Download or read book Probabilistic Fatigue Methodology and Wind Turbine Reliability written by and published by . This book was released on 1996 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind turbines subjected to highly irregular loadings due to wind, gravity, and gyroscopic effects are especially vulnerable to fatigue damage. The objective of this study is to develop and illustrate methods for the probabilistic analysis and design of fatigue-sensitive wind turbine components. A computer program (CYCLES) that estimates fatigue reliability of structural and mechanical components has been developed. A FORM/SORM analysis is used to compute failure probabilities and importance factors of the random variables. The limit state equation includes uncertainty in environmental loading, gross structural response, and local fatigue properties. Several techniques are shown to better study fatigue loads data. Common one-parameter models, such as the Rayleigh and exponential models are shown to produce dramatically different estimates of load distributions and fatigue damage. Improved fits may be achieved with the two-parameter Weibull model. High b values require better modeling of relatively large stress ranges; this is effectively done by matching at least two moments (Weibull) and better by matching still higher moments. For this purpose, a new, four-moment {open_quotes}generalized Weibull{close_quotes} model is introduced. Load and resistance factor design (LRFD) methodology for design against fatigue is proposed and demonstrated using data from two horizontal-axis wind turbines. To estimate fatigue damage, wind turbine blade loads have been represented by their first three statistical moments across a range of wind conditions. Based on the moments [mu]1{hor_ellipsis}[mu]3, new {open_quotes}quadratic Weibull{close_quotes} load distribution models are introduced. The fatigue reliability is found to be notably affected by the choice of load distribution model.
Download or read book Probabilistic Fatigue Methodology and Wind Turbine Reliability written by and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probabilistic fatigue reliability assessment of the wind turbine s structural components written by and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Methods of Structural Safety written by H. O. Madsen and published by Courier Corporation. This book was released on 2006-01-01 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: Uncertainties about analytical models, fluctuations in loads, and variability of material properties contribute to the small but real probability of structure failures. This advanced engineering text describes methods developed to deal with stochastic aspects of structural behavior, providing a framework for evaluating, comparing, and combining stochastic effects. Starting with the general problem of consistent evaluation of the reliability of structures, the text proceeds to examination of the second-moment reliability index methods that describe failure in terms of one or more limit states. It presents first-order reliability methods for computation of failure probabilities for individual limit states and for systems; and it illustrates identification of the design parameters most affecting reliability. Additional subjects include a self-contained presentation of extreme-value theory and stochastic processes; stationary, evolutionary, and nonlinear aspects of stochastic response of structures; a stochastic approach to material fatigue damage and crack propagation; and stochastic models for several natural and manufactured loads.
Download or read book CYCLES 2 0 written by Alok K. Jha and published by . This book was released on 1997 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: CYCLES is a computer program that computes the fatigue reliability of mechanical components. It includes a rather flexible model of uncertainty, both in distribution parameters of randomly varying quantities (e.g., load environment parameters such as wave height, wind speed, etc.) and in uncertain material properties (e.g., S-N fatigue properties). The formulation is intended to be of general applicability across a range of fatigue problems. Applications are shown here to offshore structures and wind turbines, both of which may experience fatigue problems. These models are efficiently analyzed through FORM/SORM techniques (first-and second-order reliability methods). A simple, analytical 9-function (limit state) is established, which may be directly incorporated into standard FORM/SORM software packages. We describe here one such code, which includes a 24-variable formulation, its capabilities, input parameters, and output. Fatigue reliability results are shown from this code for both wave and wind applications, including failure probability variation across a range of target fatigue lives.
Download or read book Chances in Wind Energy written by Herman Frederik Veldkamp and published by . This book was released on 2006 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probabilistic Fatigue Methodology for Six Nines Reliability written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-10 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fleet readiness and flight safety strongly depend on the degree of reliability that can be designed into rotorcraft flight critical components. The current U.S. Army fatigue life specification for new rotorcraft is the so-called six nines reliability, or a probability of failure of one in a million. The progress of a round robin which was established by the American Helicopter Society (AHS) Subcommittee for Fatigue and Damage Tolerance is reviewed to investigate reliability-based fatigue methodology. The participants in this cooperative effort are in the U.S. Army Aviation Systems Command (AVSCOM) and the rotorcraft industry. One phase of the joint activity examined fatigue reliability under uniquely defined conditions for which only one answer was correct. The other phases were set up to learn how the different industry methods in defining fatigue strength affected the mean fatigue life and reliability calculations. Hence, constant amplitude and spectrum fatigue test data were provided so that each participant could perform their standard fatigue life analysis. As a result of this round robin, the probabilistic logic which includes both fatigue strength and spectrum loading variability in developing a consistant reliability analysis was established. In this first study, the reliability analysis was limited to the linear cumulative damage approach. However, it is expected that superior fatigue life prediction methods will ultimately be developed through this open AHS forum. To that end, these preliminary results were useful in identifying some topics for additional study. Everett, R. A., Jr. and Bartlett, F. D., Jr. and Elber, Wolf Langley Research Center...
Download or read book Die Chroniken der Stadt herausgegeben written by and published by . This book was released on 1858 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probabilistic Fatigue Methodology for Six Nines Reliability written by and published by . This book was released on 1990 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in wind turbine blade design and materials written by D.J. Lekou and published by Elsevier Inc. Chapters. This book was released on 2013-10-31 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chapter discusses the topic of probabilistic analysis of wind turbine blades. First, structural analysis models, the definition of ‘failure’ and the treatment of random variables will be explored, focusing on the challenges involved in a probabilistic design depending on the choices made during each step. Next, the various probabilistic methods (Monte Carlo method, first-order reliability method, Edgeworth expansion method, response surface method) will be described. Issues arising out of the use of composite material structures, in applications such as wind turbine blades, as well as other aspects relating to wind energy applications will be highlighted, and techniques will be discussed through examples.
Download or read book FAROW written by and published by . This book was released on 1993 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: FAROW is a computer program that evaluates the fatigue and reliability of wind turbine components using structural reliability methods. A deterministic fatigue life formulation is based on functional forms of three basic parts of wind turbine fatigue calculation: (1) the loading environment, (2) the gross level of structural response given the load environment, and (3) the local failure criterion given both load environment and gross stress response. The calculated lifetime is compared with a user specific target lifetime to assess probabilities of premature failure. The parameters of the functional forms can be defined as either constants or random variables. The reliability analysis uses the deterministic lifetime calculation as the limit state function of a FORM/SORM (first and second order reliability methods) calculation based on techniques developed by Rackwitz. Besides probability of premature failure, FAROW calculates the mean lifetime, the relative importance of each of the random variables, and the sensitivity of the results to all of the input parameters, both constant inputs and the parameters that define the random variable inputs. The ability to check the probability of failure with Monte Carlo simulation is included as an option.
Download or read book Offshore Wind Turbines written by Peter Tavner and published by IET. This book was released on 2012-08-09 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offshore Wind Turbines clearly presents the facts and figures of wind turbine operation and maintenance in the inclement offshore environment.
Download or read book Probabilistic Mechanics Structural Reliability written by Dan M. Frangopol and published by American Society of Civil Engineers. This book was released on 1996 with total page 1036 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contains three keynote papers and some 230 contributed four-page papers from the August 1996 conference, examining all aspects of probabalistic mechanics and structural reliability regarding assessment and design of structural, mechanical, marine, aerospace, geotechnical, and environmental systems. Emphasis is on concepts and methods of probability in the design of engineering systems, with particular focus on progress in stochastic mechanics in earthquake engineering, structural dynamics, and finite element methods. Annotation copyright by Book News, Inc., Portland, OR
Download or read book Probabilistic Prognostics and Health Management of Energy Systems written by Stephen Ekwaro-Osire and published by Springer. This book was released on 2017-04-25 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book proposes the formulation of an efficient methodology that estimates energy system uncertainty and predicts Remaining Useful Life (RUL) accurately with significantly reduced RUL prediction uncertainty. Renewable and non-renewable sources of energy are being used to supply the demands of societies worldwide. These sources are mainly thermo-chemo-electro-mechanical systems that are subject to uncertainty in future loading conditions, material properties, process noise, and other design parameters.It book informs the reader of existing and new ideas that will be implemented in RUL prediction of energy systems in the future. The book provides case studies, illustrations, graphs, and charts. Its chapters consider engineering, reliability, prognostics and health management, probabilistic multibody dynamical analysis, peridynamic and finite-element modelling, computer science, and mathematics.
Download or read book Wind Energy Systems written by John Dalsgaard Sørensen and published by Elsevier. This book was released on 2010-12-20 with total page 621 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large-scale wind power generation is one of the fastest developing sources of renewable energy and already makes a substantial contribution to power grids in many countries worldwide. With technology maturing, the challenge is now to increase penetration, and optimise the design, construction and performance of wind energy systems. Fundamental issues of safety and reliability are paramount in this drive to increase capacity and efficiency.Wind energy systems: Optimising design and construction for safe and reliable operation provides a comprehensive review of the latest developments in the design, construction and operation of large-scale wind energy systems, including in offshore and other problematic environments.Part one provides detailed coverage of wind resource assessment and siting methods relevant to wind turbine and wind farm planning, as well as aeroelastics, aerodynamics, and fatigue loading that affect the safety and reliability of wind energy systems. This coverage is extended in part two, where the design and development of individual components is considered in depth, from wind turbine rotors to drive train and control systems, and on to tower design and construction. Part three explores operation and maintenance issues, such as reliability and maintainability strategies and condition monitoring systems, before discussing performance assessment and optimisation routes for wind energy systems in low wind speed environments and cold climates. Part four reviews offshore wind energy systems development, from the impact of environmental loads such as wind, waves and ice, to site specific construction and integrated wind farm planning, and of course the critical issues and strategies for offshore operation and maintenance.With its distinguished editors and international teams of contributors, Wind energy systems is a standard reference for wind power engineers, technicians and manufacturers, as well as researchers and academics involved in this expanding field. - Reviews the latest developments in the design, construction and operation of large-scale wind energy systems - Offers detailed coverage of wind resource assessment and siting methods relevant to wind turbine and wind farm planning - Explores operation and maintenance issues, such as reliability and maintainability strategies and condition monitoring systems
Download or read book Reliability Analysis Methods for Wind Turbines written by L. W. M. M. Rademakers and published by . This book was released on 1992 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reliability based Design Optimization of Composite Wind Turbine Blades for Fatigue Life Under Wind Load Uncertainty written by Weifei Hu and published by . This book was released on 2015 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this study are (1) to develop an accurate and efficient fatigue analysis procedure that can be used in reliability analysis and reliability-based design optimization (RBDO) of composite wind turbine blades; (2) to develop a wind load uncertainty model that provides realistic uncertain wind load for the reliability analysis and the RBDO process; and (3) to obtain an optimal composite wind turbine blade that satisfies target reliability for durability under the uncertain wind load. The current research effort involves: (1) developing an aerodynamic analysis method that can effectively calculate detailed wind pressure on the blade surface for stress analysis; (2) developing a fatigue failure criterion that can cope with non-proportional multi-axial stress states in composite wind turbine blades; (3) developing a wind load uncertainty model that represents realistic uncertain wind load for fatigue reliability of wind turbine systems; (4) applying the wind load uncertainty model into a composite wind turbine blade and obtaining an RBDO optimum design that satisfies a target probability of failure for a lifespan of 20 years under wind load uncertainty. In blade fatigue analysis, resultant aerodynamic forces are usually applied at the aerodynamic centers of the airfoils of a blade to calculate stress/strain. However, in reality the wind pressures are applied on the blade surface. A wind turbine blade is often treated as a typical beam-like structure for which fatigue life calculations are limited in the edge-wise and/or flap-wise direction(s). Using the beam-like structure, existing fatigue analysis methods for composite wind turbine blades cannot cope with the non-proportional multi-axial stress states that are endured by wind turbine blades during operation.
