Passive Vibration Isolation

Abstract

11R2. Passive Vibration Isolation. - EI Rivin (Wayne State University, Detroit, MI). ASME Press, New York. 2003. 426 pp. ISBN 0-7918-0187-X.Reviewed by S Naguleswaran (Dept of Mech Eng, Univ of Canterbury, Christchurch, New Zealand).Vibration is used to agitate and to compact wet concrete into inaccessible places, in sieves to separate things, in vibratory conveyors, by dentists, physiotherapists, and so on. The effect of vibration can be pleasant—for example, a violin when played by a competent musician. There are several unpleasant effects which cause discomfort like a rough ride on a corrugated road or damage caused by chatter in a machine tool, wind sway to suspension bridges, earthquake to tall buildings, etc. Engineers often face the problem of attenuation of the amplitude of response of small to big systems through passive vibration isolation. The need to protect precision/sensitive instruments has changed vibration isolation into a specialist field. Considerable research effort has and is being directed towards passive vibration control resulting in several publications continuing to appear every year in various learned journals. Over the last couple of decades, monographs have appeared on passive vibration isolation and the book under review is a welcome addition. The book has a preface and four chapters with the relevant references listed after each chapter. The Preface is very well written and portions may be used in introductory undergraduate or graduate lectures. It is pointed out that “random excitations and nonlinear dynamics of vibration isolation systems each deserve a separate book.” Chapter 1—Dynamic Properties of Vibration Isolation Systems: Commences with the basic analysis of the dynamics of an undamped six-degree-of-freedom system followed by single and two-degrees-of-freedom systems under viscous damping or hysteretic damping and a brief discussion on Coulomb damping. Random excitation and “jump phenomena” due to nonlinear spring stiffness are briefly mentioned. Nonlinear damping (like aerodynamic) is not covered. Chapter 2—Principles and Criteria of Vibration Isolation: Topics discussed include the main considerations in passive vibration isolation, the selection of parameters for precision/sensitive objects, experimental selection of isolators. Vibration protection of civil engineering structures is very briefly discussed. Chapter 3—Realization of Elasticity and Damping in Vibration Isolators: Briefly describes some of the types of springs in engineering use and includes the static and dynamic characteristics of metals, polymeric and elastomeric materials. Chapter 4—Passive Vibration Isolation Means: Includes descriptions of various mats and pads used in vibration isolation, commercially available isolating mounts, pneumatic isolators and installation of machinery on vibration isolated foundations. Illustrations are good and tables have useful information. One may safely ignore Eq. (1.3.1′) and the like when the book is being read casually. List of symbols is not included—inclusion of which would have lessened the effort when the book is used as a reference. Frequent use of acronyms renders the book difficult to read. For example in page 5 the acronym CMM appears but what it stands for is found in Preface page xi or in page 138. EDM stands for elasto-damping materials and not “electrical discharge machining.” What is COTS? Answer: commercial off the shelf! The list of references at the end of each chapter is incomplete. For example only two publications on passive vibration isolation from the Journal of Sound and Vibration are listed in the book out of several which appear every year in the journal. Additional reading for topics in Chapter 3 is “Damping of Materials and Members in Structural Mechanics” by BJ Lazan (1968, Pergamon Press). Further general references in passive vibration isolation may be found in “Passive Vibration Control’ by DJ Meads (1998, John Wiley & Sons). Application of tuned vibration absorbers (often used in vibration isolation of machinery and tall structures) is not covered in the book under review. The book will be a useful addition to libraries. The book is not suitable for undergraduate courses but may be used as reading material in graduate courses provided they are informed of the incompleteness of the list of references. Each vibration problem encountered in engineering will have unique features and the book will give an indication as to how to approach the problem and design/consulting engineers will find the book handy. In the reverse of the cover page the ISBN is given as 0-7918-0187-X near the top of page and as 0-7981-0187-X near the bottom. The former is probably the correct number.