摘要
伴随着科技革命带给我们新的建筑理念以及材料的进步,现代桥梁向大跨度、轻柔、纤细的方向发展,导致了风致敏感性的增加。在所有风引起的动力作用下的振动中,又以抖振与涡激振动比较常见,因其是在低风速下容易发生的风致振动。在对本悬索桥进行抖振分析时,采用了时域分析方法,而放弃了频域分析方法。因悬索桥几何与气动非线性都比较明显,采用时域分析方法可以反应抖振响应的时间历程。由于涡激振动现在没有完善的理论解,本文借助风洞试验通过改变桥梁断面的气动外形找到了抑制涡振的有效措施。
本课题的研究是以某悬索桥为工程实例,对其进行了成桥状态时域抖振分析和涡振分析。是在计算机编程、有限元分析、风洞试验的基础上完成的。主要内容有:
(1)、根据此悬索桥构造形式,将桥梁所在场地的三维脉动风场给予适当简化,基于此用谐波合成法模拟出了此桥三维脉动风场。
(2)、采用ANSYS有限元软件,建立了某悬索桥有限元模型,对此桥进行了动力特性分析。
(3)、对静风荷载、抖振力荷载和自激力荷载进行时域化处理。采用Scanlan的准定常气动力理论计算抖振力,自激力是采用ANSYS中的Matrix27号单元来实现,对准定常气动力模型,先用双泰勒展开,导出的单元气动阻尼矩阵和气动刚度矩阵与自激力等价。考虑气动导纳的影响时,采用Liepmann提出的平板气动导纳函数来近似计算。本文还在此基础上探讨了风速、风攻角的变化影响成桥状态抖振响应的情况。
(4)、通过风洞试验确定此桥存在涡振,并且进一步通过试验研究出抑制此桥涡振的有效措施。
(5)、总结本文对悬索桥抖振与涡振的研究,有一定的工程参考价值,并且指出了需要进一步有待解决的问题。
With the revolution of science and technology to bring us new architectural concept and material progress,modern bridge is developing into the longspan、flexible、slender phase,which bring about the increase of wind-induced sensitivity. In all the vibration under the dynamic action caused by the wind,again with buffeting and vortex-induced vibration are more common,because they are likely to happen under the wind induced vibration of the low speed. On the analysis of the buffeting for this suspension bridges, use the time domain method, and give up the frequency domain analysis method. Because of geometry and aerodynamic force nonlinear are obvious for suspension bridge, the analysis of time domain method can reaction time history of buffeting response. Because of vortex-induced vibrations now has no perfect theoretical solution, this paper makes use of the wind tunnel test by changing the bridge sections of aerodynamic configuration found the effective measures to restrain vortex-induced vibration.
In this thesis,taking a suspension bridge as a project example,time-domain buffeting analysis at using stage and vortex analysis is studied.It is done on the basis of computer programing、 finite element analysis and wind tunnel test.The research is mainly focused on the following aspects:
(1).Acoording to the properties of both the structural style of long-span suspension bridge and the wind field characteristics,a practical method is introduced to simplify three dimensional stochastic wind velocity field, and on this basis simulate the fluctuating wind field for this bridge with harmonic synthesis simulates.
(2).Establish a finite element model of this suspension bridges by using the finite element program ANSYS,then analyse the dynamic characteristics.
(3).The static wind load、buffeting force and self-excited force are converted to the time-domain form The buffeting force is calculated based on the quasi-steady aerodynamic force theory proposed by Scanlan. The self-excited forces are input in ANSYS through Matrix27,by applying two-variable Taylor expansion to the quasi-steady aerodynamic force model,the12-order element aerodyamic damping matrix and aerodynamic stiffness matrix equivalent to self-excited force order are derived. Using the plate aerodynamic admittances function. to consider the influence of aerodynamic admittance function. The paper also considerthe influence of buffeting response under different wind speed、different wind angle of attack to bridge.
(4). Through the wind tunnel test to determine this bridge exist vortex vibration, further research out the effective suppression measures for this bridge vortex-induced vibration through the wind tunnel test.
(5). The research work done in this thesis is analysed and summarized, has the certain reference value in the project of similar problems, furthermore points out the problems need to be solved in further research.
引文
[1]项海帆.现代桥梁抗风理论与实践.人民交通出版社.2005
[2]项海帆.风工程力学及大跨度桥梁的风致振动.2002
[3]陈政清.桥梁风工程.人民交通出版社.2005
[4]A.G DvaenPort Buffeting of a suspension bridge by storm winds[J].Struct Div., ASCE, 1962,88(3)233—268.
[5]Scanlan R H.The action of flexible bridges under wind II buffeting theory [J].Sound and Vib.,1978,60(2)201—211.
[6]蒋永林、强士中、廖海黎.斜拉桥抖振响应中联合承载函数的计算.西南交通大学学报,2001,36(1)
[7]丁顺泉.大跨度桥梁耦合颤抖振响应分析.同济大学出版社.2007
[8]杨咏漪.独塔斜拉桥抖振时变可靠度研究.西南交通大学硕士论文.2003
[9]Lin Y K,Li Q C.New stochastic theory forbridge stability inturbulent flow 〔J〕. Journal ofEngineeringMechanics,1993,119(1):113-127.
[10]Q.Ding, P.K.K.Lee and S.H.Lo.Time domain buffeting analysis ofsuspension bridges subjected to turbulentwindwith effective attack angle 〔J〕. Journal of Sound and Vrbriation,2000,233(2):311-327.
[11]刘春华,项海帆,顾明.大跨度桥梁抖振响应的空间非线性时程分析方法(J).同济大学学报,1996,24(4):380-385.
[12]曹映泓,大跨度桥梁非线性颤振和抖振时程分析[D].上海:同济大学,1999.
[13]Scanlan R H,et al.Indical aerodynamic functions for bridges decks[J].J.Engrg.Mech. Div.ASCE,1974,100(4):657-672.
[14]埃米尔·希缪,罗伯特·H·斯坎伦.风对结构的作用—风工程导论(刘尚培、项海帆等译).同济大学出版社,1992
[15]《公路桥梁抗风设计指南》编写组.公路桥梁抗风设计指南[M].人民交通出版社,1996
[16]Scanlan R H.The action of flexible bridges under wind,I:flutter theory[J].J.Sound and Vib.,1978,60(2):187-199.
[17]李永乐.风-车-桥系统非线性空间耦合振动研究.博士学位论文.西南交通大学,2003
[18]M.Shinozuka,C.B.Yun,H.Seya.Stochastic methods in wind engineering.J.Wind Eegineering and Industrial Aerodynamics.1990(36):829-843
[19]N.N.Minth,T.Miyata.H.Yamada,Y.Sanada.Numerical simulation of wind turb-ulence and buffeting analysis of long-span bridges.J.Wind Engineering and Industrial Aerodynamics.1990,83:301-315
[20]公路桥梁抗风设计规范
[21]赵翔龙Fortran90学习教程.北京大学出版社,2000
[22]胡亮,基于特征正交分解的桥梁风场随机模拟,华中科技大学博士学位论文,2007
[23]王新敏AN SYS工程结构数值分析。人民交通出版社,2007
[24]谭学民 大跨度斜拉桥风致抖振时域分析.博士学位论文.华南理工大学,1999
[25]R.Kiviluoma.Coupled-mode buffeting and flutter anaslysis of bridges.Comp-ut.Struct, 1998,70219-228
[26]X.Z.Chen,M.Matsumoto,A.Kareem.Aerodynamic coupling effects on flutter and buffeting of bridges. J.Engng.Mech,2000,126(1):7-16
[27]靳欣华 项海帆 陈艾荣.平板气动导纳识别理论及测量.同济大学学报.2003
[28]张晋媛.大跨度斜拉桥线性抖振时域分析.西南交通大学硕士学位论文.成都:西南交通大学土木工程学院,2010
[29]Sears W.R.Some aspects of non-stationary airfoil theory and its practical application.J.Aero nautical Science,1941,8 (3)
[30]Liepmann H.W. On the application of statistical concepts to the buffeting proplem.J.Aeronautical Seience,1952,19(12):793-800
[31]MiyataT,Yamada H,Boonyapinyo V.Analytieal Investigation on the Respo-nse of a very long Suspension Bridge Under Gust Wind [A].Proceedings of Ninth international Conference on Wind Engineering[C],1995:-006-1017
[32]曹风产.桥梁气动弹性问题的数值计算.博士学位论文.上海:同济大学.1999
[33]葛俊颖.桥梁工程(上).中国铁道出版社.2007
[34]范立础.桥梁工程(下).人民交通出版社
[35]陈艾荣、艾辉林.计算桥梁空气动力学—大涡模拟.人民交通出版社.2010
[36]M.D.Paola.Digital simulation of wind field velocity.J. Wind Engineering and Industrial Aerodynamics,1998(74-76),91-109
[37]Y.Li,A.Kareem.Simulation of multivariate random processes:hybrid DFT and digitai filtering approach.J.Engineering Mechanice,Vol.119(3),1993,1078-1098
[38]肖信Origin 8.0实用教程—科技作图与数据分析.中国电力出版社.2008
[39]叶卫平、方安平、于本方Origin 7.0科技绘图及数据分析.机械工业出版社.2003
[40]项海帆、陈伟、顾明.桥梁抖振反应谱的实用计算方法.土木工程学报,1995
[41]Davenport A GThe application of statistical concepts to the wind loading of structures[J].Proc ICE,1961,19:449-472
[42]Davenport A GBuffeting of a suspension bridge by storm winds[J].J Struct Engrg Div ASCE,1962,88(6):233-264
[43]Jain A,Jones N P, Scanlan R H.Coupled flutter and buffeting analysis of long-span bridges[J].J Struct Engrg ASCE,1996,122(7):716-725.
[44]Scanlan R H.Gade R H.Motion of suspension bridge spans under gusty wind[J].J Struct Engrg Div ASCE,1977,103(9):1867-1883.
[45]DAVENPORT A G. The response of slender, line-like structures to a gusty wind. Proc. Inst. of Civil Engineering,1962,23(4)389-408
[46]蒋永林、强士中、廖海黎.薄板结构气动导纳试验研究.流体力学实验与测量.2001
[47]陈伟.大跨度桥梁抖振反映谱研究[D].上海:同济大学,1993.
[48]曾宪武,韩大建.大跨桥梁风致抖振时域分析及在ANSYS中的实现.桥梁建设,2004(1):9-12
[48]Bucher C G, Lin Y K. Stochastic stability of bridges considering coupled modes. Journal of Engineering Mechanics[J],1988,114(12):2055-2071.
[50]Bucher C G Lin Y K.Effect of wind turbulence on motion stability of long-span bridges[J]. J. Wind. Eng. Ind. Aerodyn.1990,36:1355-1364.
[51]Lin Y K, Motion of suspension bridges in turbulent winds. J.of Engineering Mechanics,ASCE 105(6),1979:921-932
[52]江帆 黄鹏Fluent高级应用与实例分析.清华大学出版社.2008
[53]施文杰,大跨度斜拉桥主梁断面气动导纳试验研究,重庆大学硕士学位论文,2009
[54]曹映泓、项海帆、周颖,大跨度桥梁颤振和抖振统一时程分析,土木工程学报,2000
[55]于洪刚.大跨度拱桥气动参数识别及风振响应研究.[D].上海:同济大学土木工程学院,2008.
[56]曹映泓、项海帆、周颖,大跨度桥梁随机风场的模拟.土木工程学报,1998,31(3)
[57]袁波、应惠清、徐佳炜,基于线性滤波法的脉动风速模拟及其MATLAB程序的实现,结构工程师,2007,8
[58]孔令智 斜拉桥钢箱梁涡振控制措施试验研究.硕士学位论文.重庆交通大学.2009
[59]徐泉 大跨度桥梁涡激振动及其气动减振措施研究.硕士学位论文.西南交通大学.2007