流线闭口箱梁断面涡振过程分布气动力演变特性
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摘要
涡激振动是大跨度桥梁在低风速下较常见的风致振动现象,探究涡振机理是桥梁涡激振动效应评价与控制的重要前提.为深入研究涡振机理,立足于涡振发展的完整过程分布气动力与结构行为同步演变特性分析,深入揭示了分布气动力及其结构行为作用机制.以典型大跨度桥梁闭口流线型箱梁断面为对象,实现了弹性悬挂节段模型同步测力、测振和测压风洞试验.针对典型涡振过程风速关键结点,对比研究了涡振发生前、锁定区上升区、振幅极值点、下降区以及涡振后等不同时期箱梁表面分布气动力演变特性.研究表明,涡振过程箱梁分布气动力特性具有明显的变迁历程,集中体现在涡振锁定区内外表面气动力特性具有显著差异,压力系数根方差、振动卓越频率处压力系数等统计参数与涡振振幅高度相关,气动力与涡振振幅具有明显同步演化关系,尤其是上表面下游、下表面与下游风嘴转角附近区域气动力演变特性显著,是引起涡振的主要原因.该研究为涡振机理研究提供了一种新的思路和方法,未来可应用于其他类型主梁断面.
The vortex-induced vibration( VIV) is a typical phenomenon of wind-induced vibration in low windvelocities, especially for the long-span bridges, and an important prerequisite for the evaluation and control of thevibration effects on bridges. Based on synchronously evolutionary characteristics analysis of distributed aerodynamicforces and structural effects during VIV, characteristic of distributed aerodynamic forces and their effects onstructural behaviors were conducted to reveal the mechanism of VIV. Aiming at a traditional streamlined closed-boxgirder of long-span bridges, wind tunnel tests of synchronal measurement of force and displacement responses ofspring-suspended sectional model were conducted. Pressure-measured tests were implemented to investigate thespatial aerodynamic distribution of the girder during VIV. Surface pressure distributions in different amplitude-developing period during VIV were compared, including pre-VIV period, ascent stage, amplitude extreme point,descent stage and post-VIV period. It is found that aerodynamic characteristics of the model has obvious changesduring VIV, indicating that there are obvious differences between lock-in period and non-VIV period. Thedistributed aerodynamic forces and the amplitudes of aerodynamic forces at predominant frequency are positivelycorrelated with the amplitude of VIV responses. The aerodynamic characteristics and the VIV response during VIVare synergistic, especially nearby downstream region of upper surface and the corner region of lower surface and tailwind fairing, which is the main cause of VIV. This study provides a new way for the research on the mechanism ofVIV, and can be applied to other cross-sections.
The vortex-induced vibration( VIV) is a typical phenomenon of wind-induced vibration in low windvelocities, especially for the long-span bridges, and an important prerequisite for the evaluation and control of thevibration effects on bridges. Based on synchronously evolutionary characteristics analysis of distributed aerodynamicforces and structural effects during VIV, characteristic of distributed aerodynamic forces and their effects onstructural behaviors were conducted to reveal the mechanism of VIV. Aiming at a traditional streamlined closed-boxgirder of long-span bridges, wind tunnel tests of synchronal measurement of force and displacement responses ofspring-suspended sectional model were conducted. Pressure-measured tests were implemented to investigate thespatial aerodynamic distribution of the girder during VIV. Surface pressure distributions in different amplitude-developing period during VIV were compared, including pre-VIV period, ascent stage, amplitude extreme point,descent stage and post-VIV period. It is found that aerodynamic characteristics of the model has obvious changesduring VIV, indicating that there are obvious differences between lock-in period and non-VIV period. Thedistributed aerodynamic forces and the amplitudes of aerodynamic forces at predominant frequency are positivelycorrelated with the amplitude of VIV responses. The aerodynamic characteristics and the VIV response during VIVare synergistic, especially nearby downstream region of upper surface and the corner region of lower surface and tailwind fairing, which is the main cause of VIV. This study provides a new way for the research on the mechanism ofVIV, and can be applied to other cross-sections.
引文
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[6]许福友,丁威,姜峰,等.大跨度桥梁涡激振动研究进展与展望[J].振动与冲击,2010,29(10):40-49.XU Fuyou,DING Wei,JIANG Feng,et al.Research progress andprospect of vortex-induced vibration of long-span bridges[J].Journal of Vibration and Shock,2010,29(10):40-49.
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[13]许福友,林志兴,李永宁,等.气动措施抑制桥梁涡振机理研究[J].振动与冲击,2010,29(1):73-76.XU Fuyou,LIN Zhixing,LI Yongning,et al.Study on themechanism of vibrating vibration of bridge by aerodynamic measures[J].Journal of Vibration and Shock,2010,29(1):73-76.
[14]郭增伟,赵林,葛耀君,等.基于桥梁断面压力分布统计特性的抑流板抑制涡振机理研究[J].振动与冲击,2012,31(7):89-94.GUO Zengwei,ZHAO Lin,GE Yaojun,et al.Mechanism analysisfor vortex-induced vibration reduction of a flat streamlined steel box-shaped girder with airflow-suppressing board based on statisticalproperty of surface pressure[J].Journal of Vibration and Shock,2012,31(7):89-94.
[15]胡传新,杨立坤,周志勇.动态测压与POD方法相结合对桥梁涡振的分析[J].力学季刊,2013,34(4):591-598.HU Chuanxin,YANG Likun,ZHOU Zhiyong.Research on vortexvibration of bridge based on POD and dynamic pressuremeasurement[J].Chinese Quarterly of Mechanics,2013,34(4):591-598.
[16]WU T,KAREEM A.Vortex-induced vibration of bridge decks:Avolterra series based model[J].Journal of Engineering MechanicsASCE,2013,139(12):1831-1843.
[17]MASHNAD M,JONES N P.A model for vortex-induced vibrationanalysis of long-span bridges[J].Journal of Wind Engineering&Industrial Aerodynamics,2014,134:96-108.
[18]LAIMA S,LI H.Effects of gap width on flow motions around twin-box girders and vortex-induced vibrations[J].Journal of WindEngineering&Industrial Aerodynamics,2015,139:37-49.
[19]YUAN W Y,LAIMA S,CHEN W L,et al.Investigation on thevortex-and-wake-induced vibration of a separated-box bridge girder[J].Journal of Fluids and Structures,2017,70:145-161.
[20]XU K,ZHAO L,GE Y J.Reduced-order modeling and calculationof vortex-induced vibration for large-span bridges[J].Journal ofWind Engineering&Industrial Aerodynamics,2017,167:228-241.
[21]XU F Y,YING XY,LI Y L,et al.Experimental explorations of thetorsional vortex-induced vibrations of a bridge deck[J].Journal ofBridge Engineering,2016,21(12):1-10.
[22]KURODA S.Numerical simulation of flow around a box girder of along span suspension bridge[J].Journal of Wind Engineering&Industrial Aerodynamics,1997,67(4):239-252.
[2]FUJINO Y.Wind-Induced vibration and control of Trans-Tokyo BayCrossing Bridge[J].Journal of Structural Engineering,2002,128(8):1012-1025.
[3]BALLISTA R C,PFEIL M S.Reduction of vortex-inducedoscillations of Rio-Nileroi bridge by dynamic control devices[J].Journal of Wind Engineering and Industrial Aerodynamics,2000,84(3):273-288.
[4]LI H,LAIMA S,OU J,et al.Investigation of vortex-inducedvibration of a suspension bridge with two separated steel box girdersbased on field measurements[J].Engineering Structures,2011,33(6):1894-1907.
[5]LI H,LAIMA S,ZHANG Q,et al.Field monitoring and validationof vortex-induced vibrations of a long-span suspension bridge[J].Journal of Wind Engineering&Industrial Aerodynamics,2014,124(7):54-67.
[6]许福友,丁威,姜峰,等.大跨度桥梁涡激振动研究进展与展望[J].振动与冲击,2010,29(10):40-49.XU Fuyou,DING Wei,JIANG Feng,et al.Research progress andprospect of vortex-induced vibration of long-span bridges[J].Journal of Vibration and Shock,2010,29(10):40-49.
[7]SIMIU E,SCANLAN R H.Wind effects on structures:Fundamentalsand applications to design[M].2nd ed.New York:John Wiley&Sons,Inc.,1986.
[8]LARSEN A.A generalized model for assessment of vortex-inducedvibrations of flexible structures[J].Journal of Wind Engineering andIndustrial Aerodynamics,1995,57(2/3):281-294.
[9]LARSEN A,WALTHER J H.Aeroelastic analysis of bridge girdersections based on discrete vortex simulations[J].Journal of WindEngineering&Industrial Aerodynamics,1997,67(97):253-265.
[10]NAGAO F,UTSUNOMIYA H,YOSHIOKA E,et al.Effects ofhandrails on separated shear flow and vortex-induced oscillation[J].Journal of Wind Engineering&Industrial Aerodynamics,1997,69(97):819-827.
[11]DIANA G,RESTA F,BELLOLI M,et al.On the vortex sheddingforcing on suspension bridge deck[J].Journal of Wind Engineering&Industrial Aerodynamics,2006,94(5):341-363.
[12]张文明,葛耀君,杨詠昕,等.带挑臂箱梁涡振气动控制试验[J].哈尔滨工业大学学报,2010,42(12):1948-1952.ZHANG Wenming,GE Yaojun,YANG Yongxin,et al.Experimental study on aerodynamic control of the vortex-inducedvibrations of a box girder with projecting slab[J].Journal of HarbinInstitute of Technology,2010,42(12):1948-1952,1989.
[13]许福友,林志兴,李永宁,等.气动措施抑制桥梁涡振机理研究[J].振动与冲击,2010,29(1):73-76.XU Fuyou,LIN Zhixing,LI Yongning,et al.Study on themechanism of vibrating vibration of bridge by aerodynamic measures[J].Journal of Vibration and Shock,2010,29(1):73-76.
[14]郭增伟,赵林,葛耀君,等.基于桥梁断面压力分布统计特性的抑流板抑制涡振机理研究[J].振动与冲击,2012,31(7):89-94.GUO Zengwei,ZHAO Lin,GE Yaojun,et al.Mechanism analysisfor vortex-induced vibration reduction of a flat streamlined steel box-shaped girder with airflow-suppressing board based on statisticalproperty of surface pressure[J].Journal of Vibration and Shock,2012,31(7):89-94.
[15]胡传新,杨立坤,周志勇.动态测压与POD方法相结合对桥梁涡振的分析[J].力学季刊,2013,34(4):591-598.HU Chuanxin,YANG Likun,ZHOU Zhiyong.Research on vortexvibration of bridge based on POD and dynamic pressuremeasurement[J].Chinese Quarterly of Mechanics,2013,34(4):591-598.
[16]WU T,KAREEM A.Vortex-induced vibration of bridge decks:Avolterra series based model[J].Journal of Engineering MechanicsASCE,2013,139(12):1831-1843.
[17]MASHNAD M,JONES N P.A model for vortex-induced vibrationanalysis of long-span bridges[J].Journal of Wind Engineering&Industrial Aerodynamics,2014,134:96-108.
[18]LAIMA S,LI H.Effects of gap width on flow motions around twin-box girders and vortex-induced vibrations[J].Journal of WindEngineering&Industrial Aerodynamics,2015,139:37-49.
[19]YUAN W Y,LAIMA S,CHEN W L,et al.Investigation on thevortex-and-wake-induced vibration of a separated-box bridge girder[J].Journal of Fluids and Structures,2017,70:145-161.
[20]XU K,ZHAO L,GE Y J.Reduced-order modeling and calculationof vortex-induced vibration for large-span bridges[J].Journal ofWind Engineering&Industrial Aerodynamics,2017,167:228-241.
[21]XU F Y,YING XY,LI Y L,et al.Experimental explorations of thetorsional vortex-induced vibrations of a bridge deck[J].Journal ofBridge Engineering,2016,21(12):1-10.
[22]KURODA S.Numerical simulation of flow around a box girder of along span suspension bridge[J].Journal of Wind Engineering&Industrial Aerodynamics,1997,67(4):239-252.