Wind Loads Research Articles

Tower cranes mixed H2/H∞ under wind load research on active vibration control

The offshore platform tower crane is affected by sea breeze, which causes severe vibration, which causes damage to the crane structure and reduces the working efficiency and performance of the crane. Therefore, the vibration suppression under the complex environment of sea breeze has become a key problem to be solved in practical engineering. Firstly, a pulsating wind excitation model with wind speed changing at any time is established to simulate the time sequence of downwind and crosswise wind loads, which is used to reflect the actual wind speed fluctuations. Secondly, the pulsating wind model is applied to the crane finite element model, and the structural vibration characteristics are explored by analyzing the dynamics of the tower crane under wind excitation，the dynamic model of tower crane system under pulsating wind excitation is established, and the system state equation is constructed. Considering the vibration displacement performance of tower crane structure, a hybrid [Formula: see text] optimal performance vibration active control strategy is proposed. Finally, simulation experiments are carried out. The results show that, compared with the AA controller under the same conditions, the root mean square of displacement under downwind excitation decreases by 65.77%, 64.31% and 63.13%, respectively, and the root mean square of displacement under transverse wind excitation decreases by 62.8%, 65.51% and 62.6%, respectively. The results show that the proposed control method can effectively suppress tower crane vibration.

Non-Stationary Wind Loading Identification for Large Transmission Tower Based on Dynamic Finite-Element Model Updating

An effective approach to deal with the structural failures of transmission towers in tornadic events is to develop good structural health monitoring (SHM) systems for them. However, the strategy for SHM of transmission towers against tornados should be different from the conventional atmospheric boundary layer (ABL) winds oriented ones, as the non-stationary nature of the tornados significantly differentiates them from the ABL winds. To satisfy the need of obtaining the highly time-varying whole-field stress on the structure in the course of the tornadic event for effective SHM, an innovative transient tornadic load distribution identification method is proposed for use, which is based on the field structural mode shape measurement and dynamic finite-element (FE) model updating. Via a numerical case study, it is noted that good effectiveness is achieved for the new load distribution identification method. Employing the Modal Assurance Criteria based FE model updating technique, the new method has the advantage of being easily embraced in practical SHM systems. It is found that when the transient tornadic velocity profile to be identified is noticeably different from the mode shape of the structure without undertaking external loads, the identified load pattern is very accurate for the new approach.

Study on Wind Resistance Performance of Transmission Tower Using Fixture-Type Reinforcement Device

Transmission towers are an important component of the electric system, and their tall structural characteristics make them susceptible to failure under strong winds. Therefore, it is crucial to enhance the wind resistance of the transmission tower structures. This paper uses the finite element method to investigate the influence of a fixture-type reinforcement device (FRD) on the load-bearing performance of the transmission tower structure and explores the effects of different numbers of fixture pairs on the reinforcement. Based on this, the paper further analyzes the stress characteristics and failure modes of a typical tower structure under wind loads in two directions and investigates the influence of different reinforcement lengths on the wind resistance performance of the tower structure. The research results indicate that the FRD can effectively improve the deformation mode and failure characteristics of steel components under axial load. At the same time, using the FRD can effectively reduce the deformation of tower structures under strong wind, and only reinforcing three angled steel components can reduce the tower top displacement by about 55% and more.

Transmission line trip faults under extreme snow and ice conditions: a case study

Extreme weather events, particularly snow and ice storms, present significant threats to the stability and reliability of high-voltage transmission lines, leading to substantial disruptions in power supply. This study delves into the causes and consequences of transmission line trip faults that occur under severe winter conditions, with a focused case study in Inner Mongolia—an area frequently impacted by snow and ice hazards. By systematically analyzing field data collected during critical periods of ice accumulation, this research identifies and examines key factors contributing to faults, such as conductor galloping, insulator degradation, and structural fatigue. These issues are often exacerbated by prolonged exposure to low temperatures and high wind speeds, which further compromise the integrity of transmission infrastructure. In addition to field observations, comprehensive testing of the affected insulators and components reveals mechanical and electrical vulnerabilities that play a significant role in the occurrence of trip faults. To combat these challenges, the paper proposes a series of mitigation and prevention strategies. These include enhancing design specifications to ensure resilience against increased ice and wind loads, deploying real-time monitoring systems capable of detecting early indicators of conductor galloping and ice accumulation, and employing advanced de-icing technologies to reduce the risk of ice-related failures. Moreover, the integration of unmanned aerial vehicles (UAVs) and artificial intelligence (AI)-based fault detection tools presents promising opportunities for improving remote monitoring capabilities and enabling proactive maintenance interventions. By leveraging these innovative technologies, the resilience of transmission lines in harsh climates can be significantly enhanced. The findings of this study not only provide a comprehensive framework for minimizing the impact of extreme weather on transmission infrastructure but also contribute valuable insights toward fostering a more reliable and resilient power grid capable of withstanding the challenges posed by an increasingly volatile climate.

Investigating Alternative Application Ranges for Floating Offshore Wind

The current technological developments within the offshore wind industry reveal a trend towards larger wind turbine MW-classes for both bottom-fixed and floating support structures. Furthermore, bottom-fixed designs are modified and enhanced to also serve deeper offshore sites. Apart from these technological developments, another trend of a competitive nature, related to politics and other stakeholders, can be observed: ever-higher targets are specified for offshore wind energy, while national offshore water areas are limited and divided among various stakeholders in terms of their use. This situation raises the following questions, which are discussed in this paper: 1. Should and could floating offshore wind be extended to shallow-water regions? 2. What benefits can be gained when going beyond traditional floating wind technologies, and what does this mean in detail? 3. What are the motivations, challenges, and solutions for coexistence options? The investigations reveal that floating solutions are more than just options for supporting offshore wind turbines at very-deep-water sites. By extending the traditional application ranges of floating wind turbine systems and going beyond traditional floating offshore wind technologies, additional benefits can be reaped, and worldwide climate and renewable energy targets can be met in harmony with other stakeholders.

Dynamic reliability estimation of onshore wind turbine tower based on frequency-domain method

With the upscaling of wind turbine, the issue of dynamic reliability of wind turbine towers has become increasingly evident. However, the complexity and nonlinearity of wind turbine dynamics present significant challenges in evaluating their dynamic reliability under stochastic loads, requiring substantial computational resources. In this paper, a computationally cost-effective frequency-domain method is proposed as a means of estimating the dynamic reliability of an onshore wind turbine tower. An analytical approach is employed to obtain the power spectral density (PSD) of the rated wind speed and load on the rotating blades. Secondly, a dynamic model of onshore horizontal axis onshore wind turbine is established using flexible multi-body dynamics (MBD). The linear time-varying dynamic equation is transformed into a linear time-invariant form through the application of statistical linearization method. Subsequently, complex modal analysis is used to employ the displacements and internal forces of the tower. Moreover, the first-passage reliability and fatigue reliability of the wind turbine tower are determined through power spectral analysis. A numerical example of a 5-MW wind turbine is presented to demonstrate that the proposed method yields results in good agreement with Monte Carlo simulations (MCS), thereby demonstrating its effectiveness. The reliability analysis of the 5-MW wind turbine reveals that over a 20-year design life, the first-passage reliability is 0.9997 when adopting fore-after displacement at the tower top as the failure criterion, and the fatigue reliability of the tower base is 0.9445.

Active wind load sharing optimization of double skin glazed façade design

Active wind load sharing optimization of double skin glazed façade design

دراسة السلوك الديناميكي لمدخنة في محطة توليد كهرباء طرابلس-الغرب

This paper investigates the vibration behavior of a chimney at the Tripoli-West power plant under wind loads. Finite element models of the chimney are developed to analyze the existing chimney structure, and assess the impact of repositioning the supporting rings typically used in such chimneys. Both free vibration modal analysis and forced vibration harmonic analysis are performed using ANSYS software, considering the wind loads in the area. The final recommendations focus on the vibration response and the influence of the supporting rings and their locations along the chimney, aiming to mitigate undesired vibrations and structural fatigue problems. Keywords: Structural vibration, Industrial chimneys, Finite Element Analysis (FEA).

Effects of side ratio on wind load characteristics on high-rise building

This study investigates the impact of varying side ratios (SR) on wind loads in high-rise buildings using wind tunnel tests and large eddy simulations. It assesses surface wind load by analyzing static three-component force coefficients and shape factors across different SRs. The results show that the model with D/B = 0.5 exhibits the largest mean and r.m.s drag forces, while the model with square cross section (D/B = 1) experiences the lowest torque. Meanwhile, the model with D/B = 0.5 reveals strong vertical but relatively weak horizontal wind pressure correlation. In addition, models with large SRs exhibit altered wind pressure mechanisms due to the occurrence of flow reattachment and secondary separation, resulting in lower side-surface correlation compared to small SR models.

Experimental and numerical study on creep deformation and failure characteristics of ETFE cushion structures

ETFE (ethylene-tetrafluoroethylene) cushion structures with small self-weight are typical wind-sensitive structures that are prone to large deformation and even failure under wind loads. This paper is aimed to investigate the deformation and failure behaviors of ETFE cushion structures subjected to static wind loads. Firstly, calibration mock-up experiments were carried out using a load simulation system and a photogrammetry system. Then, structural responses could be calculated based on force density theory, which were used to validate and correct the calibration numerical model inputs. Finally, same inputs from calibration numerical model were assigned to full-size numerical model and used to predict the structural behavior of a full-size mock-up in an inflation experiment. The comparison between experimental and simulation results validates numerical models integrating material creep response surface, real initial geometry, and actual loading protocol for predicting structural behavior of ETFE cushion structures. Additionally, it is observed that creep deformation constitutes a substantial portion of the total deformation under high static wind loads. The primary factors influencing the failure of ETFE cushions are identified as stress distribution and initial defects.

Biomechanics of plant stems with square and circular cross-sections: what is the advantage of quadratic stems over cylindrical ones?

Although plant stem cross-sections are most often circular, some are square, triangular or elliptic, but these are rare. The advantage of quadratic stems over cylindrical ones, if one exists, is unclear. Here we propose a (bio) mechanical advantage of square-stemmed plants. Our idea is based on the fact that the second moment of inertia I of a stem, depending on the shape of the cross-section, determines the plant’s resistance to bending and torsion deformations induced by wind load and gravitation: a larger I results in greater mechanical resistance. When can a quadratic stem have a larger I than a cylindrical stem of comparable material? We calculated the rotation-invariant I of quadratic and cylindrical hollow stems with the same cross-section area as functions of the quotient k of the inner and outer dimensions, and the quotient Q of the outer dimensions of square and circlular stems. We determined those configurations of the geometric control parameters k and Q for which the I of a quadratic stem is larger than that of a cylindrical one; that is, the former stem is more resistant to mechanical deformations than the latter. This finding provides a clear mechanical benefit of square-stemmed over circle-stemmed plants.

Experimental study and numerical simulation on the bearing behavior of the modified suction caisson under misalignment lateral cyclic and monotonic loadings

Suction caissons for offshore wind turbines are subjected to lateral misalignment wind and wave loads during service life, leading to the occurrence of accumulate deflection and changes in lateral bearing capacity. Experimental studies and numerical simulations were performed to investigate the motion mode, accumulated lateral deflection, and bearing capacity of a modified suction caisson (MSC) under misalignment lateral cyclic and monotonic loadings. Under misalignment lateral cyclic and monotonic loadings, the motion behavior of the MSC is combined with the translation, rotation, and torsion. The direction of MSC motion lies between cyclic and monotonic loading directions. The angle between the motion direction and cyclic loading direction is far less than that between the motion direction and monotonic loading direction. Under the same cyclic and monotonic load values, the maximum accumulated deflection was obtained when the angle between lateral cyclic and monotonic loading directions (which is defined as the misalignment angle) equals 30°. In addition, the lateral bearing capacity of the MSC after misalignment cyclic and monotonic loading was found to decrease with increasing the misalignment angle. The minimum lateral bearing capacity of the MSC after misalignment loading was obtained when the misalignment angle equals 180°. Based on the model test and simulation results, the method applying the model test results to the practical engineering is proposed.

Research on numerical simulation of wind load on high-rise buildings along the street based on BIM model

Research on numerical simulation of wind load on high-rise buildings along the street based on BIM model

Benefits and Challenges of California Offshore Wind Electricity: An Updated Assessment

Offshore wind (OSW) technology has recently been included in California’s plans to achieve 100% carbon-free electricity by 2045. As an emerging technology, many features of OSW are changing more rapidly than established renewable options and are shaped by local circumstances in unique ways that limit transferrable experiences globally. This paper fills a gap in the literature by providing an updated technological assessment of OSW in California to determine its viability and competitiveness in the state’s electricity generation mix to achieve its near-term energy and environmental goals. Through a critical synthesis and extrapolation of technical, social, and economic analyses, we identify several major improvements in its potential. First, we note that while estimates of OSW’s costs per MWh of installed capacity have generally documented and projected a long-term decline, recent technical, microeconomic, and macroeconomic factors have caused significant backsliding of this momentum. Second, we project that the potential dollar value benefits of OSW’s greenhouse gas reduction capabilities have increased by one to two orders of magnitude, primarily due to major upward revisions of the social cost of carbon. Several co-benefits, including enhanced reliability, economic growth, and environmental justice, look to be increasingly promising due to a combination of technological advances and policy initiatives. Despite these advancements, OSW continues to face several engineering and broader challenges. We assess the current status of these challenges, as well as current and future strategies to address them. We conclude that OSW is now overall an even more attractive electricity-generating option than at the beginning of this decade.

Floating Offshore Wind Technology Development in Japan and Abroad

Floating Offshore Wind Technology Development in Japan and Abroad

Erection and structural design errors of structural steel warehouses

Structural steel is commonly used to construct warehouses such as storage warehouse, truck terminals, industrial buildings, and warehouse supermarkets. These structures are usually one story structures that it is easy to analysis as two dimensional structures and can be designed and fabricated in a short time. The safety of these structures to withstand vertical and lateral loads is essential. In practice sometimes erection and design errors may cause structural local or global failures to these structures especially under major earthquakes and strong wind loads. In this paper some of the erection and design errors that engineers should avoid are presented.

Dynamic Comfort Considerations in the Design of High-rise Buildings

<p>The following paper provides research analysis on the influence of wind on a building, considering the regional and local climate conditions, to improve dynamic stability and reduce wind disruption effects on high-rise reinforced concrete buildings. The main aspect of disturbance in living conditions is caused by wind loads on the building. The data is based on structural analysis, generated by the “Lira CAD 2013” ​​software, for a construction project of a 19-story residential building, completed in Georgia’s capital Tbilisi, 58 Kavtaradze St., in accordance with the given necessary requirements and restrictions by general terms and conditions of the Georgian state law. Computer aided modeling provides the ability to simulate and define parameters caused by the wind disruption on an actual site. Calculation process is based on variables specified by state law for each region of the country. Modified accelerations which have been caused by wind in multi-story, high-rise buildings have significantly greater values on upper floors, and reaching the edges ​​​​of the minimum living comfort criteria. The given study features the estimation for high-rise buildings under various combinations of loads. High-rise buildings have gone under significant restrictions due to use of conventional rigid frames as structural elements in the construction process. That process tends to develop a series of new research and findings for proper architectural forms, which became possible using the new generation of fast digital computing software and hardware.</p>

Development of a mathematical model of dependence of specific volumetric electrical resistance of SIW-4 insulation on factors affecting its reliability

Insulation of self-supporting insulated wire (SIW-4) is the object of the study, and the subject of the study is a mathematical model of the dependence of the specific volume electrical resistance of the SIW-4 insulation on the factors affecting its reliability. The resulting mathematical model will allow us to proceed to the development of a method for predictive assessment of the residual life of the insulation material of the conductor under study. At the first stage of the work, the influence of external factors on the electrical parameters of the SIW-4 insulation material has been studied. When forming the goal of the study, namely, obtaining a mathematical model of the dependence of the specific volume resistance of the wire insulation on the influence of external factors, difficult operating conditions have been taken into account. SIW-4 is intended for use outside buildings, i. e. it is exposed to solar radiation, wind load, precipitation, temperature changes, etc. Within the framework of this study, the following most significant factors have been considered: alternating electric current, ambient temperature and period of operation. These factors have been selected taking into account the possibility of conducting a multifactorial experiment and fully characterize such properties of product reliability as durability and failure-free operation. During the multifactorial analysis, the task was to select the minimum and maximum values of each factor under study, followed by the compilation of a planning matrix for a full factorial experiment. The resulting mathematical model allows us to determine the effective value of the specific volume electrical resistance of the SIW-4 insulation material depending on its operation under the given specific conditions. It also opens up the possibility of developing the second stage of the study, associated with the construction of an algorithm for the method of predictive assessment of the residual life of the insulation material of the conductor under study.

Fluid Dynamic Assessment of Tall Buildings with a Variety of Complicated Geometries

The exponential increase in population has led to a shortage of land for constructing tall buildings, resulting in the need to design irregular structures due to the limited availability of land. Assessing the impact of wind-generated effects can be achieved utilizing the Computational Fluid Dynamics (CFD) method, specifically employing ANSYS. This involves resolving the intricate fluid dynamics problem through numerical analysis using the ANSYS software. The validation study is performed on a standard shape-building model where the result is compared with experimental values and other international standards. The outcomes are presented in a graphical format, such as mean pressure, streamline, and pressure distribution in the vertical and horizontal planes. This research has studied four building models with equal area and height. Models A and B have regular shapes, while Models C and D exhibit an irregular ‘Y’ shape. The wind incidence angle was adjusted between 0 and 180 degrees at every 15-degree interval. The results were validated to ensure the accuracy of the numerical techniques employed. This involved performing validation and grid sensitivity analyses, which showed consistent results comparable to experimental data and established international standards. Model-C irregular-shaped buildings demonstrated the highest efficiency in minimizing wind loads among the building models examined in this study.

Large Eddy Simulation of Flow Around Twin Tower Buildings in Tandem Arrangements with Upstream Corner Modification

The aerodynamic performance of twin tall buildings immersed in the atmospheric boundary layer was numerically investigated by adopting the spatial-averaged large eddy simulation (LES) method. This study focused on the effects of corner cutting and chamfering. The buildings were both square and sectional with a width-to-height ratio of 1:6, and were arranged in a tandem configuration with a spacing ratio of 2.0. The corner-cutting and chamfering measures were only applied to the upstream cylinder, with a corner modification rate of 10%. To generate the turbulent inflow boundary condition (IBC) for LES, steady-state equilibrium IBC expressions were introduced into the vortex method, which were implemented in the commercial code Ansys Fluent. The present simulation method and solution parameters were first verified by comparing the simulated wind field and the wind pressure distribution on a single tall building with those of the wind tunnel test. The influences of the corner-cutting and chamfering measures on the wind load of the tandem buildings were then comparatively studied concerning the statistical values of their aerodynamic force coefficients and wind pressure coefficients. The influence mechanism was analyzed based on the simulated time-averaged flow field and the instantaneous vortex structure around the buildings. The results indicated that upstream corner-cutting and chamfering measures can induce a diffusion angle shift in the separated shear flow from the leading edge of the upstream building, thus affecting the separation and reattachment of the separated upstream flow on the downstream building. Among the measures studied, upstream corner cutting is more effective in reducing wind pressure and aerodynamic force coefficients.