By Eugene I. Rivin
Provides background theory and practical solutions for engineers that face vibration problems causing equipment failure, downtime, and extra maintenance costs.
It emphasizes proven, effective techniques that are not yet widely used on equipment for microelectronics, MEMS, and nanotechnology, as well as process plants, power generation, oil, gas, petrochemicals, and other industries.
Vibration isolation is a vibration control technique in which the source of vibration excitation and the object to be protected are separated by an auxiliary system comprising special devices called vibration isolators or vibration isolating mounts.
The four chapters of the book describe:
- basic analytical tools for designing such systems
- principles and criteria for assigning principal parameters (natural frequencies and damping values) necessary for successful functioning of passive vibration isolation systems for major groups of objects (vibration-sensitive objects, vibration-generating objects, general purpose machinery)
- static and dynamic characteristics of the most widely used materials for vibration isolators
- basic designs of vibration isolators for various applications
Addressing practitioners, the book offers problems and solutions relevant not only to the isolation of stationary sensitive equipment, but also to civil engineering and transport applications.
Today, tolerances on acceptable levels of vibration are becoming more stringent, just as the number and intensity of vibration sources is increasing - for example, as machine operating speeds become faster, or cutting inserts in machine tools improve to allow heavier cuts.
Passive Vibration Isolation enables practitioners to make better informed and more effective choices when solving vibration problems.
Review of: Passive Vibration Isolation
Eugene I. Rivin
The American Society of Mechanical Engineers, New York, 2003
ISBN 079810187X
From the ASME Journal of Vibration and Acoustics (April 2004)
The basic principles of vibration isolation have been known for centuries and this topic is covered in every vibration text, although rarely thoroughly and not always from a realistic viewpoint. Not since the publication of C. E. Crede's 1951 classic "Vibration and Shock Isolation" has there appeared a book that treats all of the important aspects of this subject. The present book does this and more; it summarizes the current state of the technology and also discusses the salient characteristics of the available hardware and materials.
"Passive Vibration Isolation" presents a rather comprehensive treatment of its subject matter, including analysis of basic systems and their dynamic processes, criteria for isolation of many sensitive and vibration-producing items, materials employed in isolators, and the design of isolators and isolation systems. As its title implies, the book does not address active vibration isolation.
The first of the book's four chapters deals with the basics of isolation of rigid bodies, including consideration of all six degrees of freedom. It presents the relevant equations, but dwells more extensively on simpler situations and practical real-life applications. It also addresses two-stage isolation, nonlinearity effects, wave effects in isolators, and isolation in the presence of random excitation and of shock excitation.
The second chapter begins with a discussion of isolation of vibration-sensitive items. It puts forth vibration limits for a number of instruments and machines and for some of these items also lists the inertial properties one would need to design an isolation system. It indicates the selection criteria for suitable isolation systems and discusses the practical selection of isolators. It includes consideration of the effects of motions induced by the isolated items and of non-rigidity of the isolated item. It also touches briefly on vibration protection of buildings. Having addressed isolation of sensitive items, the chapter continues similarly with isolation of vibration-producing items, also taking into account non-rigidity of supporting structures. Finally, it provides guidelines for the practical isolation of commonly encountered machines that are neither particularly sensitive nor the sources of considerable vibrations, and it includes a section on mounting of engines and machinery in vehicles.
The third chapter deals with isolator elements. It describes metal springs of various kinds and presents their design equations, and it deals similarly with a variety of damping elements. It discusses the dynamic behaviors of elastomeric materials and components in considerable detail, and also addresses fibrous and wire-mesh mesh materials, high-damping metals, and pneumatic isolators.
The final chapter focuses on practical isolation means, beginning with isolating mats and pads, then proceeding to isolators with rubber elements, including a discussion of the generally under-appreciated constant-natural-frequency isolators. It continues with coil spring isolators and with isolators incorporating wire mesh and cables. It describes low-stiffness isolators that include buckled elements and a variety of pneumatic isolation systems. It concludes with sections that deal with means for avoiding short-circuiting of isolation by piping and cables and with power transmission couplings.
Each chapter includes an extensive list of references, many of which were written by the author. The reference lists include a considerable number of older publications in Russian, as well as some of the newest technical and trade literature, reflecting the author's vast background and experience. The little extra patience and careful study one needs to exert in order to cope with the book's dense packing of theoretical information and quantitative practical data, coupled with some slightly awkward English, generally is well worth while.
This book represents an invaluable resource for engineers concerned with the design and selection of isolation systems and isolators. It deserves thorough study and belongs in the library of every vibration engineer.
Eric E. Ungar
Acentech, Incorporated
Cambridge, MA
- Publisher:
ASME
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Publish Date: 2003
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Pages: 432
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Language: English
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ISBN: 079180187X
Table of Contents
TABLE OF CONTENTS
Dynamic Properties of Vibration Isolation Systems
General Comments. Inertia and Geometric Properties of Typical Machines and Other Mechanical Devices. Basic Characteristics of Elastic Mounts (Vibration Isolators). Elastically Supported Solid Object Dynamic Coupling. Dynamics of Single-Degree-of-Freedom Vibration Isolation System. Vibration Isolator with Viscous Damper. Vibration Isolator with Internal (Hysteresis) Damping. "Relaxation" Isolation System with Viscous Damper. Single-Degree-of-Freedom System with Motion Transformation. Dynamics of Two-Degrees-of-Freedom Vibration Isolation System. Generic Two-Degrees-of-Freedom System with Damping. Vibration Isolator with Intermediate Mass (Two-Stage Isolator). Three-Degrees-of-Freedom (Planar) Vibration Isolation System. Dynamics of Planar Isolation System. Natural Frequencies of Planar Vibration Isolation System. Planar Vibration Isolation System with Inclined Mounts. Focal Equi-Frequency System. Vibration Isolation System Under Random Excitation. Definitions. Travel of Random Vibration Through Dynamic System. Vibration Isolation System Under Pulse Excitation. Nonlinearity in Vibration Isolation Systems. Wave Effects in Vibration Isolators.
Principles and Criteria of Vibration Isolation
Damping vs. Heat Generation in Vibration Isolators.
Isolation of Vibration-Sensitive Objects. Ambient Vibrations. Detrimental Effects of Vibration. Model of Vibration Transmission. Principles and Criteria of Vibration Isolation. Isolation from Steady-State Vibration. Practical Selection of Vibration Isolation Parameters for Precision Objects. Vibration Isolation Systems. Side issues for Vibration Isolated Precision Equipment. Reduction of Mobility of Isolated Objects Caused by Internal Dynamic Forces. Vibration Protection of Civil Engineering Structures. Isolation Requirements for Vibration-Producing Objects. Objects Producing Single Frequency Excitations. Objects Producing Unidirectional Excitation. Objects Producing Multidirectional Excitation. Objects Producing Polyharmonic Excitations. Objects Producing Conservative Impact Excitations. Objects Producing Pulses of Inertial Nature. General Purpose Machinery and Equipment. Influence of Mounting Conditions on Dynamics Stability (Chatter). Vibration Levels of General Purpose Machines. Influence of Vibration Isolation on Bearing Loads. Influence of Vibration Isolation on Noise. Vibration Isolated Objects Installed on Non-Rigid Supporting Structures. Engine and Machinery Mounting in Vehicles. Experimental Selection of Isolators. Role of Damping in Vibration Isolation.
Realization of Elasticity and Damping in Vibration Isolators
General Comments. Metal Elastic Elements (Springs). Coil Springs. Statically Nonlinear Coil Springs. Slotted Springs. Belleville Springs. Dampers. Viscous Dampers. Dry (Coulomb) Friction Dampers. Electromagnetic Dampers. Elasto-Damping Materials (EDM). Meshed Fibrous Materials. Wire-Mesh Materials and Cables. Felt. Elastomeric (Rubberlike) Materials. Static Deformation Characteristics of Rubberlike Materials. Streamlined ("Ideal Shape") Rubber Elements. Thin-Layered Rubber-Metal Laminates. Elastic Stability of Laminated Rubber Parts. Dynamic Characteristics of Rubberlike Materials. Creep of Rubberlike Materials. Plastic Materials. High Damping Metals. Pneumatic Flexible Elements. Hydromounts (Basics).
Passive Vibration Isolation Means
General Comments. Material Selection for Vibration Isolation. Isolating Mats and Pads. Rubber Mats. Plastic and Fibrous Pads. Vibration Isolators with Rubber Flexible Elements. Machinery and Engine Mounts. Constant Natural Frequency (CNF) Vibration Isolators. General Comments; Variable Stiffness Isolators. Designs of CNF Isolators. Vibration Isolators with Metal Flexible Elements. General Comments. Vibration Isolators with Coil Springs. Wire Mesh and Cable Isolators. High Angular Stiffness and Anisotropic Vibration Isolation Systems. Low Stiffness Isolators. Buckling and Negative Stiffness. Pneumatic Isolators. General Comments. General Purpose Pneumatic Isolators. Self-Leveling Isolators. Vibration Isolated Foundations and Installation Systems. Installation Systems with Inertia Blocks. Installation System with Reference Frame. Isolation of Non-Supporting Connections of Isolated Objects. Power Transmission Couplings.