CFRP斜拉索的局部彎曲受力及非線性振動特性分析
發(fā)布時間：2018-08-07 09:33
【摘要】：近年來,國內(nèi)外多座CFRP纜索承重試驗橋梁的成功應用,吸引了眾多橋梁工程師的眼球。CFRP材料憑借其強度高、質(zhì)量輕、耐腐蝕等優(yōu)良性能,成為斜拉索的理想材料;應用CFRP索替換傳統(tǒng)鋼索可以有效提高斜拉橋的跨越能力和承載能力。經(jīng)過眾多學者的努力,CFRP斜拉橋的整體受力性能方面已經(jīng)有了不少研究成果,但已有研究卻很少涉及CFRP斜拉索的局部受力性能及非線性振動特性等方面,這使得CFRP斜拉索的靜動力性能不能得到全面的認識,阻礙了CFRP材料在實際超大跨斜拉橋中的應用。本文圍繞CFRP斜拉索的局部彎曲受力、CFRP拉索本身的 自耦合‖以及CFRP拉索與梁結(jié)構(gòu)的 互耦合‖現(xiàn)象開展了研究工作。具體工作內(nèi)容如下:1、采用解析法對均勻彎曲剛度斜拉索的端部彎曲應力進行了分析;以蘇通大橋的部分拉索為研究對象,討論了彈性模量、索長、初始張拉力等因素對相同條件下的CFRP和鋼拉索的端部彎曲應力的影響;最后用經(jīng)典疲勞分析方法對兩種拉索進行了拉彎疲勞性能分析,得出了CFRP斜拉索的端部彎曲應力小于鋼索,疲勞性能明顯優(yōu)于鋼索的結(jié)論。2、建立了斜拉索的三維非線性振動方程,并利用多尺度法分析了拉索發(fā)生內(nèi)共振的條件和振動模式,著重求解了主共振下的面內(nèi)外頻率比為1:1的內(nèi)共振模式。結(jié)合數(shù)值方法計算了CFRP和鋼拉索發(fā)生受迫振動時的內(nèi)共振響應;討論了初始擾動、阻尼比等因素對拉索內(nèi)共振的影響。分析發(fā)現(xiàn):兩種拉索內(nèi)共振規(guī)律基本相同,但CFRP索進入穩(wěn)態(tài)運動的時間短,最大振幅和穩(wěn)態(tài)振幅均小于鋼索。3、分別建立了拉索在可動邊界條件下的振動方程以及索-梁結(jié)構(gòu)的二維非線性振動方程。采用多尺度法和數(shù)值法相結(jié)合,對CFRP索-梁結(jié)構(gòu)和鋼索-梁結(jié)構(gòu)的自由振動和受迫振動響應進行了分析;討論了拉索阻尼、初始擾動等因素對兩種索-梁結(jié)構(gòu)共振響應的影響。結(jié)果表明:CFRP索-梁結(jié)構(gòu)的耦合共振特性優(yōu)于鋼索-梁結(jié)構(gòu)。
[Abstract]:In recent years, the successful application of many CFRP cable bearing test bridges at home and abroad has attracted the attention of many bridge engineers. Because of its high strength, light weight, corrosion resistance and other excellent properties, it has become an ideal material for stay cables. The span capacity and bearing capacity of cable-stayed bridge can be improved effectively by replacing traditional steel cable with CFRP cable. Through the efforts of many scholars, there have been a lot of research results on the overall mechanical behavior of CFRP cable-stayed bridge, but few studies have been done on the local mechanical behavior and nonlinear vibration characteristics of CFRP cables. As a result, the static and dynamic properties of CFRP cables can not be fully understood, which hinders the application of CFRP materials in practical super-span cable-stayed bridges. In this paper, the local bending force of CFRP cables and the self-coupling of CFRP cables and beam structures are studied. The concrete work is as follows: 1. The end bending stress of cable with uniform bending stiffness is analyzed by analytical method, and the elastic modulus and length of cable are discussed with part of cable of Sutong Bridge as the research object. The influence of the initial tension on the end bending stress of CFRP and steel cables under the same conditions was studied, and the bending fatigue behavior of the two kinds of cables was analyzed by classical fatigue analysis method. The conclusion that the bending stress at the end of CFRP cable is smaller than that of steel cable and the fatigue property is obviously superior to that of cable is obtained. The three-dimensional nonlinear vibration equation of cable is established, and the conditions and modes of internal resonance of cable are analyzed by using multi-scale method. The internal resonance mode with an out of plane frequency ratio of 1:1 under the main resonance is emphatically solved. The internal resonance response of CFRP and steel cable under forced vibration is calculated by numerical method, and the effects of initial disturbance and damping ratio on the internal resonance are discussed. It is found that the two kinds of internal resonance law are basically the same, but the time of entering steady state motion of CFRP cable is short. The maximum amplitude and steady amplitude are smaller than cable. 3. The vibration equations of cable under movable boundary conditions and the two-dimensional nonlinear vibration equations of cable-beam structures are established respectively. The free and forced vibration responses of CFRP cable-beam structure and cable-beam structure are analyzed by means of multi-scale method and numerical method, and the effects of cable damping and initial disturbance on the resonance response of two cable-beam structures are discussed. The results show that the coupling resonance of the cable-beam structure is better than that of the cable-beam structure.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：U441.3;U448.27
[Abstract]:In recent years, the successful application of many CFRP cable bearing test bridges at home and abroad has attracted the attention of many bridge engineers. Because of its high strength, light weight, corrosion resistance and other excellent properties, it has become an ideal material for stay cables. The span capacity and bearing capacity of cable-stayed bridge can be improved effectively by replacing traditional steel cable with CFRP cable. Through the efforts of many scholars, there have been a lot of research results on the overall mechanical behavior of CFRP cable-stayed bridge, but few studies have been done on the local mechanical behavior and nonlinear vibration characteristics of CFRP cables. As a result, the static and dynamic properties of CFRP cables can not be fully understood, which hinders the application of CFRP materials in practical super-span cable-stayed bridges. In this paper, the local bending force of CFRP cables and the self-coupling of CFRP cables and beam structures are studied. The concrete work is as follows: 1. The end bending stress of cable with uniform bending stiffness is analyzed by analytical method, and the elastic modulus and length of cable are discussed with part of cable of Sutong Bridge as the research object. The influence of the initial tension on the end bending stress of CFRP and steel cables under the same conditions was studied, and the bending fatigue behavior of the two kinds of cables was analyzed by classical fatigue analysis method. The conclusion that the bending stress at the end of CFRP cable is smaller than that of steel cable and the fatigue property is obviously superior to that of cable is obtained. The three-dimensional nonlinear vibration equation of cable is established, and the conditions and modes of internal resonance of cable are analyzed by using multi-scale method. The internal resonance mode with an out of plane frequency ratio of 1:1 under the main resonance is emphatically solved. The internal resonance response of CFRP and steel cable under forced vibration is calculated by numerical method, and the effects of initial disturbance and damping ratio on the internal resonance are discussed. It is found that the two kinds of internal resonance law are basically the same, but the time of entering steady state motion of CFRP cable is short. The maximum amplitude and steady amplitude are smaller than cable. 3. The vibration equations of cable under movable boundary conditions and the two-dimensional nonlinear vibration equations of cable-beam structures are established respectively. The free and forced vibration responses of CFRP cable-beam structure and cable-beam structure are analyzed by means of multi-scale method and numerical method, and the effects of cable damping and initial disturbance on the resonance response of two cable-beam structures are discussed. The results show that the coupling resonance of the cable-beam structure is better than that of the cable-beam structure.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：U441.3;U448.27
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1 蘇達根,高德虎,張志杰;斜拉索失效原因分析[J];工業(yè)建筑;1999年09期
2 李國平;斜拉索非線性分析的狀態(tài)修正法[J];同濟大學學報(自然科學版);2000年01期
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