Wind-induced Vibration Response Research Articles

Numerical Simulation and Wind Tunnel Test on the Wind-Induced Response of Three Typical Types of Greenhouse Main Structures

Investigating the wind-induced vibration response of the greenhouse structure, and the wind pressure distribution on its surface takes on a critical significance when the main structure is under large wind loads. A computational fluid dynamics-based study was conducted, and wind tunnel tests were performed to study the wind pressure distribution on the surface of the greenhouse structure. First, three types of greenhouses, including Venlo, Round-arch, and Saw-tooth type greenhouses, were selected as the design models for the study. In addition, the double-span, four-room structure model was built to explore the wind pressure distribution and the extreme wind pressure coefficient on the greenhouse surface for 13 (0°–180°, every 15°) directions of the wind direction to obtain the wind load characteristics in the greenhouse surface under different conditions. The results of the wind tunnel tests were consistent with those of the simulations, with the maximum wind pressure in the X-direction occurring at 30°-wind and the maximum wind pressure in the Y-direction at 75°-wind. The maximum negative wind pressure acting locally on the roof of the greenhouse was twice the maximum positive pressure acting on the windward side of the greenhouse. Accordingly, it is necessary to strengthen the structure in regions sensitive to wind direction with significant response to wind.

Study on Wind-Induced Response of Transmission Tower-Line System under Downburst Wind

Downburst is the main source of extreme wind speed in non-typhoon areas, which has caused a large amount of transmission line damage all over the world. In order to reveal the wind-induced vibration response characteristics of a transmission tower-line system under downburst, the nonlinear dynamic analysis of a single tower and tower-line system is carried out, and the amplification effect of tower-line coupling and fluctuating wind on the dynamic response is studied. Then, the effects of three wind field parameters closely related to the average wind profile on the wind-induced response of the tower-line system are studied. The results show that under the action of the downburst, the tower-line coupling weakens the dynamic response to a certain extent, and the dynamic amplification factor of a single tower and tower-line system is 1.1 ~ 1.3; for the self-supporting tower, when the height of the peak wind speed is close to the height of tower, the responses of the structure are more unfavorable. When the vector superposition method is used, the storm moving speed (Vt) has little effect on the wind-induced response of the tower-line system. For large-span structures such as tower-line systems, to ensure the safety of the structural design, the value of the characteristic radius (Rc) should not be too small.

A novel eddy current damper system for multi-mode high-order vibration control of ultra-long stay cables

Recently, the multi-mode high-order wind-induced vibration of the ultra-long stay cables has been observed on several cable-stayed bridges, which may result in a visual panic of the users and the fatigue of the stay cables at anchorage ends. In order to investigate the multi-mode high-order wind-induced vibration characteristics of ultra-long stay cables, a vibration monitoring system (VMS) of the stay cables is established on the Sutong Bridge (STB). Furthermore, to suppress the in-plane and out-of-plane vibration responses of the stay cables simultaneously, a novel eddy current damper system (ECDS) is proposed in this study. The damping coefficients of the ECDS for multi-mode high-order vibration of the stay cables are determined via a modified method. Moreover, laboratory tests are conducted to evaluate the performance of the developed dampers. Furthermore, the field tests of seven stay cables of the STB are carried out to identify the modal damping ratios of the cable-damper system via the free vibration method. The results show that it is feasible to provide sufficient additional modal damping ratios for multi-mode high-order vibration of ultra-long stay cables applying the ECDS proposed in this study. Finally, the one-year field measurements of the wind-induced vibration responses of the seven stay cables of the STB are carried out to validate the ECDS suppress effects on multi-mode high-order vibration control of ultra-long stay cables. The measurement results show that the multi-mode high-order vibration responses of the monitored stay cables of the STB are effectively suppressed.

Field measurement and analysis on wind-induced vibration response of single column lightning rod

Field measurement and analysis on wind-induced vibration response of single column lightning rod

Wind Field Characteristics of Butte and the Influence on the Wind-Induced Responses of Transmission Towers

The computational fluid dynamics (CFD) simulation on the butte was carried out to obtain the wind field characteristics for a specific mountain in the hilly area of eastern China. Then, the speed-up ratios of butte at each location distributed by height were calculated. The simulation results were compared with the specified value of mountain wind field acceleration ratio in various codes. The finite element model of the transmission tower line system is established by ANSYS, and the wind-induced vibration response of the structural system under the single mountain wind field is calculated, which is compared with the results of flat ground. The results show that the mountain will hinder the fluid passing through it. There is a deceleration zone in front of the mountain and a flow separation phenomenon behind the mountain. The speed-up ratios at the butte top where accelerating effect are the biggest among all positions of the butte. As the height increases, they approach 1. The speed-up ratios calculated by the Chinese code and the Australian code are linearly changing along the ridge of the butte and are symmetric at the windward side and leeward side. The biggest speed-up ratios are calculated by the Chinese code, and the smallest ratios are calculated by CFD. The wind-induced vibration response of the transmission tower line system is influenced by the wind speed-up ratios and reaches the maximum at the top of the butte. The simulation results at the windward side are close to the values calculated by the Australia code and the Euro code, but at the top and leeward side, they are far smaller than others.

Analysis of Wind-Induced Vibration Response of High-Rise Structure of Heat Sink Tower Based on Large Eddy Simulation

Analysis of Wind-Induced Vibration Response of High-Rise Structure of Heat Sink Tower Based on Large Eddy Simulation

Optimization of anti-wind disturbance ability of a long-span cable-driven parallel camera robot based on a Genetic Algorithm

The cable-driven parallel camera robot is a long-span cable-supported high-rise structure, which is easy to produce vibration response due to wind disturbance, which affects its normal work. In this paper, the method of structural optimization is used to improve the first-order natural frequency of the system to keep it away from the energy truncation frequency, so as to reduce the wind-induced vibration response of the system. In order to avoid the defect of premature convergence of standard genetic algorithm, an adaptive multi-island genetic algorithm based on population information entropy is proposed for structure optimization. the simulation results show that the algorithm can more effectively improve the first-order natural frequency of the system and improve the wind disturbance resistance of the system.

Numerical simulation of wind veering effects on aeroelastic responses of thousand-meter-scale super high-rise buildings

The atmospheric boundary layer (ABL) consists of the atmospheric surface layer (ASL) and the Ekman layer. In the Ekman layer, which typically accounts for the upper 90% of the ABL, the wind veering is generally remarkable along the height. In the wind-resistant design of thousand-meter-scale super high-rise buildings, it is of vital importance to consider the wind veering effects. However, the relevant research on this issue has been rare so far. In this study, based on the authors’ previous study on wind loads acting on thousand-meter-scale super high-rise buildings immersed in the veering wind field, the structural aeroelastic responses of a thousand-meter-scale square-section building model with an aspect ratio of 9:1 under various reduced wind velocities without considering wind veering at 0° wind direction and considering wind veering at 75° wind direction are numerically simulated by utilizing the commercial software ANSYS Workbench 19.1. The wind veering effects on structural aeroelastic responses are comprehensively analyzed. Additionally, the structural dynamic responses with and without considering aeroelasticity are compared. The effects of aerodynamic damping on wind-induced vibration responses are further discussed, and the underlying mechanisms are illustrated in the light of instantaneous flow fields.

Research on Wind-induced Vibration Control of High-rise Steel Structures Based on Machine Learning Algorithm

In recent years, the research on vibration control of high-rise steel structures has developed vigorously, and many research results have been applied to practical projects. The main purpose of wind-induced vibration control of high-rise steel structures is to reduce the discomfort of occupants and the damage of precision equipment and non-structural components. This kind of high-rise steel tower structure is highly flexible, and under the action of strong wind load, the dynamic response of the structure is also great, which has a very adverse impact on the safety of the structure itself, the technological requirements of the building and the comfort level, etc. Therefore, it is increasingly important to effectively control the wind-induced vibration response of the structure. Machine learning algorithm is the research hotspot of gust prediction, and its advantage lies in that this kind of method can establish the nonlinear relationship between gust related variables and gust without depending on some specific parameters. Due to the uncertainty of the control system including structural system and control, the complexity of mathematical model and difficult to grasp dynamic characteristics, the wind-induced vibration control effect of high-rise buildings needs to be further improved. In this paper, the wind-induced vibration control of high-rise steel structures is described in detail by using machine learning algorithm.

Experimental study on wind-induced vibration and aerodynamic mitigation measures of a building over 800 meters

The new-generation high-rise buildings are taller and more flexible than before. Rigid model and aeroelastic model tests of a proposed steel super high-rise building with a height of 838 m were carried out in two simulated typical wind fields defined in the Chinese code [1] and the ISO standard (ISO 4354) in an atmospheric boundary layer wind tunnel. The wind pressure distributions of the building were obtained through the rigid model tests and then the wind-induced vibration responses of the building were calculated. Through the aeroelastic model test, the vibration responses of the building, which naturally include the wind–structure coupling effects, were directly obtained. The test results shows that strong crosswind vortex-induced resonance may appear at high wind speeds. Based on these results, the crosswind aerodynamic damping of the building was then studied. Finally, seven aerodynamic measures for controlling the wind-induced vibrations of the building were proposed and tested. The results show that the seven proposed aerodynamic measures can reduce the dynamic responses of buildings in different degrees.

Wind-resistant performance and failure modes for a semi-submersible offshore platform during jacking closure

Currently, the construction process of large offshore platforms worldwide involves building the topside and hull separately and then having them integrated. The jacking closure scheme by overlapped support tower bearing the topside is a new integration method, which has a great advantage over other traditional methods in vertical bearing capacity. But its weak bearing capacity to lateral forces like wind load limits the jacking height. Moreover, few engineering examples and academic researches also cause insufficient understanding of it. Therefore, this paper, based on the first deep-water semi-submersible platform with the10,000-ton oil storage worldwide, i.e. “Deep Sea No. 1” energy station, aims to evaluate the wind-resistant performance during the jacking closure process. Firstly, the background and the jacking closure scheme of this project are introduced in detail. Secondly, the finite element models (FEMs) of the jacking system are established according to the overlapped characteristics of jacking towers and the corresponding failure criteria. Then, the wind-induced vibration response is simulated, and the static pushover is conducted to evaluate the ultimate bearing capacity and its influencing factors. The failure criteria are checked using ANSYS parameter design language. It is found that “the occurrence of tensile stress on the contact surface” is the first and main failure mode of the structure. Additionally, the results also reveal that the strand cables can not only improve the ultimate bearing capacity of the structure but also change its weak direction. However, the improvement is gradually weakened with the increase of jacking height. In contrast, the contribution of the bracing pipes to the structural bearing capacity is always significant. These findings can be used to develop a more reasonable closure plan.

Investigation of the Scruton Number Effects of Wind-Induced Unsteady Galloping Responses of Bridge Suspenders

When the critical wind speed of vortex-induced resonance is close to that of quasi-steady galloping, a type of coupled wind-induced vibration that is different from divergent galloping can easily occur in a rectangular bar. It is a type of “unsteady galloping” phenomenon wherein the response amplitude increases linearly with the increase in the wind speed, while a limit cycle oscillation is observed at each wind speed, whose mechanism is still in research. Mass and damping are the key parameters that affect the coupling degree and amplitude response estimation. For a set of rectangular section member models with a width-to-height ratio of 1.2, by adjusting the equivalent stiffness, equivalent mass, and damping ratio of the model system and performing comparative tests on the wind-induced vibration response of the same mass with different damping ratios, it is possible to achieve the same damping ratio with different masses and the same Scruton number with different masses and damping combinations under the same Reynolds number. The results show that the influence of the mass and damping parameters on the “unsteady galloping” amplitude response is independent, and the weight is the same in the coupling state. The Scruton number “locked interval” (12.4–30.6) can be found in the “unsteady galloping” amplitude response, and the linear slope of the dimensionless wind speed amplitude response curve does not change with the Scruton number in the “locked interval.” In addition, a “transition interval” (26.8–30.6) coexists with the “locked interval” wherein the coupling state of the wind-induced vibration is converted into the uncoupled state. The empirical formula for estimating the “unsteady galloping” response amplitude is modified and can be used to predict the amplitude within the design wind speed range of similar engineering members.

Extracting Time-Varying Mean Component of Non-Stationary Winds Utilizing Vondrak Filter and Genetic Algorithm: A Wind Engineering Perspective

The time-varying mean (TVM) component plays a vital role in the characterization of non-stationary winds, whereas it is difficult to extract the TVM accurately or to validate it quantitively. To deal with this problem, this paper first develops two additional conditions for the TVM extraction from the perspective of structural wind-induced vibration response, then presents an approach, based on the combination of Vondrak filter and genetic algorithm (Vondrak-G), to derive the optimal TVM from non-stationary wind speed records as well as its turbulence characteristics (i.e. gust factor, turbulence intensity, and turbulence integral length scale). Furthermore, the wind characteristics obtained by the Vondrak-G approach are compared with those by a conventional approach derived for stationary winds, demonstrating that the results by the Vondrak-G approach are evidently more accurate. This paper aims to provide an effective method for accurately extracting the TVM and then evaluating wind characteristics of the non-stationary wind.

Universal simplified spectral models and closed form solutions to the wind-induced responses for high-rise structures

High-rise structures are characterized as wind-sensitive vertical structures, estimating the wind-induced vibration response is a key to the structural design procedure. This study presented universal wind load spectral models for high-rise structures, including tri-para and κ model for along-wind load characterized by power dissipating with frequency and analog filter model for cross-wind load dominant by power concentration induced by vortex excitation. The spectral models appear to provide good agreement with wind tunnel data of buildings with various configurations. With analog filter approach, the along-wind spectra can be approximated by a linear filter polynomial and the cross-wind spectra is expressed by a quadratic filter polynomial. Thus forming a simple differential equation for the along- and cross-wind excitation based on a pseudo idea white noise. The closed form solutions to the wind-induced responses are derived based on analog filter approach. The Lyapunov equations are also provided in the state-space for high-rise structures with and without extra damping devices. The presented closed form solutions can provide a powerful tool in codification and vibration control optimization.

Wind-induced vibration fragility of outer-attached tower crane to super-tall buildings: A case study

To gain insight into the wind-induced safety concerns associated with attached tower cranes during the construction of super-tall buildings, a 606 m level frame-core tube super-tall building is selected to investigate the wind-induced vibration response and fragility of an outer-attached tower crane at all stages of construction. The wind velocity time history samples are artificially generated and used to perform dynamic response analyses of the crane to observe the effects of wind velocity and wind direction under its working and non-working resting state. The adverse effects of the relative displacement response at different connection supports are also identified. The wind-resistant fragility curves of the crane are obtained by introducing the concept of incremental dynamic analysis. The results from the investigation indicate that a large relative displacement between the supports can substantially amplify the response of the crane at high levels. Such an effect becomes more serious when the lifting arm is perpendicular to the plane of the connection supports. The flexibility of super-tall buildings should be considered in the design of outer-attached tower cranes, especially for anchorage systems. Fragility analysis can be used to specify the maximum appropriate height of the tower crane for each performance level.

Influence of coverage of fin-shaped rods on flow-induced vibration and power extraction of cylinder-based wind energy harvester

Wind-induced vibration (WIV) and power extraction performances of a circular cylinder with symmetrically installed fin-shaped rods (FSR) were experimentally and numerically investigated under different coverages. The FSR coverage which is expressed as an angle (α) is measured from the upstream edge to the downstream edge of the rod. The effect of FSR installation angle (θ) which is the angle from the stagnation point of cylinder to the upstream edge of the rod was also considered in this work. The FSR cylinder is exposed in uniform wind and allowed to vibrate in cross-flow direction. The output electric power is realized by piezoelectric patch. It is found that, for most cases, the output power of FSR cylinder increases monotonously with the rise of α for a given wind velocity (U). In addition, the tendency of output voltage varies with the wind velocity is highly similar to that of output power. The maximum values of output voltage and power are 19.70 V and 1.90 mW can be obtained when α= 20° (θ= 60°). The WIV responses of FSR cylinder show that the amplitudes of FSR cylinder increase with the rise of α for low installation angle (θ= 0°, 30°) and the maximum amplitudes exceed 2D (D: diameter of circular cylinder) can be observed for α= 40°/50° (θ= 30°) and α= 20° (θ= 60°). The reduced frequency of cylinder for θ= 0° and 30° does not sensitive to the coverage (α). It is worth noting that multiple frequencies can be captured for high coverage. Due to the boundary layer separating point moves in downstream direction with the increase of U and α, the vortex pattern switches from 2S to 2P.

Vibration behavior of an overhead conductor under updraft winds

At present, the wind-induced response analysis of an overhead conductor is mainly based on the action of horizontal normal wind. However, for crossing hillsides or extremely strong winds, such a conductor will bear the action of updraft wind, which will change the geometry of the conductor and make its structural dynamic characteristics nonlinear to some extent. In this work, the in-plane and out-of-plane two-dimensional nonlinear equations were established under the action of self-weight and updraft wind. Furthermore, the improved equations of conductor tension and sag were obtained, and the wind-induced vibration response was further investigated. The results showed that the updraft wind caused the nonlinearity of the tension and sag of the overhead conductor, and the nonlinear geometric change significantly affected its resonance response, which exceeded 25% if the wind speed was 50 m/s. In addition, because the proportion of the resonance response in the total wind-induced response was different, the influence of the wind attack angle calculated using the gust response factor method on the gust response factor was slightly larger than that calculated using the the American society of civil engineers method.

Wind-induced vibration response analysis of Chinese solar greenhouses

Chinese solar greenhouses (CSG) are widely used in agricultural and horticultural industries in China. With the characteristics of lightweight, small stiffness and high flexibility, CSG are sensitive to wind loads. In this study, based on Davenport wind spectrum, the fluctuating wind speed time histories were simulated by harmony superposition method. The wind-induced vibration response of a 12 m span CSG was investigated by using ANSYS in time domain. The time histories of stress and displacement were obtained. The results show that both the stress and displacement under instantaneous wind loads are obviously larger than those under the corresponding mean wind loads. The most dangerous section appears near the front foot of the CSG structure. The critical wind speeds for dynamic and static instability are 38.7 and 58.5 m/s, respectively. Finally, a recommended nodal displacement wind vibration coefficient is given for practical structures. The analytical results can provide a reference for dynamic analysis and wind resistance design of CSG structures in the future.

Mode-superposition response spectrum method for wind-induced vibration analysis of structures

The calculation process of time history analysis method is complicated and time-consuming which is not convenient for wide application and promotion in engineering design. Based on the idea of mode decomposition in structural seismic response analysis, the fluctuating wind response spectrum and the mode decomposition response spectrum method for wind-induced vibration analysis are derived in this paper. Taking a high-rise building structure as an example, this paper uses the method proposed in this paper, the time history analysis method and the method of my country's load code to compare the wind-induced vibration response analysis. The results show that the method proposed in this paper is simple, effective and convenient for engineering application.

Study of Wind-Induced Vibration of a High-Rise and Thin-Walled Steel Tower

Wang, X.; Song, B.; Qian, Y., and Lao, J., 2020. Study of wind-induced vibration of a high-rise and thin-walled steel tower. In: Yang, D.F. and Wang, H. (eds.), Recent Advances in Marine Geology and Environmental Oceanography. Journal of Coastal Research, Special Issue No. 108, pp. 78–82. Coconut Creek (Florida), ISSN 0749-0208.There are many high-rise and thin-walled structures in the coastal environment. These structures easily produce vibrations under the action of wind load. Thus, it is necessary to study the wind-induced vibration response of the steel tower. The AR model method is used to simulate the natural pulsating wind velocity spectrum in different return periods. In addition, the wind-induced vibration responses of the integrated steel tower are successfully calculated using a numerical wind tunnel method. The reliability of the numerical method is verified by onsite monitoring. The results show that the responses of displacement amplitude gradually increase along with height. The larger the wind velocity, the larger the displacement response of the structure. The maximum displacement does not exceed the limit for displacement of the structure. The stress decreases along with the height, and there is a mutation of stress at the position of the variable cross-section. The greater the wind velocity, the higher the stress. Therefore, for wind resistance evaluation of this steel tower, the bottom and variable cross-sections should be controlled by stress and the top should be controlled by displacement.