Engineering vibration Fourth Edition ; International Version Inman
- 1. Engineering vibration Fourth Edition ; International Version Inman download pdf https://ebookfinal.com/download/engineering-vibration-fourth-edition- international-version-inman/ Visit ebookfinal.com today to download the complete set of ebook or textbook!
- 2. Here are some recommended products that we believe you will be interested in. You can click the link to download. 2009 International Plumbing Code Softcover Version 1st Edition International Code Council https://ebookfinal.com/download/2009-international-plumbing-code- softcover-version-1st-edition-international-code-council/ International Energy Conservation Code 2003 Looseleaf Version International Energy Conservation Code Looseleaf 1st Edition International Code Council https://ebookfinal.com/download/international-energy-conservation- code-2003-looseleaf-version-international-energy-conservation-code- looseleaf-1st-edition-international-code-council/ Introduction to Management 13th Edition International Student Version John R. Schermerhorn https://ebookfinal.com/download/introduction-to-management-13th- edition-international-student-version-john-r-schermerhorn/ Guide To Energy Management International Version 5th Edition Barney L. Capehart https://ebookfinal.com/download/guide-to-energy-management- international-version-5th-edition-barney-l-capehart/
- 3. Extra high voltage AC transmission engineering Fourth Edition Begamudre https://ebookfinal.com/download/extra-high-voltage-ac-transmission- engineering-fourth-edition-begamudre/ Flood Control and Drainage Engineering Fourth Edition S.N. Ghosh https://ebookfinal.com/download/flood-control-and-drainage- engineering-fourth-edition-s-n-ghosh/ Mechanical Vibration and Shock Analysis Random Vibration 3rd ed Edition Lalanne https://ebookfinal.com/download/mechanical-vibration-and-shock- analysis-random-vibration-3rd-ed-edition-lalanne/ Elements of Chemical Reaction Engineering Fourth Edition H. Scott Fogler https://ebookfinal.com/download/elements-of-chemical-reaction- engineering-fourth-edition-h-scott-fogler/ 2009 International Residential Code For One and Two Family Dwellings Soft Cover Version 1st Edition International Code Council https://ebookfinal.com/download/2009-international-residential-code- for-one-and-two-family-dwellings-soft-cover-version-1st-edition- international-code-council/
- 5. Engineering vibration Fourth Edition ; International Version Inman Digital Instant Download Author(s): Inman, Daniel J ISBN(s): 9789332518483, 5375445565 Edition: Fourth edition ; International version File Details: PDF, 19.82 MB Year: 2013 Language: english
- 6. This is a special edition of an established title widely used by colleges and universities throughout the world. Pearson published this exclusive edition for the benefit of students outside the United States and Canada. If you purchased this book within the United States or Canada you should be aware that it has been imported without the approval of the Publisher or Author. Pearson International Edition Engineering Vibration Inman FOURTH EDITION INTERNATIONAL EDITION INTERNATIONAL EDITION ISBN-13: ISBN-10: 978-0-273-76844-9 0-273-76844-1 9 7 8 0 2 7 3 7 6 8 4 4 9 9 0 0 0 0 The editorial team at Pearson has worked closely with educators around the globe to inform students of the ever-changing world in a broad variety of disciplines. Pearson Education offers this product to the international market, which may or may not include alterations from the United States version. Engineering Vibration FOURTH EDITION Daniel J. Inman INTERNATIONAL EDITION
- 7. Engineering Vibration Fourth Edition Daniel J. Inman University of Michigan International Editions contributions by Ramesh Chandra Singh Delhi Technological University Boston Columbus Indianapolis New York San Francisco Upper Saddle River Amsterdam Cape Town Dubai London Madrid Milan Munich Paris Montréal Toronto Delhi Mexico City São Paulo Sydney Hong Kong Seoul Singapore Taipei Tokyo A01_INMA8449_04_PIE_FM.indd 1 23/02/13 7:52 PM
- 8. Pearson Education Limited Edinburgh Gate Harlow Essex CM20 2JE England and Associated Companies throughout the world Visit us on the World Wide Web at: www.pearsoninternationaleditions.com © Pearson Education Limited 2014 The rights of Daniel J. Inman to be identified as author of this work have been asserted by him in accordance with the Copyright, Designs and Patents Act 1988. Authorized adaptation from the United States edition, entitled Engineering Vibration, Fourth Edition, ISBN 978-0-13-287169-3, by Daniel J. Inman, published by Pearson Education © 2014. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without either the prior written permission of the publisher or a license permitting restricted copying in the United Kingdom issued by the Copyright Licensing Agency Ltd, Saffron House, 6–10 Kirby Street, London EC1N 8TS. All trademarks used herein are the property of their respective owners.The use of any trademark in this text does not vest in the author or publisher any trademark ownership rights in such trademarks, nor does the use of such trademarks imply any affiliation with or endorsement of this book by such owners. Microsoft and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published as part of the services for any purpose.All such documents and related graphics are provided “as is” without warranty of any kind. Microsoft and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all warranties and conditions of merchantability, whether express, implied or statutory, fitness for a particular purpose, title and non-infringement. In no event shall Microsoft and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from the services. The documents and related graphics contained herein could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Microsoft and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time. Partial screen shots may be viewed in full within the software version specified. Microsoft® and Windows® are registered trademarks of the Microsoft Corporation in the U.S.A. and other countries.This book is not sponsored or endorsed by or affiliated with the Microsoft Corporation. ISBN 10: 0-273-76844-1 ISBN 13: 978-0-273-76844-9 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library 10 9 8 7 6 5 4 3 2 1 14 13 12 11 10 Typeset in Times New Roman 10/12 by Integra Software Services. Printed and bound by Courier Westford in The United States of America The publisher’s policy is to use paper manufactured from sustainable forests. Editorial Director, Computer Science, Engineering, and Advanced Mathematics: Marcia J. Horton Acquisitions Editor: Norrin Dias Editorial Assistant: Jennifer Lonschein Senior Managing Editor: Scott Disanno Publisher, International Edition: Angshuman Chakraborty Publishing Administrator and Business Analyst, International Edition: Shokhi Shah Khandelwal Associate Print and Media Editor, International Edition: Anuprova Dey Chowdhuri Acquisitions Editor, International Edition: Shivangi Ramachandran Publishing Administrator, International Edition: Hema Mehta Project Editor, International Edition: Karthik Subramanian Senior Manufacturing Controller, Production, International Edition: Trudy Kimber Art Director: Jayne Conte Cover Designer: Bruce Kenselaar Art Editor: Greg Dulles Manufacturing Buyer: Lisa McDowell Marketing Manager: Tim Galligan A01_INMA8449_04_PIE_FM.indd 2 23/02/13 7:52 PM
- 9. 3 Contents Preface 8 1 Introduction To Vibration and the Free Response 13 1.1 Introduction to Free Vibration 14 1.2 Harmonic Motion 25 1.3 Viscous Damping 33 1.4 Modeling and Energy Methods 43 1.5 Stiffness 58 1.6 Measurement 70 1.7 Design Considerations 75 1.8 Stability 80 1.9 Numerical Simulation of the Time Response 84 1.10 Coulomb Friction and the Pendulum 93 Problems 107 MATLAB Engineering Vibration Toolbox 127 Toolbox Problems 128 2 Response To Harmonic Excitation 129 2.1 Harmonic Excitation of Undamped Systems 130 2.2 Harmonic Excitation of Damped Systems 142 2.3 Alternative Representations 156 2.4 Base Excitation 163 2.5 Rotating Unbalance 172 2.6 Measurement Devices 178 A01_INMA8449_04_PIE_FM.indd 3 23/02/13 7:52 PM
- 10. 4 Contents 2.7 Other Forms of Damping 182 2.8 Numerical Simulation and Design 192 2.9 Nonlinear Response Properties 200 Problems 209 MATLAB Engineering Vibration Toolbox 226 Toolbox Problems 226 3 General Forced Response 228 3.1 Impulse Response Function 229 3.2 Response to an Arbitrary Input 238 3.3 Response to an Arbitrary Periodic Input 247 3.4 Transform Methods 254 3.5 Response to Random Inputs 259 3.6 Shock Spectrum 267 3.7 Measurement via Transfer Functions 272 3.8 Stability 274 3.9 Numerical Simulation of the Response 279 3.10 Nonlinear Response Properties 291 Problems 299 MATLAB Engineering Vibration Toolbox 313 Toolbox Problems 313 4 Multiple-Degree-of-Freedom Systems 315 4.1 Two-Degree-of-Freedom Model (Undamped) 316 4.2 Eigenvalues and Natural Frequencies 330 4.3 Modal Analysis 344 4.4 More Than Two Degrees of Freedom 352 4.5 Systems with Viscous Damping 368 4.6 Modal Analysis of the Forced Response 374 A01_INMA8449_04_PIE_FM.indd 4 23/02/13 7:52 PM
- 11. Contents 5 4.7 Lagrange’s Equations 381 4.8 Examples 389 4.9 Computational Eigenvalue Problems for Vibration 401 4.10 Numerical Simulation of the Time Response 419 Problems 427 MATLAB Engineering Vibration Toolbox 445 Toolbox Problems 445 5 Design for Vibration Suppression 447 5.1 Acceptable Levels of Vibration 448 5.2 Vibration Isolation 454 5.3 Vibration Absorbers 467 5.4 Damping in Vibration Absorption 475 5.5 Optimization 483 5.6 Viscoelastic Damping Treatments 491 5.7 Critical Speeds of Rotating Disks 497 Problems 503 MATLAB Engineering Vibration Toolbox 513 Toolbox Problems 513 6 Distributed-Parameter Systems 514 6.1 Vibration of a String or Cable 516 6.2 Modes and Natural Frequencies 520 6.3 Vibration of Rods and Bars 531 6.4 Torsional Vibration 537 6.5 Bending Vibration of a Beam 544 6.6 Vibration of Membranes and Plates 556 6.7 Models of Damping 562 6.8 Modal Analysis of the Forced Response 568 A01_INMA8449_04_PIE_FM.indd 5 23/02/13 7:52 PM
- 12. 6 Contents Problems 578 MATLAB Engineering Vibration Toolbox 584 Toolbox Problems 584 7 Vibration Testing and Experimental Modal Analysis 585 7.1 Measurement Hardware 587 7.2 Digital Signal Processing 591 7.3 Random Signal Analysis in Testing 596 7.4 Modal Data Extraction 600 7.5 Modal Parameters by Circle Fitting 603 7.6 Mode Shape Measurement 608 7.7 Vibration Testing for Endurance and Diagnostics 618 7.8 Operational Deflection Shape Measurement 621 Problems 623 MATLAB Engineering Vibration Toolbox 627 Toolbox Problems 628 8 Finite Element Method 629 8.1 Example:The Bar 631 8.2 Three-Element Bar 637 8.3 Beam Elements 642 8.4 Lumped-Mass Matrices 650 8.5 Trusses 653 8.6 Model Reduction 658 Problems 661 MATLAB Engineering Vibration Toolbox 668 Toolbox Problems 668 Appendix A Complex Numbers and Functions 669 Appendix B Laplace Transforms 675 A01_INMA8449_04_PIE_FM.indd 6 23/02/13 7:52 PM
- 13. Contents 7 Appendix C Matrix Basics 680 Appendix D The Vibration Literature 692 Appendix E List of Symbols 694 Appendix F Codes and Web Sites 699 Appendix G Engineering Vibration Toolbox and Web Support700 References 702 Answers to Selected Problems 704 Index 711 A01_INMA8449_04_PIE_FM.indd 7 23/02/13 7:52 PM
- 14. 8 Preface This book is intended for use in a first course in vibrations or structural dynamics for undergraduates in mechanical, civil, and aerospace engineering or engineer- ing mechanics. The text contains the topics normally found in such courses in accredited engineering departments as set out initially by Den Hartog and refined by Thompson. In addition, topics on design, measurement, and computa- tion are addressed. Pedagogy Originally, a major difference between the pedagogy of this text and competing texts is the use of high level computing codes. Since then, the other authors of vibrations texts have started to embrace use of these codes. While the book is written so that the codes do not have to be used, I strongly encourage their use. These codes (Mathcad® , Matlab® , and Mathematica® ) are very easy to use, at the level of a programmable calculator, and hence do not require any prereq- uisite courses or training. Of course, it is easier if the students have used one or the other of the codes before, but it is not necessary. In fact, the Matlab® codes can be copied directly and will run as listed. The use of these codes greatly enhances the student’s understanding of the fundamentals of vibration. Just as a picture is worth a thousand words, a numerical simulation or plot can enable a completely dynamic understanding of vibration phenomena. Computer calcula- tions and simulations are presented at the end of each of the first four chapters. After that, many of the problems assume that codes are second nature in solving vibration problems. Another unique feature of this text is the use of “windows,” which are distributed throughout the book and provide reminders of essential informa- tion pertinent to the text material at hand. The windows are placed in the text at points where such prior information is required. The windows are also used to summarize essential information. The book attempts to make strong connections to previous course work in a typical engineering curriculum. In particular, refer- ence is made to calculus, differential equations, statics, dynamics, and strength of materials course work. A01_INMA8449_04_PIE_FM.indd 8 23/02/13 7:52 PM
- 15. Preface 9 WHAT’S NEW IN THIS EDITION Most of the changes made in this edition are the result of comments sent to me by students and faculty who have used the 3rd edition. These changes consist of improved clarity in explanations, the addition of some new examples that clarify concepts, and enhanced problem statements. In addition, some text material deemed outdated and not useful has been removed. The computer codes have also been updated. However, software companies update their codes much faster than the publishers can update their texts, so users should consult the web for updates in syntax, commands, etc. One consistent request from students has been not to reference data appearing previously in other examples or problems. This has been addressed by providing all of the relevant data in the problem statements. Three undergraduate engineering students (one in Engineering Mechanics, one in Biological Systems Engineering, and one in Mechanical Engineering) who had the prerequisite courses, but had not yet had courses in vibra- tions, read the manuscript for clarity. Their suggestions prompted us to make the fol- lowing changes in order to improve readability from the student’s perspective: Improved clarity in explanations added in 47 different passages in the text. In addition, two new windows have been added. Twelve new examples that clarify concepts and enhanced problem statements have been added, and ten examples have been modified to improve clarity. Text material deemed outdated and not useful has been removed. Two sections have been dropped and two sections have been completely rewritten. All computer codes have been updated to agree with the latest syntax changes made in Matlab, Mathematica, and Mathcad. Fifty-four new problems have been added and 94 problems have been modi- fied for clarity and numerical changes. Eight new figures have been added and three previous figures have been modified. Four new equations have been added. Chapter 1: Changes include new examples, equations, and problems. New textual explanations have been added and/or modified to improve clarity based on student sug- gestions. Modifications have been made to problems to make the problem statement clear by not referring to data from previous problems or examples. All of the codes have been updated to current syntax, and older, obsolete commands have been replaced. Chapter 2: New examples and figures have been added, while previous exam- ples and figures have been modified for clarity. New textual explanations have also been added and/or modified. New problems have been added and older problems modified to make the problem statement clear by not referring to data from previ- ous problems or examples. All of the codes have been updated to current syntax, and older, obsolete commands have been replaced. A01_INMA8449_04_PIE_FM.indd 9 23/02/13 7:52 PM
- 16. 10 Preface Chapter 3: New examples and equations have been added, as well as new problems. In particular, the explanation of impulse has been expanded. In addition, previous problems have been rewritten for clarity and precision. All examples and problems that referred to prior information in the text have been modified to pres- ent a more self-contained statement. All of the codes have been updated to current syntax, and older, obsolete commands have been replaced. Chapter 4: Along with the addition of an entirely new example, many of the examples have been changed and modified for clarity and to include improved information. A new window has been added to clarify matrix information. A fig- ure has been removed and a new figure added. New problems have been added and older problems have been modified with the goal of making all problems and examples more self-contained. All of the codes have been updated to current syntax, and older, obsolete commands have been replaced. Several new plots intermixed in the codes have been redone to reflect issues with Mathematica and Matlab’s automated time step which proves to be inaccurate when using singu- larity functions. Several explanations have been modified according to students’ suggestions. Chapter 5: Section 5.1 has been changed, the figure replaced, and the example changed for clarity. The problems are largely the same but many have been changed or modified with different details and to make the problems more self-contained. Section 5.8 (Active Vibration Suppression) and Section 5.9 (Practical Isolation Design) have been removed, along with the associated problems, to make room for added material in the earlier chapters without lengthening the book. According to user surveys, these sections are not usually covered. Chapter 6: Section 6.8 has been rewritten for clarity and a window has been added to summarize modal analysis of the forced response. New problems have been added and many older problems restated for clarity. Further details have been added to several examples. A number of small additions have been made to the to the text for clarity. Chapters 7 and 8: These chapters were not changed, except to make minor corrections and additions as suggested by users. Units This book uses SI units. The 1st edition used a mixture of US Customary and SI, but at the insistence of the editor all units were changed to SI. I have stayed with SI in this edition because of the increasing international arena that our engineering graduates compete in. The engineering community is now completely global. For instance, GE Corporate Research has more engineers in its research center in India than it does in the US. Engineering in the US is in danger of becoming the ‘gar- ment’ workers of the next decade if we do not recognize the global work place. Our engineers need to work in SI to be competitive in this increasingly international work place. A01_INMA8449_04_PIE_FM.indd 10 23/02/13 7:52 PM
- 17. Preface 11 Instructor Support This text comes with a bit of support. In particular, MS PowerPoint presentations are available for each chapter along with some instructive movies. The solutions manual is available in both MS Word and PDF format (sorry, instructors only). Sample tests are available. The MS Word solutions manual can be cut and pasted into presentation slides, tests, or other class enhancements. These resources can be found at www.pearsoninternationaleditions.com/inman and will be updated often. Please also email me at daninman@umich.edu with corrections, typos, questions, and suggestions. The book is reprinted often, and at each reprint I have the option to fix typos, so please report any you find to me, as others as well as I will appreciate it. Student Support The best place to get help in studying this material is from your instructor, as there is nothing more educational than a verbal exchange. However, the book was writ- ten as much as possible from a student’s perspective. Many students critiqued the original manuscript, and many of the changes in text have been the result of sug- gestions from students trying to learn from the material, so please feel free to email me (daninman@umich.edu) should you have questions about explanations. Also I would appreciate knowing about any corrections or typos and, in particular, if you find an explanation hard to follow. My goal in writing this was to provide a useful resource for students learning vibration for the first time. Acknowledgements The cover photo of the unmanned air vehicle is provided courtesy of General Atomics Aeronautical Systems, Inc., all rights reserved. Each chapter starts with two photos of different systems that vibrate to remind the reader that the material in this text has broad application across numerous sectors of human activity. These photographs were taken by friends, students, colleagues, relatives, and some by me. I am greatly appreciative of Robert Hargreaves (guitar), P. Timothy Wade (wind mill, Presidential helicopter), General Atomics (Predator), Roy Trifilio (bridge), Catherine Little (damper), Alex Pankonien (FEM graphic), and Jochen Faber of Liebherr Aerospace (landing gear). Alan Giles of General Atomics gave me an informative tour of their facilities which resulted in the photos of their products. Many colleagues and students have contributed to the revision of this text through suggestions and questions. In particular, Daniel J. Inman, II; Kaitlyn DeLisi; Kevin Crowely; and Emily Armentrout provided many useful comments from the perspective of students reading the material for the first time. Kaitlyn and Kevin checked all the computer codes by copying them out of the book to A01_INMA8449_04_PIE_FM.indd 11 23/02/13 7:52 PM
- 18. 12 Preface make sure they ran. My former PhD students Ya Wang, Mana Afshari, and Amin Karami checked many of the new problems and examples. Dr. Scott Larwood and the students in his vibrations class at the University of the Pacific sent many sug- gestions and corrections that helped give the book the perspective of a nonresearch insitution. I have implemented many of their suggestions, and I believe the book’s explanations are much clearer due to their input. Other professors using the book, Cetin Cetinkaya of Clarkson University, Mike Anderson of the University of Idaho, Joe Slater of Wright State University, Ronnie Pendersen of Aalborg University Esbjerg, Sondi Adhikari of the Universty of Wales, David Che of Geneva College, Tim Crippen of the University of Texas at Tyler, and Nejat Olgac of the University of Conneticut, have provided discussions via email that have led to improvements in the text, all of which are greatly appreciated. I would like to thank the review- ers: Cetin Cetinkaya, Clarkson University; Dr. Nesrin Sarigul-Klijn, University of California–Davis; and David Che, Geneva College. Many of my former PhD students who are now academics cotaught this course with me and also offered many suggestions. Alper Erturk (Georgia Tech), Henry Sodano (University of Florida), Pablo Tarazaga (Virginia Tech), Onur Bilgen (Old Dominian University), Mike Seigler (University of Kentucky), and Armaghan Salehian (University of Waterloo) all contributed to clarity in this text for which I am grateful. I have been lucky to have wonderful PhD students to work with. I learned much from them. I would also like to thank Prof. Joseph Slater of Wright State for reviewing some of the new materials, for writing and managing the associated toolbox, and constantly sending suggestions. Several colleagues from government labs and com- panies have also written with suggestions which have been very helpful from that perspective of practice. I have also had the good fortune of being sponsored by numerous companies and federal agencies over the last 32 years to study, design, test, and analyze a large variety of vibrating structures and machines. Without these projects, I would not have been able to write this book nor revise it with the appreciation for the practice of vibration, which I hope permeates the text. Last, I wish to thank my family for moral support, a sense of purpose, and for putting up with my absence while writing. Daniel J. Inman Ann Arbor, Michigan The publishers wish to thank Nilamber Kumar Singh of Birla Institute of Technology, Mesra for reviewing the content of the International Edition. A01_INMA8449_04_PIE_FM.indd 12 23/02/13 7:52 PM
- 19. 13 Introduction to Vibration and the Free Response 1 Vibration is the subdiscipline of dynamics that deals with repetitive motion. Most of the examples in this text are mechanical or structural elements. However, vibration is prevalent in biological systems and is in fact at the source of communication (the ear vibrates to hear and the tongue and vocal cords vibrate to speak). In the case of music, vibrations, say of a stringed instrument such as a guitar, are desired. On the other hand, in most mechanical systems and structures, vibration is unwanted and even destructive. For example, vibration in an aircraft frame causes fatigue and can eventually lead to failure. An example of fatigue crack is illustrated in the circle in the photo on the bottom left. Everyday experiences are full of vibration and usually ways of mitigating vibration. Automobiles, trains, and even some bicycles have devices to reduce the vibration induced by motion and transmitted to the driver. The task of this text is to teach the reader how to analyze vibration using principles of dynamics. This requires the use of mathematics. In fact, the sine function provides the fundamental means of analyzing vibration phenomena. The basic concepts of understanding vibration, analyzing vibration, and predicting the behavior of vibrating systems form the topics of this text. The concepts and formulations presented in the following chapters are intended to provide the skills needed for designing vibrating systems with desired properties that enhance vibration when it is wanted and reduce vibration when it is not. This first chapter examines vibration in its simplest form in which no external force is present (free vibration). This chapter introduces both the important concept of natural frequency and how to model vibration mathematically. The Internet is a great source for examples of vibration, and the reader is encouraged to search for movies of vibrating systems and other examples that can be found there. M01_INMA8449_04_PIE_C01.indd 13 2/21/13 6:45 PM
- 20. 14 Introduction to Vibration and the Free Response Chap. 1 1.1 Introduction to Free Vibration Vibration is the study of the repetitive motion of objects relative to a stationary frame of reference or nominal position (usually equilibrium). Vibration is evident everywhere and in many cases greatly affects the nature of engineering designs.The vibrational properties of engineering devices are often limiting factors in their per- formance. When harmful, vibration should be avoided, but it can also be extremely useful. In either case, knowledge about vibration—how to analyze, measure, and control it—is beneficial and forms the topic of this book. Typical examples of vibration familiar to most include the motion of a guitar string, the ride quality of an automobile or motorcycle, the motion of an airplane’s wings, and the swaying of a large building due to wind or an earth- quake. In the chapters that follow, vibration is modeled mathematically based on fundamental principles, such as Newton’s laws, and analyzed using results from calculus and differential equations. Techniques used to measure the vibra- tion of a system are then developed. In addition, information and methods are given that are useful for designing particular systems to have specific vibrational responses. The physical explanation of the phenomena of vibration concerns the inter- play between potential energy and kinetic energy. A vibrating system must have a component that stores potential energy and releases it as kinetic energy in the form of motion (vibration) of a mass. The motion of the mass then gives up kinetic en- ergy to the potential-energy storing device. Engineering is built on a foundation of previous knowledge and the subject of vibration is no exception. In particular, the topic of vibration builds on pre- vious courses in dynamics, system dynamics, strength of materials, differential equations, and some matrix analysis. In most accredited engineering programs, these courses are prerequisites for a course in vibration. Thus, the material that follows draws information and methods from these courses. Vibration analysis is based on a coalescence of mathematics and physical observation. For example, consider a simple pendulum. You may have seen one in a science museum, in a grandfather clock, or you might make a simple one with a string and a marble. As the pendulum swings back and forth, observe that its motion as a function of time can be described very nicely by the sine function from trigonometry. Even more interesting, if you make a free-body diagram of the pendulum and ap- ply Newtonian mechanics to get the equation of motion (summing moments in this case), the resulting equation of motion has the sine function as its solution. Further, the equation of motion predicts the time it takes for the pendulum to repeat its motion. In this example, dynamics, observation, and mathematics all come into agreement to produce a predictive model of the motion of a pendulum, which is easily verified by experiment (physical observation). M01_INMA8449_04_PIE_C01.indd 14 2/21/13 6:45 PM
- 21. Sec. 1.1 Introduction to Free Vibration 15 This pendulum example tells the story of this text. We propose a series of steps to build on the modeling skills developed in your first courses in statics, dy- namics, and strength of materials combined with system dynamics to find equations of motion of successively more complicated systems. Then we will use the tech- niques of differential equations and numerical integration to solve these equations of motion to predict how various mechanical systems and structures vibrate. The following example illustrates the importance of recalling the methods learned in the first course in dynamics. Example 1.1.1 Derive the equation of motion of the pendulum in Figure 1.1. m l O g mg l O Fy Fx m (b) (a) Figure 1.1 (a) A schematic of a pendulum. (b) The free-body diagram of (a). Solution Consider the schematic of a pendulum in Figure 1.1(a). In this case, the mass of the rod will be ignored as well as any friction in the hinge. Typically, one starts with a photograph or sketch of the part or structure of interest and is immediately faced with having to make assumptions. This is the “art” or experience side of vibration analysis and modeling. The general philosophy is to start with the simplest model possible (hence, here we ignore friction and the mass of the rod and assume the motion remains in a plane) and try to answer the relevant engineering questions. If the simple model doesn’t agree with the experiment, then make it more complex by relaxing the assump- tions until the model successfully predicts physical observation. With the assumptions in mind, the next step is to create a free-body diagram of the system, as indicated in Figure 1.1(b), in order to identify all of the relevant forces. With all the modeled forces identified, Newton’s second law and Euler’s second law are used to derive the equa- tions of motion. In this example Euler’s second law takes the form of summing moments about point O. This yields ΣMO = J𝛂 M01_INMA8449_04_PIE_C01.indd 15 2/21/13 6:45 PM
- 22. 16 Introduction to Vibration and the Free Response Chap. 1 where MO denotes moments about the point O, J = ml2 is the mass moment of inertia of the mass m about the point O, l is the length of the massless rod, and 𝛂 is the angu- lar acceleration vector. Since the problem is really in one dimension, the vector sum of moments equation becomes the single scalar equation Jα(t) = -mgl sin θ(t) or ml2 θ $ (t) + mgl sin θ(t) = 0 Here the moment arm for the force mg is the horizontal distance l sin θ, and the two overdots indicate two differentiations with respect to the time, t. This is a second-order ordinary differential equation, which governs the time response of the pendulum. This is exactly the procedure used in the first course in dynamics to obtain equations of motion. The equation of motion is nonlinear because of the appearance of the sin(θ) and hence difficult to solve. The nonlinear term can be made linear by approximating the sine for small values of θ(t) as sin θ ≈ θ. Then the equation of motion becomes θ $ (t) + g l θ(t) = 0 This is a linear, second-order ordinary differential equation with constant coefficients and is commonly solved in the first course of differential equations (usually the third course in the calculus sequence). As we will see later in this chapter, this linear equa- tion of motion and its solution predict the period of oscillation for a simple pendulum quite accurately. The last section of this chapter revisits the nonlinear version of the pendulum equation. n Since Newton’s second law for a constant mass system is stated in terms of force, which is equated to the mass multiplied by acceleration, an equation of motion with two time derivatives will always result. Such equations require two constants of integration to solve. Euler’s second law for constant mass systems also yields two time derivatives. Hence the initial position for θ(0) and velocity of θ # (0) must be specified in order to solve for θ(t) in Example 1.1.1. The term mgl sin θ is called the restoring force. In Example 1.1.1, the restoring force is gravity, which provides a potential-energy storing mechanism. However, in most structures and machine parts the restoring force is elastic. This establishes the need for background in strength of materials when studying vibrations of structures and machines. As mentioned in the example, when modeling a structure or machine it is best to start with the simplest possible model. In this chapter, we model only sys- tems that can be described by a single degree of freedom, that is, systems for which Newtonian mechanics result in a single scalar equation with one displacement coor- dinate. The degree of freedom of a system is the minimum number of displacement coordinates needed to represent the position of the system’s mass at any instant of time. For instance, if the mass of the pendulum in Example 1.1.1 were a rigid body, free to rotate about the end of the pendulum as the pendulum swings, the angle of rotation of the mass would define an additional degree of freedom. The problem would then require two coordinates to determine the position of the mass in space, hence two degrees of freedom. On the other hand, if the rod in Figure 1.1 is flexible, M01_INMA8449_04_PIE_C01.indd 16 2/21/13 6:45 PM
- 23. Sec. 1.1 Introduction to Free Vibration 17 its distributed mass must be considered, effectively resulting in an infinite number of degrees of freedom. Systems with more than one degree of freedom are dis- cussed in Chapter 4, and systems with distributed mass and flexibility are discussed in Chapter 6. The next important classification of vibration problems after degree of freedom is the nature of the input or stimulus to the system. In this chapter, only the free response of the system is considered. Free response refers to analyzing the vibration of a system resulting from a nonzero initial displacement and/or velocity of the system with no external force or moment applied. In Chapter 2, the response of a single-degree-of-freedom system to a harmonic input (i.e., a sinusoidal applied force) is discussed. Chapter 3 examines the response of a sys- tem to a general forcing function (impulse or shock loads, step functions, random inputs, etc.), building on information learned in a course in system dynamics. In the remaining chapters, the models of vibration and methods of analysis become more complex. The following sections analyze equations similar to the linear version of the pen- dulum equation given in Example 1.1.1. In addition, energy dissipation is introduced, and details of elastic restoring forces are presented. Introductions to design, measure- ment, and simulation are also presented. The chapter ends with the introduction of high-level computer codes (Matlab® , Mathematica, and Mathcad) as a means to visualize the response of a vibrating system and for making the calculations required to solve vibration problems more efficiently. In addition, numerical simulation is intro- duced in order to solve nonlinear vibration problems. 1.1.1 The Spring–Mass Model From introductory physics and dynamics, the fundamental kinematical quantities used to describe the motion of a particle are displacement, velocity, and accelera- tion vectors. In addition, the laws of physics state that the motion of a mass with changing velocity is determined by the net force acting on the mass. An easy de- vice to use in thinking about vibration is a spring (such as the one used to pull a storm door shut, or an automobile spring) with one end attached to a fixed object and a mass attached to the other end. A schematic of this arrangement is given in Figure 1.2. fk mg m m 0 (a) (b) Figure 1.2 A schematic of (a) a single-degree-of-freedom spring–mass oscillator and (b) its free-body diagram. M01_INMA8449_04_PIE_C01.indd 17 2/21/13 6:45 PM
- 24. 18 Introduction to Vibration and the Free Response Chap. 1 Ignoring the mass of the spring itself, the forces acting on the mass consist of the force of gravity pulling down (mg) and the elastic-restoring force of the spring pulling back up (fk). Note that in this case the force vectors are collinear, reducing the static equilibrium equation to one dimension easily treated as a scalar. The nature of the spring force can be deduced by performing a simple static experiment. With no mass attached, the spring stretches to the position labeled x0 = 0 in Figure 1.3. As successively more mass is attached to the spring, the force of gravity causes the spring to stretch further. If the value of the mass is recorded, along with the value of the displacement of the end of the spring each time more mass is added, the plot of the force (mass, denoted by m, times the acceleration due to gravity, denoted by g) versus this displacement, denoted by x, yields a curve similar to that illustrated in Figure 1.4. Note that in the region of values for x between 0 and about 20 mm (millimeters), the curve is a straight line. This indicates that for deflections less than 20 mm and forces less than 1000 N (newtons), the force that is applied by the spring to the mass is pro- portional to the stretch of the spring. The constant of proportionality is the slope of the straight line between 0 and 20 mm. For the particular spring of Figure 1.4, the constant is 50 Nmm, or 5 * 104 Nm. Thus, the equation that describes the force applied by the spring, denoted by fk, to the mass is the linear relationship fk = kx (1.1) The value of the slope, denoted by k, is called the stiffness of the spring and is a property that characterizes the spring for all situations for which the displacement is less than 20 mm. From strength-of-materials considerations, a linear spring of stiffness k stores potential energy of the amount 1 2 kx2 . x0 g x1 x2 x3 Figure 1.3 A schematic of a massless spring with no mass attached showing its static equilibrium position, followed by increments of increasing added mass illustrating the corresponding deflections. x fk 20 mm 0 103 N Figure 1.4 The static deflection curve for the spring of Figure 1.3. M01_INMA8449_04_PIE_C01.indd 18 2/21/13 6:45 PM
- 25. Sec. 1.1 Introduction to Free Vibration 19 Note that the relationship between fk and x of equation (1.1) is linear (i.e., the curve is linear and fk depends linearly on x). If the displacement of the spring is larger than 20 mm, the relationship between fk and x becomes nonlinear, as indi- cated in Figure 1.4. Nonlinear systems are much more difficult to analyze and form the topic of Section 1.10. In this and all other chapters, it is assumed that displace- ments (and forces) are limited to be in the linear range unless specified otherwise. Next, consider a free-body diagram of the mass in Figure 1.5, with the mass- less spring elongated from its rest (equilibrium or unstretched) position. As in the earlier figures, the mass of the object is taken to be m and the stiffness of the spring is taken to be k. Assuming that the mass moves on a frictionless surface along the x direction, the only force acting on the mass in the x direction is the spring force. As long as the motion of the spring does not exceed its linear range, the sum of the forces in the x direction must equal the product of mass and acceleration. Summing the forces on the free-body diagram in Figure 1.5 along the x direc- tion yields mx $ (t) = -kx(t) or mx $ (t) + kx(t) = 0 (1.2) where x $ (t) denotes the second time derivative of the displacement (i.e., the accel- eration). Note that the direction of the spring force is opposite that of the deflection (+ is marked to the right in the figure). As in Example 1.1.1, the displacement vec- tor and acceleration vector are reduced to scalars, since the net force in the y direc- tion is zero (N = mg) and the force in the x direction is collinear with the inertial force. Both the displacement and acceleration are functions of the elapsed time t, as denoted in equation (1.2). Window 1.1 illustrates three types of mechanical sys- tems, which for small oscillations can be described by equation (1.2): a spring–mass system, a rotating shaft, and a swinging pendulum (Example 1.1.1). Other examples are given in Section 1.4 and throughout the book. One of the goals of vibration analysis is to be able to predict the response, or motion, of a vibrating system. Thus it is desirable to calculate the solution to equation (1.2). Fortunately, the differential equation of (1.2) is well known and is covered extensively in introductory calculus and physics texts, as well as in texts on differential equations. In fact, there are a variety of ways to calculate this solution. These are all discussed in some detail in the next section. For now, it is sufficient to present a solution based on physical observation. From experience y x kx mg N m x0 k 0 Friction-free surface Rest position (a) (b) Figure 1.5 (a) A single spring–mass system given an initial displacement of x0 from its rest, or equilibrium, position and zero initial velocity. (b) The system’s free- body diagram. M01_INMA8449_04_PIE_C01.indd 19 2/21/13 6:45 PM
- 26. Random documents with unrelated content Scribd suggests to you:
- 27. sootiness. Color of head, beautiful silvery blue, which gets darker on ears; the back, various shades of dark blue, inclining to silver on lower parts of body and legs. Tail is generally the same shade or a little darker than the back. Tail.—Perfectly straight, not too long, carried almost level with back; nicely fringed or feathered. Legs and Feet.—Legs short and straight, well set under body, both legs and feet well covered with silky hair. (In a good specimen the legs are scarcely seen.)
- 28. THE TERRIER (DANDIE DINMONT). William Wanton Dunnell’s. Kelso Count. Origin.—Mentioned in 1800 by Davidson as springing from Tarr, reddish and wire-haired (a bitch), and Pepper (shaggy and light), which shows true terrier blood. Uses.—An essentially vermin-dog, “dead game;” and when a fox, otter, etc., is to be bolted it is unsurpassed. It is a curious fact that when unearthing its game it generally does its fighting on its back, tearing and scratching its opponent’s throat with tooth and nail. * Scale of Points, Etc. Value. Head 10
- 29. Eyes 5 Ears 5 Neck 5 Body 20 Tail 5 Legs and feet 10 Coat 15 Color 5 Size and weight 10 General appearance 10 Total 100 Head.—Strongly made and large, with muscles well developed; skull broad between ears, growing less toward eyes; forehead well domed. Head covered with soft, silky hair, not confined to a mere topknot. Cheeks have a gradual taper toward muzzle, which is deep and strong and about 3 inches in length. Muzzle covered with darker hair than topknot, the top part being generally bare for about 1 inch from back of nose, where it is about 1 inch broad. Nose and inside of mouth black or dark-colored. Teeth strong and very large, level in front, the upper ones overlapping the under ones. “Swine mouth” is objectionable, but not so much so as the bulldog mouth. Eyes wide apart, full, large, round, bright, full of determination, set low and prominent, and of a rich, dark hazel. Ears large, pendulous, set well back, wide apart, and low on skull, hanging close to cheek, tapering to a point, the tapering being mostly on the back part. They are covered with soft, straight brown hair (sometimes almost black), with a feather of light hair about 2 inches from tip. The feather does not show, sometimes, till the dog is 2 years old. Leather rather thin. Length of ear 3 to 4 inches. Neck.—Very muscular and strong, and well set into shoulders. Body.—Long, strong, and flexible; ribs well sprung; chest deep; back rather low at shoulder; a
- 30. slight, gradual droop from loins to root of tail. Tail.—Rather short (8 to 10 inches), covered on upper side with wiry hair, darker than on body; a feather of about 2 inches, getting shorter as it nears the tip; simitar-like, not curled nor twisted and when excited carried gaily above the level of the body. Legs and Feet.—Fore legs short, immense muscular development and bones set wide apart; feet well formed, not flat. “Bandy legs” objectionable. Hair on fore legs and feet of blue dog should be tan; on a mustard dog a darker shade than on head, which is creamy white. Hind legs are rather longer than front ones, rather wide apart, with feet smaller than front ones, without feather and dew-claws; claws should be dark. Coat.—Very important. Hair should be 2 inches long, and that from skull to root of tail a mixture of hard and soft hair. The hard hair should be wiry, the coat being pily, that under body being softer and lighter in color than on top. Color.—Pepper or mustard. The pepper ranges from dark blue black to a light silver gray; the mustards from a red brown to pale fawn, the head being creamy white, with legs and feet darker than head. Claws are dark as in other colors. Nearly all Dandies have some white on chest and white claws. Size.—Eight to eleven inches at shoulder. Limit weight, 24 pounds. Length.—From top of shoulder to root of tail should be twice the dog’s height.
- 31. THE TERRIER (FOX, SMOOTH- COATED). August Belmont’s. Champion Blemton Victor II. Origin.—Evidently a very judicious cross between a beagle and a bull-terrier. Uses.—Essentially a vermin-dog of the highest order, and capable of worrying a fox when it has taken to earth. It is used by the operatives in some parts of England for coursing rabbits. * The Various Parts of the Head, Body, Etc. Scale of Points by Rawdon B. Lee.
- 32. Value. Head, jaws, and ears 20 Neck 5 Shoulders and chest 10 Back and loins 10 Stern and hind quarters 10 Legs and feet 15 Coat 10 Size, symmetry, and character 20 Total 100 Head.—Skull flat, moderately narrow, gradually decreasing in width to eyes. Not much stop, but there should be more dip in profile between forehead and top jaw than in the greyhound. Cheeks must not be full. Ears V-shaped, small, of moderate thickness, drooping forward close to cheek, not hanging by side of head. Jaws strong and muscular, of fair punishing strength. There should not be much falling away below eyes. This part of head should be moderately chiseled out, but not like a wedge. Nose tapering and black. Eyes dark, small, rather deep set, full of fire and intelligence; nearly circular in shape. Teeth nearly level. Neck.—Clean, muscular, without throatiness, of fair length, and gradually widening to shoulders. Shoulders and Chest.—Shoulders long and sloping, well laid back, clearly cut at withers; chest deep and not broad. Back.—Short, straight, and strong, with no appearance of slackness. Loins.—Powerful and very slightly arched. Fore ribs moderately arched; back ribs deep. The dog should be well ribbed up. Hind Quarters.—Strong, muscular, quite free from droop or crouch; thighs long and powerful; hocks near the ground.
- 33. Stern.—Set on rather high, carried gaily, but not over back or curled; of good strength, anything approaching a “pipe-stopper” tail being especially objectionable. Legs.—Straight, showing little or no appearance of ankle in front; strong in bone, short and straight in pastern. Both fore and hind legs carried straight forward in traveling; stifles not turning outward; elbows perpendicular to the body. Feet.—Round, compact, not large; soles hard and tough; toes moderately arched, and turned neither in nor out. Coat.—Smooth, flat, hard, dense, and abundant. Belly and under side of thighs should not be bare. Color.—White should predominate; brindle, red, or liver markings are objectionable. Symmetry, Size, and Character.—The dog must present a generally gay, lively, and active appearance. Bone and strength in a small compass, but this does not mean that a fox-terrier should be cloggy or in any way coarse. Speed and endurance must be looked to as well as power, and the symmetry of the foxhound taken as a model. The terrier must on no account be leggy, nor must it be too short in leg. It should stand like a cleverly made hunter, covering a lot of ground, yet with a short back. Weight is not a certain criterion of a terrier’s fitness for its work; general shape, size, and contour are the main points; it should not scale over 20 pounds in show condition.
- 34. THE TERRIER (FOX, WIRE-HAIRED). G. M. Carnochan’s, 46 Exchange Place, New York. Thornfield Knockout. With the exception of the coat, which should be broken, the origin, uses, and scale of points of this breed are identical with the smooth-coated variety. The harder and more wiry the texture of the coat is, the better. The dog should not look nor feel woolly, and there should be no silky hair. The coat should not be too long, but it should show a marked difference from the smooth species.
- 36. THE TERRIER (IRISH). W. J. Comstock’s, Providence, R. I. Dunmurry. Origin.—Mr. George R. Krehl, editor of the London (England) “Stockkeeper” and English vice-president of the Irish Terrier Club, says this is a true and distinct breed, indigenous to Ireland, and that no man can trace its origin, which is lost in antiquity. Uses.—Rabbiting, and as a vermin-dog. * Scale of Points, Etc.
- 37. Value. Head, jaws, teeth, and eyes 15 Ears 5 Legs and feet 10 Neck 5 Shoulders and chest 10 Back and loins 10 Hind quarters and stern 10 Coat 15 Color 10 Size and symmetry 10 Total 100 Negative Points. White nails, toes, and feet 10 Much white on chest 10 Ears cropped 5 Mouth undershot 10 Coat shaggy or curly 10 Uneven in color 5 Total 50 Head.—Long; skull flat, rather narrow between ears, free from wrinkle; stop hardly visible. Jaws strong, muscular, but not too full in cheek, and of good punishing length. There should be a slight falling away below the eye, so as not to have a greyhound appearance. Hair on face same description as on body: short (about ¼ inch long), almost smooth and straight; a slight beard is permissible, and that is characteristic. Teeth strong and level. Lips not so tight as a bull-terrier’s, but well fitting. Nose black. Eyes dark hazel, small, not prominent, full of life, fire, and intelligence. Ears, when uncut, small and V-shaped, of moderate thickness, set well up, dropping forward close to cheek, free from
- 38. fringe, and hair thereon shorter and generally darker in color than the body. Neck.—Fair length, gradually widening toward shoulders, free from throatiness, with a slight sort of frill at each side of neck, running nearly to corner of ear, which is characteristic. Shoulders and Chest.—Shoulders must be fine, long, sloping; chest deep, muscular, but neither full nor wide. Back and Loins.—Body moderately long; back strong, straight, with no appearance of slackness; loins broad, powerful, slightly arched; ribs fairly sprung, rather deep than round. Hind Quarters.—Well under the dog, strong, muscular; thighs powerful; hocks near the ground; stifles not much bent. Stern.—Generally docked, free from fringe or feather; set on pretty high; carried gaily, but not over back, nor curled. Feet and Legs.—Feet strong, tolerably round, moderately small; toes arched, neither turned out nor in; black toe-nails. Legs moderately long, well set on, perfectly straight, plenty of bone and muscle; pasterns short and straight; fore and hind legs moving straight forward when traveling; stifles not turned outward; legs free of feather, and covered with hair as on head. Coat.—Hard, wiry, not soft nor silky, not so long as to hide outlines of body; straight, flat, no shagginess, no lock nor curl. Color.—“Whole-colored,” the most preferable being bright red, wheaten, yellow, and gray; brindle disqualifying. White sometimes appears on chest and feet; more objectionable on the latter. Symmetry.—The dog must present an active, lively, lithe, and wiry appearance; lots of substance, free of clumsiness, and framed on the “lines of speed.” Temperament.—The Irish terrier, as a breed, is remarkably good- tempered, notably so with mankind, it being admitted, however, that
- 39. it is perhaps a little too ready to resent interference on part of other dogs, hence called “daredevils.” Weight.—Sixteen to twenty-four pounds. Disqualifications.—Nose cherry or red; brindle color.
- 40. THE TERRIER (MALTESE). Mrs. J. P. Wade’s, Corona, L. I. Flossie. Origin.—Indigenous to the island of Malta, and spoken of by Aristotle, b.c. 370, as the lap-dog of the fashionable Greeks and Romans. Uses.—A pet dog essentially. Scale of Points, Etc. Value. Size 15 Coat 15
- 41. Color 15 Color of eyes 10 Color of nose 10 Tail 10 Ears 5 Legs and body 10 Symmetry 10 Total 100 As no standard is adopted, the following is the description of the dog. Weight.—Five pounds; limit, seven pounds. Color.—All white, with long, silky hair, looking like spun glass, straight, not curly, length not less than 7 inches. Head and Body.—Nose and eyes black. Tail turned or doubled into coat on back. Ears small, drooping, well clad with hair. Mouth level; teeth white. Black-coated specimens are very rare and desirable. Defect.—Ears with fawn markings.
- 42. THE TERRIER (SCOTTISH). Newcastle Kennels, Brookline, Mass. Bellingham Bailiff. Bonny C. Origin.—Nothing definite of this breed can be traced, though it was for years known in Scotland as the Skye terrier. Uses.—Unearthing vermin, badgers, foxes, etc. * Scale of Points, Etc. Value. Skull 7½
- 43. Muzzle 7½ Eyes 5 Ears 5 Neck 5 Chest 5 Body 15 Legs and feet 10 Tail 2½ Coat 15 Size 10 Color 2½ General appearance 10 Total 100 General Appearance.—The face should bear a very sharp, bright, and active expression, and head carried up. The dog should look compact and be possessed of great muscle in his hind quarters. A Scottish terrier cannot be too powerfully put together. Head.—Skull long, slightly domed, covered with short, hard hair about ¾ inch long or less; skull not quite flat. Muzzle very powerful, tapering toward nose, which should be black and of good size; jaws level; teeth square, though the nose projects somewhat over the mouth. Eyes wide apart, dark brown or hazel, small and piercing. Ears very small, prick or half prick, sharp-pointed, the hair not long, and free from any fringe on top. Neck.—Short, thick, muscular; strongly set on sloping shoulders. Chest.—Broad and proportionately deep. Body.—Moderate length, rather flat-sided, well ribbed up, and exceedingly strong in hind quarters. Legs and Feet.—Legs short, and very heavy in bone, the front ones being straight or slightly bent, and well set on under body; hocks bent; thighs very muscular; feet strong, small, and thickly covered with short hair.
- 44. Tail.—About 7 inches long, carried with a slight bend, and never cut. Coat.—Rather short (about 2 inches), intensely hard, wiry, and very dense. Size.—About 16 pounds for a dog; 14 pounds for a bitch. Colors.—Steel or iron gray, brindle, black, red, wheaten, yellow, or mustard color. White markings are most objectionable. Height.—Nine to twelve inches. Faults.—Large or light eyes; silky or curly coat.
- 45. THE TERRIER (SKYE). (From Ladies’ Kennel Journal.) Laird Duncan. Origin.—Entirely lost. Indigenous, no doubt, to Scotland. Uses.—A good, gamy vermin-dog, hardy and tough. * Scale of Points, Etc. Value. Size 15 Head 15 Ears 10 Body 15 Tail 10 Legs 10
- 46. Coat 20 Color 5 Total 100 Head.—Long; powerful jaws, incisors closing level, or upper jaws just fitting under. Skull wide at front of brow, narrowing between ears, tapering to muzzle, with little falling in between or behind eyes. Eyes hazel, medium size, close set. Muzzle black. Ears, when pricked, not large; erect at outer edges, slanting toward each other inward. When pendent, larger, hanging straight, and flat and close at front. Body.—Preëminently long and low; shoulders broad; chest deep; ribs well sprung, oval-shaped, giving flat appearance to sides. Hind quarters full and well developed. Back level, and declining from top of hip to shoulders. Neck long and well crested. Tail.—When hanging, upper half perpendicular, under half thrown backward in a curve. When raised, a prolongation of outline of back, not rising higher nor curling up. Legs and Feet.—Legs short, straight, muscular, no dew-claws. Feet large, pointing forward. Coat (Double).—Under coat short, close, soft, and woolly; and over coat long (5½ inches), hard, straight, flat, free from crisp or curl. Hair on head shorter, softer, veiling forehead and eyes; on ears, overhanging inside, falling down, not heavily, but surrounding ear like fringe; tail also feathered. Color.—Dark or light blue, or gray or fawn with black points. Height and Length.—Height at shoulder 9 inches; length, occiput to root of tail, 22½ inches. Weight.—Dogs, 18 pounds; bitches, 16 pounds. Disqualifications.—Doctored ears or tail; weight over 20 pounds; over- or under-shot jaws.
- 48. TERRIERS (TOY). Toy terriers are judged by the same points as the large specimens of the same breed.
- 49. THE TERRIER (WELSH). John Brett’s, Closter, N. J. Tory II. Origin.—Claimed by some to be of Welsh origin, by others of English origin. However that may be, the breed was only recognized by the English Kennel Club in 1886, and catalogued under title of “Welsh or English wire-haired black-and-tan terriers.” Uses.—Essentially a vermin-dog, “dead game.” * Scale of Points, Etc. Value. Head 20
- 50. Neck and shoulders 10 Body 10 Loins and hind quarters 10 Legs and feet 15 Coat 15 Color 10 Symmetry 10 Total 100 Head.—Skull flat, rather wider between ears than the wire-haired fox-terrier. Jaws powerful, clean cut, rather deeper and more punishing—giving head a more masculine appearance than that usually seen on a fox-terrier. Stop not too defined; fair length from stop to end of nose. Nose black. Ears V-shaped, small, not too thin, set on fairly high, carried forward and close to cheek. Eyes small, not too deeply set in nor protruding, dark hazel, expressive, and indicating abundant pluck. Neck.—Moderate length and thickness, slightly arched and sloping. Body.—Back short, well ribbed up; loins strong; good depth and moderate width of chest; shoulders long, sloping, well set back; hind quarters strong; thighs muscular; hocks moderately straight, and well let down. Stern set on moderately high, and not too gaily carried. Legs and Feet.—Legs straight, muscular, good bone, strong pasterns. Feet cat-like. Coat.—Wiry, hard, very close, and abundant. Color.—Black or grizzle and tan, free from pencilings on toes. Size and Weight.—Fifteen inches in dogs; average weight, 20 pounds.
- 52. THE TERRIER (WHITE ENGLISH). L. A. Van Zandt’s, New City, N. Y. Tommy Atkins II. Origin.—Wholly unknown, but the greatest number come from Manchester (England). Uses.—A very companionable gamy dog. * Scale of Points, Etc.
- 53. Value. Head 20 Eyes and expression 15 Neck and shoulders 10 Legs, feet, and chest 15 Coat 10 Stern 10 Symmetry 10 Size 10 Total 100 Head.—Narrow, long, level, almost flat; skull wedge-shaped, well filled below eyes, not lippy. Eyes small, black, oblong, and set fairly close. Nose black. Ears cropped and standing perfectly erect. Neck and Shoulders.—Neck fairly long, tapering; shoulders sloping, no throatiness, slightly arched at occiput. Body.—Chest narrow, deep; body short, curving upward at loins; ribs well sprung. Legs and Feet.—Legs perfectly straight, well under body, moderate bone; feet cat-like. Tail.—Moderate length, and set on where arch of back ends; thick where it joins body, tapering, and not carried higher than the back. Coat.—Close, hard, short, glossy. Color.—Pure white; colored markings disqualify. Weight.—Limit, 20 pounds; 14 pounds preferable.
- 54. THE TERRIER (YORKSHIRE). Mrs. F. Senn’s, 278 West Eleventh Street, New York. Duke of Gainsboro. Origin.—This dog’s home is Manchester (England), where it is said to have been originated, the black-and-tan, Skye, and Maltese terriers all being credited with its paternity. Except in color, it resembles greatest the latter dog. Uses.—Essentially a toy dog, beautiful and aristocratic. * Scale of Points, Etc.
- 55. Value. Quantity and color of hair on body 25 Quality of coat 15 Tan 15 Head 10 Eyes 5 Mouth 5 Ears 5 Legs and feet 5 General appearance 10 Tail 5 Total 100 General Appearance.—A long-coated, well-proportioned pet dog; coat straight and hanging evenly down each side, parted from nose to end of tail; very compact in form, neat, sprightly, and bearing an important air. Head.—Rather small, flat, not too round in skull, broad at muzzle; black nose. Hair on muzzle very long, of bright golden tan, unmixed with dark or sooty hair. Hair on sides of head very long, and of deeper tan than on center of head. Eyes medium in size, not prominent, dark, with intelligent expression; edges of eyelids dark. Ears cut or uncut, quite erect; if not cut, V-shaped, small, and erect, covered with short hair; color deep tan. Mouth even; teeth sound; a loose tooth or two not objectionable. Body.—Very compact, good loins, and level on top of back. Coat.—Hair as long and straight as possible, not wavy; glossy, like silk, not woolly; extending from back of head to root of tail. Color bright steel blue, not intermingled with fawn, light or dark hairs. Legs and Feet.—Legs quite straight; hair on same a bright golden tan, a shade lighter at ends than at roots. Feet round as possible;
- 56. toe-nails black. Weight.—Divided, viz., under 5 pounds, over 5 pounds; limit, 12 pounds.
- 57. Welcome to our website – the ideal destination for book lovers and knowledge seekers. With a mission to inspire endlessly, we offer a vast collection of books, ranging from classic literary works to specialized publications, self-development books, and children's literature. Each book is a new journey of discovery, expanding knowledge and enriching the soul of the reade Our website is not just a platform for buying books, but a bridge connecting readers to the timeless values of culture and wisdom. With an elegant, user-friendly interface and an intelligent search system, we are committed to providing a quick and convenient shopping experience. Additionally, our special promotions and home delivery services ensure that you save time and fully enjoy the joy of reading. Let us accompany you on the journey of exploring knowledge and personal growth! ebookfinal.com