scholarly journals Dynamic Impedance of the Wide-Shallow Bucket Foundation for Offshore Wind Turbine using Coupled Finite–Infinite Element Method

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4370 ◽  
Author(s):  
Lian ◽  
Jiang ◽  
Dong ◽  
Zhao ◽  
Zhao
Keyword(s):  
Large Scale ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Soil Thickness ◽  
Soil Stiffness ◽  
Bucket Foundation ◽  
Infinite Element ◽  
Dynamic Impedance ◽  
Element Technique

The dynamic impedances of foundation play an important role in the dynamic behavior and structural stability of offshore wind turbines (OWT). Though the behaviors of bucket foundation, which are considered as a relatively innovative foundation type under static loading, have been extensively investigated, the corresponding dynamic performances were neglected in previous research. This study focuses on the dynamic impedances of wide-shallow bucket foundations (WSBF) under the horizontal and rocking loads. Firstly, the numerical model was established to obtain the dynamic impedances of WSBF using the coupled finite-infinite element technique (FE-IFE). The crucial parameters affecting the dynamic responses of WSBF are investigated. It is shown that the skirt length mainly affects the rocking dynamic impedance and the diameter significantly affects the horizontal and coupling impedances, especially when the diameter is larger than 34 m. The overall dynamic responses of WSBF are profoundly affected by the relative soil thickness and the multi-layer soil stiffness. Additionally, dynamic impedances of WSBF are insensitive to the homogeneous soil stiffness. Lastly, the safety threshold curve was calculated according to the OWT, which can provide essential reference for the design of the OWT supported by large scale WSBF.

Study on the Bearing Mechanism of Bucket Foundation for Offshore-Wind Turbine in Soft Clay

2011 ◽  
Vol 71-78 ◽  
pp. 1795-1804
Author(s):  
Jian Feng Wang ◽  
Hai Tao Dai ◽  
Ming Qin
Keyword(s):  
Large Scale ◽  
Soft Clay ◽  
Bending Moment ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Horizontal Load ◽  
Vertical Load ◽  
Bucket Foundation ◽  
Finite Element Software ◽  
Moment Load

Based on numerical platform of large-scale finite element software, this paper investigates the function mechanisms of vertical load, horizontal load, and bending moment load of soft-clay-base bucket foundation. Then the corresponding load bearing characteristics of each load type of soft-clay-base bucket foundation are determined.

Model Test and Numerical Analysis of an Offshore Bottom Fixed Pentapod Wind Turbine Under Seismic Loads

2016 ◽  
Author(s):  
Wenhua Wang ◽  
Zhen Gao ◽  
Xin Li ◽  
Torgeir Moan ◽  
Bin Wang
Keyword(s):  
Wind Turbine ◽  
Wind Wave ◽  
Seismic Analysis ◽  
Wind Farms ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Test Model ◽  
Structural Dynamic ◽  
Load Conditions

In the last decade the wind energy industry has developed rapidly in China, especially offshore. For a water depth less than 20m, monopile and multi-pile substructures (tripod, pentapod) are applied widely in offshore wind farms. Some wind farms in China are located in high seismicity regions, thus, the earthquake load may become the dominant load for offshore wind turbines. This paper deals with the seismic behavior of an offshore wind turbine (OWT) consisting of the NREL 5MW baseline wind turbine, a pentapod substructure and a pile foundation of a real offshore wind turbine in China. A test model of the OWT is designed based on the hydro-elastic similarity. Test cases of different load combinations are performed with the environmental conditions generated by the Joint Earthquake, Wave and Current Simulation System and the Simple Wind Field Generation System at Dalian University of Technology, China, in order to investigate the structural dynamic responses under different load conditions. In the tests, a circular disk is used to model the rotor-nacelle system, and a force gauge is fixed at the center of the disk to measure the wind forces during the tests. A series of accelerometers are arranged along the model tower and the pentapod piles, and strain gauges glued on the substructure members are intended to measure the structural dynamic responses. A finite element model of the complete wind turbine is also established in order to compare the theoretical results with the test data. The hydro-elastic similarity is validated based on the comparison of the measured dynamic characteristics and the results of the prototype modal analysis. The numerical results agree well with the experimental data. Based on the comparisons of the results, the effect of the wind and sea loads on the structural responses subjected to seismic is demonstrated, especially the influence on the global response of the structure. It is seen that the effect of the combined seismic, wind, wave and current load conditions can not be simply superimposed. Hence the interaction effect in the seismic analysis should be considered when the wind, wave and current loads have a non-negligible effect.

One damping estimation approach of the parked offshore wind turbine supported by wide-shallow bucket foundation

2021 ◽  
Vol 235 ◽  
pp. 109387
Author(s):  
Jijian Lian ◽  
Junni Jiang ◽  
Xiaofeng Dong ◽  
Haijun Wang ◽  
Huan Zhou
Keyword(s):  
Wind Turbine ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Bucket Foundation ◽  
Damping Estimation

Study on the Dynamic Response for Floating Foundation of Offshore Wind Turbine

2011 ◽  
Author(s):  
Yougang Tang ◽  
Jun Hu ◽  
Liqin Liu
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wave Load ◽  
Mooring Lines ◽  
Floating Foundation ◽  
Wind Turbine System ◽  
Sea Area

The wind resources for ocean power generation are mostly distributed in sea areas with the distance of 5–50km from coastline, whose water depth are generally over 20m. To improve ocean power output and economic benefit of offshore wind farm, it is necessary to choose floating foundation for offshore wind turbine. According to the basic data of a 600kW wind turbine with a horizontal shaft, the tower, semi-submersible foundation and mooring system are designed in the 60-meter-deep sea area. Precise finite element models of the floating wind turbine system are established, including mooring lines, floating foundation, tower and wind turbine. Dynamic responses for the floating foundation of offshore wind turbine are investigated under wave load in frequency domain.

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