Nonlinear Stochastic Models for Ocean Wave Loads and Responses of Offshore Structures and Vessels
Author: Alok K. Jha
Publisher:
Published: 1997
Total Pages: 404
ISBN-13:
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Modeling Nonlinear Stochastic Ocean Loads as Diffusive Stochastic Differential Equations to Derive the Dynamic Responses of Offshore Wind Turbines
Author: David F. H. Larson
Publisher:
Published: 2016
Total Pages: 54
ISBN-13:
DOWNLOAD EBOOKA procedure is developed for modeling stochastic ocean wave and wind loads as diffusive stochastic differential equations (SDE) in a state space form to derive the response statistics of offshore structures, specifically wind turbines. Often, severe wind and wave systems are highly nonlinear and thus treatment as linear systems is not applicable, leading to computationally expensive Monte Carlo simulations. Using Stratonovich-form diffusive stochastic differential equations, both linear and nonlinear components of the wind thrust can be modeled as 2 state SDE. These processes can be superposed with both the linear and nonlinear (inertial and viscous) wave forces, also modeled as a multi-dimensional state space SDE. Furthermore, upon implementing the ESPRIT algorithm to fit the autocorrelation function of any real sea state spectrum, a simple 2-state space model can be derived to completely describe the wave forces. The resulting compound state-space SDE model forms the input to a multi-dimension state-space Fokker-Planck equation, governing the dynamical response of the wind turbine structure. Its solution yields response, fatigue and failure statistics-information critical to the design of any offshore structure. The resulting Fokker-Planck equation can be solved using existing numerical schemes.
Extreme Response of Nonlinear Ocean Structures
Author: Rune Torhaug
Publisher:
Published: 1996
Total Pages: 126
ISBN-13:
DOWNLOAD EBOOKNonlinear Waves and Offshore Structures
Author: Cheung Hun Kim
Publisher: World Scientific
Published: 2008
Total Pages: 539
ISBN-13: 9810248849
DOWNLOAD EBOOKThe responses of offshore structures are significantly affected by steep nonlinear waves, currents and wind, leading to phenomena such as springing and ringing of TLPs, slow drift yaw motion of FPSOs and large oscillations of Spar platforms due to vortex shedding. Research has brought about significant progress in this field over the past few decades and introduced us to increasingly involved concepts and their diverse applicability. Thus, an in-depth understanding of steep nonlinear waves and their effects on the responses of offshore structures is essential for safe and effective designs.This book deals with analyses of nonlinear problems encountered in the design of offshore structures, as well as those that are of immediate practical interest to ocean engineers and designers. It presents conclusions drawn from recent research pertinent to nonlinear waves and their effects on the responses of offshore structures. Theories, observations and analyses of laboratory and field experiments are expounded such that the nonlinear effects can be clearly visualized.
Nonlinear and Stochastic Dynamics of Compliant Offshore Structures
Author: Seon Mi Han
Publisher: Springer Science & Business Media
Published: 2013-04-17
Total Pages: 281
ISBN-13: 9401599122
DOWNLOAD EBOOKThe purpose of this monograph is to show how a compliant offshore structure in an ocean environment can be modeled in two and three di mensions. The monograph is divided into five parts. Chapter 1 provides the engineering motivation for this work, that is, offshore structures. These are very complex structures used for a variety of applications. It is possible to use beam models to initially study their dynamics. Chapter 2 is a review of variational methods, and thus includes the topics: princi ple of virtual work, D'Alembert's principle, Lagrange's equation, Hamil ton's principle, and the extended Hamilton's principle. These methods are used to derive the equations of motion throughout this monograph. Chapter 3 is a review of existing transverse beam models. They are the Euler-Bernoulli, Rayleigh, shear and Timoshenko models. The equa tions of motion are derived and solved analytically using the extended Hamilton's principle, as outlined in Chapter 2. For engineering purposes, the natural frequencies of the beam models are presented graphically as functions of normalized wave number and geometrical and physical pa rameters. Beam models are useful as representations of complex struc tures. In Chapter 4, a fluid force that is representative of those that act on offshore structures is formulated. The environmental load due to ocean current and random waves is obtained using Morison's equa tion. The random waves are formulated using the Pierson-Moskowitz spectrum with the Airy linear wave theory.
Dynamics of Offshore Structures
Author: James F. Wilson
Publisher: John Wiley & Sons
Published: 2003-01-03
Total Pages: 343
ISBN-13: 0471275654
DOWNLOAD EBOOKUnique, cutting-edge material on structural dynamics and natural forces for offshore structures Using the latest advances in theory and practice, Dynamics of Offshore Structures, Second Edition is extensively revised to cover all aspects of the physical forces, structural modeling, and mathematical methods necessary to effectively analyze the dynamic behavior of offshore structures. Both closed-form solutions and the Mathematica(r) software package are used in many of the up-to-date example problems to compute the deterministic and stochastic structural responses for such offshore structures as buoys; moored ships; and fixed-bottom, cable-stayed, and gravity-type platforms. Throughout the book, consideration is given to the many assumptions involved in formulating a structural model and to the natural forces encountered in the offshore environment. These analyses focus on plane motions of elastic structures with linear and nonlinear restraints, as well as motions induced by the forces of currents, winds, earthquakes, and waves, including the latest theories and information on wave mechanics. Topics addressed include multidegree of freedom linear structures, continuous system analysis (including the motion of cables and pipelines), submerged pile design, structural modal damping, fluid-structure-soil interactions, and single degree of freedom structural models that, together with plane wave loading theories, lead to deterministic or time history predictions of structural responses. These analyses are extended to statistical descriptions of both wave loading and structural motion. Dynamics of Offshore Structures, Second Edition is a valuable text for students in civil and mechanical engineering programs and an indispensable resource for structural, geotechnical, and construction engineers working with offshore projects.
Stochastically Excited Nonlinear Ocean Structures
Author: Michael F. Shlesinger
Publisher: World Scientific
Published: 1998
Total Pages: 340
ISBN-13: 9789810233921
DOWNLOAD EBOOKOcean structures, including ships, boats, piers, docks, rigs and platforms, are subject to fair weather wind and waves, as well as violent storms. A scientific analysis of these structures, under varying conditions, requires a mix of civil engineering, physics and applied mathematics. Chapters by experts in these fields are presented which explore the nonlinear responses of ocean structures to stochastic forcing. Theoretical methods calculate aspects of time, frequency and phase space responses. Probabilities governed by stochastic differential equations arc investigated directly or through moment correlations, such as power spectra. Calculations can also involve level crossing statistics and first passage times. Tiffs book will help scientists study stochastic nonlinear equations and help engineers design for short term survivability of structures in storms and long life in the face of everyday fatigue.
Stochastic Dynamics of Marine Structures
Author: Arvid Naess
Publisher: Cambridge University Press
Published: 2013
Total Pages: 425
ISBN-13: 0521881552
DOWNLOAD EBOOKFor students and professionals, this covers theory and methods for stochastic modelling and analysis of marine structures under environmental loads.
Stochastic Dynamic Response and Stability of Ships and Offshore Platforms
Author: Yingguang Wang
Publisher: Springer Nature
Published: 2023-11-25
Total Pages: 368
ISBN-13: 9819958539
DOWNLOAD EBOOKThis textbook investigates in detail the methods for stochastic dynamic response and stability analyses of nonlinear systems (especially ships and ocean engineering systems), elucidating the advantages and disadvantages of each of the methods (the statistical linearization method, the perturbation method, the Monte Carlo Simulation method, the numerical path integration method, the global geometric method and the first passage theory). Studies on stochastic dynamic analysis of nonlinear systems have attracted engineers and scientists from various disciplines, such as aeronautical, civil, mechanical and ocean engineering. Pursuing a systematic approach, this book establishes a fundamental framework for this topic, while emphasizing the importance of accurate and efficient analysis as well as the significant influence of choosing a suitable method in the design and optimization of various nonlinear engineering systems (especially ships and ocean engineering systems). The textbook is intended for upper undergraduate and graduate students who are interested in advanced dynamic analysis technologies, researchers investigating nonlinear systems under stochastic dynamic excitations, and civil/mechanical/structural/ocean engineers working on designing and optimization of real-world nonlinear engineering systems. The basis of English translation of this book from its Chinese original manuscript was done with the help of artificial intelligence. A subsequent human revision of the content was done by the author.
Ocean Waves
Author: Michel K. Ochi
Publisher: Cambridge University Press
Published: 1998-03-28
Total Pages: 333
ISBN-13: 052156378X
DOWNLOAD EBOOKDescribes the stochastic method for ocean wave analysis - vital information for design and operation of ships.
