Structural topology optimization of the transition piece for an offshore wind turbine with jacket foundation

2016 ◽  
Vol 85 ◽  
pp. 1214-1225 ◽  
Author(s):  
Yeon-Seung Lee ◽  
José A. González ◽  
Ji Hyun Lee ◽  
Young Il Kim ◽  
K.C. Park ◽  
...  
Keyword(s):  
Topology Optimization ◽  
Wind Turbine ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Structural Topology Optimization ◽  
Structural Topology ◽  
Transition Piece

scholarly journals Analysis of Tightening Sequence Effects on Preload Behaviour of Offshore Wind Turbine M72 Bolted Connections

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4406 ◽  
Author(s):  
Braithwaite ◽  
Mehmanparast
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Fe Model ◽  
Bolted Connections ◽  
Minimum Requirement ◽  
Offshore Wind Turbines ◽  
Sequence Effects ◽  
Transition Piece

Offshore wind turbines in shallow waters are predominantly installed using a monopile foundation, onto which a transition piece and wind turbine are attached. Previously, the monopile to transition piece (MP-TP) connection was made using a grouted connection, however, cases of grout failure causing turbine slippage, among other issues, were reported. One solution is to use bolted ring flange connections, which involve using a large number of M72 bolts to provide a firm fixing between the MP-TP. It is in the interest of offshore wind operators to reduce the number of maintenance visits to these wind turbines by maintaining a preload (Fp) level above the minimum requirement for bolted MP-TP connections. The present study focuses on the effect of the tightening sequence on the Fp behaviour of M72 bolted connections. A detailed finite element (FE) model of a seven-bolt, representative segment of a monopile flange was developed with material properties obtained from the available literature. Three analyses were made to examine the effect on Fp after tightening, including the initial Fp level applied to the bolts, the tightening sequence and the effect of an additional tightening pass.

scholarly journals Steady State Motion Analysis of an Offshore Wind Turbine Transition Piece During Installation Based on Outcrossing of the Motion Limit State

2015 ◽  
Author(s):  
Wilson Guachamin-Acero ◽  
Torgeir Moan ◽  
Zhen Gao
Keyword(s):  
Wind Turbine ◽  
Limit State ◽  
Horizontal Displacement ◽  
Outcrossing Rate ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Suggested Approach ◽  
Transition Piece ◽  
Monitoring Phase

Installation of OffshoreWind Turbine structural components need to be executed in sea states for which their dynamic responses are expected to remain within a safe domain or perform a limited number of outcrossings from the safe boundary beyond which the responses may lead to unsafe working conditions, large impact loads or even structural failure. A critical installation activity limiting the installation of a Transition Piece TP is often the motion monitoring phase of the mating points until its landing on the foundation. The operational limit is normally given by the horizontal displacement and the safe domain could conveniently be defined by a circle of radius r in the horizontal plane. This paper presents an existing general accurate method and its solution to estimate the outcrossing rate of dynamic responses for a circular safe boundary in short crested seas which is applicable for the motion monitoring phase of offshore wind turbine components prior to mating. The required input is calculated from spectral analysis in the frequency domain and the solution is derived for Gaussian processes. It is found that both 1st and 2nd order responses have to be included and that the Gaussian assumption for the slow drift motions is not valid so that its real PDF is required. Also wave spreading has large influence in the outcrossing rate and should realistically be applied. The suggested approach is in agreement with real offshore practice, and is efficient when compared with time domain simulations. Then, the outcrossing rate method could help on Marine Operations decision making during critical installation activities.

Experimental Study for SPAR Type Floating Offshore Wind Turbine With Blade-Pitch Control

2013 ◽  
Author(s):  
Toshiki Chujo ◽  
Yoshimasa Minami ◽  
Tadashi Nimura ◽  
Shigesuke Ishida
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Offshore Wind ◽  
Scale Model ◽  
Offshore Wind Turbine ◽  
Experimental Proof ◽  
Pitch Control ◽  
Model Experiments ◽  
North Eastern ◽  
North Eastern Part

The experimental proof of the floating wind turbine has been started off Goto Islands in Japan. Furthermore, the project of floating wind farm is afoot off Fukushima Prof. in north eastern part of Japan. It is essential for realization of the floating wind farm to comprehend its safety, electric generating property and motion in waves and wind. The scale model experiments are effective to catch the characteristic of floating wind turbines. Authors have mainly carried out scale model experiments with wind turbine models on SPAR buoy type floaters. The wind turbine models have blade-pitch control mechanism and authors focused attention on the effect of blade-pitch control on both the motion of floater and fluctuation of rotor speed. In this paper, the results of scale model experiments are discussed from the aspect of motion of floater and the effect of blade-pitch control.

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