Nonlinear Dynamic Analysis of Offshore Structures

Nonlinear Dynamic Analysis of Offshore Structures
Author:
Publisher:
Total Pages:
Release: 2009
Genre:
ISBN:
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In this thesis consideration is given to a selection of nonlinear dynamic problems in the field of offshore engineering. Hydrodynamic loading on fixed horizontal and vertical tubular members and the dynamic response of articulated towers together with the distribution of shear force and bending moment along the tower are investigated using various wave theories. Effects of nonlinear convective acceleration terms in the calculation of fluid inertia forces and moments are examined and attention is given to integration of wave forces up to the free surface for vertical members. Calculation of fluid loading at the displaced position of the articulated tower and any Mathieu type instabilities that may occur have been considered. The dynamic analysis of a damaged Single Anchor Leg Storage (SALS) system subject to loss of buoyancy in the yoke chamber is studied. The equations of motion of the yoke/riser system are derived assuming large displacements and solved in the time domain. Time histories of the response, variations of the riser tension, velocities of riser top end and the time histories of pivot reactions are given. Natural periods and mode shapes for small displacements of the system are calculated. Two methods of simulating random seas, both represented by a sum of harmonic wave components, are used to simulate second order low frequency (slow drift) force on a tanker in head seas by Pinkster's time domain method. In one method the wave amplitudes are generated randomly from a Rayleigh distribution and in the other they are obtained deterministically via the wave spectrum. Time histories of slow drift force and response together with simulation results with various duration lengths are presented and compared. Estimates of the extreme vessel response and its relation to rms value are compared with the result of a commonly used method of determining peak/rms ratios. The results of these investigations highlight the importance of accurately simulating nonlinear effe.

Dynamic Analysis and Design of Offshore Structures

Dynamic Analysis and Design of Offshore Structures
Author: Srinivasan Chandrasekaran
Publisher: Springer
Total Pages: 449
Release: 2017-10-12
Genre: Technology & Engineering
ISBN: 9811060894
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This book introduces readers to various types of offshore platform geometries. It addresses the various environmental loads encountered by these structures, and provides detailed descriptions of the fundamentals of structural dynamics in a classroom style, helping readers estimate damping in offshore structures and grasp these aspects’ applications in preliminary analysis and design. Basic concepts of structural dynamics are emphasized through simple illustrative examples and exercises. Design methodologies and guidelines, which are FORM based concepts, are explained through a selection of applied sample structures. Each chapter also features tutorials and exercises for self-learning. A dedicated chapter on stochastic dynamics helps students to extend the basic concepts of structural dynamics to this advanced domain of research. Hydrodynamic response of offshore structures with perforated members is one of the most recent research applications, and has proven to be one of the most effective means of retrofitting offshore structures. In addition, the book integrates the concepts of structural dynamics with the FORM-evolved design of offshore structures, offering a unique approach. This new edition is divided into seven chapters, each of which has been updated. Each chapter also includes a section on frequently asked Questions and Answers (Q&A), which enhances understanding of this complex subject through easy and self-explanatory text. Furthermore, the book presents valuable content with respect to new and recent research carried out by the author in structural dynamics. All numeric examples have been re-checked with more additional explanations. New exercises have been added to improve understanding of the subject matter. Computer coding is also included (wherever possible) to aid computer-based learning of the contents of the book. The book can serve as a textbook for senior undergraduate and graduate courses in civil, structural, applied mechanics, mechanical, aerospace, naval architecture and ocean engineering programs. The book can also serve as a text for professional learning and development programs or as a guide for practicing and consulting offshore structural engineers. The contents of this book will be useful to graduate students, researchers, and professionals alike.

Dynamics of Fixed Marine Structures

Dynamics of Fixed Marine Structures
Author: N. D. P. Barltrop
Publisher: Butterworth-Heinemann
Total Pages: 785
Release: 2013-10-22
Genre: Technology & Engineering
ISBN: 1483162559
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Dynamics of Fixed Marine Structures, Third Edition proves guidance on the dynamic design of fixed structures subject to wave and current action. The text is an update of the ""UR8"" design guide ""Dynamics of Marine Structures"" with discussion of foundations, wind turbulence, offshore installations, earthquakes, and strength and fatigue. The book employs analytical methods of static and dynamic structural analysis techniques, particularly the statistical and spectral methods when applied to loading and in the calculating dynamic responses. The statistical methods are explained when used to wave, wind, and earthquake calculations, together with the problems encountered in actual applications. Of importance to fixed offshore platforms are the soil properties and foundation covering soil behavior, site investigation, testing, seabed stability, gravity structures, and the use of single piles. Methods of forecasting, measuring, and modeling of waves and currents are also presented in offshore structure construction. Basic hydrodynamics is explained in understanding wave theory, and some description is given to forecasting of environmental conditions that will affect the structures. The effects of vortex-induced vibrations on the structure are explained, and the three methods that can prevent vortex-induced oscillations are given. Wind turbulence or wind loads are analyzed against short natural period or long natural periods of structures. The transportation of offshore platforms, installation, and pile driving, including examples of the applications found in the book, are given as well. The guide is helpful for offshore engineers, designers of inshore jetties, clients needing design and analysis work, specialists related to offshore structural engineering, and students in offshore engineering.

Offshore Compliant Platforms

Offshore Compliant Platforms
Author: Srinivasan Chandrasekaran
Publisher: John Wiley & Sons
Total Pages: 263
Release: 2020-02-05
Genre: Technology & Engineering
ISBN: 1119669804
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A guide to the analysis and design of compliant offshore structures that highlights a new generation of platforms Offshore Compliant Platforms provides an authoritative guideto the analysis and design of compliant offshore structures and puts the focus on a new generation of platforms such as: triceratops, Buoyant Leg Storage and Regasification platforms. Whilst the authors – noted experts on the topic – include basic information on the conceptual development of conventional platforms, the book presents detailed descriptions of the design and development of new deep-water platforms. The book describes the preliminary design of triceratops in ultra-deep waters and presents a detailed analysis of environmental loads that are inherent in offshore locations such as wave, wind and current. The new methodology for the dynamic analysis of triceratops under ice loads, predominantly in ice-covered regions, is also examined with detailed parametric studies. In addition, the book covers the structural geometry and the various methods of analysis for assessing the performance of any other similar offshore platform under the special loads. A discussion of the fatigue analysis and service life prediction is also included. This important book: • Includes the analysis and design of compliant offshore structures with a focus on a new generation of platforms • Examines the preliminary design of triceratops in ultra-deep waters • Covers an analysis of environmental loads that are inherent in offshore locations such as wave, wind and current • Reviews the structural geometry and various methods of analysis for assessing the performance of any other similar offshore platform under special loads • Discusses fatigue analysis and service life prediction Written for engineers and researchers across engineering including civil, mechanical, structural, offshore, ocean and naval architecture, Offshore Compliant Platforms fills the need for a guide to new offshore platforms that provides an understanding of the behaviour of these structures under different loading conditions.

Offshore Mechanics

Offshore Mechanics
Author: Madjid Karimirad
Publisher: John Wiley & Sons
Total Pages: 305
Release: 2018-05-07
Genre: Technology & Engineering
ISBN: 1119216621
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Covers theoretical concepts in offshore mechanics with consideration to new applications, including offshore wind farms, ocean energy devices, aquaculture, floating bridges, and submerged tunnels This comprehensive book covers important aspects of the required analysis and design of offshore structures and systems and the fundamental background material for offshore engineering. Whereas most of the books currently available in the field use traditional oil, gas, and ship industry examples in order to explain the fundamentals in offshore mechanics, this book uses more recent applications, including recent fixed-bottom and floating offshore platforms, ocean energy structures and systems such as wind turbines, wave energy converters, tidal turbines and hybrid marine platforms. Offshore Mechanics covers traditional and more recent methodologies used in offshore structure modelling (including SPH and hydroelasticity models). It also examines numerical techniques, including computational fluid dynamics and finite element method. Additionally, the book features easy-to-understand exercises and examples. Provides a comprehensive treatment for the case of recent applications in offshore mechanics for researchers and engineers Presents the subject of computational fluid dynamics (CFD) and finite element methods (FEM) along with the high fidelity numerical analysis of recent applications in offshore mechanics Offers insight into the philosophy and power of numerical simulations and an understanding of the mathematical nature of the fluid and structural dynamics with focus on offshore mechanic applications Offshore Mechanics: Structural and Fluid Dynamics for Recent Applications is an important book for graduate and senior undergraduate students in offshore engineering and for offshore engineers and researchers in the offshore industry.

Nonlinear Dynamics of Compliant Offshore Structures

Nonlinear Dynamics of Compliant Offshore Structures
Author: Patrick Bar-Avi
Publisher: Routledge
Total Pages: 181
Release: 2017-12-04
Genre: Technology & Engineering
ISBN: 1351428241
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This monograph provides a general background to the modelling of a special class of offshore structures known as compliant structures. External forcing is resisted by buoyancy and tension forces which increase when the structure is slightly offset from its equilibrium. The technical development given in this book is presented in such a way as to highlight the adaptability of the modelling, and the reader is shown how the techniques described can be applied to a variety of different offshore structures.