CFRP斜拉索的局部弯曲受力及非线性振动特性分析
发布时间：2018-08-07 09:33
【摘要】：近年来,国内外多座CFRP缆索承重试验桥梁的成功应用,吸引了众多桥梁工程师的眼球。CFRP材料凭借其强度高、质量轻、耐腐蚀等优良性能,成为斜拉索的理想材料;应用CFRP索替换传统钢索可以有效提高斜拉桥的跨越能力和承载能力。经过众多学者的努力,CFRP斜拉桥的整体受力性能方面已经有了不少研究成果,但已有研究却很少涉及CFRP斜拉索的局部受力性能及非线性振动特性等方面,这使得CFRP斜拉索的静动力性能不能得到全面的认识,阻碍了CFRP材料在实际超大跨斜拉桥中的应用。本文围绕CFRP斜拉索的局部弯曲受力、CFRP拉索本身的 自耦合‖以及CFRP拉索与梁结构的 互耦合‖现象开展了研究工作。具体工作内容如下:1、采用解析法对均匀弯曲刚度斜拉索的端部弯曲应力进行了分析;以苏通大桥的部分拉索为研究对象,讨论了弹性模量、索长、初始张拉力等因素对相同条件下的CFRP和钢拉索的端部弯曲应力的影响;最后用经典疲劳分析方法对两种拉索进行了拉弯疲劳性能分析,得出了CFRP斜拉索的端部弯曲应力小于钢索,疲劳性能明显优于钢索的结论。2、建立了斜拉索的三维非线性振动方程,并利用多尺度法分析了拉索发生内共振的条件和振动模式,着重求解了主共振下的面内外频率比为1:1的内共振模式。结合数值方法计算了CFRP和钢拉索发生受迫振动时的内共振响应;讨论了初始扰动、阻尼比等因素对拉索内共振的影响。分析发现:两种拉索内共振规律基本相同,但CFRP索进入稳态运动的时间短,最大振幅和稳态振幅均小于钢索。3、分别建立了拉索在可动边界条件下的振动方程以及索-梁结构的二维非线性振动方程。采用多尺度法和数值法相结合,对CFRP索-梁结构和钢索-梁结构的自由振动和受迫振动响应进行了分析;讨论了拉索阻尼、初始扰动等因素对两种索-梁结构共振响应的影响。结果表明:CFRP索-梁结构的耦合共振特性优于钢索-梁结构。
[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.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：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.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U441.3;U448.27
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