Vibration of Nearly Periodic Structures and Mistuned Bladed Rotors
Vibration of Nearly Periodic Structures and Mistuned Bladed Rotors

Author: Alok Sinha

Publisher: Cambridge University Press

Published: 2017-06-16

Total Pages: 201

ISBN-13: 1108101348

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This is the first comprehensive volume on nearly periodic structures and mistuned blade vibration. Alok Sinha presents fundamental concepts and state-of-the-art techniques in the analysis of free and forced response of a nearly periodic structure, weaving together his own work (covering thirty-five years of research in this field) with works by other researchers. He also discusses similarities between tools used in bladed rotor analysis and condensed matter physics. Specific subjects covered include the reasons behind mode localization, the reasons behind amplitude amplification of steady-state response, state-of-the-art computational techniques for mistuned bladed rotors including multistage rotors, identification of mistuning from measured response, vibration localization in linear atomic chains, and analysis of two-dimensional periodic structures.

Vibrations of Rotationally Periodic Structures
Vibrations of Rotationally Periodic Structures

Author: Andres M. Rodriguez

Publisher:

Published: 2022

Total Pages: 0

ISBN-13:

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Blisk components are an integral part of jet engines and power generation systems. Composed of a single monolithic structure, integral blisks combine the blade-and-disk portion of primary components such as the fan, compressor stage, or turbine stage. This design modification increases the aerodynamic performance while decreasing the cost and eliminating time of assembly. However, these benefits come with the loss of blade-disk connection interfaces, which greatly reduces the structure’s damping and its ability to attenuate unwanted structural vibrations. Blisk dynamics are impacted by mistuning, which is a disruption of the periodic symmetry of otherwise identical bladed sections. This disruption degrades the overall performance of components. This dissertation advances theoretical and experimental studies into mistuning, both in terms of characterization and vibration localization. A theoretical analysis of wave propagation in periodic structures shows that vibration localization arises from two separate generating mechanisms: an isolated defect or random variations throughout the structure. Through two novel metrics--the band flatness factor and the localization amplification criterion--we establish a unique approach to identifying localized modes on cyclic structures. We present a novel framework that distinguishes between the response of the tuned and mistuned system. A characteristic single-degree-of-freedom response of the tuned system to engine-order forcing forms the basis of our mistuning characterization framework. The actual mistuning (or tuned system) characterization is performed through computations of a modified modal assurance criterion, termed here the modal mistuning criterion. The modal mistuning criterion uses frequency response function data obtained from engine order-forcing profiles and tuned system modes derived from a model to compute the modal contribution to a mistuned response. Finally, this mistuning characterization metric is validated through experimental tests on multiple academic blisk components.

Random Vibrations
Random Vibrations

Author: Loren D. Lutes

Publisher: Elsevier

Published: 2004-01-24

Total Pages: 651

ISBN-13: 0080470033

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The topic of Random Vibrations is the behavior of structural and mechanical systems when they are subjected to unpredictable, or random, vibrations. These vibrations may arise from natural phenomena such as earthquakes or wind, or from human-controlled causes such as the stresses placed on aircraft at takeoff and landing. Study and mastery of this topic enables engineers to design and maintain structures capable of withstanding random vibrations, thereby protecting human life.Random Vibrations will lead readers in a user-friendly fashion to a thorough understanding of vibrations of linear and nonlinear systems that undergo stochastic—random—excitation. - Provides over 150 worked out example problems and, along with over 225 exercises, illustrates concepts with true-to-life engineering design problems - Offers intuitive explanations of concepts within a context of mathematical rigor and relatively advanced analysis techniques. - Essential for self-study by practicing engineers, and for instruction in the classroom.

Vibration of Periodic Structures
Vibration of Periodic Structures

Author: Gautam SenGupta

Publisher: Elsevier

Published: 2023-10-27

Total Pages: 268

ISBN-13: 0323990231

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Vibration of Periodic Structures introduces the fundamentals of periodic structure theory by considering the simplest model – wave propagation in an infinitely long periodic spring-mass system. It then shows how the knowledge of the stop and pass bands can be utilized to find the natural frequency distribution in a finite periodic structure. The basic concepts are further extended to wave propagation in infinitely long periodically supported beams and plates; distribution of natural frequencies of a similar structure of finite length; vibration of skin-stringer structures; and structuralacoustic properties of a section of an aircraft fuselage, based on a combination of the finite element method and the periodic structure theory, in a highly cost-effective manner.This book is a valuable resource of information for practicing engineers in various industries, e.g., civil, mechanical, or aerospace engineering, dealing with vibration of structures with periodic properties, including prediction of supersonic flutter characteristics of aerospace structures. It will also prove to be a beneficial reference for researchers involved with wave propagation in metamaterials and phononic devices."Readers who have wanted a clear and connected account of vibration of periodic structures will find this treatment accessible and stimulating and will want to add this volume to their personal or institutional library. – Prof. Earl Dowell, Duke University, Durham, NC, USA - Shows how the periodic structure theory can be combined with the finite element method to model a section of an airplane fuselage to study its structural-acoustic characteristics - Features developing methods for predicting the dynamics of periodic structures in a cost-effective manner - Guides the reader to predict and reduce response of periodically stiffened structures to random excitations

Random Vibrations
Random Vibrations

Author: Paul H. Wirsching

Publisher: Courier Corporation

Published: 2006-01-01

Total Pages: 465

ISBN-13: 0486450155

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The most comprehensive text and reference available on the study of random vibrations, this book was designed for graduate students and mechanical, structural, and aerospace engineers. In addition to coverage of background topics in probability, statistics, and random processes, it develops methods for analyzing and controlling random vibrations. 1995 edition.

Introduction to Random Vibrations
Introduction to Random Vibrations

Author: N. C. Nigam

Publisher: MIT Press (MA)

Published: 1983

Total Pages: 368

ISBN-13:

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Introduction to Random Vibrations presents a brief review of probability theory, a concise treatment of random variables and random processes, and a comprehensive exposition of the theory of random vibrations.

Some Engineering Applications in Random Vibrations and Random Structures
Some Engineering Applications in Random Vibrations and Random Structures

Author: Giora Maymon

Publisher: AIAA (American Institute of Aeronautics & Astronautics)

Published: 1998

Total Pages: 288

ISBN-13:

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This text synthesizes a wealth of useful information for analyzing random vibrations and structures into one coherent body of knowledge. It takes a practical yet progressive look at two major fields related to random analysis: linear and geometrically nonlinear structures, and the behavior of random structures under random loads. System harmonics and oscillations, random functions, and the theory of random vibration are covered extensively throughout the text, which includes innovative methods for calculating the probability of failure of dynamic systems. Simplified examples demonstrate applications for daily use and present new approaches to failure analysis. The author evaluates the use of random process methods for the stochastic analysis of crack growth in detail, providing a better description of failures resulting from crack propagation. For young engineers, the book touches on finite element programs such as ANSYS and the probabilistic analysis program PROBAN, facilitating solutions to more complex problems. It also illustrates how to write a FORTRAN program to build a numerical procedure suitable for the design needs.