Wyniki wyszukiwania - Biblioteka Nauki

1

Design and strength calculations of the tripod support structure for offshore power plant

100%

Dymarski C. , Dymarski P. , Żywicki J.

Polish Maritime Research

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2015

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tom nr 1

36--46

EN

The support structure being the object of the analysis presented in the article is Tripod. According to the adopted assumptions, it is a foundation gravitationally set in the water region of 60 m in depth, not fixed to the seabed, which can be used for installing a 7MW wind turbine. Due to the lack of substantial information on designing and strength calculations of such types of structures in the world literature, authors have made an attempt to solve this problem within the framework of the abovementioned project. In the performed calculations all basic loads acting on the structure were taken into account, including: the self mass of the structure, the masses of the ballast, the tower and the turbine, as well as hydrostatic forces, and aero- and hydrodynamic forces acting on the entire object in extreme operating conditions.

2

Design of structure of tension leg platform for 6 MW offshore wind turbine based on FEM analysis

100%

Żywicki J. , Dymarski P. , Ciba E. , Dymarski C.

Polish Maritime Research

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2017

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tom S 1

230--241

EN

The article presents the calculation and design stages of the TLP platform serving as a supporting construction of a 6 MW offshore wind turbine. This platform is designed to anchor at sea at a depth of 60 m. The authors presented the method of parameterization and optimization of the hull geometry. For the two selected geometry variants, the load and motion calculations of the platform subjected to wind, wave and current under 50-year storm conditions were performed. The maximum load on the structure was determined in these extreme storm conditions. For these loads, the MES calculation of the designed platform was performed for the selected variant. Authors have presented a method for calculating maximum wind, wave and current stresses on the structure during the worst storm in the past 50 years. For these loads the MES endurance calculations of the designed platform were made. Based on the results of these calculations, the required structural changes and recalculations have been made in succession to the structural design of the platform, which meets the design requirements and has the required ad hoc strength. The article contains stress analysis in „difficult” nodes of constructions and discusses ways of solving their problems. The work is part of the WIND-TU-PLA project from the NCBR Research Agreement (Agreement No. MARTECII / 1/2014).

3

Short review and 3-D FEM analysis of basic types of foundation for offshore wind turbines

100%

Iwicki P. , Przewłócki J.

Polish Maritime Research

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2020

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tom nr 3

31--39

EN

Some problems of the foundations of offshore wind turbines are considered in this paper. A short review is presented on the two basic types of foundations, i.e. monopiles and gravity foundations, including their basic features and applications as well as general design considerations. Also, some issues regarding analysis are discussed, including geotechnical problems and modelling techniques. A numerical model of offshores turbine and some preliminary computations are presented. Finite element analysis was carried out for wind turbines supported on both gravity and monopile foundations. The wind turbine tower, blades (simplified model), gravity foundation and part of the surrounding soil are included in the model. The turbine was loaded by wind and loads induced by waves, inertia and gravity. Both non-linear static and dynamic analysis of the wind turbine was performed. The displacements and stresses under the tower foundations were calculated and a comparison analysis carried out.

4

Maintenance grouping optimization for offshore wind turbine considering opportunities based on rolling horizon approach

88%

Lua Y. , Suna L. , Kanga J. , Zhang X.

Polish Maritime Research

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2018

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tom nr 2

123--131

EN

In future, offshore wind turbines may be consider a crucial part in the supply of energy. Maintenance processes are directed to attain a safe and reliable operation of offshore machines and wind turbines. In this paper, an opportunistic maintenance strategy for offshore wind turbine is proposed, considering imperfect maintenance and the preventive maintenance durations. Reliability Centric Maintenance serves as a proactive tactic to operations and maintenance by inhibiting the possible reasons of poor performance and controlling failures. Other components can implement the opportunistic preventive maintenances if one component has reached its reliability threshold. According to the rolling horizon approach, it is of great importance to update the maintenance planning for the sake of the short-term information. By figuring out the best combination, the maintenance schedule in the mission time has been finally determined. Failure information are obtained from previous studies to accomplish the calculations. The outcomes indicate that the maintenance cost has been dramatically reduced through the application of opportunistic maintenance.

5

Reliability based analysis and design of a tripod offshore wind turbine structure assuring serviceability performance

88%

Zhang J. , Kang W. H. , Zhang C. , Sun K.

Polish Maritime Research

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2018

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tom nr 4

139--148

EN

Typical tripod foundations are designed using deterministic computational models according to relevant standards and codes. However, for more cost-safety balanced design, uncertainties in significant parameters should be considered in preliminary design to ensure meeting a specific probabilistic safety target in the context of the complex configuration of a tripod structure. In this article, uncertainties associated with design parameters and modelling errors are considered using Monte Carlo simulations, in order to determine the key structural design parameters, and to determine the optimal balance between design parameters and design requirements. A Spearman rank-order correlation based analysis is carried out to understand the effects of design variables on maximum deformation, total weight, and natural frequency, and to have insight about important design parameters for improvement of a preliminary design. It is found that the tower diameter has the most significant effect on the maximum displacement on the hub as validated through engineering case studies. In addition, a statistical framework, which identifies influential design parameters and provides reliability evaluation, is proposed for the structural design of a tripod OWT system. The design cases considered in this study indicate that a simple deterministic design check cannot guarantee the required reliability level of the structure, and the cost-safety balance can be achieved by a reliability analysis with the consideration of the uncertainties in the structure.

6

Effective method for determining environmental loads on supporting structures for offshore wind turbines

75%

Dymarski P. , Ciba E. , Marcinkowski T.

Polish Maritime Research

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2016

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tom nr 1

52--60

EN

This paper presents a description of an effective method for determining loads due to waves and current acting on the supporting structures of the offshore wind turbines. This method is dedicated to the structures consisting of the cylindrical or conical elements as well as (truncates) pyramids of polygon with a large number of sides (8 or more). The presented computational method is based on the Morison equation, which was originally developed only for cylindrically shaped structures. The new algorithm shown here uses the coefficients of inertia and drag forces that were calculated for non-cylindrical shapes. The analysed structure consists of segments which are truncated pyramids on the basis of a hex decagon. The inertia coefficients, CM, and drag coefficients, CD, were determined using RANSE-CFD calculations. The CFD simulations were performed for a specific range of variation of the period, and for a certain range of amplitudes of the velocity. In addition, the analysis of influence of the surface roughness on the inertia and drag coefficients was performed. In the next step, the computations of sea wave, current and wind load on supporting structure for the fifty-year storm were carried out. The simulations were performed in the time domain and as a result the function of forces distribution along the construction elements was obtained. The most unfavourable distribution of forces will be used, to analyse the strength of the structure, as the design load.

7

Design of jack-up platform for 6 MW WIND TURBINE: parametric analysis based dimensioning of platform legs

75%

Dymarski P.

Polish Maritime Research

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2019

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tom nr 2

183--197

EN

The article presents the results of the research conducted within the framework of the project entitled WIND-TU-PLA (ERA-NET, MARTEC II), the general aim of which was to design and analyse supporting structures for wind turbines intended for operation on the South Baltic area. The research part described in the article aimed at developing a preliminary design for a jack-up platform which can operate on water areas with depth of 40 m. The main task was to determine optimal dimensions of platform legs and the radius of their spacing. Two jack-up platform concepts differing by spacing radius and hull dimensions were designed with the intention to be used as a supporting structure for a 6-MW offshore wind turbine. For each concept, the parametric analysis was performed to determine optimal dimensions of platform legs (diameter Dleg and plating thickness tleg). Relevant calculations were performed to assess the movements of the platform with parameters given in Table 1 in conditions simulating the action of the most violent storm in recent 50 years. The obtained results, having the form of amplitudes of selected physical quantities, are shown in comprehensive charts in Fig. 6 and 7. Based on the critical stress values (corresponding to the yield stress), the area was defined in which the impact strength conditions are satisfied (Fig. 14). Then, the fatigue strength analysis was performed for two selected critical leg nodes (Fig. 12). Its results were used for defining the acceptable area with respect to structure’s fatigue (Fig. 14). Geometric parameters were determined which meet the adopted criteria, Table 6. The decisive criterion turned out to be the fatigue strength criterion, while the yield point criterion appeared to be an inactive constraint.

8

DeepCwind semi-submersible floating offshore wind turbine platform with a nonlinear multi-segment catenary mooring line and intermediate buoy

75%

Motallebi M. , Ghassemi H. , Shokouhian M.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2022

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tom nr 69 (141)

20--34

EN

In this paper, to improve the mechanical behavior of DeepCwind semi-submersible floating offshore wind turbine (FOWT) platform mooring lines, the nonlinear catenary cables of the platform were divided into multi-segment and intermediate buoys. Mathematical formulations of the boundary element method (BEM) governing the dynamics of mooring line systems with buoy devices were described. This study was applied to the OC4-DeepCwind semi-submersible FOWT platform, which is designed for a 200-meter water depth with mooring lines consisting of three catenary steel chain cables at 120° angles to each other. The dynamic response of the multi-segment catenary mooring lines with different buoy radiuses and different positions along the cables was investigated. The full-scale platform was modeled in ANSYS-AQWA software, and the simulations were performed under harsh offshore conditions. The mooring line’s general arrangement, tension, strain and uplift force for different buoy radiuses and their position along the cable are presented and discussed. Moreover, platform motions in three directions (surge, heave, and pitch) were also analyzed. It was concluded that by correctly selecting the buoy volume and position along the cable, the tension of the cable may be reduced by up to 45%. By incorrectly selecting the buoy, the results caused adverse effects.

9

Numerical and experimental analysis of the wave induced forces on the tripod support structure. Laboratory study

75%

Kraskowski M. , Pastwa K. , Kowalczyk S. , Marcinkowski T.

Biuletyn Instytutu Morskiego w Gdańsku

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2017

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tom Vol. 32, No. 1

21--29

EN

The presented work was realized within the framework of the AQUILO project, aiming to create the base of knowledge for prospective future investments in offshore wind energy on the Baltic Sea. The presented part of the work is focused on the experimental validation of numerical method of evaluation of the wave-induced forces on the bottom-mounted support structure of the offshore wind turbine. The experimental setup and measurement equipment, including in-house developed 6-DOF (six freedom) dynamometer, are described. Comparison of performance of different methods of evaluation of wave loads for wide range of parameters is presented. The results of experiments and numerical analyses are consistent; the largest discrepancy occurred at lowest wave frequencies, i.e., largest wave lengths. This may result from increased relative error of measurements for long waves in a relatively short tank.

PL

Prezentowana praca została wykonana w ramach projektu AQUILO, mającego na celu stworzenie bazy wiedzy dla przyszłych, potencjalnych inwestycji w energetykę wiatrową na akwenach Morza Bałtyckiego. W prezentowanej pracy wykonano empiryczną walidację numerycznej metody wyznaczania obciążeń falowych działających na konstrukcję wsporczą morskiej elektrowni wiatrowej. Przedstawiono i opisano fizyczny model doświadczalny oraz urządzenia pomiarowe, włącznie z wykonanym dla tego zadania dynamometrem o sześciu stopniach swobody (6 DOF). Zaprezentowano porównanie wyników obciążeń wywołanych falowaniem, otrzymanych różnymi metodami, dla szerokiego zakresu zmienności parametrów falowania. Wyniki uzyskane z przeprowadzonych doświadczeń oraz wyniki otrzymane z modelu numerycznego wykazują zadowalającą zgodność; największe rozbieżności wystąpiły dla częstotliwości najniższych, tj. dla fal najdłuższych. Przyczynę tych rozbieżności można tłumaczyć wzrostem względnego błędu pomiarowego dla bardzo długich fal w stosunkowo krótkim basenie.

10

Dimensioning of port waterways for vessels handling offshore wind farms using the navigational risk analysis

75%

Gucma S. , Gralak R.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2022

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tom nr 70 (142)

9--19

EN

This article indicates the development trends in the construction of offshore wind turbines worldwide, and the characteristics of existing and planned ships for wind turbine installation and maintenance; it presents an approach to design ports with their future operations in mind. Problem: The safety of navigation in port waterways is the basic restrictions for the construction of harbors (terminals) to handle ships used for the construction of OWT and for increasing their size. Navigational risk is a criterion of navigational safety assessment that allows its accurate estimation in port waterways. Method: The article presents the method for dimensioning port waterways for ships serving offshore sea wind turbine transport and construction. Furthermore, a method for determining the navigational risk of jack-up vessels navigating in port waterway areas is presented. Results: The authors have determined conditions for safe operation of these ships in restricted areas and defined the basic condition of navigational safety. The presented method of navigational risk analysis refers to the departure of a loaded ship carrying offshore wind turbine components in the presently designed port terminal in Świnoujście for handling offshore wind farm projects. Conclusion: These are universal methods that can be applied to the design of ports serving vessels that install offshore wind turbines in various types of waters.

11

Dynamic analysis of a tension leg platform for offshore wind turbines

63%

Wang H.-F. , Fan Y.-H. , Liu Y.

Journal of Power Technologies

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2014

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tom Vol. 94, nr 1

42--49

EN

The design for floating offshore wind turbine tension leg platform (FOWT-TLP) is economic, feasible and less platform motion comparing other floating structure, especially in deep water. In this paper, introducing spar floating structure advantage into tension leg platform to propose a conceptualization floating offshore wind turbine tension leg platform (HIT-FOWT-TLP). Concrete ballast model is arranged in the bottom of the spoke bottom plane to be as permanent ballast and much water ballast can be considered in single column, which can adjust gravity center by water freely to obtain dynamic feature that we needs and easy to assemble comparing other concepts; spoke part are considered in dimension and mass. The new model is only 49% of NREL-TLP model’s displacement, in mass it is only 27% of NREL-TLP model. We compare the hydrodynamic characteristic parameters and the RAO value in same environmental situation with NREL-TLP model. The result shows that in roll, sway and pitch motion, the new model has better performance.

12

Wykorzystanie nadprzewodników wysokotemperaturowych w energetyce odnawialnej - w morskich turbinach wiatrowych

63%

Sosnowski J.

Inżynieria Elektryczna

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2020

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tom nr 3

16--19

PL

W ostatnich latach kryzysu energetycznego i ekologicznego duży nacisk jest położony na rozwój energetyki odnawialnej. W obszarze przemysłu wiatrowego, stanowiącego - obok fotowoltaiki, gospodarki wodnej i biomasy - jeden z jej głównych filarów, powstało wiele komercyjnych oraz, przydomowych konstrukcji turbin wiatrowych, widoczny jest także postęp w budowie urządzeń związanych z ich eksploatacją. Zainteresowanie przemysłem wiatrowym wynika z ekologiczności tej formy energii, jak też jej stosunkowo niskiej ceny, która dla lądowych elektrowni wiatrowych kształtuje się na poziomie 52 EUR/MWh1. Jednak instalacja nowych farm wiatrowych na lądzie, szczególnie w obszarach nadbrzeżnych, gdzie panują optymalne warunki wietrzne, nie jest już obecnie tak prosta, ze względu na brak wolnej przestrzeni. Jest to jedna z przyczyn budowy farm wiatrowych bezpośrednio w morzu. Przykładem są Dania, Niemcy i Belgia, które preferują lokalizację farm wiatrowych na Morzu Północnym i niewątpliwie analogiczna sytuacja zaistnieje także w Polsce nad Bałtykiem.

13

Concept of multi rotor array for deep off-shore wind turbine

63%

Karczewski M. , Domagalski P.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2014

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tom nr 145

61--62

EN

Coastal regions in Norway, Spain, Portugal, Japan or the United States comprise over large water depths (> 50 m) making the installation of typical bottom-fixed offshore wind turbines very difficult and expensive. Floating offshore wind turbines might be a more economic option in order to exploit the high energy potential contained in the offshore winds. According to EU-funded ORECCA R&D project these locations were all identified as Level 1 resource capacity with wind velocities ranging 8-11 m/s at 10 m a.s.l. (above sea level) [1]. Different concepts of floating support structures have already been investigated as for the first HAWT prototype, Statoil’s “Hywind” spar buoy turbine, which has been operated off the cost of Norway since 2009 [2]. However, rising costs of operation and maintenance (O&M) as well as manufacturing of large turbine rotors and generators already seriously impair and will impair this branch of energy engineering in the years to come [3]. To address these problems the paper presents a concept of an innovative floating off-shore multi-rotor array turbine.

14

Evaluation of sand p–y curves by predicting both monopile lateral response and OWT natural frequency

63%

Amel D. , Djillali A. B. , Subhamoy B. , Nasreddine A.

Studia Geotechnica et Mechanica

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2022

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tom Vol. 44, nr 1

66--81

EN

Extending the use of the p–y curves included in the regulation codes API and DNV to design large-diameter monopiles supporting offshore wind turbines (OWTs) was unsuccessful as it resulted in an inaccurate estimation of the monopile behavior. This had prompted many investigators to propose formulations to enhance the performances of Winkler model. In this paper, two case studies are considered. A case consisting of an OWT at Horns Rev (Denmark) supported by a monopile in a sandy soil was studied first. Taking the FEA using ABAQUS as reference, results of WILDOWER 1.0 (a Winkler computer code) using the recently proposed p–y curves giving design parameters were plotted and evaluated. In order to see the ability of proposed p–y curves to predict the monopile head movements, and consequently the first natural frequency (1st NF), a second case study consisting of a monopile supporting an OWT at North Hoyle (UK) was selected. The monopile head stiffness in terms of lateral, rocking, and cross-coupling stiffness coefficients, necessary for the 1st NF, were computed using both ABAQUS and WILDPOWER 1.0. Comparisons with the measured 1st NF showed that with the exception of one p–y model, none of other proposed Winkler methods is able to predict accurately this parameter.