Comparative Analysis Of Transient Dynamics Of Large Scale Offshore Wind Turbines With Different Foundation Structure Under Seismic
DOWNLOAD
Download Comparative Analysis Of Transient Dynamics Of Large Scale Offshore Wind Turbines With Different Foundation Structure Under Seismic PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get Comparative Analysis Of Transient Dynamics Of Large Scale Offshore Wind Turbines With Different Foundation Structure Under Seismic book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages. If the content not found or just blank you must refresh this page
Comparative Analysis Of Transient Dynamics Of Large Scale Offshore Wind Turbines With Different Foundation Structure Under Seismic
DOWNLOAD
Author : Minnan Yue
language : en
Publisher:
Release Date : 2019
Comparative Analysis Of Transient Dynamics Of Large Scale Offshore Wind Turbines With Different Foundation Structure Under Seismic written by Minnan Yue and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with Electronic books categories.
In this paper, a structural dynamic response comparison between jacket foundation large-scale offshore wind turbines (OWTs) and monopile ones under wind and seismic loads is demonstrated. The interaction between flexible soil and pile foundation is described by Winkler soil-structure interaction (SSI) model. The National Renewable Energy Laboratory (NREL) 5 MW large-scale OWT is studied via the finite element model. The structural transient dynamic response of these two structures under normal operating conditions at rated wind speed and earthquake is calculated. The results show that under the action of seismic and turbulent wind, the jacket has better wind and seismic resistance, and the displacement of the top of the tower is small, which can effectively protect the blades and the nacelle. Compared with monopile, the range of the Mises equivalent stress amplitude of the jacket wind turbine was reduced and the average value was decreased at the time of the seismic. The study also found that the existing jacket design will have a local strain energy surge.
Design Of Foundations For Offshore Wind Turbines
DOWNLOAD
Author : Subhamoy Bhattacharya
language : en
Publisher: John Wiley & Sons
Release Date : 2019-04-29
Design Of Foundations For Offshore Wind Turbines written by Subhamoy Bhattacharya and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-04-29 with Technology & Engineering categories.
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.
A Comparison Of Alternative Foundation Models For Offshore Wind Turbines And Resulting Long Term Loads
DOWNLOAD
Author : Erica Angelyn Bush
language : en
Publisher:
Release Date : 2009
A Comparison Of Alternative Foundation Models For Offshore Wind Turbines And Resulting Long Term Loads written by Erica Angelyn Bush and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with categories.
Accurate estimation of structural design loads for wind turbines can help improve cost-effectiveness of wind energy. This study concentrates on predicting long-term characteristic loads for a single design load case for offshore wind turbines associated with an ultimate limit state. Specifically, we study how alternative foundation modeling assumptions and load variability can influence characteristic tower and blade load estimates needed in design. Six foundation models with varying degrees of complexity are compared for a utility-scale 5MW offshore wind turbine. The fixed base model does not account for soil-pile interaction. The apparent fixity model, the modified apparent fixity model, the coupled springs model, and the distributed springs model account for soil-pile interaction by linearizing the lateral stiffness, while the p-y curves model accounts for soil-pile interaction by incorporating the nonlinear response. Accounting for soil-pile flexibility allows the wind turbine model to have similar dynamic characteristics as the true structure. This study shows that accurate structural dynamics is required to produce accurate long-term tower loads, but not necessarily accurate long-term blade loads. All foundation models, including the fixed base model, are shown sufficient for predicting long-term blade load estimates, but flexible foundation models are needed to predict long-term tower loads. We show that linear and nonlinear flexible foundation models are fairly interchangeable for predicting long-term loads for our environmental conditions, wind turbine, and sand profiles because deflections generally stay in the initial quasi-linear range of the p-y curves. In this study, we extrapolate long-term loads using 2D inverse first-order reliability method (FORM) and 3D inverse FORM. The 3D inverse FORM approach accounts for the variability in the load, while the 2D inverse FORM approach does not. We show that characteristic tower and blade loads are strongly influenced by load variability and suggest that it be considered in any effort to predict characteristic long-term loads for design of offshore wind turbines.
Structural Integrity Of Offshore Wind Turbines Oversight Of Design Fabrication And Installation
DOWNLOAD
Author : National Research Council (U.S.). Committee on Offshore Wind Energy Turbine Structural and Operating Safety
language : en
Publisher: Transportation Research Board
Release Date : 2011-09-02
Structural Integrity Of Offshore Wind Turbines Oversight Of Design Fabrication And Installation written by National Research Council (U.S.). Committee on Offshore Wind Energy Turbine Structural and Operating Safety and has been published by Transportation Research Board this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011-09-02 with Business & Economics categories.
"The U.S. Department of the Interior's Bureau of Ocean Energy Management, Regulation, and Enforcement (BOEMRE) is responsible for the orderly, safe, and environmentally responsible development of offshore renewable energy on the outer continental shelf (OCS). The Committee on Offshore Wind Energy Turbine Structural and Operating Safety that authored this report was tasked with reviewing BOEMRE's proposed approach to overseeing the design of offshore wind turbines for structural integrity. The committee was asked to review the applicability and adequacy of standards and practices that could be used for the design, fabrication and installation of offshore wind turbines. It was also asked to review the role of third-party certified verification agents (CVAs) and the expertise and qualifications needed to carry out the role of a CVA. The committee's findings are presented in the following chapters: (1) Introduction; (2) Offshore Wind Technology and Status; (3) Standards and Practices; (4) A Risk-Informed Approach to Performance Assurance; (5) Role of Third-Party Oversight and Certified Verification Agents; (6) Qualifications Needed by Certified Verification Agents; and (7) Summary of Key Findings and Recommendations."--Pub. desc.
A Comparison Of Methods For Computation Of Wave Forcing
DOWNLOAD
Author : Olga Glöckner
language : en
Publisher: GRIN Verlag
Release Date : 2018-05-17
A Comparison Of Methods For Computation Of Wave Forcing written by Olga Glöckner and has been published by GRIN Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-05-17 with Technology & Engineering categories.
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.
Experimental And Numerical Seismic Response Of Offshore Wind Turbines Supported On Bucket Foundations
DOWNLOAD
Author : Muhammad Zayed
language : en
Publisher:
Release Date : 2022
Experimental And Numerical Seismic Response Of Offshore Wind Turbines Supported On Bucket Foundations written by Muhammad Zayed and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with categories.
Bucket foundations have proven to be an efficient cost-effective option for a wide range of offshore applications. Motivated by the strong growth in offshore wind energy, this dissertation aims to investigate the seismic response of bucket foundations. A scaled soil-structure model of a 3.45 Megawatt (MW) utility-scale Offshore Wind Turbine (OWT) was tested on medium-size 1-g shake table. A preliminary testing phase resulted in developing new approaches for: i) tracking shear wave velocity variation within the ground during seismic excitation, and ii) generating accumulated ground deformation via asymmetric base shaking. Thereafter, the OWT model was subjected to a series of harmonic and earthquake-like excitations. From the collected data, key features of the overall system response were gleaned. Utilizing the experimental data, a nonlinear finite element (FE) model was calibrated to simulate the observed seismic response. The developed FE model was then extended to investigate the seismic behavior of a representative utility-scale OWT in sands under earthquake motions, combined with operational wind load effects. A parametric study is conducted to investigate influence of: i) soil stiffness and strength, ii) ground motion characteristics, iii) soil permeability, iv) bucket size, and v) damping on the OWT seismic response. The results suggest that: i) the near field pore water pressure build-up and bucket rotation are correlated, ii) ground motion characteristics have direct impact on the permanent bucket rotation, iii) lower soil permeability results in larger rotation due to the higher near field pore water pressure build-up, iv) permanent bucket rotation tends to reach a maximum and a minimum at the lower and upper bounds of soil permeability, respectively, reflecting the fully drained and undrained conditions, v) the difference in permanent bucket rotation between undrained and drained conditions tends to decrease with increasing soil stiffness, vi) Within the range of investigated scenarios, an essentially linear correlation was noted between the OWT fundamental frequency and the permanent bucket rotation, and vii) viscous damping at higher frequencies might have a significant effect on the bucket moment rotation response. As such, the gained insights provide guidance for seismic design of bucket foundation offshore wind turbines.
Design And Analysis Of Suction Pile Based Large Scale Offshore Wind Turbines Under Earthquakes And Typhoons
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2022
Design And Analysis Of Suction Pile Based Large Scale Offshore Wind Turbines Under Earthquakes And Typhoons written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with categories.
Applied Mechanics Reviews
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 1948
Applied Mechanics Reviews written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1948 with Mechanics, Applied categories.
An Experimental And Numerical Study Of Wind Turbine Seismic Behavior
DOWNLOAD
Author : Ian Prowell
language : en
Publisher:
Release Date : 2011
An Experimental And Numerical Study Of Wind Turbine Seismic Behavior written by Ian Prowell and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Earthquake resistant design categories.
This dissertation presents an experimental and numerical investigation into the seismic response of modern wind turbines. Currently, no consensus exists in the industry and there is significant interest in improving prediction of the behavior of wind turbines simultaneously subjected to wind, earthquake, and operational excitation. To this end, an experimental program was planned in order to evaluate seismic loading of wind turbines. In 2004, a preliminary shake table test of a 65-kW utility scale wind turbine was conducted that provided an experimental basis to begin the work discussed herein. A monitoring campaign was performed at Oak Creek Energy Systems in Mojave, California to assess variability of in-situ dynamic characteristics of two modern wind turbines (900-kW and 1.5-MW rated power) under different operational states and wind conditions. A second shake table experiment with a more extensive test program and improved instrumentation was executed, in which orientation of shaking and operational state were found to significantly influence response. Using the finite element program OpenSees, beam-column models of the tested specimens were constructed and calibrated. Collected data provided a basis to show that such a model could reproduce salient characteristics including natural frequencies, mode shapes, and dynamic response time histories for a parked turbine. In-situ results were used to guide construction of full turbine-foundation-soil models that provided insight into soil-structure interaction phenomena. An existing tool to simulate turbine dynamics, the FAST code, was extended to include seismic loading to allow simulation of operational turbines subjected to base shaking and validated based on shake table results. Using a calibrated model of the tested 900-kW turbine it is shown that neglecting aerodynamics results in significant over estimation of the tower bending demand. An investigation of turbines ranging from 65-kW to 5-MW concluded that consideration of aerodynamics and operational state becomes increasingly important with size. The updated FAST code was demonstrated to accurately reproduce observed dynamics of operating turbines, providing a validated tool for seismic design of turbines. These contributions clarify that operational state and orientation of shaking are important considerations and enable the development of a new generation of turbines that appropriately consider seismic loads.
Dynamic Analysis Of An Offshore Wind Turbine Taking Into Account The Soil Foundation Structure Interaction
DOWNLOAD
Author : Philip Alkhoury
language : en
Publisher:
Release Date : 2021
Dynamic Analysis Of An Offshore Wind Turbine Taking Into Account The Soil Foundation Structure Interaction written by Philip Alkhoury and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
Wind energy has received a vast attention in recent years. Multi-megawatt offshore wind turbines (OWTs) mounted on large diameter monopiles are being widely used nowadays in practice. There is a general acceptance that the overall weight of OWTs must be kept to a minimum to reduce their cost. This eventually resulted in a highly flexible slender structure that is dynamically-sensitive. The high sensitivity to the highly variable external loads demands special design consideration regarding the natural frequency of the OWT system which must be outside the excitations frequencies to avoid resonance. In addition to the resonance avoidance criterion, OWTs must verify stringent serviceability design requirements during their lifetime, which demand the consideration of a reliable numerical tool with an advanced soil constitutive model for the computation of the OWT dynamic responses. Modal and dynamic analyses of such complicated structures have been well-covered in literature using different aeroelastic simulation tools based on a limited number of degrees of freedom and/or make use of simplified assumptions related to the OWT superstructure, the soil-foundation interaction and the soil behavior. In response to these challenges, this thesis presents a three-dimensional finite element (FE) model that reflects the OWT behavior to a high degree of accuracy and that is used for the computation of the OWT modal and dynamic responses. Another aim of this thesis is to study the excessive vibration mitigation of OWTs. In this regard, this thesis presents a novel technique in which FE analysis is combined with a control system to study the real-time performance of an active tuned mass damper in reducing the OWT vibrations.