Dynamic impedance of monopiles for offshore wind turbines considering scour-hole dimensions

Zhang, Hao; Liang, Fayun; Zheng, Hanbo

doi:10.1016/j.apor.2020.102493

Cited by 28 publications

(9 citation statements)

References 57 publications

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“…Currently, offshore wind-power foundations, which are commonly used around the world, mainly include gravity foundation, pile foundation, tripod foundation, jacket foundation, bucket foundation, etc. [10][11][12][13][14][15], as shown in Figure 2 [16]. Due to near-sea conditions, wind resources are limited and the increasing energy demand has promoted the development of offshore wind power in deeper water areas.…”

Section: Figurementioning

confidence: 99%

Laboratory Study of Integrated Wet-Towing of a Triple-Bucket Jacket Foundation for Far-Offshore Applications

Yan

Guo

Wang

et al. 2021

JMSE

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As a form of clean and low-carbon green energy, offshore wind power occupies an important position in the global energy structure. With the rapid development of the wind power industry, wind power projects gradually develop from offshore to far-offshore sea areas. The multi-bucket jacket foundation is a considerable foundation type for far off-shore projects, but high installation costs involving ship transportation with parted components and field installation has significantly hindered its wide application. In this study, based on a 6.7-MW triple-bucket jacket foundation (TBJF) project of a deep-sea wind farm in China, a new integrated wet-towing method of “jacket + triple-bucket foundation” composite structure was proposed, which is suitable for far long-distance transportation of far-offshore applications. The static-model test of both self-stability and wet-towing stability was conducted. Based on the test and the numerical results, the natural period of the foundation for different draft depths in hydrostatic water and the stability for different eccentric loads were first evaluated. Then, the effects of different wet-towing modes and sea conditions on the stability of the TBJF were investigated. Finally, the optimal wet-towing mode and applicable sea conditions for the TBJF structure were proposed.

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Section: Figurementioning

confidence: 99%

Laboratory Study of Integrated Wet-Towing of a Triple-Bucket Jacket Foundation for Far-Offshore Applications

Yan

Guo

Wang

et al. 2021

JMSE

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“…For instance, van der Tempel (2006) investigated the frequency and fatigue of piles under different scour depths and concluded that scour has little effect on the natural frequencies but a major effect on fatigue damage. Zhang et al (2021) found that scour depth has a significant influence on monopile impedance. Rezaei et al (2018) showed that scour leads to an increase in the maximum bending moment of the monopile and a shortening of the fatigue life.…”

Section: Introductionmentioning

confidence: 98%

Effect of scour on the fatigue life of offshore wind turbines and its prevention through passive structural control

Cao,

Wu,

Yang

et al. 2024

Wind Energ. Sci.

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Abstract. Offshore wind turbine (OWT) support structures are exposed to the risk of fatigue damage and scour, and this risk can be effectively mitigated by installing structural control devices such as tuned mass dampers (TMDs). However, time-varying scour altering OWTs' dynamic characteristics has an impact on the TMD design and fatigue life, which has rarely been studied before. In this paper, a simplified modal model is used to investigate the influence of scour and a TMD on the fatigue life evaluation of a 5 MW OWT's support structure, and a traditional method and a newly developed optimization technique are both presented to obtain TMD parameters. This optimization technique aims at finding optimal parameters of the TMD which maximize the fatigue life of a hotspot at the mudline, and the effect of time-varying scour can be considered. This study assumes that the TMD operates in the fore–aft (FA) direction, while the vibration in the side–side (SS) direction is uncontrolled. Results show that scour can decrease the fatigue life by about 24.1 % and that the TMD can effectively suppress vibration and increase the fatigue life. When the scour depth reaches 1.3 times the pile diameter, the TMD with a mass ratio of 1 % can increase the fatigue life of an OWT's support structure by about 64.6 %. Further, it is found that the fatigue life can be extended by 25 % with the TMD optimized by the proposed optimization technique rather than using a traditional design method which does not take the change in dynamic characteristics into account.

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“…The vibration theory of pile foundation is the theoretical basis for the dynamic design of the foundations of wind turbines, bridges and other facilities, which has received extensive attention from scholars in the past few decades [1][2][3][4]. Throughout the development of the vibration theory of pile foundation, it can be seen that the pile-soil dynamic interaction models are alwaysthe main line of research regarding the vibration problems of pile foundation.…”

Section: Introductionmentioning

confidence: 99%

Vertical Dynamic Impedance of a Viscoelastic Pile in Arbitrarily Layered Soil Based on the Fictitious Soil Pile Model

Yang

Wang

et al. 2022

Energies

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The vertical vibration of a viscoelastic pile immersed in arbitrarily layered soil is investigated by taking the interaction among pile, pile surrounding soil (PSS) and pile end soil (PES) into account. Firstly, considering both the stratification and stress wave effect of soil, a mathematical model of the pile–soil system is established based on the fictitious soil pile (FSP) model. Then, utilizing the impedance function transfer method and Laplace transform technique, the analytical solutions of the vertical dynamic impedance of pile are derived in the frequency domain. The analytical solutions are validated by comparing them with other existing solutions. Finally, a parametric study is put forward to investigate the properties of PES on the vertical dynamic impedance of pile. The results reveal that the properties of PES have a significant effect on the vertical dynamic impedance of pile, but there is a critical influence thickness for this effect. For the cases of the PES thickness exceeding the critical influence thickness, further increase of PES thickness will not affect the dynamic behavior of the pile–soil system.

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Dynamic impedance of monopiles for offshore wind turbines considering scour-hole dimensions

Cited by 28 publications

References 57 publications

Laboratory Study of Integrated Wet-Towing of a Triple-Bucket Jacket Foundation for Far-Offshore Applications

Laboratory Study of Integrated Wet-Towing of a Triple-Bucket Jacket Foundation for Far-Offshore Applications

Effect of scour on the fatigue life of offshore wind turbines and its prevention through passive structural control

Vertical Dynamic Impedance of a Viscoelastic Pile in Arbitrarily Layered Soil Based on the Fictitious Soil Pile Model

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