Design Considerations for Monopile Founded Offshore Wind Turbines Subject to Breaking Waves

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ISBN 13 :
Total Pages : 172 pages
Book Rating : 4.:/5 (865 download)

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Book Synopsis Design Considerations for Monopile Founded Offshore Wind Turbines Subject to Breaking Waves by : Garrett Reese Owens

Download or read book Design Considerations for Monopile Founded Offshore Wind Turbines Subject to Breaking Waves written by Garrett Reese Owens and published by . This book was released on 2013 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: The majority of offshore wind farms utilize monopile substructures. As these wind farms are typically located in water depths less than 30 meters, the effect of breaking waves on these structures is of great concern to design engineers. This research investigation examines many of the practical considerations and alternative ways of estimating breaking wave forces. A survey of existing European wind farms is used to establish a realistic range of basic design parameters. Based upon this information a parametric study was pursued and a series of realistic design scenarios were evaluated. Comparisons include the sensitivity to the wave force model as well as to analytical and numerical wave theories used to evaluate the wave kinematics. In addition, the effect of different kinematics stretching techniques for linear waves is addressed. Establishing whether the bathymetry will induce spilling or plunging wave breaking is critical. Spilling wave breaking can be addressed using existing wave and wave force theories; however for plunging wave breaking an additional impact force must be introduced. Dimensionless design curves are used to display pertinent trends across the full range of design cases considered. This research study provides insight into the evaluation of the maximum breaking wave forces and overturning moment for both spilling and plunging breaking waves as a function of bottom slope. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148179

Design of Foundations for Offshore Wind Turbines

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Publisher : John Wiley & Sons
ISBN 13 : 1119128153
Total Pages : 392 pages
Book Rating : 4.1/5 (191 download)

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Book Synopsis Design of Foundations for Offshore Wind Turbines by : Subhamoy Bhattacharya

Download or read book Design of Foundations for Offshore Wind Turbines written by Subhamoy Bhattacharya and published by John Wiley & Sons. This book was released on 2019-03-01 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive reference covering the design of foundations for offshore wind turbines As the demand for “green” energy increases the offshore wind power industry is expanding at a rapid pace around the world. Design of Foundations for Offshore Wind Turbines is a comprehensive reference which covers the design of foundations for offshore wind turbines, and includes examples and case studies. It provides an overview of a wind farm and a wind turbine structure, and examines the different types of loads on the offshore wind turbine structure. Foundation design considerations and the necessary calculations are also covered. The geotechnical site investigation and soil behavior/soil structure interaction are discussed, and the final chapter takes a case study of a wind turbine and demonstrates how to carry out step by step calculations. Key features: New, important subject to the industry. Includes calculations and case studies. Accompanied by a website hosting software and data files. Design of Foundations for Offshore Wind Turbines is a must have reference for engineers within the renewable energy industry and is also a useful guide for graduate students in this area.

Breaking Wave Loads and Stress Analysis of Jacket Structures Supporting Offshore Wind Turbines

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ISBN 13 :
Total Pages : 249 pages
Book Rating : 4.:/5 (89 download)

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Book Synopsis Breaking Wave Loads and Stress Analysis of Jacket Structures Supporting Offshore Wind Turbines by : Louise Claire Devaney

Download or read book Breaking Wave Loads and Stress Analysis of Jacket Structures Supporting Offshore Wind Turbines written by Louise Claire Devaney and published by . This book was released on 2012 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: In terms of future power generation in UK and Germany, offshore wind is the next big player with 40GW and 32GW capacity planned for installation in both countries respectively by 2030. The latest Round 3 of sites owned by the Crown Estate explore deeper water depths of up to 78m in the Irish Sea. Foundations for offshore wind structures consume around 25% of the total project cost therefore the design of support structures is the subject of this thesis. The current state-of-the-art support structure options available for offshore wind turbines have been outlined in this thesis with an evaluation of the preliminary design of monopile and jacket solutions. This assessment resulted in further studies into the loading acting on a monopile foundation along with research into the fatigue design of multiplanar tubular joints for jacket structures. Mathematical modelling of linear and nonlinear waves combined with the Morison equation was completed to check the effects of breaking waves on a monopile foundation. Results indicated that measured forces were up to a factor of 2.5 times greater than calculated values, which suggests that loads could be under predicted if the effects of breaking are not considered. The theoretical maximum wave height before breaking was then linked to wind speed and a comparison of overturning moments from the two loads was made. Wave loads dominated at water depths of around 30m for lower wind speeds but this depth decreased to around 12m as wind speeds approached cut-out of 25m/s. For deeper water depths and larger capacity turbines, jackets are the preferred design solution. Joint design in FLS is the critical aspect of jacket design with castings often required to provide adequate capacity. A review of stress concentration factors (SCF) for tubular joints indicated that the coded approach, which uses SCF equations for uniplanar joints, could be missing the multiplanar effects. Finite element (FE) modelling of multiplanar tubular joints was completed using ANSYS Workbench to examine the effects of loading in out-of plane braces. Carry-over of stress from the loaded brace of the joint to unloaded neighbouring braces was observed which implies the importance of modelling joints as multiplanar geometries. A parameter study in ANSYS Workbench covering 1806 different geometrical configurations and loads was carried out with a regression of the data to give new sets of SCF equations for multiplanar tubular joints. SCFs from these equations were improved compared to Efthymiou but difficulties were encountered when superimposing the output (including Efthymiou). Further work on the superposition of individual load cases was therefore recommended for future work.

Soil-Structure Modeling and Design Considerations for Offshore Wind Turbine Monopile Foundations

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (944 download)

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Book Synopsis Soil-Structure Modeling and Design Considerations for Offshore Wind Turbine Monopile Foundations by : Wystan Carswell

Download or read book Soil-Structure Modeling and Design Considerations for Offshore Wind Turbine Monopile Foundations written by Wystan Carswell and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Offshore wind turbine (OWT) support structures account for 20-25% of the capital cost for offshore wind installations, making it essential to optimize the design of the tower, substructure, and foundation to the extent possible. This dissertation focuses on monopile foundations, as the vast majority (approximately 75%) of currently installed OWTs are supported by monopile structures. The objective of this dissertation is to provide information on the behavior of monopile support structures to better substantiate design and planning decisions and to provide a basis for reducing the structural material costs. In pursuit of these objectives, research is presented on the topics of hysteretic soil-structure damping (referred to as foundation damping), cyclic degradation of soil properties, and the impact of marine growth on OWT monopile support structures. OWTs are lightly damped structures that must withstand highly uncertain offshore wind and wave loads. In addition to stochastic load amplitudes, the dynamic behavior of OWTs must be designed with consideration of stochastic load frequency from waves and mechanical load frequencies associated with the spinning rotor during power production. The close proximity of the OWT natural frequency to excitation frequencies combined with light damping necessitates a thorough analysis of various sources of damping within the OWT system; of these sources of damping, least is known about the contributions of damping from soil-structure interaction (foundation damping), though researchers have back-calculated foundation damping from "rotor-stop" tests after estimating aerodynamic, hydrodynamic, and structural damping with numerical models. Because design guidelines do not currently recommend methods for determining foundation damping, it is typically neglected. The significance of foundation damping on monopile-supported OWTs subjected to extreme storm loading was investigated using a linear elastic two-dimensional finite element model. A simplified foundation model based on the soil-pile mudline stiffness matrix was used to represent the monopile, and hysteretic energy loss in the foundation was converted into a viscous, rotational dashpot at the mudline to represent foundation damping. The percent critical damping contributed to the OWT structural system by foundation damping was quantified using the logarithmic decrement method on a finite element free vibration time history, and stochastic time history analysis of extreme storm conditions indicated that mudline OWT foundation damping can significantly decrease the maximum and standard deviation of mudline moment. Further investigation of foundation damping on cyclic load demand for monopile-supported OWTs was performed considering the design situations of power production, emergency shutdown, and parked conditions. The NREL 5MW Reference Turbine was modeled using the aero-hydro-elastic software FAST and included linear mudline stiffness and damping matrices to take into account soil-structure interaction. Foundation damping was modeled using viscous rotational mudline dashpots which were calculated as a function of hysteretic energy loss, cyclic mudline rotation amplitude, and OWT natural frequency. Lateral monopile capacity can be significantly affected by cyclic loading, causing failure at cyclic load amplitudes lower than the failure load under monotonic loading. For monopiles in clay, undrained clay behavior under short-term cyclic soil-pile loading (e.g. extreme storm conditions) typically includes plastic soil deformation resulting from reductions in soil modulus and undrained shear strength which occur as a function of pore pressure build-up. These impacts affect the assessment of the ultimate and serviceability limit states of OWTs via natural frequency degradation and accumulated permanent rotation at the mudline, respectively. Novel combinations of existing p-y curve design methods were used to compare the impact of short-term cyclic loading on monopiles in soft, medium, and stiff clay. Marine growth increases mass and surface roughness for offshore structures, which can reduce natural frequency and increase hydrodynamic loads, and can also interfere with corrosion protection and fatigue inspections. Design standards and guidelines do not have a unified long-term approach for marine growth on OWTs, though taking into account added mass and increased drag is recommended. Some standards recommend inspection and cleaning of marine growth, but this would negate the artificial reef benefits which have been touted as a potential boon to the local marine habitat. The effects of marine growth on monopile-supported OWTs in terms of natural frequency and hydrodynamic loading are examined, and preliminary recommendations are given from the engineering perspective on the role of marine growth in OWT support structure design.

An Integrated Nonlinear Wind-Waves Model for Offshore Wind Turbines

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Publisher : Firenze University Press
ISBN 13 : 8866550515
Total Pages : 232 pages
Book Rating : 4.8/5 (665 download)

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Book Synopsis An Integrated Nonlinear Wind-Waves Model for Offshore Wind Turbines by : Enzo Marino

Download or read book An Integrated Nonlinear Wind-Waves Model for Offshore Wind Turbines written by Enzo Marino and published by Firenze University Press. This book was released on 2010 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a numerical model capable of simulating offshore wind turbines exposed to extreme loading conditions. External condition-based extreme responses are reproduced by coupling a fully nonlinear wave kinematic solver with a hydro-aero-elastic simulator. First, a two-dimensional fully nonlinear wave simulator is developed. The transient nonlinear free surface problem is formulated assuming the potential theory and a high-order boundary element method is implemented to discretize Laplace's equation. For temporal evolution a second-order Taylor series expansion is used. The code, after validation with experimental data, is successfully adopted to simulate overturning plunging breakers which give rise to dangerous impact loads when they break against wind turbine substructures. Emphasis is then placed on the random nature of the waves. Indeed, through a domain decomposition technique a global simulation framework embedding the numerical wave simulator into a more general stochastic environment is developed. The proposed model is meant as a contribution to meet the more and more pressing demand for research in the offshore wind energy sector as it permits taking into account dangerous effects on the structural response so as to increase the global structural safety level.

Structural Integrity of Offshore Wind Turbines

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Publisher : National Academies Press
ISBN 13 : 0309225159
Total Pages : 109 pages
Book Rating : 4.3/5 (92 download)

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Book Synopsis Structural Integrity of Offshore Wind Turbines by : Transportation Research Board

Download or read book Structural Integrity of Offshore Wind Turbines written by Transportation Research Board and published by National Academies Press. This book was released on 2011-09-02 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB Special Report 305: Structural Integrity of Offshore Wind Turbines: Oversight of Design, Fabrication, and Installation explores the U.S. Department of the Interior's Bureau of Ocean Energy Management, Regulation, and Enforcement (BOEMRE) approach to overseeing the development and safe operation of wind turbines on the outer continental shelf, with a focus on structural safety. The committee that developed the report recommended that in order to facilitate the orderly development of offshore wind energy and support the stable economic development of this nascent industry, the United States needs a set of clear requirements that can accommodate future design development. The report recommends that BOEMRE develop a set of requirements that establish goals and objectives with regard to structural integrity, environmental performance, and energy generation. The committee found that the risks to human life and the environment associated with offshore wind farms are substantially lower than for other industries such as offshore oil and gas, because offshore wind farms are primarily unmanned and contain minimal quantities of hazardous substances. This finding implies that an approach with significantly less regulatory oversight may be taken for offshore wind farms. Under this approach, industry would be responsible for proposing sets of standards, guidelines, and recommended practices that meet the performance requirements established by BOEMRE. The domestic industry can build on standards, guidelines, and practices developed in Europe, where the offshore wind energy is further developed, but will have to fill gaps such as the need to address wave and wind loadings encountered in hurricanes. The report also includes findings and recommendations about the role that certified verification agents (third party evaluators) can play in reviewing packages of standards and project-specific proposals.

Floating Offshore Wind Energy

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Publisher : Springer
ISBN 13 : 3319293982
Total Pages : 345 pages
Book Rating : 4.3/5 (192 download)

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Book Synopsis Floating Offshore Wind Energy by : Joao Cruz

Download or read book Floating Offshore Wind Energy written by Joao Cruz and published by Springer. This book was released on 2016-08-20 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a state-of-the-art review of floating offshore wind turbines (FOWT). It offers developers a global perspective on floating offshore wind energy conversion technology, documenting the key challenges and practical solutions that this new industry has found to date. Drawing on a wide network of experts, it reviews the conception, early design stages, load & structural analysis and the construction of FOWT. It also presents and discusses data from pioneering projects. Written by experienced professionals from a mix of academia and industry, the content is both practical and visionary. As one of the first titles dedicated to FOWT, it is a must-have for anyone interested in offshore renewable energy conversion technologies.

A comparison of methods for computation of wave forcing

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Publisher : GRIN Verlag
ISBN 13 : 3668705224
Total Pages : 137 pages
Book Rating : 4.6/5 (687 download)

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Book Synopsis A comparison of methods for computation of wave forcing by : Olga Glöckner

Download or read book A comparison of methods for computation of wave forcing written by Olga Glöckner and published by GRIN Verlag. This book was released on 2018-05-17 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diploma Thesis from the year 2014 in the subject Engineering - Civil Engineering, grade: 1,0, University of Hannover (A&M University Texas, Ludwig-Franzius-Institut für Wasserbau, Ästuar- und Küsteningenieurwesen), language: English, abstract: Unlike fossil fuels (for example oil, coal and natural gas), wind energy is a renewable energy resource. Since winds at sea are stronger and more consistent than onshore winds, the demand for offshore wind turbines has increased over the last years. As energy can be produced more efficient in deeper water, several floating offshore wind turbine constructions, such as the OC3 Hywind spar-buoy, have been proposed. The design of floating wind turbines depends on the simulation of the system behavior caused by exciting forces. This thesis deals with the comparison between different methods for calculating wave forces and resulting platform motions of a floating offshore wind turbine. On the one hand, wave exciting loads computed with Morison’s equation are compared to the hydrodynamic forces simulated by the open source code FAST on the basis of the diffraction theory. On the other hand, response motions of the floating structure are simulated by the commercial offshore software SESAM in the frequency domain and compared with the motions calculated by FAST in the time domain.

Offshore Wind Energy Technology

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Publisher : John Wiley & Sons
ISBN 13 : 1119097762
Total Pages : 455 pages
Book Rating : 4.1/5 (19 download)

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Book Synopsis Offshore Wind Energy Technology by : Olimpo Anaya-Lara

Download or read book Offshore Wind Energy Technology written by Olimpo Anaya-Lara and published by John Wiley & Sons. This book was released on 2018-05-29 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: A COMPREHENSIVE REFERENCE TO THE MOST RECENT ADVANCEMENTS IN OFFSHORE WIND TECHNOLOGY Offshore Wind Energy Technology offers a reference based on the research material developed by the acclaimed Norwegian Research Centre for Offshore Wind Technology (NOWITECH) and material developed by the expert authors over the last 20 years. This comprehensive text covers critical topics such as wind energy conversion systems technology, control systems, grid connection and system integration, and novel structures including bottom-fixed and floating. The text also reviews the most current operation and maintenance strategies as well as technologies and design tools for novel offshore wind energy concepts. The text contains a wealth of mathematical derivations, tables, graphs, worked examples, and illustrative case studies. Authoritative and accessible, Offshore Wind Energy Technology: Contains coverage of electricity markets for offshore wind energy and then discusses the challenges posed by the cost and limited opportunities Discusses novel offshore wind turbine structures and floaters Features an analysis of the stochastic dynamics of offshore/marine structures Describes the logistics of planning, designing, building, and connecting an offshore wind farm Written for students and professionals in the field, Offshore Wind Energy Technology is a definitive resource that reviews all facets of offshore wind energy technology and grid connection.

Reliability Based Design of Fixed Foundation Wind Turbines

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Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (93 download)

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Book Synopsis Reliability Based Design of Fixed Foundation Wind Turbines by :

Download or read book Reliability Based Design of Fixed Foundation Wind Turbines written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent analysis of offshore wind turbine foundations using both applicable API and IEC standards show that the total load demand from wind and waves is greatest in wave driven storms. Further, analysis of overturning moment loads (OTM) reveal that impact forces exerted by breaking waves are the largest contributor to OTM in big storms at wind speeds above the operating range of 25 m/s. Currently, no codes or standards for offshore wind power generators have been adopted by the Bureau of Ocean Energy Management Regulation and Enforcement (BOEMRE) for use on the Outer Continental Shelf (OCS). Current design methods based on allowable stress design (ASD) incorporate the uncertainty in the variation of loads transferred to the foundation and geotechnical capacity of the soil and rock to support the loads is incorporated into a factor of safety. Sources of uncertainty include spatial and temporal variation of engineering properties, reliability of property measurements applicability and sufficiency of sampling and testing methods, modeling errors, and variability of estimated load predictions. In ASD these sources of variability are generally given qualitative rather than quantitative consideration. The IEC 61400-3 design standard for offshore wind turbines is based on ASD methods. Load and resistance factor design (LRFD) methods are being increasingly used in the design of structures. Uncertainties such as those listed above can be included quantitatively into the LRFD process. In LRFD load factors and resistance factors are statistically based. This type of analysis recognizes that there is always some probability of failure and enables the probability of failure to be quantified. This paper presents an integrated approach consisting of field observations and numerical simulation to establish the distribution of loads from breaking waves to support the LRFD of fixed offshore foundations.

Wave Energy Devices

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Publisher : CRC Press
ISBN 13 : 1000571483
Total Pages : 273 pages
Book Rating : 4.0/5 (5 download)

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Book Synopsis Wave Energy Devices by : Srinivasan Chandrasekaran

Download or read book Wave Energy Devices written by Srinivasan Chandrasekaran and published by CRC Press. This book was released on 2022-04-19 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Designing offshore wave energy converter (WEC) devices requires a thorough understanding of many aspects of science and engineering, namely, wave hydrodynamics, wave-WEC interactions, mechanical design, analysis tools, and conducting experiments. This book provides the tools for understanding these complex systems and addresses the basic concepts of WECs through detailed analysis and design. A few devices developed and experimentally investigated are discussed in detail, some of which are considered highly novel and still in the preliminary stages of study in the existing literature. FEATURES Offers numerous detailed design methods and practical model studies Presents analysis of the dynamic response behavior of WECs based on experimental studies on scale models Covers the most recent and novel innovations in the field Includes a discussion of offshore wind farms as a green energy alternative and examines their conceptual development and design This book serves as a useful guide for both academicians and professionals in naval architecture and offshore engineering as well as in civil and structural engineering. In addition, it helps in the understanding of structural behavior in terms of risk criteria, efficiency, service life, and reliability. Readers will gain a comprehensive knowledge of the design and development of offshore wave energy devices and the preliminary design of offshore wind turbines, which are currently largely absent in the scientific literature.

Reliability-Based Optimization of Floating Wind Turbine Support Structures

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Publisher : Springer Nature
ISBN 13 : 3030968898
Total Pages : 336 pages
Book Rating : 4.0/5 (39 download)

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Book Synopsis Reliability-Based Optimization of Floating Wind Turbine Support Structures by : Mareike Leimeister

Download or read book Reliability-Based Optimization of Floating Wind Turbine Support Structures written by Mareike Leimeister and published by Springer Nature. This book was released on 2023-01-01 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book pursues the ambitious goal of combining floating wind turbine design optimization and reliability assessment, which has in fact not been done before. The topic is organized into a series of very ambitious objectives, which start with an initial state-of-the-art review, followed by the development of high-fidelity frameworks for a disruptive way to design next generation floating offshore wind turbine (FOWT) support structures. The development of a verified aero-hydro-servo-elastic coupled numerical model of dynamics for FOWTs and a holistic framework for automated simulation and optimization of FOWT systems, which is later used for the coupling of design optimization with reliability assessment of FOWT systems in a computationally and time-efficient manner, has been an aim of many groups internationally towards implementing a performance-based/goal-setting approach in the design of complex engineering systems. The outcomes of this work quantify the benefits of an optimal design with a lower mass while fulfilling design constraints. Illustrating that comprehensive design methods can be combined with reliability analysis and optimization algorithms towards an integrated reliability-based design optimization (RBDO) can benefit not only the offshore wind energy industry but also other applications such as, among others, civil infrastructure, aerospace, and automotive engineering.

Soil-structure Interaction Analysis of Monopile Foundations Supporting Offshore Wind Turbines

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Publisher :
ISBN 13 :
Total Pages : 161 pages
Book Rating : 4.:/5 (15 download)

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Book Synopsis Soil-structure Interaction Analysis of Monopile Foundations Supporting Offshore Wind Turbines by : Bipin Kumar Gupta

Download or read book Soil-structure Interaction Analysis of Monopile Foundations Supporting Offshore Wind Turbines written by Bipin Kumar Gupta and published by . This book was released on 2018 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Monopile foundations supporting offshore wind turbines are hollow circular steel piles of diameter 4-6 m and a slenderness ratio (length/radius) of 10-12 driven into the seabed in an average water depth of 35 m. They are subjected to large lateral forces and overturning moments at the seabed level from wind, waves, and water currents acting on the wind turbine structure. Currently, they are designed using the p-y analysis method (p is the soil reaction force per unit length at any point along the pile shaft and y is the corresponding pile displacement at that point) which has a number of shortcomings. The p-y analysis was originally developed from a few full-scale field pile-load tests on small-diameter piles (less than 2 m in diameter) and their applicability to large-diameter monopiles is questionable. Besides, it is empirical, site-specific, and does not account for the three-dimensional pile-soil interaction important for large-diameter monopiles, thereby, resulting in a conservative design and an increase in the cost of the project. Three-dimensional finite element analysis can be used for the analysis and design of monopiles, but such analyses require significantly large computational time and effort besides, the specific expertise of finite element software that further limits its use in practice. The primary objective of this thesis is to develop a computationally efficient continuum-based mathematical model that takes the three-dimensional monopile-soil interaction into account. In the thesis, three tasks are performed towards the development of the mathematical model. First, a mathematical framework is developed to analyze laterally loaded monopiles following the Timoshenko beam theory in a multilayered elastic soil deposit subjected to static lateral loading. In the analysis, it is shown that successive simplification of the analysis can lead to monopiles modeled as a Euler-Bernoulli and rigid beam. The analysis is verified with finite element solutions and the suitability of the application each of the beam theories to obtain monopile response (head-displacement and rotation) is also investigated besides, a comparison of the computational time between the present analysis and finite element analysis is also shown. In the second task, the aforementioned framework is extended to analyze monopiles embedded in a multilayered linear viscoelastic soil deposit with frequency-independent hysteretic material damping subjected to harmonic dynamic lateral loading. It is shown that the analysis can be reduced to model monopiles following the Rayleigh, Euler-Bernoulli, and rigid beam theory. The analysis is verified with well-established solution techniques reported in the literature. Further, the results and the computational time obtained from this analysis are compared with those of the analysis in the first task for four different monopiles with varying slenderness ratio currently installed in the field. The purpose of the comparison is to investigate the applicability of the dynamic analysis for obtaining monopile response which is subjected to cyclic loadings of frequency less than 1.0 Hz. It is found that the static analysis following the Euler-Bernoulli beam theory is sufficient for obtaining monopile response. In the third task, the mathematical framework developed in the first task is extended to analyze laterally loaded monopiles modeled as a Euler-Bernoulli beam in a multilayered nonlinear elastic soil deposit and subjected to static loading. In the analysis, the nonlinear elastic relationships describing the variation of shear modulus with shear strain reported in the literature either applicable to undrained clays or sandy soil deposits are utilized. The mathematical accuracy of the analysis is verified by comparing results obtained from the analysis with the results of finite element analysis. A comparison of the computational time between the present and finite element analysis is also shown to demonstrate the computational efficiency of the present analysis. The results of the analysis are further validated with the results of several full-scale field pile-load tests and the p-y analysis procedure available in the literature. The accuracy of the results from this nonlinear elastic approach is further ensured by comparing monopile response with those of finite element simulations where the soil is modeled using an elastic-plastic constitutive model. A comparison of the monopile response is also shown in the p-y analysis to investigate the appropriateness of the currently used p-y curves to analyze and design monopiles. Finally, a preliminary step-by-step design procedure for monopile foundations embedded in nonlinear elastic soil deposit is developed following the recommendations outlined in current codes of practice for offshore wind turbines.

MARE-WINT

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Author :
Publisher : Springer
ISBN 13 : 3319390953
Total Pages : 432 pages
Book Rating : 4.3/5 (193 download)

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Book Synopsis MARE-WINT by : Wiesław Ostachowicz

Download or read book MARE-WINT written by Wiesław Ostachowicz and published by Springer. This book was released on 2016-08-30 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a holistic, interdisciplinary overview of offshore wind energy, and is a must-read for advanced researchers. Topics, from the design and analysis of future turbines, to the decommissioning of wind farms, are covered. The scope of the work ranges from analytical, numerical and experimental advancements in structural and fluid mechanics, to novel developments in risk, safety & reliability engineering for offshore wind.The core objective of the current work is to make offshore wind energy more competitive, by improving the reliability, and operations and maintenance (O&M) strategies of wind turbines. The research was carried out under the auspices of the EU-funded project, MARE-WINT. The project provided a unique opportunity for a group of researchers to work closely together, undergo multidisciplinary doctoral training, and conduct research in the area of offshore wind energy generation. Contributions from expert, external authors are also included, and the complete work seeks to bridge the gap between research and a rapidly-evolving industry.

Renewable Energy Systems

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Publisher : Springer
ISBN 13 : 9781461458197
Total Pages : 1898 pages
Book Rating : 4.4/5 (581 download)

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Book Synopsis Renewable Energy Systems by : Martin Kaltschmitt

Download or read book Renewable Energy Systems written by Martin Kaltschmitt and published by Springer. This book was released on 2012-12-06 with total page 1898 pages. Available in PDF, EPUB and Kindle. Book excerpt: Humanity is facing a steadily diminishing supply of fossil fuels, causing researchers, policy makers, and the population as a whole to turn increasingly to alternative and especially renewable sources of energy to make up this deficit. Gathering over 80 peer-reviewed entries from the Encyclopedia of Sustainability Science and Technologies, Renewable Energy Systems provides an authoritative introduction to a wide variety of renewable energy sources. State-of-the-art coverage includes geothermal power stations, ocean energy, renewable energy from biomass, waste to energy, and wind power. This comprehensive, two-volume work provides an excellent introduction for those entering these fields, as well as new insights for advanced researchers, industry experts, and decision makers.

On- and Offshore Wind Turbines. Technology and Design

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Publisher :
ISBN 13 : 9783346114495
Total Pages : 102 pages
Book Rating : 4.1/5 (144 download)

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Book Synopsis On- and Offshore Wind Turbines. Technology and Design by : Muhammad Muzzamil

Download or read book On- and Offshore Wind Turbines. Technology and Design written by Muhammad Muzzamil and published by . This book was released on 2019-09-16 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Master's Thesis from the year 2019 in the subject Engineering - Power Engineering, language: English, abstract: Wind power production is an emerging industry because of green power production and restriction placed on previous environmental hazardous power production technologies. Due to advancements in this field in the recent decades more energy production with smaller turbines has become possible. This aspect of wind turbines has encouraged the world to develop megawatt scale turbines. Bigger turbines that were constructed onshore brought their new problems with them like noise pollution and wind turbulence and requiring higher towers. Due to this the wind industry is rapidly shifting to installing offshore structures that give more uniform winds at shorter heights and has no noise pollution problems. That's why the design of offshore wind turbine structure has been explained in this thesis. This thesis also aims to carry out a study of the design of the foundation most frequently used in offshore wind structures, i.e. the monopile. The design of this type of wind structures implemented at sea where, the wind action combined with the action of the waves and sea currents. The quantification of these actions mainly followed the DNV (Det Norske Veritas) standards, while using and referencing the contribution provided by other design standards. This thesis presents the design of hypothetical wind turbine supporting structure in Karachi (Arabian Sea), as well as the theoretic basis and calculations that were performed in order to obtain the loads and safety verifications for a specific design.

Design Load Analysis of Two Floating Offshore Wind Turbine Concepts

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Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (945 download)

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Book Synopsis Design Load Analysis of Two Floating Offshore Wind Turbine Concepts by : Gordon M. Stewart

Download or read book Design Load Analysis of Two Floating Offshore Wind Turbine Concepts written by Gordon M. Stewart and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Much of the United States' wind resource is located over deep water where fixed-bottom offshore wind turbines are cost-prohibitive. To capture this energy, floating offshore wind turbines are being developed. However, current design standards do not explicitly cover issues relating to floating offshore wind turbines, which leads to risk and uncertainty in the design process. Two important issues that this dissertation investigates are the effect of simulation length and wind and wave misalignment on fatigue and ultimate loads. Experience in the offshore floating oil and gas industry has recommended simulation lengths of 3-6 hours, but the wind industry typically simulates between 10 minutes and one hour. The reasons for these simulation lengths is explored and recommendations for floating offshore wind turbines are made. The current offshore wind turbine design standard states that co-aligned wind and waves are a conservative ``worst-case'' scenario for loads, but this assertion may only hold true for fixed-bottom offshore turbines. A large operational design-space set of simulations are run to determine the impact of wind and wave misalignment on floating offshore turbines. Using results from both the simulation length and wind/wave misalignment study, probabilistic methods are used to determine a minimum set of simulations that is able to accurately characterize the loads response of floating platforms. Reduction of avian impacts have long been an important concern for the installation of wind farms. There is large uncertainty in the impacts of offshore wind farms on seabirds in the United States, as no offshore wind farms are currently operating. In this dissertation, experience from Europe is used to create a model of seabirds' interaction with fixed-bottom offshore wind farms. This model is used in a multi-objective optimization of the layout of a generic fixed-bottom offshore wind farm, considering both impacts on birds as well as power production. To simulate a farm comprised of floating offshore wind turbines, uncertainty in the positions of the turbines in the farm is introduced, and the layout is once again subjected to a multi-objective optimization.