Methodology for seismic risk assessment for tubular steel wind turbine towers: application to Canadian seismic environment

2011 ◽  
Vol 38 (3) ◽  
pp. 293-304 ◽  
Author(s):  
Elena Nuta ◽  
Constantin Christopoulos ◽  
Jeffrey A. Packer
Keyword(s):  
Seismic Hazard ◽  
Wind Turbine ◽  
Seismic Loading ◽  
Element Analysis ◽  
Design Spectrum ◽  
Wind Turbine Tower ◽  
Damage States ◽  
Wind Turbine Towers ◽  
Hazard Level ◽  
Hazard Levels

The seismic response of tubular steel wind turbine towers is of significant concern as they are increasingly being installed in seismic areas and design codes do not clearly address this aspect of design. The seismic hazard is hence assessed for the Canadian seismic environment using implicit finite element analysis and incremental dynamic analysis of a 1.65 MW wind turbine tower. Its behaviour under seismic excitation is evaluated, damage states are defined, and a framework is developed for determining the probability of damage of the tower at varying seismic hazard levels. Results of the implementation of this framework in two Canadian locations are presented herein, where the risk was found to be low for the seismic hazard level prescribed for buildings. However, the design of wind turbine towers is subject to change, and the design spectrum is highly uncertain. Thus, a methodology is outlined to thoroughly investigate the probability of reaching predetermined damage states under any seismic loading conditions for future considerations.

scholarly journals Structural optimisation of wind turbine towers based on finite element analysis and genetic algorithm

2016 ◽  
Author(s):  
Lin Wang ◽  
Athanasios Kolios ◽  
Maria Martinez Luengo ◽  
Xiongwei Liu
Keyword(s):  
Genetic Algorithm ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Wind Turbine ◽  
Structural Design ◽  
Structural Optimisation ◽  
Element Analysis ◽  
Wind Turbine Tower ◽  
Wind Turbine Towers ◽  
Optimisation Model

Abstract. A wind turbine tower supports the main components of the wind turbine (e.g. rotor, nacelle, drive train components, etc.). The structural properties of the tower (such as stiffness and natural frequency) can significantly affect the performance of the wind turbine, and the cost of the tower is a considerable portion of the overall wind turbine cost. Therefore, an optimal structural design of the tower, which has a minimum cost and meets all design criteria (such as stiffness and strength requirements), is crucial to ensure efficient, safe and economic design of the whole wind turbine system. In this work, a structural optimisation model for wind turbine towers has been developed based on a combined parametric FEA (finite element analysis) and GA (genetic algorithm) model. The top diameter, bottom diameter and thickness distributions of the tower are taken as design variables. The optimisation model minimises the tower mass with six constraint conditions, i.e. deformation, ultimate stress, fatigue, buckling, vibration and design variable constraints. After validation, the model has been applied to the structural optimisation of a 5MW wind turbine tower. The results demonstrate that the proposed structural optimisation model is capable of accurately and effectively achieving an optimal structural design of wind turbine towers, which significantly improves the efficiency of structural optimisation of wind turbine towers. The developed framework is generic in nature and can be employed for a series of related problems, when advanced numerical models are required to predict structural responses and to optimise the structure.

The Finite Element Analysis and Comparison of Wind Turbine Tower under Static Wind Load and Fluctuating Wind Load

2013 ◽  
Vol 446-447 ◽  
pp. 733-737
Author(s):  
Chi Chen ◽  
Hao Yuan Chen ◽  
Tian Lu
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Wind Turbine ◽  
Modal Analysis ◽  
Large Scale ◽  
Wind Load ◽  
Element Analysis ◽  
Finite Element Software ◽  
Wind Turbine Tower ◽  
Fluctuating Wind

In this paper, a 1.5 MW wind turbine tower in Dali, Yunnan Province is used as the research object, using large-scale finite element software Ansys to carry on the dynamic analysis. These natural frequencies and natural vibration type of the first five of tower are obtained by modal analysis and are compared with natural frequency to determine whether the resonance occurs. Based on the modal analysis, the results of the transient dynamic analysis are obtained from the tower, which is loaded by the static wind load and fluctuating wind load in two different forms. By comparing the different results, it provides the basis for the dynamic design of wind turbine tower.

scholarly journals Repowering Steel Tubular Wind Turbine Towers Enhancing them by Internal Stiffening Rings

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1538 ◽  
Author(s):  
Yu Hu ◽  
Jian Yang ◽  
Charalampos Baniotopoulos
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Structural Response ◽  
Critical Design ◽  
Element Size ◽  
Wind Turbine System ◽  
Design Variables ◽  
Wind Turbine Tower ◽  
Mesh Density ◽  
Wind Turbine Towers

This paper presents a robust repowering approach to the structural response of tubular steel wind turbine towers enhanced by internal stiffening rings. First, a structural response simulation model was validated by comparison with the existing experimental data. This was then followed with a mesh density sensitivity analysis to obtain the optimum element size. When the outdated wind turbine system needs to be upgraded, the wall thickness, the mid-section width-to-thickness ratio and the spacing of the stiffening rings of wind turbine tower were considered as the critical design variables for repowering. The efficiency repowering range of these design variables of wind turbine towers of various heights between 50 and 250 m can be provided through the numerical analysis. Finally, the results of efficiency repowering range of design variables can be used to propose a new optimum design of the wind turbine system when repowering a wind farm.

Vibration Characteristics Analysis of Wind Turbine Towers under Foundation Conditions

2013 ◽  
Vol 446-447 ◽  
pp. 721-727
Author(s):  
Xi Song ◽  
Yin Guang Wu ◽  
Jie Yu Li ◽  
Rong Zhen Zhao
Keyword(s):  
Dynamic Analysis ◽  
Wind Turbine ◽  
Natural Frequency ◽  
Large Scale ◽  
Horizontal Axis Wind Turbine ◽  
Static And Dynamic Analysis ◽  
Wind Turbine Tower ◽  
Characteristics Analysis ◽  
Wind Turbine Towers ◽  
Tower Foundation

Based on a kind of 1.5MW large-scale horizontal axis wind turbine tower, the mechanical modeling of a wind turbine tower-foundation is established, the static and dynamic analysis of the model is carried out by ANSYS software. The top displacement of the system is calculated by the static analysis to meet the design requirements in engineering. In dynamic analysis, each pile foundation is equivalent to a group of springs for the simulation of horizontal and vertical rigidity of the pile. The influence of top mass and foundation elasticity on wind turbine tower modes is analyzed, and calculated the natural frequency of the tower within a certain scope of rigidity in different directions about the piles foundation. The results show that the natural frequency of the wind turbine tower is influenced significantly by the mass on the tower top and foundation rigidity. The study provides a theoretical basis for optimal design of the wind turbine.

Evaluation of Aerodynamic and Seismic Coupling for Wind Turbines Using Finite Element Approach

2013 ◽  
Author(s):  
Mohammad-Amin Asareh ◽  
Jeffery S. Volz
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Large Scale ◽  
Active Regions ◽  
Seismic Loading ◽  
Wind Loading ◽  
Earthquake Excitation ◽  
Element Analysis ◽  
Simulation Codes

The behavior of a wind turbine consists of complex interactions between different components and subsystems. As more large scale wind turbines are constructed in seismically active regions, earthquake excitation makes an even more challenging problem when calculating extreme loads. Turbine specific simulation codes that directly include simulation of aerodynamics and seismic loading often include considerable simplifications to the turbine model that might cause unrealistic scenarios when designing such structures. Turbine related simulation codes are also often unfamiliar for civil engineers. For these reasons, it is desirable to come up with an approach that can handle a more realistic model that can simulate coupling between the influenced loads involved. In this work, the emphasis is put on the response of the tower of a large scale wind turbine subjected to aerodynamic and seismic loading. To capture the inclusive behavior of the structure, finite element analysis was used that consisted of shell elements for the tower, and beam elements for the blades. Various interactions were also used to model the rotation of the rotor during the operation of turbine under wind loading. Results of this approach were compared with previous findings using a selection of ground motions and turbulent wind fields. It is shown that for the turbine operational condition, the presented approach agrees well with the previously verified design codes. The outcome of this approach will provide a better understanding of more detailed structural aspects of wind turbines such as nonlinear behavior and failure criteria that might be considered necessary for a more comprehensive design.

scholarly journals A Novel Tripod Concept for Onshore Wind Turbine Towers

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5772
Author(s):  
Charis J. Gantes ◽  
Maria Villi Billi ◽  
Mahmut Güldogan ◽  
Semih Gül
Keyword(s):  
Wind Turbine ◽  
Cross Sections ◽  
Structural Features ◽  
Performance Criteria ◽  
Wind Turbine Tower ◽  
Wind Potential ◽  
Pile Cap ◽  
Tripod Concept ◽  
Wind Turbine Towers ◽  
Maintenance Requirements

A wind turbine tower assembly is presented, consisting of a lower “tripod section” and an upper tubular steel section, aiming at enabling very tall hub heights for optimum exploitation of the wind potential. The foundation consists of sets of piles connected at their top by a common pile cap below each tripod leg. The concept can be applied for the realization of new or the upgrade of existing wind turbine towers. It is adjustable to both onshore and offshore towers, but emphasis is directed towards overcoming the stricter onshore transportability constraints. For that purpose, pre-welded individual tripod parts are transported and are then bolted together during erection, contrary to fully pre-welded tripods that have been used in offshore towers. Alternative constructional details of the tripod joints are therefore proposed that address the fabrication, transportability, on-site erection and maintenance requirements and can meet structural performance criteria. The main structural features are demonstrated by means of a typical case study comprising a 180-m-tall tower, consisting of a 120-m-tall tubular superstructure on top of a 60-m-tall tripod substructure. Realistic cross-sections are calculated, leading to weight and cost estimations, thus demonstrating the feasibility and competitiveness of the concept.

scholarly journals Influence of external loads to wind turbine tower

2021 ◽  
Vol 3 (2) ◽  
pp. 112-120
Author(s):  
Marin Petrovic ◽  
Nejra Isic
Keyword(s):  
Wind Turbine ◽  
Wind Velocity ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Steel Pipes ◽  
Wind Turbine Tower ◽  
Wind Turbine Towers ◽  
Lattice Towers ◽  
The Moment ◽  
External Loads

One of the most important parts of a wind turbine is a tower. There are various designs of the wind turbine towers, and they are most often made of steel pipes, lattice towers or concrete towers. In order to increase energy density to meet the growing electricity needs, larger wind turbine projects have been developed. Larger wind turbine towers can generate more electricity, but such large sizes also create higher costs in terms of development and maintenance. This research sets up a model of a wind turbine tower, where the load to the tower is calculated by its relation to the wind velocity. Analytical approach coupled with a finite element method (FEM) is used to analyse the distribution of tower stresses under these loads. The fatigue analysis of the column is performed using the load from its own weight, the weight of the housing and the distribution of the wind velocity. The effects of different loads are also compared. The results show that the main loads of the tower are the wind force acting on the area of ??rotation of the wind turbine blades and the moment caused by the uneven wind velocity. Construction is modelled using SolidWorks modelling package, where the analysis was performed using FEM in ANSYS software. As a result of the analysis, the stress distribution in the support was determined and compared with analytical calculations.

Finite Element Analysis of Concrete Filled Double Skin Steel Tubes for Wind Turbine Tower

2014 ◽  
Vol 680 ◽  
pp. 551-556
Author(s):  
Wei Kong ◽  
Hong Liang Wang ◽  
Ying Cai
Keyword(s):  
Finite Element ◽  
Wind Speed ◽  
Wind Turbine ◽  
Normal Operation ◽  
Mode Shapes ◽  
Strength Analysis ◽  
Element Analysis ◽  
Finite Element Software ◽  
Wind Turbine Tower ◽  
Double Skin

In order to save the steel consumption,ensure the better economy of wind turbine tower,this paper designeda new concrete filled double skin steel tube for wind turbine tower,based on the parameters of 1. 5 MW wind turbine tower.A three-dimensional finite element model of wind turbine tower was built by using the finite element software ANSYS,then the static strength analysis and modal analysis were carried out,in which the stress and displacement at the top of the tower were calculated under three kinds of working conditions: normal operation with rated wind speed,normal operation with cutout wind speed and shutdown under extreme wind conditions,the natural frequency and mode shapes of the tower were obtained as well. The results show that the tower does not resonate with blades,and its structure can meet the strength and stiffness requirements of engineering.

scholarly journals A Screening Methodology for the Identification of Critical Units in Major-Hazard Facilities Under Seismic Loading

2021 ◽  
Vol 7 ◽  
Author(s):  
Daniele Corritore ◽  
Fabrizio Paolacci ◽  
Stefano Caprinozzi
Keyword(s):  
Risk Analysis ◽  
Seismic Hazard ◽  
Risk Index ◽  
Seismic Loading ◽  
Rapid Identification ◽  
Representative Case ◽  
Hazard Curve ◽  
Damage States ◽  
Critical Components ◽  
Seismic Hazard Curve

The complexity of process industry and the consequences that Na-Tech events could produce in terms of damage to equipment, release of dangerous substances (flammable, toxic, or explosive), and environmental consequences have prompted the scientific community to focus on the development of efficient methodologies for Quantitative Seismic Risk Analysis (QsRA) of process plants. Several analytical and numerical methods have been proposed and validated through representative case studies. Nevertheless, the complexity of this matter makes their applicability difficult, especially when a rapid identification of the critical components of a plant is required, which may induce hazardous material release and thus severe consequences for the environment and the community. Accordingly, in this paper, a screening methodology is proposed for rapid identification of the most critical components of a major-hazard plant under seismic loading. It is based on a closed-form assessment of the probability of damage for all components, derived by using analytical representations of the seismic hazard curve and the fragility functions of the equipment involved. For this purpose, fragility curves currently available in the literature or derived by using low-fidelity models could be used for simplicity, whereas the parameters of the seismic hazard curve are estimated based on the regional seismicity. The representative damage states (DS) for each equipment typology are selected based on specific damage states/loss of containment (DS/LOC) matrices, which are used to individuate the most probable LOC events. The risk is then assessed based on the potential consequences of a LOC event, using a classical consequence analysis, typically adopted in risk analysis of hazardous plants. For this purpose, specific probability classes will be used. Finally, by associating the Probability Class Index (PI) with Consequence Index (CI), a Global Risk Index (GRI) is derived, which provides the severity of the scenario. This allows us to build a ranking of the most hazardous components of a process plant by using a proper risk matrix. The applicability of the method is shown through a representative case study.

Sign in / Sign up

Export Citation Format

Share Document