A Review of Coupling Approaches for the Dynamic Analysis of Bottom-Supported Offshore Wind Turbines

2016 ◽  
Author(s):  
Lance Manuel ◽  
Watsamon Sahasakkul ◽  
Hieu Nguyen ◽  
Ali Sari
Keyword(s):  
Dynamic Analysis ◽  
Wind Turbines ◽  
Offshore Wind ◽  
Offshore Wind Turbines

scholarly journals Dynamic Analysis of Mooring Cables with Application to Floating Offshore Wind Turbines

2016 ◽  
Vol 142 (3) ◽  
pp. 04015101 ◽  
Author(s):  
Crescenzo Petrone ◽  
Nicholas D. Oliveto ◽  
Mettupalayam V. Sivaselvan
Keyword(s):  
Dynamic Analysis ◽  
Wind Turbines ◽  
Offshore Wind ◽  
Offshore Wind Turbines ◽  
Floating Offshore Wind Turbines

Supporting the Engineering Analysis of Offshore Wind Turbines Through Advanced Soil-Structure 3D Modelling

2017 ◽  
Author(s):  
Simone Corciulo ◽  
Omar Zanoli ◽  
Federico Pisanò
Keyword(s):  
Dynamic Analysis ◽  
Wind Turbines ◽  
Soil Structure ◽  
Current Trend ◽  
Offshore Wind ◽  
Fe Modelling ◽  
Offshore Wind Turbines ◽  
Geotechnical Design ◽  
Foundation Type ◽  
Increasing Load

Monopiles are at present the most widespread foundation type for offshore wind turbines (OWTs), due to their simplicity and economic convenience. The current trend towards increasingly powerful OWTs in deeper waters is challenging the existing procedures for geotechnical design, requiring accurate assessment of transient soil-monopile interaction and, specifically, of the associated modal frequencies. In this work, advanced 3D finite element (FE) modelling is applied to the dynamic analysis of soil-monopile-OWT systems under environmental service loads. Numerical results are presented to point out the interplay of soil non-linearity and cyclic hydro-mechanical (HM) coupling, and its impact on transient response of the system at increasing load magnitude. It is shown how the lesson learned from advanced modelling may directly inspire simplified, yet effective, spring models for the engineering dynamic analysis of OWTs.

scholarly journals STRUCTURAL ANALYSIS OF JACKET FOUNDATIONS FOR OFFSHORE WIND TURBINES IN TRANSITIONAL WATER

Brodogradnja ◽  
2021 ◽  
Vol 72 (1) ◽  
pp. 109-124
Author(s):  
Issa Fowai ◽  
◽  
Zhang Jianhua ◽  
Ke Sun ◽  
Bin Wang ◽  
...  
Keyword(s):  
Dynamic Analysis ◽  
Modal Analysis ◽  
Static Analysis ◽  
Wind Turbines ◽  
Offshore Wind ◽  
Von Mises Stress ◽  
Mode Shapes ◽  
Offshore Wind Turbines ◽  
Static And Dynamic Analysis ◽  
Von Mises

Most of the offshore wind turbines (OWT) recently installed in Europe, China and North America are in shallow water. However, unlocking the full potential of OWT lies in deeper waters. Jacket substructures have presented themselves as a reliable foundation concept for transitional water depth. This study focuses on the structural static and dynamic analysis of the traditional jacket substructures (with X and K bracing) and the recently patented three-legged twisted jackets (with a twisted angle of 30 and 60 degrees) for deployment in transitional water (beyond 60 m). To facilitate comparison, the dimensions of all the jackets remain the same, while, the geometric configurations are distinct. Static analysis was implemented to better understand the global load bearing behaviour of the jackets. First, the global displacement patterns at the tower top are compared. The individual reactions at mud-line were investigated, followed by the evaluation of the maximum von Mises stress. Subsequently, this research went on to investigate the effect of dynamic loading. In this dynamic analysis, three main critical points were considered, including the wave point (67 m), the platform and the tower top. A modal analysis was performed to compute the mode shapes and natural frequencies for all the jackets. The first five modes of all the jackets were also checked against the results available for the OC4 project. A similar analytical approach was adopted for the structural design of monopile or tripod foundations for offshore wind turbines. The results showed that in the static analysis both the traditional jackets and the twisted jackets were safe under the provided load combination. The twisted jacket proved to possess excellent structural behaviour compared to the traditional four-legged jackets, while maintaining the merits of lower material usage with fewer nodes. Analysing the von Mises stress revealed that the maximum stress occurred at the transition piece and close to the working platform. The modal analysis results of the jackets demonstrated that the twisted jackets (30 and 60 degrees) with the first natural frequency of 0.29 and 0.31 Hz fell under the soft-stiff design category whereas the traditional four-legged jackets were classified as stiff-stiff designs. The discovered structural performance of OWTs equipped with various jacket foundations contributes to the preliminary structural selection and optimal design of foundations of OWTs to be installed in transitional water.

Integrated Dynamic Analysis of Floating Offshore Wind Turbines

2006 ◽  
Author(s):  
Finn Gunnar Nielsen ◽  
Tor David Hanson ◽  
Bjo̸rn Skaare
Keyword(s):  
Wind Speed ◽  
Dynamic Analysis ◽  
Wind Turbines ◽  
Control Strategy ◽  
Rotor Blade ◽  
Offshore Wind ◽  
Offshore Wind Turbines ◽  
Pitch Control ◽  
Floating Offshore Wind Turbines ◽  
Wind Velocities

Two different simulation models for integrated dynamic analysis of floating offshore wind turbines are described and compared with model scale experiments for the Hywind concept for floating offshore wind turbines. A variety of both environmental conditions and wind turbine control schemes are tested. A maximum power control strategy is applied for wind velocities below the rated wind speed for the wind turbine, while a constant power control strategy is achieved by controlling the rotor blade pitch for wind velocities above rated wind speed. Conventional rotor blade pitch control for wind velocities above rated wind speed introduces negative damping of the tower motion. This results in excitation of the natural frequency in pitch for the tower and may lead to unacceptable tower motions. Active damping of the undesirable tower motions is obtained by an additional pitch control algorithm based on measurement of the tower velocity.

Pitch Angle Control of Floating Offshore Wind Turbines by H∞ Control

2014 ◽  
Vol 134 (8) ◽  
pp. 1096-1103 ◽  
Author(s):  
Sho Tsujimoto ◽  
Ségolène Dessort ◽  
Naoyuki Hara ◽  
Keiji Konishi
Keyword(s):  
Wind Turbines ◽  
Pitch Angle ◽  
Offshore Wind ◽  
Offshore Wind Turbines ◽  
Floating Offshore Wind Turbines
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