Wind-induced Response Analysis Research Articles

Wind-Induced Response Analysis and Fatigue Life Prediction of a Hybrid Wind Turbine Tower Combining an Upper Steel Tube with a Lower Steel Truss

Based on the WindPACT-3MW wind turbine tower commonly used in wind power engineering, a finite element model (FEM) of a hybrid wind turbine tower combining an upper steel tube with a lower steel truss is designed and established. On this basis, a static optimization analysis, wind-induced vibration analysis, and fatigue life analysis of the hybrid tower structure are performed. The results show that under the same design parameters, the overall stiffness and static bearing capacity of the tower structure can be significantly improved by using subdivided truss webs, increasing the truss height as much as possible and increasing the width of the truss base appropriately. Under normal operation conditions, the response of the tower structure in the along-wind direction is significantly greater than the response in the crosswind direction, indicating that the aerodynamic thrust generated by the rotation of the blades is the main factor causing the wind-induced vibration of the tower structure. For the tower structure analyzed in this study, when considering the entire range of wind speeds from the cut-in wind speed to the cut-out wind speed, the fatigue life of the structure is 38.5 years.

Wind-Induced Response Analysis of the Transmission Tower-Line System Considering the Joint Effect

Wind load is one of the main control loads of transmission tower-line systems. Numerical simulation is the main method for studying the structural wind-induced response. The establishment of a refined transmission tower simulation model is the basis for accurately analyzing the dynamic response of a transmission tower-line system under a wind load. This paper first considered the mechanical properties of bolted joints under cyclic loading and established a transmission tower-line system model considering the joint effects. Then, the wind load was generated by the harmonic superposition method, and the wind dynamic time-history analysis of the tower-line system was conducted. The influence of the joint effect on the wind-induced response of the transmission tower-line system was studied, and the effects of turbulence intensity and wind attack angle on the bolted joint slip effect were discussed. The results showed that the joint effect significantly increased the displacement response of the transmission tower subjected to wind loads and affected the normal service performance of the tower-line system. When the turbulence intensity is 10%, the top displacement of the tower model considering the joint effect is approximately 2 times that of the ideal rigid frame model. After considering the joint effect, the additional [Formula: see text] effect caused by the increased displacement resulted in an increase in the stress of 75.6% members, and the maximum stress of the main member was located near the upper diaphragm of the tower leg. Therefore, considering the joint slip effect in angle steel transmission towers can improve the accuracy of the dynamic response analysis of transmission lines.

Across-wind fluctuating aerodynamic force acting on large aspect-ratio rectangular prisms

This work addresses the aerodynamic characteristics and spatial structure of the across-wind fluctuating aerodynamic force and its influence on wind-induced responses of rectangular prisms. Seven rectangular rigid models with different side ratios (1/4–4) are constructed, and simultaneous pressure tests are conducted in turbulent boundary layer flows. According to the measured data, separation and reattachment characteristics, span-wise correlation coefficients, and coherences are calculated, and then an empirical coherence function model is obtained. By comparing this model with traditional coherence models, the main factors affecting the coherence of the across-wind fluctuating aerodynamic force are presented and discussed. The proposed normalized coherence model takes into account factors such as the vortex shedding, side ratio, building feature size, the spatial location, and frequency correction. The non-dimensional joint acceptance function is presented, based on which the influence of the coherence function model on across-wind fluctuating wind load evaluation and wind-induced response analysis is compared and analyzed.

Analysis of random wind-induced response of isolation structure with viscoelastic damper and TMD

The analysis method of wind vibration response of the seismically isolated structure with viscoelastic damper and tuned mass damper(TMD) under Davenport wind load was studied systematically. Firstly, using the general integral models of viscoelastic dampers to establish the exact dynamic integral-differential response equations in original structural space for isolated structure with general linear viscoelastic damper and TMD. Then, adopting the transfer function method to obtain the exact non-orthogonal modal superposition solution in original structural space for the displacement response standard deviation and the equivalent wind force transient response in the time domain of the isolated structure with viscoelastic damper and TMD under wind loading. These exact solutions can accurately discover the vibration properties of viscoelastic dissipative structures. That is, the dissipative structural modes are not orthogonal, the dynamic equations cannot be decoupled with the structural modes, while transient structural response can be accurately represented as an individual superposition of modal responses. The analysis of the calculation example showed that the isolated structure with viscoelastic damper and TMD can more effectively reduce the actual values of wind-induced displacement response standard deviation, equivalent wind vibration force and design value of equivalent wind. Since the results obtained in this paper are exact solutions, it can provide a theoretical basis for the design of the structures with viscoelastic damper and TMD, the optimization of damper and TMD parameters.

Analysis of wind-induced responses of landing assembled Chinese solar greenhouses

The wind-induced responses of a landing assembled Chinese solar greenhouse (CSG) were investigated by considering fluctuating wind speeds. Fluctuating wind speeds were simulated using the harmony superposition method. The dynamic properties of the CSG were extracted using modal analysis. The displacement and bending stress of the CSG under mean and instantaneous wind loads were compared. The results showed that both the displacement and bending stress under the south wind (0° direction) were lower than those under the north wind (180° direction). When the wind direction was 0°, the maximum displacement and bending stress under instantaneous wind loads were 1.926 and 1.673 times those under mean wind loads, respectively. When the wind direction was 180°, the maximum displacement and bending stress under instantaneous wind loads were 2.054 and 2.003 times those under mean wind loads, respectively. To estimate the nodal displacement wind vibration coefficients and quantify the amplification effects of instantaneous wind loads, the effects of the structural damping ratios, sectional dimensions, and simulated wind speed samples on the wind-induced responses of the CSG were investigated. Finally, a global nodal displacement wind vibration coefficient of 2.0 is recommended for the case study. These results can provide a reference for the wind-resistance design of landing assembled CSG. • Fluctuating wind speeds were simulated using the harmony superposition method. • The wind-induced responses of a landing assembled CSG were investigated. • The dynamic properties of the CSG were extracted using modal analysis. • The nodal displacement wind vibration coefficients were obtained.

Wind-Induced Response Analysis for a Fatigue-Prone Asymmetric Steel Arch Bridge with Inclined Arch Ribs

Steel arch bridges with inclined arch ribs under strong wind fields are prone to fatigue damage due to the stress concentration at the position of hanger connections. Therefore, it is essential to perform the wind-induced response analysis for specified shape hangers, such as inclined hangers, to determine the stress distribution and corresponding influencing factors. In this study, wind-induced response analysis for a fatigue-prone asymmetric steel arch bridge with inclined arch ribs is performed by the numerical simulation approach. The investigated bridge hangers’ models are established by using the COMSOL Multiphysics software. The wind-induced stress of the bridge hangers under different wind directions is obtained based on the finite element method. The influential factor of the stress distribution of the bridge hangers on both the windward side and the leeward side is discussed. In addition, the stress peaks of the long hanger and short hanger are achieved for further fatigue analysis. This paper provides a reference for determining the critical fatigue-prone position of an asymmetric steel arch bridge with inclined arch ribs.

Spatial correlation of along-wind fluctuating aerodynamic force acting on large aspect-ratio rectangular prisms

This work examines the spatial correlation of the along-wind aerodynamic fluctuating force and its influence on wind-induced responses of high-rise buildings. Seven rectangular rigid models with different side ratios (1/4-4) are made, and simultaneous pressure experiments are conducted under turbulent boundary layer flows. Using the measured data, span-wise correlation coefficients are calculated, and then empirical coherence functions are obtained. In comparing with the traditional coherence models, the main factors affecting the coherence of the along-wind fluctuating aerodynamic force are presented and discussed in this study. A normalized coherence model was proposed, considering factors such as the windward side width, aspect ratio, separation distance from the ground, and low frequency correction. Further, the nondimensional joint acceptance function is presented, based on which the influence of the coherence model on along-wind wind load evaluation and wind-induced response analysis is compared. Finally, for convenience of engineering application, a simplified formula consistent with the revealed coherence properties is recommended.

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

Study on wind-induced response of a large-span roof by using finite particle method

The wind-induced response analysis of large-span roof using finite particle method (FPM) is discussed in this paper. Based on vector mechanics, FPM is an intrinsic method to study responses of structures under dynamic excitation. It adopts separated particles that governed by Newton’s second law to describe structural behaviors, especially geometric nonlinearity. As the previous damping treatments in FPM are inadequate for studying the wind-induced responses of large-san roof, two enhanced treatments based on Rayleigh damping for approximatively estimating damping forces in the FPM are proposed and are verified through numerical pseudo-dynamic example. To study the wind-induced responses of a large-span roof, the wind-tunnel tests of pressure measurement are carried out to obtain time histories of wind loads on the large-span roof. The FPM is further employed to estimate wind-induced responses of the large-span roof. Wind-induced displacement and internal forces responses obtained by FPM are compared with results from finite element method (FEM). The results from FPM meet well with results from the FEM, which presents the capability of FPM to study the wind-induced responses of large-span roof.

Wind tunnel tests and dynamic analysis of wind-induced response of a transmission tower on a hill

A hill with a lattice transmission tower presents complex wind field characteristics. The commonly used computational fluid dynamics (CFD) simulations are difficult to analyze the wind resistance and dynamic responses of the transmission tower due to structural complexity. In this study, wind tunnel tests and numerical simulations are conducted to analyze the wind field of the hill and the dynamic responses of the transmission tower built on it. The hill models with different slopes are investigated by wind tunnel tests to measure the wind field characteristics, such as mean speed and turbulence intensity. The study shows that the existence of a transmission tower reduces the wind speed on the leeward slope significantly but has little effect on the windward slope. To study the dynamic behavior of the transmission tower, a hybrid analysis procedure is used by introducing the measured experimental wind information to the finite element tower model established using ANSYS. The effects of hill slope on the maximum displacement response of the tower are studied. The results show that the maximum value of the response is the largest when the hill slope is 25° compared to those when hill slope is 15° and 35°. The results extend the knowledge concerning wind tunnel tests on hills of different terrain and provide a comprehensive understanding of the interactive effects between the hill and existing transmission tower regarding to the wind field characteristics and structural dynamic responses.

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.

Field measurement-based wind-induced response analysis of multi-tower building with tuned mass damper

The 246.8-m-tall Beijing Olympic Tower (BOT) is a new landmark in Beijing City, China. Its unique architectural style with five sub-towers and a large tower crown gives rise to complex dynamic characteristics. Thus, it is wind-sensitive, and a double-stage pendulum tuned mass damper (DPTMD) has been installed for vibration mitigation. In this study, a finite-element analysis of the wind-induced responses of the tower based on full-scale measurement results was performed. First, the structure of the BOT and the full-scale measurement are introduced. According to the measured dynamic characteristics of the BOT, such as the natural frequencies, modal shapes, and damping ratios, an accurate finite-element model (FEM) was established and updated. On the basis of wind measurements, as well as wind-tunnel test results, the wind load on the model was calculated. Then, the wind-induced responses of the BOT with the DPTMD were obtained and compared with the measured responses to assess the numerical wind-induced response analysis method. Finally, the wind-induced serviceability of the BOT was evaluated according to the field measurement results for the wind-induced response and was found to be satisfactory for human comfort.

Time-domain model for prediction of generalized 3DOF buffeting response of tall buildings using 2D aerodynamic sectional properties

A time-domain method to calculate the buffeting response of a rectangular tall building (AR of B/D = 1.5 and H/D = 6) in along-wind, across-wind and torsional degrees of freedom using 2D aerodynamic sectional properties is presented here. The aerodynamic sectional properties were identified first using wind tunnel section models. Aerodynamic damping, which is critical in wind-induced response analysis of tall buildings, was calculated using the identified aeroelastic derivatives (flutter derivatives) and validated by comparing with those extracted directly from the response measurements of aeroelastic models of the tall building. A good agreement between the numerically simulated responses and the experimental measurements of an aeroelastic model (1:175 scale) shows the capability of the proposed method in the prediction of generalized 3DOF buffeting response of tall buildings in a wide range of wind speeds. Furthermore, the response of a tall building with two other cross-sectional shapes, circular and elliptical, was calculated using the developed method and compared amongst the three cross-sectional shapes to study the effect of cross section on buffeting response. The relative dependency of buffeting response of a tall building along each of the 3DOF on cross section, wind speed as well as angle of attack was assessed. Finally, the effect of taper on tall building’s buffeting response was studied using the developed method which showed that taper could significantly reduce the wind-induced response of tall buildings. The time-domain method to assess wind loads and buffeting response of tall buildings based on experimentally or theoretically derived aerodynamic properties of two-dimensional sections, as presented here, provides a viable and perhaps the only alternative to methods based on aeroelastic model tests and CFD simulations.

Analysis of wind-induced responses and GLF for super-large cooling towers

Based on wind tunnel tests, time-varying wind pressure distribution on the finite element model of a super-large hyperbolic cooling tower under group-tower environment were reconstructed by the radial basis function (RBF) method. The results were applied in time-domain calculations of wind-induced responses of the cooling tower. Then, the gust loading factor (GLF) method adopted in current engineering practice was analyzed. The results indicate that: due to some inevitable limitations, the existing GLF scheme, in which a unified amplification factor G is adopted to calculate the equivalent static wind loads, may not be applicable for super-large cooling towers.

Reconstruction of wind pressure fields on cooling towers by radial basis function and comparisons with other methods

Radial basis function (RBF) method is introduced and studied for its application in the reconstruction of the wind pressure field of cooling towers based on wind tunnel tests. Three main aspects of work have been done: first, the reasonable value of constant C and the appropriate choice of source points in the method were studied, and the rationality of the method was validated; second, reconstruction performance of the RBF method was studied by comparing with proper orthogonal decomposition (POD) method and linear interpolation (LI) method; third, wind pressure field reconstruction and wind-induced response calculation of a super-large hyperbolic cooling tower was performed to demonstrate the practical application of RBF method. Some conclusions are drawn: (i) the value of constant C has significant influence on the reconstruction accuracy of RBF, and can be set as 0.03 times of its maximum value; (ii) the RBF method performs best in general among the three methods, and the outcomes of POD method are highly related to the expanding method used to obtain the eigenmodes at reconstruction points; (iii) RBF method is practicable for the time-domain analysis of wind-induced responses of cooling towers.

Numerical Analysis of Wind-Induced Response of a Wrinkled Membrane

Membranes have been popularly used in the fields of civil engineering and aerospace engineering. When wrinkled, a membrane loses its stiffness in the direction perpendicular to wrinkles and is more sensitive to wind loads. This paper numerically studied the wind-induced responses of a wrinkled membrane and their variations with respect to wind speed, wind direction and wrinkling deformation. Based on the stability theory of plates and shells, the wrinkling deformation of a rectangular membrane under shear was obtained by post-buckling analysis. Then, by using the wind load derived from a wind tunnel test, the dynamic responses of the wrinkled membrane were numerically analyzed for different wind speeds, wind directions and wrinkling deformations. The results indicate the following: (1) the displacement and extreme stresses of a membrane are gradually intensified with an increase in the wind speed; (2) the wind direction plays an important role in the displacement, but it has little effect on the stresses and (3) the displacement increases with the wrinkling deformation, and the extreme stresses are intensified with an increase in the pre-tension. This study on the wind-induced responses of a wrinkled membrane is helpful to the understanding of the complex behavior of a wrinkled membrane under wind loads while reducing the adverse effects of wrinkling deformation and ensuring the dynamic stability of membrane structures.

An Experimental Investigation of Streamwise and Vertical Wind Fields on a Typical Three-Dimensional Hill

To study the streamwise and vertical wind fields on a typical three-dimensional hill, wind tunnel tests were performed. The mean values and turbulence intensities of the streamwise and vertical wind speeds of the typical positions above the hill were measured, and they are presented in the form of contour maps for design. Furthermore, the speed-up of the mean wind speeds in the streamwise direction was compared with codes. Finally, the windage yaw of a jumper cable was examined as an example of how to take into account the streamwise and vertical wind field influence on the wind load in the analysis of wind-induced responses. The results show that the most significant speed-up effect in the streamwise direction occurs on the hill crest, and the wind speed-up decreases with the increase of the height. Overall, the wind speed-up along the crosswind center line is larger than that along the along-wind center line of the hill. In the codes, the speed-up effect specified for the structure at half the height of the upstream side of the hill is relatively conservative. With regard to the mean wind speed in the vertical direction, the wind climbing effect located at half the height of the upstream side of the hill is the most significant. The area with the stronger turbulence intensity appears at the foot of the upstream and downstream sides of the hill. The influence of the vertical wind on the jumper cable is remarkable where the wind climbing effect is the most significant, which is worthy of attention in the design of the structure immersed in a hilly terrain-disturbed wind field.

Analysis of wind-induced response of down lead transmission line-connection fitting systems in ultrahigh-voltage substations

Based on a certain 1,000-kV ultrahigh-voltage substation, a finite element model is established for the down lead transmission line (DLTL)-connection fitting system using the ABAQUS software. The mechanical properties of the bushing terminal and the connection fitting under equivalent static loads corresponding to various wind speeds are analyzed. The analytical results are compared with experimental results to verify the correctness of the model. On this basis, the effects of the connection fitting type, the DLTL system type and the suspension location of the DLTL system on the mechanical properties of the bushing terminal are discussed. The dynamic response of the DLTL-connection fitting system to various wind speeds is investigated through simulation. The results are as follows. From a mechanical perspective, the bushing terminal with an “I”-shaped connection fitting is notably superior to that with a “U”-shaped connection fitting; however, the “I”-shaped connection fitting system must be strengthened. Compared to the “λ”-shaped DLTL system that is currently and commonly used, the “π”-shaped DLTL system is more reasonable, but the offset of its suspension point must be controlled (0–3 m is recommended). When considering the vibration caused by pulsating winds, the maximum stress on the bushing terminal increases significantly, and premature failure is risked. In engineering design, a dynamic amplification factor no less than 2.0 is recommended for use to consider this adverse effect.

Study on wind-induced response of a simplified model of transmission tower based on finite particle method

A reduced model of a transmission tower was established based on the principle of equivalent stiffness. The finite particle method was used to analyse the wind-induced response of the reduced model. The analysis of the dynamic characteristics of the reduced model shows that the accuracy of the equivalent formula proposed in this paper was very high. Compared with the first five order natural frequencies of the complete model, the maximum calculation error of the reduced model was only 0.87%. Since the first order shear deformation beam theory was used in the reduced model, the interpolation-independent element shape functions were developed to avoid the shear locking phenomenon. Moreover, the formula for calculating the internal force of Timoshenko beam for finite particle method was derived. By using two successive Euler angles, a new method for separating the rigid motion and pure deformation of the element was proposed. The computational efficiency of this method is significantly improved, and the computational time is less than half of that of the traditional finite particle method. The results of wind-induced response analysis of the transmission tower show that the simplified model proposed in this paper can obtain highly accurate displacement response of the structure, and the maximum error of the RMS of the displacements at the top of the tower is less than 3.2%. This model is suitable for studying the dynamic response of transmission tower line system and evaluating the effect of the wind-induced vibration control of damping device.

Aerodynamic Performance and Wind-Induced Responses of Large Wind Turbine Systems with Meso-Scale Typhoon Effects

The theoretical system of existing civil engineering typhoon models is too simplified and the simulation accuracy is very low. Therefore, in this work a meso-scale weather forecast model (WRF) based on the non-static Euler equation model was introduced to simulate typhoon “Nuri” with high spatial and temporal resolution, focusing on the comparison of wind direction and wind intensity characteristics before, during and after the landing of the typhoon. Moreover, the effectiveness of the meso-scale typhoon “Nuri” simulation was verified by a comparison between the track of the typhoon center based on minimum sea level pressure and the measured track. In this paper, the aerodynamic performance of large wind turbines under typhoon loads is studied using WRF and CFD nesting technology. A 5 MW wind turbine located in a wind power plant on the southeast coast of China has been chosen as the research object. The average and fluctuating wind pressure distributions as well as airflow around the tower body and eddy distribution on blade and tower surface were compared. A dynamic and time-historical analysis of wind-induced responses under different stop positions was implemented by considering the finite element complete transient method. The influence of the stop position on the wind-induced responses and wind fluttering factor of the system were analyzed. Finally, under a typhoon process, the most unfavorable stop position of the large wind turbine was concluded. The results demonstrated that the internal force and wind fluttering factor of the tower body increased significantly under the typhoon effect. The wind-induced response of the blade closest to the tower body was affected mostly. The wind fluttering factor of this blade was increased by 35%. It was concluded from the analysis that the large wind turbine was stopped during the typhoon. The most unfavorable stop position was at the complete overlapping of the lower blade and the tower body (Condition 1). The safety redundancy reached the maximum when the upper blade overlapped with the tower body completely (Condition 5). Therefore, it is suggested that during typhoons the blade of the wind turbine be rotated to Condition 5.