)、国家973计划项目(2012CB026200)子课题的支持下,围绕GFRP桥面板构件黏结界面失效、断裂行为等亟待解决的关键问题,对GFRP桥面板构件间粘结界面破坏模式、破坏机理进行分析,对粘结界面断裂行为进行研究；分析荷载和温度作用下GFRP桥面板结构的力学响应特别是黏结界面的力学响应。主要研究工作如下：(1)分析了GFRP桥面板黏结接头的破坏模式、破坏机理。以单搭黏结接头的胶层为研究对象,基于Hart-Smith公式计算了GFRP单搭接界面的弹性、弹塑性应力分布,根据胶层最大剪应变准则得到了胶层剪切失效时接头的极限承载力,并探讨了搭接参数对弹性应力和极限承载力的影响。随后,开展了GFRP桥面板黏结界面力学性能的试验研究,得到了黏结界面实际的破坏模式,分析了其破坏机理,考虑了黏结参数对黏结强度的影响,建立了复杂应力状态下的FRP界面黏结强度准则。研究成果可为GFRP桥面板黏结界面安全评估提供科学依据。(2)基于弹性地基梁理论,考虑了GFRP板的剪切变形、以及裂尖转角和位移对梁变形的影响,对双悬臂(DCB)胶结试件进行了分析,得到了柔度与Ⅰ型能量释放率的解析式。考虑胶层对变形的影响,利用Goodman弹性夹层假设推导了4ENF和4MMB试件在四点弯作用下的挠度变形公式,得到了Ⅱ型和混合型能量释放率解析表达式。开展了复合材料Ⅰ型、Ⅱ型和混合型试件胶结界面断裂试验研究。将试验测得的临界荷载结合理论公式求得其界面裂纹断裂韧性,线性回归得到裂纹尖端复合变形下的断裂准则。此外,对粘结界面裂纹扩展进行了有限元数值模拟,验证了提出的断裂准则的正确性。(3)通过GFRP桥面板的静力试验,发现了粘结界面破坏先于其他破坏模式首先发生。通过对黏结界面端的应力场分析,得到了桥面板粘结界面端的奇异系数,并提出了减小应力奇异性的办法。根据Chamis模型方法,建立了包含黏结胶层GFRP桥面板的细观力学有限元模型,将有限元计算结果与GFRP桥面板静载试验结果进行了对比。研究发现在荷载作用下,构件间胶结界面的剪应力较大,应用第二章提出的粘结界面强度准则得到了界面失效系数最大值达0.66,而材料的蔡-吴系数为0.42,表明界面为桥面板结构设计的薄弱环节。分析了管材截面参数和胶层参数对GFRP界面应力的影响。对GFRP桥面板在荷载作用下的稳定性进行了验算,讨论了顶底板厚、腹板厚度、构件高度、倒角半径对桥面板屈曲性能的影响。(4)采用弹性等效理论将GFRP桥面板弹性等效为正交异性板。根据正交异性板壳理论,基于基尔霍夫假定,推导了温度作用下GFRP桥面板的挠曲面控制微分方程,应用纳维解法计算出了板的挠度、转角和内力。分析了三种温差模式对GFRP桥面板力学性能的影响,结果表明：温差作用对GFRP桥面结构强度的影响非常不利,整体降温引起的桥面板内应力值和胶界面应力值大于整体升温、梯度温度变化作用,需将整体降温在GFRP桥面板设计中重点加以考虑。(5)对含黏结界面裂缝桥面板的受力性能进行了数值分析。采用虚拟裂纹闭合法计算了不同工况下GFRP构件间粘结界面裂纹尖端的能量释放率,确立了不利工况下的能量释放率,并采用第三章胶结裂纹断裂准则进行了评价；研究了能量释放率随裂缝深度的变化规律,根据Paris公式计算了胶结裂纹的疲劳寿命。分析了裂纹存在造成的桥面板内应力重分布,对桥面板屈曲临界荷载、强度和刚度的不利影响。为提高GFRP桥面板的使用寿命,建议控制好桥面板粘结界面施工质量,尽量避免胶结裂纹产生。
[Abstract]:The GFRP bridge deck has the advantages of light quality, high strength and corrosion resistance. In recent years, the bonding interface of.GFRP components has been widely used in bridge engineering. It is an important part of the GFRP bridge panel. It determines whether the components can effectively coordinate the load and bear the deformation caused by the temperature change. The performance of the bonding interface is good or bad to the structure. It can have important effects. In practical engineering, it often occurs because the bonding interface is first destroyed and endanger the whole structure. The overall bearing capacity of the structure is often not determined by the strength of the material of the bridge panel itself, but on the bonding strength and fracture toughness of the interface. This paper is in the National Natural Science Foundation (5087804850978055). Under the support of the sub project of the national 973 Plan Project (2012CB026200), the key problems that need to be solved, such as the failure of the bonding interface of the GFRP bridge panel and the fracture behavior, are analyzed. The fracture mechanism of the bonding interface between the members of the GFRP bridge panel is analyzed, the fracture behavior of the bonded boundary surface is studied, and the GFRP bridge under the action of load and temperature is analyzed. The mechanical response of the panel structure is especially the mechanical response of the bonding interface. The main research work is as follows: (1) the failure mode and failure mechanism of the adhesive joint of the GFRP bridge panel are analyzed. The elastic, elastic and plastic stress distribution of the single lap interface of GFRP is calculated based on the Hart-Smith formula, and the plastic stress distribution is calculated on the basis of the glue layer. The maximum shear strain criterion is used to obtain the ultimate bearing capacity of the joint during the shear failure of the rubber layer, and the effect of the lap parameters on the elastic stress and the ultimate bearing capacity is discussed. Then, the mechanical properties of the bonding interface of the GFRP bridge deck are studied. The actual failure mode of the bonding interface is obtained. The failure mechanism of the bonding interface is analyzed, and the bonding parameter is considered. The adhesive strength criterion of FRP interface under complex stress state is established. The research results can provide a scientific basis for the safety assessment of the bonding interface of the GFRP bridge panel. (2) based on the elastic foundation beam theory, the shear deformation of the GFRP plate, the effect of the angle and displacement of the crack tip on the deformation of the beam are considered, and the cementation of the double cantilever (DCB) is cemented. An analytical formula for the flexibility and energy release rate of type I was obtained. Considering the effect of the adhesive layer on the deformation, the deflection and deformation formula of 4ENF and 4MMB specimens under four point bending were derived by using the Goodman elastic sandwich hypothesis, and the analytical expressions of the energy release rate of type II and mixed type were obtained. The fracture toughness of the interface crack is obtained by the critical load combined with the theoretical formula, and the fracture criterion under the composite deformation at the crack tip is obtained by linear regression. Furthermore, the finite element numerical simulation of the crack propagation of the bonding interface is carried out, and the correctness of the proposed fracture criterion is verified. (3) through the static test of the GFRP bridge deck, it is found that the failure of the bond interface is first occurring first. Through the analysis of the stress field at the end of the boundary, the singular coefficient of the end of the visco boundary surface of the bridge deck is obtained, and the method of reducing the singularity of the stress is proposed. According to the Chamis model, the GFRP bridge containing the adhesive layer is established. The finite element finite element model of the panel is compared with the results of the static load test of the GFRP bridge deck. It is found that the shear stress of the cementation interface between the components is larger under the load. The maximum value of the interfacial inefficiency coefficient is 0.66, and the Chua Wu coefficient of the material is obtained by the second chapter. For 0.42, it is shown that the interface is the weak link of the bridge deck structure design. The effect of the section parameters of the pipe and the adhesive layer parameters on the stress of the GFRP interface is analyzed. The stability of the GFRP bridge panel under the load is checked, and the influence of the thickness of the top and bottom, the thickness of the web, the height of the member and the radius of the reverse angle on the buckling performance of the bridge deck is discussed. (4) the use of the projectile. The elastic equivalent theory of the GFRP bridge deck is equivalent to the orthotropic plate. Based on the orthotropic plate and shell theory, based on Kirchhoff's hypothesis, the differential equation for the control of the flexure surface of the GFRP bridge panel is derived. The deflection, the rotation angle and the internal force of the plate are calculated by the Navier method. The mechanical properties of the three kinds of temperature difference modes for the GFRP bridge panel are analyzed. The results show that the effect of temperature difference on the strength of GFRP bridge deck is very unfavorable. The stress value of the bridge panel and the stress value of the adhesive interface are greater than the whole temperature, and the gradient temperature changes. It is necessary to take the whole temperature in the design of the GFRP bridge deck to consider. (5) the fracture bridge deck with the bonding interface is affected by the temperature. The numerical analysis of the force performance is carried out. The energy release rate at the crack tip of the bonding interface between GFRP members under different working conditions is calculated by using the virtual crack closure method. The energy release rate under the unfavorable condition is established, and the third chapters of the cemented crack fracture criterion are used to evaluate the energy release rate with the fracture depth. The fatigue life of the cemented crack is calculated according to the Paris formula. The adverse effects on the critical load, strength and stiffness of the bridge deck caused by the existence of cracks are analyzed. In order to improve the service life of the GFRP bridge panel, it is suggested that the working quality of the bonding interface of the bridge deck is well controlled and the cementation crack can be avoided as much as possible.

【学位授予单位】：东南大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U443.31;U446

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