Structural Analysis of Conical Bottom-Supported Offshore Wind Turbine Foundation

2011 ◽  
Vol 117-119 ◽  
pp. 726-729
Author(s):  
Yuan Lin Zhao ◽  
Zhi Wen Zhu ◽  
Shi Deng
Keyword(s):  
Wind Turbine ◽  
Low Cost ◽  
Element Model ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Shallow Sea ◽  
Offshore Wind Power ◽  
The Finite Element Model ◽  
Conical Bottom ◽  
Survival Condition

In this paper, a kind of conical bottom-supported offshore wind turbine foundation was developed. The finite element model was built in SESAM and the structure was analyzed in operating condition and survival condition. The result shows that both the bearing platform and the conical bottom can satisfy the requirement of displacement and strength. The new kind of platform can be applied in shallow sea and offshore, easy to tow, and has low cost, which is helpful to offshore wind power exploitation.

scholarly journals Low cost of sustainable work and maintenance for offshore wind power speed-increasing device

2019 ◽  
Vol 118 ◽  
pp. 02016
Author(s):  
Fei Wang ◽  
Shijie Sun
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Power Transmission ◽  
Low Cost ◽  
Economic Benefits ◽  
Offshore Wind ◽  
Maintenance Cost ◽  
Offshore Wind Turbine ◽  
Speed Increase ◽  
Offshore Wind Power

For the problem of wind turbine outage caused by the failure of wind power transmission devices, we proposed an offshore wind power transmission device with low sustainable operation and low maintenance cost. Through the combination of gearbox A and B, the power transmission of the offshore wind turbine is uninterrupted, and the continuous operation of grid-connected power generation enhances the economic benefits of offshore wind turbines. The maritime maintenance man-hours is reduced by moving the speed increase gearbox A from the offshore wind turbine site to the land for maintenance inspection, and the maintenance cost is significantly reduced.

scholarly journals Support condition monitoring of offshore wind turbines using model updating techniques

2019 ◽  
Vol 19 (4) ◽  
pp. 1017-1031 ◽  
Author(s):  
Ying Xu ◽  
George Nikitas ◽  
Tong Zhang ◽  
Qinghua Han ◽  
Marios Chryssanthopoulos ◽  
...  
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Model Updating ◽  
Element Model ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Support Condition ◽  
Offshore Wind Turbines ◽  
Wind Turbine System

The offshore wind turbines are dynamically sensitive, whose fundamental frequency can be very close to the forcing frequencies activated by the environmental and turbine loads. Minor changes of support conditions may lead to the shift of natural frequencies, and this could be disastrous if resonance happens. To monitor the support conditions and thus to enhance the safety of offshore wind turbines, a model updating method is developed in this study. A hybrid sensing system was fabricated and set up in the laboratory to investigate the long-term dynamic behaviour of the offshore wind turbine system with monopile foundation in sandy deposits. A finite element model was constructed to simulate structural behaviours of the offshore wind turbine system. Distributed nonlinear springs and a roller boundary condition are used to model the soil–structure interaction properties. The finite element model and the test results were used to analyse the variation of the support condition of the monopile, through an finite element model updating process using estimation of distribution algorithms. The results show that the fundamental frequency of the test model increases after a period under cyclic loading, which is attributed to the compaction of the surrounding sand instead of local damage of the structure. The hybrid sensing system is reliable to detect both the acceleration and strain responses of the offshore wind turbine model and can be potentially applied to the remote monitoring of real offshore wind turbines. The estimation of distribution algorithm–based model updating technique is demonstrated to be successful for the support condition monitoring of the offshore wind turbine system, which is potentially useful for other model updating and condition monitoring applications.

Research on the Dynamic Response of Floating Foundation of a Tri-Floater Offshore Wind Turbine

2013 ◽  
Vol 275-277 ◽  
pp. 852-855 ◽  
Author(s):  
Zhuang Le Yao ◽  
Chao He Chen ◽  
Yuan Ming Chen
Keyword(s):  
Wind Turbine ◽  
Transfer Functions ◽  
Reference Value ◽  
Element Model ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wave Load ◽  
Floating Foundation ◽  
Wind Turbine System ◽  
Offshore Wind Industry

In this paper, the overall finite element model is established, to analyze the small-sized floating foundation of a tri-floater and to make a local optimization on the stress concentration area. The transfer functions and the response spectrums of wave load and motion of floating wind turbine system are calculated by AQWA. Besides the concept of the floating foundation group is put forward in this paper. It is small in structure, easy to assemble, and it can be developed for any power of wind field.This concept has a certain reference value for the development of offshore wind industry in China.

The Analysis and Application on the Typhoon-Induced Vibration Control of the Wind Turbine with a Pendulum Damper

2013 ◽  
Vol 773 ◽  
pp. 193-198 ◽  
Author(s):  
Jing Li ◽  
Jian Yun Chen ◽  
Xiao Bo Chen
Keyword(s):  
Wind Turbine ◽  
Three Dimensional ◽  
Element Model ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Superposition Method ◽  
Strong Wind ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

As a kind of high-rise structure, the offshore wind turbine is sensitive to wind load; it can generate strong dynamic responses to the excitation of typhoon. In this paper, a three-dimensional finite element model of offshore wind turbine is established with ADINA, responses under strong wind excitation are numerically simulated and performed subsequently. The fluctuating wind velocity time series are simulated by the method of HSM (harmony superposition method). Based on the modal and tine-history analyses of the structures together with self-vibration character, the pendulum damper is employed to control the resulting undesirable vibrations that are induced by wind. With the damper installed, the displacement and acceleration of the tower are reduced by as much as 40% using 1% of the total effective mass.

scholarly journals Passive Control of a Pentapod Offshore Wind Turbine Under Earthquakes by Using Tuned Mass Damper

2017 ◽  
Author(s):  
Wenhua Wang ◽  
Zhen Gao ◽  
Xin Li ◽  
Torgeir Moan ◽  
Bin Wang
Keyword(s):  
Wind Turbine ◽  
Seismic Waves ◽  
Passive Control ◽  
Element Model ◽  
Tuned Mass Damper ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Mass Damper ◽  
And Control

The finite element model (FEM) of a pentapod offshore wind turbine (OWT) is established in the newly compiled FAST. The dynamic responses of the OWT are analyzed in detail. Further, a tuned mass damper as a passive control strategy is applied in order to reduce the OWT responses under seismic loads. The influence of the tuned mass damper (TMD) locations, mass and control frequencies on the reduction of OWT responses are investigated. A general configuration of TMD can effectively reduce the local and global responses to some degree, but due to the complexity of characteristics of the OWT structure and seismic waves, the single TMD can not obtain consistent controlling effects.

Finite Element Analysis of Large Diameter Grouted Connections

2007 ◽  
Author(s):  
Lars P. Nielsen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Wind Turbine ◽  
Large Diameter ◽  
Wind Farms ◽  
Element Model ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Joint Research ◽  
Element Analysis

When considering offshore monopile foundations designed for wind turbine support structures, a grouted connection between the monopile and an overlapping transition piece has become the de facto standard. These connections rely on axial loads being carried primarily by the bond between the steel and grout as shear. Given the critical nature of the grouted connection in a system with zero redundancy, the current design verification requirement is that a finite element analysis is performed to ascertain the viability of the connection with respect to combined axial and bending capacity whilst pure axial capacity is handled as a decoupled phenomenon using simple analytical formulas. The present paper addresses the practical modeling aspects of such a finite element model, covering subjects such as constitutive formulations for the grout, mesh density, and steel/grout interaction. The aim of the paper is to discuss different modeling approaches and, to the extent possible, provide basic guidelines for the minimum requirements valid for this type of analysis. This discussion is based on the accumulated experience gained though the independent verification of more than 10 currently operational offshore wind farms that have been certified by DNV, as well as the significant joint research and development with industry captured in the DNV Offshore Standard for Design of Offshore Wind Turbine Structures DNV-OS-J101. Moreover, general observations relating to the basic subjects such as overall geometric extent of the model, inclusion of secondary structures, detail simplification, boundary conditions, load application etc. are presented based on the authors more than 3 year involvement on the subject at DNV.

Study on the Coexistence of Offshore Wind Farms and Cage Culture

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1960
Author(s):  
Hsing-Yu Wang ◽  
Hui-Ming Fang ◽  
Yun-Chih Chiang
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Wind Farm ◽  
Wind Farms ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Offshore Wind Farms ◽  
Offshore Wind Power ◽  
Waves And Currents ◽  
The Waves

In this study, a hydrodynamic model was used that includes the effects of wave–current interactions to simulate the wave and current patterns before and after offshore wind turbine installation in western Taiwan. By simulating the waves and currents after the offshore wind turbine was established, the waves and currents caused by the wind turbine were seen to have a limited range of influence, which is probably within an area about four to five times the size of the diameter (12–15 m) of the foundation structure. Overall, the analysis of the simulation results of the wave and current patterns after the offshore wind turbines were established shows that the underwater foundation only affected the local area near the pile structure. The wind farm (code E) of the research case can be equipped with about 720 cage cultures; if this is extended to other wind farms in the western sea area, it should be possible to produce economic-scale farming operations such as offshore wind power and fisheries. However, this study did not consider the future operation of the entire offshore wind farm. If the operation and maintenance of offshore wind farms are not affected, and if the consent of the developer is obtained, it should be possible to use this method to provide economically large-scale farming areas as a mutually beneficial method for offshore wind power generation and fisheries.

scholarly journals Health Monitoring and Safety Evaluation of the Offshore Wind Turbine Structure: A Review and Discussion of Future Development

2019 ◽  
Vol 11 (2) ◽  
pp. 494 ◽  
Author(s):  
Jijian Lian ◽  
Ou Cai ◽  
Xiaofeng Dong ◽  
Qi Jiang ◽  
Yue Zhao
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Health Monitoring ◽  
Safety Evaluation ◽  
Development Trend ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Offshore Wind Power ◽  
Health Monitoring Systems ◽  
Evaluation Techniques

With the depletion of fossil energy, offshore wind power has become an irreplaceable energy source for most countries in the world. In recent years, offshore wind power generation has presented the gradual development trend of larger capacity, taller towers, and longer blades. The more flexible towers and blades have led to the structural operational safety of the offshore wind turbine (OWT) receiving increasing worldwide attention. From this perspective, health monitoring systems and operational safety evaluation techniques of the offshore wind turbine structure, including the monitoring system category, data acquisition and transmission, feature information extraction and identification, safety evaluation and reliability analysis, and the intelligent operation and maintenance, were systematically investigated and summarized in this paper. Furthermore, a review of the current status, advantages, disadvantages, and the future development trend of existing systems and techniques was also carried out. Particularly, the offshore wind power industry will continue to develop into deep ocean areas in the next 30 years in China. Practical and reliable health monitoring systems and safety evaluation techniques are increasingly critical for offshore wind farms. Simultaneously, they have great significance for strengthening operation management, making efficient decisions, and reducing failure risks, and are also the key link in ensuring safe energy compositions and achieving energy development targets in China. The aims of this article are to inform more scholars and experts about the status of the health monitoring and safety evaluation of the offshore wind turbine structure, and to contribute toward improving the efficiency of the corresponding systems and techniques.

Model Updating of Soil-Structure Interface of Monopiled Offshore Wind Turbines

2020 ◽  
Author(s):  
Shuai Cong ◽  
Sau-Lon James Hu ◽  
Hua-Jun Li
Keyword(s):  
Wind Turbine ◽  
Soil Structure ◽  
Model Updating ◽  
Element Model ◽  
Offshore Wind ◽  
Soil Structure Interaction ◽  
Offshore Wind Turbine ◽  
Finite Element Model Updating ◽  
Offshore Wind Turbines ◽  
Stiffness And Damping

Abstract As the vibration analysis of an offshore wind turbine (OWT) system should consider its soil-structure interaction, a recent article proposed a simple soil-structure interface model. It includes a horizontal spring, a rotational spring and a rotational dash-pot at the interface. Developing a finite element model updating method on correcting the soil-structure interface coefficients based on the true response measurements is highly desired. This paper develops an accurate and efficient model updating method for simultaneously updating the stiffness and damping parameters of the soil-structure interface of a monopiled offshore wind turbine, when only a few measured modal frequencies and damping ratios are available. The performance of the proposed method is numerically demonstrated through a simulated National Renewable Energy Laboratory 5-MW (NREL 5-MW) reference turbine.

Scour Assessment and Measurements for Pile-Supported Wind Turbine Foundations

2013 ◽  
Author(s):  
Bruno Stuyts ◽  
David Cathie ◽  
Yi Xie
Keyword(s):  
Wind Turbine ◽  
Time Scale ◽  
Rapid Development ◽  
Element Model ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Scour Depth ◽  
Central Column ◽  
Pile Interaction ◽  
Equilibrium Scour Depth

With the rapid development of offshore wind energy in Europe, a large number of piled structures are being installed. In areas with sandy seabed conditions, erosion of sediment by the actions of wave and current can negatively influence foundation capacity. An accurate prediction model of scour around the piles is therefore required. Well-accepted scour prediction methods exist; both for the equilibrium scour depth and the time scale of scour [1] around single piles. These standard formulas have been combined with metocean data and a hindcasting model to calculate the expected scour depth around piles of wind turbine tripod foundations. Other causes of scour, such as pile-pile interaction, effect of proximity of structural members to the seabed, and seabed mobility were also assessed in order to determine the amount of global scour to be considered. The scour predictions were compared to measurements taken at an offshore wind turbine foundation at Park Alpha Ventus (PAV) in the German North Sea [2]. The data showed very good agreement with the measured scour around the piles. Both the equilibrium scour depth and time scale of scour were well predicted using the hindcasting model. The measured scour below the central column of the tripod structure exceeded expectations; this is believed to be due to a pumping effect during storm episodes. Finally, the effect of scour on the vertical effective stress around the tripod piles was assessed with a finite element model. Local scour had an important effect while scour below the centre of the structure had a much more limited effect. Considering the combined effects of multiple pile interaction, scour below the central column, and making an allowance for seabed mobility, an equivalent global scour depth for pile capacity calculations was established.

Sign in / Sign up

Export Citation Format

Share Document