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  本文選題：預應力 + 纖維��； 參考：《西南科技大學》2017年碩士論文

【摘要】：FRP具有輕質(zhì)高強、耐腐蝕、抗疲勞等獨特優(yōu)勢,粘貼FRP加固技術在各類加固項目中已得到了廣泛的應用。近年來,采用預應力纖維加固技術對損傷鋼管進行修復得到了學者們的青睞,然而在施加預應力過程中,如何確定預應力值是解決預應力纖維加固管線的關鍵問題。本文對預應力纖維加固壓力管線的力學行為進行了分析,著重對預應力纖維加固壓力管線的臨界屈曲和強度失效展開了深入的研究,為采用預應力纖維加固修復壓力管線提供了理論依據(jù)。主要的工作可以闡述為以下五個方面:(1)研究了管道屈曲的基本分析方法、失穩(wěn)類型和穩(wěn)定性分析方法,分析了預應力纖維加固鋼管模型下最適合的屈曲研究方法,即瑞利-里茲法,瑞利-里茲法是勢能駐值原理和最小勢能原理基礎上的一個近似方法。根據(jù)屈曲變形假設的撓度函數(shù)是采用里茲法解決管道在外壓作用下屈曲問題的關鍵。(2)預應力纖維加固鋼管的臨界屈曲研究分析。建立預應力纖維加固鋼管的力學模型,根據(jù)曲率方程、平衡方程、幾何方程、物理方程推導了鋼管在預應力作用下的撓度微分方程,并發(fā)現(xiàn)在鋼管荷載對稱中心處取得極限應變。(3)根據(jù)殼體屈曲時的形態(tài),將屈曲過程分為前屈曲過程和后屈曲過程�？紤]薄膜應力的影響,根據(jù)幾何方程、平衡方程、物理方程,根據(jù)圣維南定理,推導了鋼管在預應力作用下的變形協(xié)調(diào)方程和屈曲控制方程,采用里茲法,根據(jù)鋼管在預應力作用下的變形情況,建立了鋼管在預應力作用下的撓度微分方程,依據(jù)勢能駐值原理,得到了鋼管在預應力作用下屈曲的臨界值。(4)預應力作用下彈塑性分析研究。根據(jù)預應力纖維加固鋼管的力學模型,得到了預應力作用下鋼管環(huán)向應力和徑向應力的分布。并基于強度理論,對鋼管在預應力作用下的彈塑性問題進行了分析,得到了僅在內(nèi)壓或者預應力作用下鋼管環(huán)向應力和徑向應力的分布規(guī)律。(5)預應力纖維加固鋼管的試驗研究。通過預應力纖維加固鋼管的試驗初步驗證了通過理論得到的應力、應變的理論公式,并得到了鋼管在預應力作用下環(huán)向方向和軸向方向的應變的分布情況。
[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.
【學位授予單位】：西南科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TE973

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本文編號：1899434