预应力纤维加固管线的力学分析研究

发布时间：2018-05-17 02:11

本文选题：预应力 + 纤维　；参考：《西南科技大学》2017年硕士论文

【摘要】：FRP具有轻质高强、耐腐蚀、抗疲劳等独特优势,粘贴FRP加固技术在各类加固项目中已得到了广泛的应用。近年来,采用预应力纤维加固技术对损伤钢管进行修复得到了学者们的青睐,然而在施加预应力过程中,如何确定预应力值是解决预应力纤维加固管线的关键问题。本文对预应力纤维加固压力管线的力学行为进行了分析,着重对预应力纤维加固压力管线的临界屈曲和强度失效展开了深入的研究,为采用预应力纤维加固修复压力管线提供了理论依据。主要的工作可以阐述为以下五个方面:(1)研究了管道屈曲的基本分析方法、失稳类型和稳定性分析方法,分析了预应力纤维加固钢管模型下最适合的屈曲研究方法,即瑞利-里兹法,瑞利-里兹法是势能驻值原理和最小势能原理基础上的一个近似方法。根据屈曲变形假设的挠度函数是采用里兹法解决管道在外压作用下屈曲问题的关键。(2)预应力纤维加固钢管的临界屈曲研究分析。建立预应力纤维加固钢管的力学模型,根据曲率方程、平衡方程、几何方程、物理方程推导了钢管在预应力作用下的挠度微分方程,并发现在钢管荷载对称中心处取得极限应变。(3)根据壳体屈曲时的形态,将屈曲过程分为前屈曲过程和后屈曲过程。考虑薄膜应力的影响,根据几何方程、平衡方程、物理方程,根据圣维南定理,推导了钢管在预应力作用下的变形协调方程和屈曲控制方程,采用里兹法,根据钢管在预应力作用下的变形情况,建立了钢管在预应力作用下的挠度微分方程,依据势能驻值原理,得到了钢管在预应力作用下屈曲的临界值。(4)预应力作用下弹塑性分析研究。根据预应力纤维加固钢管的力学模型,得到了预应力作用下钢管环向应力和径向应力的分布。并基于强度理论,对钢管在预应力作用下的弹塑性问题进行了分析,得到了仅在内压或者预应力作用下钢管环向应力和径向应力的分布规律。(5)预应力纤维加固钢管的试验研究。通过预应力纤维加固钢管的试验初步验证了通过理论得到的应力、应变的理论公式,并得到了钢管在预应力作用下环向方向和轴向方向的应变的分布情况。
[Abstract]:FRP has many unique advantages such as lightweight, high strength, corrosion resistance, fatigue resistance, etc. It has been widely used in various reinforcement projects. In recent years, the application of prestressed fiber reinforcement technology to repair damaged steel pipe has been favored by scholars. However, in the process of applying prestressing force, how to determine the prestress value is the key problem to solve the problem of prestressed fiber reinforced pipeline. In this paper, the mechanical behavior of prestressed fiber reinforced pressure pipeline is analyzed, and the critical buckling and strength failure of prestressed fiber reinforced pressure pipeline are studied deeply. It provides a theoretical basis for the reinforcement and repair of pressure pipelines with prestressed fiber. The main work can be described as the following five aspects: 1) the basic analysis method, the instability type and the stability analysis method of the pipeline buckling are studied, and the most suitable buckling research method under the prestressed fiber reinforced steel pipe model is analyzed. The Rayleigh-Ritz method is an approximate method based on the stationary principle of potential energy and the principle of minimum potential energy. According to the deflection function of buckling assumption is the key to solve the buckling problem of pipeline under external pressure by Ritz method) the critical buckling analysis of steel pipe strengthened by prestressed fiber is carried out. The mechanical model of prestressed fiber reinforced steel pipe is established. According to the curvature equation, equilibrium equation, geometric equation and physical equation, the deflection differential equation of steel pipe under prestressing force is derived. It is also found that the ultimate strain at the center of steel tube load is obtained. (3) according to the shape of shell buckling, the buckling process is divided into pre-buckling process and post-buckling process. Considering the effect of thin film stress, according to geometric equation, equilibrium equation, physical equation, according to Saint Venant's theorem, the deformation coordination equation and buckling control equation of steel pipe under prestressing force are derived, and the Ritz method is used. According to the deformation of steel tube under prestressing force, the differential equation of deflection of steel pipe under prestress is established, and the principle of standing value of potential energy is used. The critical value of buckling of steel pipe under prestress is obtained. According to the mechanical model of prestressed fiber reinforced steel pipe, the distribution of circular stress and radial stress of steel pipe under prestressing force is obtained. Based on the strength theory, the elastic-plastic problem of steel pipe under prestress is analyzed, and the experimental study on the distribution of circumferential stress and radial stress of steel pipe under internal pressure or prestress is obtained. The theoretical formulas of stress and strain of steel pipe strengthened by prestressed fiber are preliminarily verified, and the distribution of the strain in the circumferential direction and the axial direction under the action of prestress is obtained.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE973

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