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1
Tang, Haojun, KM Shum, Qiyu Tao, and Jinsong Jiang. "Vortex-induced vibration of a truss girder with high vertical stabilizers." Advances in Structural Engineering 22, no. 4 (May 31, 2018): 948–59. http://dx.doi.org/10.1177/1369433218778656.
Повний текст джерелаАнотація:
To improve the flutter stability of a long-span suspension bridge with steel truss stiffening girder, two vertical stabilizers of which the total height reaches to approximately 2.9 m were planned to install on the deck. As the optimized girder presents the characteristics of a bluff body more, its vortex-induced vibration needs to be studied in detail. In this article, computational fluid dynamics simulations and wind tunnel tests are carried out. The vortex-shedding performance of the optimized girder is analyzed and the corresponding aerodynamic mechanism is discussed. Then, the static aerodynamic coefficients and the dynamic vortex-induced response of the bridge are tested by sectional models. The results show that the vertical stabilizers could make the incoming flow separate and induce strong vortex-shedding behind them, but this effect is weakened by the chord member on the windward side of the lower stabilizer. As the vortex-shedding performance of the optimized girder is mainly affected by truss members whose position relationships change along the bridge span, the vortex shed from the girder can hardly have a uniform frequency so the possibility of vortex-induced vibration of the bridge is low. The data obtained by wind tunnel tests verify the results by computational fluid dynamics simulations.
2
Cantero, Daniel, Ole Øiseth, and Anders Rønnquist. "Indirect monitoring of vortex-induced vibration of suspension bridge hangers." Structural Health Monitoring 17, no. 4 (August 1, 2017): 837–49. http://dx.doi.org/10.1177/1475921717721873.
Повний текст джерелаАнотація:
Wind loading of large suspension bridges produces a variety of structural responses, including the vortex-induced vibrations of the hangers. Because it is impractical to monitor each hanger, this study explores the possibility of assessing the presence of these vibrations indirectly by analyzing the responses elsewhere on the structure. To account for the time-varying nature of the wind velocity, it is necessary to use appropriate time–frequency analysis tools. The continuous wavelet transform and the short-term Fourier transform are used here to obtain clear correlations between the vortex shedding frequency and the energy content of the Hardanger Bridge responses. The analysis of recorded signals from a permanent monitoring system installed on the deck and a temporary system installed on some of the hangers shows that it is possible to indirectly detect hanger-related vortex-induced vibrations from the deck response. Furthermore, this study elaborates on the detection of the two types of vortex-induced vibrations (cross-flow and in-line), the spatial variability of the results, and a possibility to automate the detection process. The ideas reported can be implemented readily in existing structural health monitoring systems for large cable-supported structures not only to identify vortex-induced vibrations but also to gain a better understanding of their structural response.
3
Song, M. T., D. Q. Cao, and W. D. Zhu. "Vortex-Induced Vibration of a Cable-Stayed Bridge." Shock and Vibration 2016 (2016): 1–14. http://dx.doi.org/10.1155/2016/1928086.
Повний текст джерелаАнотація:
The dynamic response of a cable-stayed bridge that consists of a simply supported four-cable-stayed deck beam and two rigid towers, subjected to a distributed vortex shedding force on the deck beam with a uniform rectangular cross section, is studied in this work. The cable-stayed bridge is modeled as a continuous system, and the distributed vortex shedding force on the deck beam is modeled using Ehsan-Scanlan’s model. Orthogonality conditions of exact mode shapes of the linearized undamped cable-stayed bridge model are employed to convert coupled governing partial differential equations of the original cable-stayed bridge model with damping to a set of ordinary differential equations by using Galerkin method. The dynamic response of the cable-stayed bridge is calculated using Runge-Kutta-Felhberg method in MATLAB for two cases with and without geometric nonlinear terms. Convergence of the dynamic response from Galerkin method is investigated. Numerical results show that the geometric nonlinearities of stay cables have significant influence on vortex-induced vibration of the cable-stayed bridge. There are different limit cycles in the case of neglecting the geometric nonlinear terms, and there are only one limit cycle and chaotic responses in the case of considering the geometric nonlinear terms.
4
Bai, Ling, and Ke Liu. "Research on Vortex-Induced Vibration Behavior of Steel Arch Bridge Hanger." Applied Mechanics and Materials 137 (October 2011): 429–34. http://dx.doi.org/10.4028/www.scientific.net/amm.137.429.
Повний текст джерелаАнотація:
A fluid-structure interaction numerical simulation technique based on CFD has been developed to study the vortex-induced vibration behavior of steel arch bridge hanger. Above all, wind acting on bridge hanger is simulated by using Flunet and then vortex-induced dynamic motion of hanger is solved by method in the User Defined Function (UDF). Finally hanger’s transient vibration in wind is achieved by dynamic mesh method provided by Fluent. Using this technique, the vortex-induced vibration behavior of hanger of the Nanjing Dashengguan Yangtze River Bridge is analyzed, including vibration amplitude, vibration-started wind speed and vortex shedding frequency. The study also considers influences of different section type (rectangle, chamfered rectangle and H) of hanger. The following conclusions are obtained. Firstly hanger of different section has different vibration behavior. Secondly vibration-started wind speed of different section hanger differs with each other. Thirdly relation between vibration amplitude and incoming wind speed varies obviously. At the same time, numerical results are compared with those of one wind tunnel test and the out coming is satisfied. Relation between vibration amplitude and wind speed in both numerical simulation and wind tunnel test is similar because vibration-started wind speed in numerical result has only 10% discrepancy with that in wind tunnel test while vibration amplitude’s discrepancy is only 15%. Consequently, analysis results show the reliability of this numerical simulation technique.
5
Oh, Seungtaek, Sung-il Seo, Hoyeop Lee, and Hak-Eun Lee. "Prediction of Wind Velocity to Raise Vortex-Induced Vibration through a Road-Rail Bridge with Truss-Shaped Girder." Shock and Vibration 2018 (August 27, 2018): 1–10. http://dx.doi.org/10.1155/2018/2829640.
Повний текст джерелаАнотація:
Vortex-induced vibration (VIV) of bridges, related to fluid-structure interaction and maintenance of bridge monitoring system, causes fatigue and serviceability problems due to aerodynamic instability at low wind velocity. Extensive studies on VIV have been performed by directly measuring the vortex shedding frequency and the wind velocity for indicating the largest girder displacement. However, previous studies have not investigated a prediction of wind velocity to raise VIV with a various natural frequency of the structure because most cases have been focused on the estimation of the wind velocity and peeling-off frequency by the mounting structure at the fixed position. In this paper, the method for predicting wind velocity to raise VIV is suggested with various natural frequencies on a road-rail bridge with truss-shaped girder. For this purpose, 12 cases of dynamic wind tunnel test with different natural frequencies are performed by the resonance phenomenon. As a result, it is reasonable to predict wind velocity to raise VIV with maximum RMS displacement due to dynamic wind tunnel tests. Furthermore, it is found that the natural frequency can be used instead of the vortex shedding frequency in order to predict the wind velocity on the dynamic wind tunnel test. Finally, curve fitting is performed to predict the wind velocity of the actual bridge. The result is shown that predicting the wind velocity at which VIV occurs can be appropriately estimated at arbitrary natural frequencies of the dynamic wind tunnel test due to the feature of Strouhal number determined by the shape of the cross section.
6
Fang, Chen, Zewen Wang, Haojun Tang, Yongle Li, and Zhouquan Deng. "Vortex-Induced Vibration of a Tall Bridge Tower with Four Columns and the Wake Effects on the Nearby Suspenders." International Journal of Structural Stability and Dynamics 20, no. 09 (August 2020): 2050105. http://dx.doi.org/10.1142/s0219455420501059.
Повний текст джерелаАнотація:
With the increasing span of suspension bridges, the towers have higher heights and have become more flexible, and so do the nearby suspenders. Not only are the towers easy to be affected by winds, but also the nearby suspenders by the wake flow of the towers. To enhance the structural stiffness, a bridge tower may be designed with more columns, but this design may lead to strong aerodynamic interference among the columns, complicating the wind-induced behaviors of the tower and nearby suspenders. In this paper, wind tunnel tests and numerical simulations were carried out to investigate the vortex-induced vibration of a tall bridge tower with four columns, and the wake effects on nearby suspenders. The results show that the displacement response at the tower top increases with the increasing wind speed. No obvious lock-in region is observed, as different cross-sections of the tower show different vortex shedding characteristics. The vortex shedding characteristics are determined mainly by the aerodynamic forces acting on the leeward columns. In the wake of the tower, the aerodynamic forces of the suspenders have the same dominant frequencies as the shedding frequencies of the vortices from the tower. The frequencies may approach the natural frequencies of the suspenders, causing possible wake-induced vibration that should be avoided for a good design.
7
Luo, Nan, Ai Xia Liang, Hai Li Liao, and Mei Yu. "Wind Tunnel Investigations for the Free Standing Tower of the Penang Second Bridge." Applied Mechanics and Materials 256-259 (December 2012): 1577–81. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.1577.
Повний текст джерелаАнотація:
The Penang Second Bridge is a new bridge under construction in Penang, Malaysia. The aerodynamic behavior of the bridge was one of the main concerns. This paper summarizes of the wind tunnel testing of the 1:40 scaled aeroelastic model testing for the free standing tower. The wind tunnel Investigations were carried out with the objective of verifying the detailed design of bridge towers through measurement of the buffeting response to turbulent wind, susceptibility to galloping instabilities and susceptibility to vortex shedding excitation in smooth oncoming flow.The test results show that explicit vortex-induced vibration was observed for the completed free standing tower, however it will not affect the safety of the tower, and the buffeting response of tower is within acceptable range under the designed wind speed.
8
Xu, Kun, Yaojun Ge, Lin Zhao, and Xiuli Du. "Experimental and Numerical Study on the Dynamic Stability of Vortex-Induced Vibration of Bridge Decks." International Journal of Structural Stability and Dynamics 18, no. 03 (February 27, 2018): 1850033. http://dx.doi.org/10.1142/s0219455418500335.
Повний текст джерелаАнотація:
The dynamic stability of vortex-induced vibration (VIV) of circular cylinders has been well investigated. However, there have been few studies on this topic for bridge decks. To fill this gap, this study focuses on the dynamic stability of a VIV system for bridge decks. Some recently developed techniques for nonlinear dynamics are adopted, for example, the state space reconstruction and Poincare mapping techniques. The dynamic stability of the VIV system is assessed by combining analytical and experimental approaches, and a typical bridge deck is analyzed as a case study. Results indicate that the experimentally observed hysteresis phenomenon corresponds to the occurrence of saddle-node bifurcation of the VIV system. Through the method proposed in this study, the evolution of dynamic stability of the VIV system versus wind velocity is established. The dynamic characteristics of the system are further clarified, which offers a useful clue to understanding the VIV system for bridge decks, while providing valuable information for mathematical modeling.
9
Li, Chunguang, Yu Mao, Yan Han, Kai Li, and C. S. Cai. "Experimental Study on the Spanwise Correlation of Vortex-Induced Force Using Large-Scale Section Model." Shock and Vibration 2021 (September 13, 2021): 1–14. http://dx.doi.org/10.1155/2021/5430985.
Повний текст джерелаАнотація:
To investigate the spanwise correlation of vortex-induced forces (VIF) of a typical section of a streamlined box girder, wind tunnel tests of simultaneous measurement of force and displacement responses of a sectional model were conducted in a smooth flow. The spanwise correlation of VIF and pressure coefficients on the measurement points of an oscillating main deck were analyzed in both the time domain and frequency domain, respectively. The research results indicated that the spanwise correlation of VIF and pressure coefficients on the measurement points were related to the amplitudes of vortex-induced vibration (VIV), both of them weakened with the increase of spanwise distance; the maximum value of spanwise correlation coefficient is situated at the ascending stage of the lock-in region, rather than at the extreme amplitude point. The amplitudes of VIV showed different impacts on the spanwise correlation of pressure coefficients on the measurement points of the upper and lower surfaces, for which the maximum value of the spanwise correlation coefficients is located at the extreme amplitude point and the ascending stage of the lock-in region, respectively. Furthermore, the spanwise correlation of the pressure coefficients decreases continually from the upstream to downstream of the main deck; large coherence of vortex-induced forces and pressure appears around the frequency of vortex shedding, and the coherence of VIF and pressure becomes smaller with the increase in the spanwise distance.
10
Li, Hui, Yue Quan Bao, Shun Long Li, Wen Li Chen, Shu Jin Laima, and Jin Ping Ou. "Monitoring, Evaluation and Control for Life-Cycle Performance of Intelligent Civil Structures." Advances in Science and Technology 83 (September 2012): 105–14. http://dx.doi.org/10.4028/www.scientific.net/ast.83.105.
Повний текст джерелаАнотація:
This paper includes five parts. The first is the sensing technology, in which ultrasonic-based sensing technology for scour monitoring of bridge piers, electro-chemistry-based distributed concrete cracks and automobile wireless sensors are introduced. The second is the application of compressive sensing technology in structural health monitoring, in which the recovery of lose data for wireless senor networks, spatial distribution of vehicles on the bridge and localization of acoustic emission source by using compressive technique are included. The third is damage monitoring and identification of seismically excited structures, in which data-driven seismic localization approach and nonlinear hysteretic model identification approach are proposed. The fourth is the monitoring for wind and wind effects of long-span bridges, the vortex-induced vibration of deck, suspended cables and stay cables is observed and the buffeting of bridge under Typhoon is also measured. The last one is the data analysis, modeling and safety evaluation of bridges based on structural health monitoring techniques.
11
Kwok, K. C. S., X. R. Qin, C. H. Fok, and P. A. Hitchcock. "Wind-induced pressures around a sectional twin-deck bridge model: Effects of gap-width on the aerodynamic forces and vortex shedding mechanisms." Journal of Wind Engineering and Industrial Aerodynamics 110 (November 2012): 50–61. http://dx.doi.org/10.1016/j.jweia.2012.07.010.
Повний текст джерела
12
Wang, Chaoqun, Xugang Hua, Zhiwen Huang, and Qing Wen. "Aerodynamic Characteristics of Coupled Twin Circular Bridge Hangers with Near Wake Interference." Applied Sciences 11, no. 9 (May 4, 2021): 4189. http://dx.doi.org/10.3390/app11094189.
Повний текст джерелаАнотація:
Much work has been devoted to the investigation and understanding of the flow-induced vibrations of twin cylinders vibrating individually (e.g., vortex-induced vibration and wake-induced galloping), but little has been devoted to coupled twin cylinders with synchronous galloping. The primary objective of this work is to investigate the aerodynamic forcing characteristics of coupled twin cylinders in cross flow and explore their effects on synchronous galloping. Pressure measurements were performed on a stationary section model of twin cylinders with various cylinder center-to-center distances from 2.5 to 11 diameters. Pressure distributions, reduced frequencies and total aerodynamic forces of the cylinders are analyzed. The results show that the flow around twin cylinders shows two typical patterns with different spacing, and the critical spacing for the two patterns at wind incidence angles of 0° and 9° is in the range of 3.8D~4.3D and 3.5D~3.8D, respectively. For cylinder spacings below the critical value, vortex shedding of the upstream cylinder is suppressed by the downstream cylinder. In particular, at wind incidence angles of 9°, the wake flow of the upstream cylinder flows rapidly near the top edge and impacts on the inlet edge of the downstream cylinder, which causes a negative and positive pressure region, respectively. As a result, the total lift force of twin cylinders comes to a peak while the total drag force jumps to a higher value. Moreover, there is a sharp drop of total lift coefficient for α = 9–12°, indicating the potential galloping instability. Finally, numerical simulations were performed for the visualization of the two flow patterns.
13
MA, RU-JIN, and XIAO-HONG HU. "AEROELASTIC MODEL TEST STUDY ON A BRIDGE PYLON CONSIDERING THE INTERFERENCE EFFECTS OF SURROUNDING STRUCTURES." International Journal of Structural Stability and Dynamics 13, no. 05 (May 28, 2013): 1350011. http://dx.doi.org/10.1142/s0219455413500119.
Повний текст джерелаАнотація:
The interference effect between buildings has been a popular issue in structural wind engineering for a long time. Most researches about this issue have been focused mainly on high-rise buildings. For long-span bridges, the interference effects between structures are rarely discussed. In this paper, an aerodynamic elastic model test of a free-standing bridge pylon located adjacent to two large-scale cooling towers is presented. Through the mode analysis, the structure mode shapes are obtained. Then by the simulation of the two cooling towers in the boundary layer during the aeroelastic model test, the vibration responses of the bridge pylon in smooth and turbulence flows are obtained respectively. The study shows that the interference effect of the two huge-volume cooling towers on the wind induced vibration responses of the bridge pylon should not be neglected. In smooth flow, due to the regular shedding vortex from the upwind cooling towers, the interference effect is evident in that strong resonant responses are induced on the lower-order modes of the downwind bridge pylon. However, in turbulence flow, this kind of interference effect is greatly reduced. Moreover, more attention should be paid to the case when the cooling towers are located at the perfectly right upwind direction of the bridge pylon. Their interference effect will certainly cause great resonant vibrations in the longitudinal direction, which cannot be ignored for granted. Furthermore, the turbulence flow at the bridge pylon considering the interference effect is measured through a 1:500 flow experiment to discover the interference effect of the cooling towers. In the end, a dynamic magnification factor is proposed to take the interference effect into consideration, with a value of 2.25 suggested for the design of pylons.
14
Fang, Chen, Ruijie Hu, Haojun Tang, Yongle Li, and Zewen Wang. "Experimental and numerical study on vortex-induced vibration of a truss girder with two decks." Advances in Structural Engineering, November 12, 2020, 136943322096902. http://dx.doi.org/10.1177/1369433220969026.
Повний текст джерелаАнотація:
Vortex-induced vibration (VIV) depends on aerodynamic shapes of bridge girders, which should be treated carefully in the design of long-span bridges. This paper studies the VIV performance of a suspension bridge with the truss girder which contains two separated decks. Although truss girders generally show better VIV performance than box girders, significant vibrations of this type of girders occurred in the wind tunnel tests based on a large-scale sectional model. Several lock-in regions with the same vibration frequency were observed, corresponding to different shedding vortices. Computational fluid dynamics (CFD) simulations were carried out, and monitoring points were set behind different components to study the characteristics of the shed vortices. As the truss girder consists of many members, the results show that various vortices with different dominant frequencies are formed in the wake flow. The vertical VIV of the bridge is probably driven by the vortices behind or above the upper deck, which is related to the guardrails. The torsional VIV of the bridge is probably driven by the vortices behind or below the lower deck, which is related to the service road at lower wind speeds while may be related the vertical stabilizers at higher wind speeds.
15
Zhu, Le-Dong, Xiao-Liang Meng, Zhongxu Tan, and Qing Zhu. "Full bridge analysis of nonlinear vortex-induced vibration considering incomplete span-wise correlation of vortex-induced force." Advances in Structural Engineering, October 25, 2022, 136943322211358. http://dx.doi.org/10.1177/13694332221135899.
Повний текст джерелаАнотація:
Responses of vortex-induced vibration (VIV) of long-span bridges are commonly measured at first via wind tunnel tests of sectional model and then converted to the prototype ones of the corresponding full bridges by some approximate formulae. In this paper, a time-domain full bridge analysis method was presented for predicting nonlinear VIV responses mode-by-mode based on a polynomial type of nonlinear mathematical model of vortex-induced force (VIF) on bridge deck cross section. In this method, the motion-dependant self-excited force (SEF) components of VIF were regarded as fully correlated span-wise in the case of smooth flow, while the motion-independent harmonic pure vortex-shedding force (PVSF) component of VIF was regarded as incompletely correlated along the bridge span. To take into account the incomplete span-wise correlation of PVSF, an equivalent generalized PVSF including the effect of the incomplete span-wise correlation of PVSF was defined by using a span-wise correlation coefficient of PVSF which could be obtained through a sectional model wind tunnel test of simultaneous pressure measurement. As an application example, the VIV responses of 12 vertical modes of a steel box deck cable stayed bridge with a main span of 688 m were analysed, and were compared with those converted with two approximate converting formulae, respectively, based on Scanlan’s linear and nonlinear mathematical model of VIF. It is found that the influence of the incomplete span-wise correlation of PVSF on the bridge VIV response is very small and can then be ignored.
16
Song, Daeun, Woojin Kim, Oh-Kyoung Kwon, and Haecheon Choi. "Vertical and torsional vibrations before the collapse of the Tacoma Narrows Bridge in 1940." Journal of Fluid Mechanics 949 (September 23, 2022). http://dx.doi.org/10.1017/jfm.2022.748.
Повний текст джерелаАнотація:
We perform a three-dimensional direct numerical simulation of flow over the Tacoma Narrows Bridge to understand the vertical and torsional vibrations that occurred before its collapse in 1940. Real-scale structural parameters of the bridge are used for the simulation. The Reynolds number based on the free-stream velocity and height of the deck fence is lower ( ${Re}=10\ 000$ ) than the actual one on the day of its collapse ( ${Re}=3.06 \times 10^{6}$ ), but the magnitude of a fluid property is modified to provide the real-scale aerodynamic force and moment on the deck. The vertical and torsional vibrations are simulated through two-way coupling of the fluid flow and structural motion. The vertical vibration occurs from the frequency lock-in with the vortex shedding, and its wavelength and frequency agree well with the recorded data in 1940. After saturation of the vertical vibration, a torsional vibration resulting from the aeroelastic fluttering grows exponentially in time, with its wavelength and frequency in excellent agreement with the recorded data of the incident. The critical flutter wind speed for the growth of torsional vibration is obtained as $3.56 < U_c / (f_{nat} B) \le 4$ , where $U_{c}$ is the critical flutter wind speed, $f_{nat}$ is the natural frequency of the torsional vibration and $B$ is the deck width. Finally, apart from the actual vibration process in 1940, we perform more numerical simulations to investigate the roles of the free-stream velocity and vertical vibration in the growth of the torsional vibration.
17
Duan, Qingsong, Cunming Ma, Jiankun Li, Qiusheng Li, and Jingmiao Shang. "Vortex-induced vibration characteristics of two open girders: A comparison of experimental and numerical investigation." Advances in Structural Engineering, May 25, 2022, 136943322211012. http://dx.doi.org/10.1177/13694332221101231.
Повний текст джерелаАнотація:
Open girder sections are vulnerable to vortex-induced vibrations (VIV) because of their bluff aerodynamic characteristics. A comparative investigation was conducted by wind tunnel tests and numerical simulation. Firstly, based on sectional model wind tunnel tests, the VIV performance of semi-open girder and separated edge-boxes open girder was studied with consideration of the influence of the equivalent mass, wind attack angle and damping ratio. The aerodynamic parameters Scruton number ( S c) and Strouhal number ( S t) of two girders were analyzed contrastively. In addition, VIV amplitudes corresponding to the real bridge girders were calculated by the linear and nonlinear theories. Then, flow fields around two semi-open girder sections were investigated on the basis of computational fluid dynamics. The results show that vertical and torsional VIVs of two open girders are observed, at +3°and +5° wind attack angles. There were two vertical VIV regions and the maximum amplitude in the second vertical VIV region is significantly larger than that in the first one. For the semi-open girder and separated edged-box open girder, the vertical VIV amplitudes at +5° wind attack angle is 115% and 75% larger than at +3° wind attack angle, respectively. The damping ratio could obviously mitigate the VIV of two girders and VIV amplitudes are decreased linearly with the S C number increases. There are vortexes above the girder deck at the opening position of the semi-open girder and the separated edge-boxes open girder. The oblique web and wind faring may break the large vortex into several smaller vortexes at the opening position, thus optimizing the vortex vibration performance of the girder. A thicker shear layer is formed at separated open-girder during the development of airflow towards backward of bridge deck, due to the effect of railings and the blunt boxes on the lower surface.