Download or read book The Dynamics of Combined Axial torsional Standing wave Ultrasonic Motors written by Daniel Kuang-Chen Liu and published by . This book was released on 2009 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: Piezoelectric ultrasonic motors have the potential to enable important applications such as endovasular surgical micro-robots due to their high torque and power density at the 0.1-1 mm diameter range. A type of ultrasonic motor that is suitable for miniaturization is the combined axial-torsional standing-wave (CATS) ultrasonic motor that generates the CATS stator motionvia pretwisted beam vibration converters.The operation of the motor involves (1) the generation of an ellipse-like stator tip trajectory when the pretwisted-beam stator is excited to vibrate in a CATS motion by a piezoelectric transducer, and (2) the transfer of frictional torque when the rotor is pressed against the stator tip. To gain a better understanding of the CATS ultrasonic motor, centimeter-scale prototypes were fabricated and tested to determine the characteristics of the motor design. Theoretical models of the pretwisted beam stator and the torque transfer mechanism were also investigated to help us predict the effects of various design parameters.The axial and torsional resonance frequencies of the pretwisted-beam stator needs to be matched for an effcient generation of the CATS stator motion. To help designers select the right analysis method for the design process, we investigated the validity of common pretwisted beam theories that assume the warping function of a pretwisted beam is locally identical to that of a prismatic beam. Through a scaling analysis of the equations governing the warping function of pretwisted beams -- derived using semi-inverse method and Hamilton's principle -- we obtained a set of criteria for checking the validity of the assumption. These criteria allow us to determine at what geometries the use of prismatic warping function will result in poor predictions of the axial resonance frequency and that alternative modelling methods are needed.Existing models of CATS motors ignore the vertical displacement of the rotor, predicting periodic behaviours that are contrary to the apparently random oscillations observed in the motor's steady-state operation. Our incorporation of the rotor's vertical motion results in a bouncing-disk model that explains various behaviours of the motor prototype, including the oscillations in the transient speed-time curve, and the effect of preload on stall torque and steady-state speed. The nonlinear dynamical system formed by the bouncing disk model shows that different stator trajectories and interface properties can give rise to complex phenomena such as period doubling bifurcation, chaos, and extremely long period "chattering orbits". Knowledge of the location and basins of attraction for these orbits gives us detailed understanding of the motor's behaviour that will help designers improve the performance of CATS ultrasonic motor.
Download or read book The Dynamics of Combined Axial torsional Standing wave Ultrasonic Motors written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Piezoelectric ultrasonic motors have the potential to enable important applications such as endovasular surgical micro-robots due to their high torque and power density at the 0.1-1 mm diameter range. A type of ultrasonic motor that is suitable for miniaturization is the combined axial-torsional standing-wave (CATS) ultrasonic motor that generates the CATS stator motion via pretwisted beam vibration converters. The operation of the motor involves (1) the generation of an ellipse-like stator tip trajectory when the pretwisted-beam stator is excited to vibrate in a CATS motion by a piezoelectric transducer, and (2) the transfer of frictional torque when the rotor is pressed against the stator tip. To gain a better understanding of the CATS ultrasonic motor, centimeter-scale prototypes were fabricated and tested to determine the characteristics of the motor design. Theoretical models of the pretwisted beam stator and the torque transfer mechanism were also investigated to help us predict the effects of various design parameters. The axial and torsional resonance frequencies of the pretwisted-beam stator needs to be matched for an effcient generation of the CATS stator motion. To help designers select the right analysis method for the design process, we investigated the validity of common pretwisted beam theories that assume the warping function of a pretwisted beam is locally identical to that of a prismatic beam. Through a scaling analysis of the equations governing the warping function of pretwisted beams -- derived using semi-inverse method and Hamilton's principle -- we obtained a set of criteria for checking the validity of the assumption. These criteria allow us to determine at what geometries the use of prismatic warping function will result in poor predictions of the axial resonance frequency and that alternative modelling methods are needed. Existing models of CATS motors ignore the vertical displacement of the rotor, predicting periodic behaviours that are co.
Download or read book Ultrasonic Motors written by Chunsheng Zhao and published by Springer Science & Business Media. This book was released on 2011-10-23 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive tutorial on ultrasonic motors for practicing engineers, researchers and graduate students. "Ultrasonic Motors: Technologies and Applications" describes the operating mechanism, electromechanical coupling models, optimization design of structural parameters, testing methods, and drive/control techniques of various ultrasonic motors and their applications. Dr. Chunsheng Zhao is a professor at Nanjing University of Aeronautics and Astronautics (NUAA) where he is Director of the Precision Driving Laboratory at NUAA. He is a member of the Chinese Academy of Science, and holds 54 patents in China and published more than 400 papers in the field of piezoelectric ultrasonic motors.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1987 with total page 956 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1988 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Piezoelectric Energy Harvesting written by Alper Erturk and published by John Wiley & Sons. This book was released on 2011-04-04 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transformation of vibrations into electric energy through the use of piezoelectric devices is an exciting and rapidly developing area of research with a widening range of applications constantly materialising. With Piezoelectric Energy Harvesting, world-leading researchers provide a timely and comprehensive coverage of the electromechanical modelling and applications of piezoelectric energy harvesters. They present principal modelling approaches, synthesizing fundamental material related to mechanical, aerospace, civil, electrical and materials engineering disciplines for vibration-based energy harvesting using piezoelectric transduction. Piezoelectric Energy Harvesting provides the first comprehensive treatment of distributed-parameter electromechanical modelling for piezoelectric energy harvesting with extensive case studies including experimental validations, and is the first book to address modelling of various forms of excitation in piezoelectric energy harvesting, ranging from airflow excitation to moving loads, thus ensuring its relevance to engineers in fields as disparate as aerospace engineering and civil engineering. Coverage includes: Analytical and approximate analytical distributed-parameter electromechanical models with illustrative theoretical case studies as well as extensive experimental validations Several problems of piezoelectric energy harvesting ranging from simple harmonic excitation to random vibrations Details of introducing and modelling piezoelectric coupling for various problems Modelling and exploiting nonlinear dynamics for performance enhancement, supported with experimental verifications Applications ranging from moving load excitation of slender bridges to airflow excitation of aeroelastic sections A review of standard nonlinear energy harvesting circuits with modelling aspects.
Download or read book Vibrations and Waves in Continuous Mechanical Systems written by Peter Hagedorn and published by John Wiley & Sons. This book was released on 2007-10-22 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: The subject of vibrations is of fundamental importance in engineering and technology. Discrete modelling is sufficient to understand the dynamics of many vibrating systems; however a large number of vibration phenomena are far more easily understood when modelled as continuous systems. The theory of vibrations in continuous systems is crucial to the understanding of engineering problems in areas as diverse as automotive brakes, overhead transmission lines, liquid filled tanks, ultrasonic testing or room acoustics. Starting from an elementary level, Vibrations and Waves in Continuous Mechanical Systems helps develop a comprehensive understanding of the theory of these systems and the tools with which to analyse them, before progressing to more advanced topics. Presents dynamics and analysis techniques for a wide range of continuous systems including strings, bars, beams, membranes, plates, fluids and elastic bodies in one, two and three dimensions. Covers special topics such as the interaction of discrete and continuous systems, vibrations in translating media, and sound emission from vibrating surfaces, among others. Develops the reader’s understanding by progressing from very simple results to more complex analysis without skipping the key steps in the derivations. Offers a number of new topics and exercises that form essential steppingstones to the present level of research in the field. Includes exercises at the end of the chapters based on both the academic and practical experience of the authors. Vibrations and Waves in Continuous Mechanical Systems provides a first course on the vibrations of continuous systems that will be suitable for students of continuous system dynamics, at senior undergraduate and graduate levels, in mechanical, civil and aerospace engineering. It will also appeal to researchers developing theory and analysis within the field.
Download or read book Understanding Acoustics written by Steven L. Garrett and published by Springer. This book was released on 2017-02-24 with total page 913 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook provides a unified approach to acoustics and vibration suitable for use in advanced undergraduate and first-year graduate courses on vibration and fluids. The book includes thorough treatment of vibration of harmonic oscillators, coupled oscillators, isotropic elasticity, and waves in solids including the use of resonance techniques for determination of elastic moduli. Drawing on 35 years of experience teaching introductory graduate acoustics at the Naval Postgraduate School and Penn State, the author presents a hydrodynamic approach to the acoustics of sound in fluids that provides a uniform methodology for analysis of lumped-element systems and wave propagation that can incorporate attenuation mechanisms and complex media. This view provides a consistent and reliable approach that can be extended with confidence to more complex fluids and future applications. Understanding Acoustics opens with a mathematical introduction that includes graphing and statistical uncertainty, followed by five chapters on vibration and elastic waves that provide important results and highlight modern applications while introducing analytical techniques that are revisited in the study of waves in fluids covered in Part II. A unified approach to waves in fluids (i.e., liquids and gases) is based on a mastery of the hydrodynamic equations. Part III demonstrates extensions of this view to nonlinear acoustics. Engaging and practical, this book is a must-read for graduate students in acoustics and vibration as well as active researchers interested in a novel approach to the material.
Download or read book Piezoelectric Actuators written by Hu Huang and published by BoD – Books on Demand. This book was released on 2021-12-08 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Taking advantage of high resolution, rapid response, and compact structure, piezoelectric actuators are widely employed for achieving precision positioning in both scientific research and industrial application. With the development of science and technology, the requirements for precision positioning are increasing. Accordingly, great efforts have been made to improve the performances of piezoelectric actuators, and significant progress has been achieved. This book discusses some recent achievements and developments of piezoelectric actuators, in terms of piezoelectric material, driving principle, structural design, modeling, and control, as well as applications.
Download or read book Ultrasonic Testing of Materials written by Josef Krautkrämer and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt: The amendments of this third English edition with respect to the second one concern beside some printing errors the replacement of some pictures in part D by more modern ones and updating the list of stand ards to the state of the fourth German edition. J OSEF KRAUTKRÄMER Cologne, January 1983 Preface to the Second Edition This seeond English edition is based on the third German edition. In view of most recent teehnologieal advanees it has beeome neeessary in many instanees to supplement the seeond German edition and to revise some parts completely. In addition to piezo-eleetric methods, others are now also extensively diseussed in Chapter 8. As for the intensity method, ultrasonie holo graphy is treated in the new Seetion 9. 4. In Part B, for reasons of syste maties, the resonanee method has been ineluded under transit-time methods. It appeared neeessary to elaborate in greater detail the defini tion of the properties of pulse-echo testing equipment and their measure ments (10. 4). The more recent findings of pulse speetroscopy (5. 6) and sound-emission analysis (12) are mentioned only in passing because their significanee is still controversial. Apart from numerous additions, partieularly those coneerning automatie testing installations, Part C also eontains a new chapter whieh deals with tests on nu eIe ar reactors (28), as weIl as abrief diseussion of surfaee-hardness tests (32. 4). It beeame impossible to include a critieal analysis of the principal standards in Chapter 33.
Download or read book Power Ultrasonics written by Juan A. Gallego-Juarez and published by Elsevier. This book was released on 2014-11-14 with total page 1167 pages. Available in PDF, EPUB and Kindle. Book excerpt: The industrial interest in ultrasonic processing has revived during recent years because ultrasonic technology may represent a flexible “green alternative for more energy efficient processes. A challenge in the application of high-intensity ultrasound to industrial processing is the design and development of specific power ultrasonic systems for large scale operation. In the area of ultrasonic processing in fluid and multiphase media the development of a new family of power generators with extensive radiating surfaces has significantly contributed to the implementation at industrial scale of several applications in sectors such as the food industry, environment, and manufacturing. Part one covers fundamentals of nonlinear propagation of ultrasonic waves in fluids and solids. It also discusses the materials and designs of power ultrasonic transducers and devices. Part two looks at applications of high power ultrasound in materials engineering and mechanical engineering, food processing technology, environmental monitoring and remediation and industrial and chemical processing (including pharmaceuticals), medicine and biotechnology. Covers the fundamentals of nonlinear propagation of ultrasonic waves in fluids and solids. Discusses the materials and designs of power ultrasonic transducers and devices. Considers state-of-the-art power sonic applications across a wide range of industries.
Download or read book Rules of Thumb for Mechanical Engineers written by J. Edward Pope and published by Gulf Professional Publishing. This book was released on 1997 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluids -- Heat transfer -- Thermodynamics -- Mechanical seals -- Pumps and compressors -- Drivers -- Gears -- Bearings -- Piping and pressure vessels -- Tribology -- Vibration -- Materials -- Stress and strain -- Fatigue -- Instrumentation -- Engineering economics.
Download or read book TEXTBOOK OF FINITE ELEMENT ANALYSIS written by P. SESHU and published by PHI Learning Pvt. Ltd.. This book was released on 2003-01-01 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Designed for a one-semester course in Finite Element Method, this compact and well-organized text presents FEM as a tool to find approximate solutions to differential equations. This provides the student a better perspective on the technique and its wide range of applications. This approach reflects the current trend as the present-day applications range from structures to biomechanics to electromagnetics, unlike in conventional texts that view FEM primarily as an extension of matrix methods of structural analysis. After an introduction and a review of mathematical preliminaries, the book gives a detailed discussion on FEM as a technique for solving differential equations and variational formulation of FEM. This is followed by a lucid presentation of one-dimensional and two-dimensional finite elements and finite element formulation for dynamics. The book concludes with some case studies that focus on industrial problems and Appendices that include mini-project topics based on near-real-life problems. Postgraduate/Senior undergraduate students of civil, mechanical and aeronautical engineering will find this text extremely useful; it will also appeal to the practising engineers and the teaching community.
Download or read book Structural Vibration written by C. Beards and published by Elsevier. This book was released on 1996-05-31 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many structures suffer from unwanted vibrations and, although careful analysis at the design stage can minimise these, the vibration levels of many structures are excessive. In this book the entire range of methods of control, both by damping and by excitation, is described in a single volume.Clear and concise descriptions are given of the techniques for mathematically modelling real structures so that the equations which describe the motion of such structures can be derived. This approach leads to a comprehensive discussion of the analysis of typical models of vibrating structures excited by a range of periodic and random inputs. Careful consideration is also given to the sources of excitation, both internal and external, and the effects of isolation and transmissability. A major part of the book is devoted to damping of structures and many sources of damping are considered, as are the ways of changing damping using both active and passive methods. The numerous worked examples liberally distributed throughout the text, amplify and clarify the theoretical analysis presented. Particular attention is paid to the meaning and interpretation of results, further enhancing the scope and applications of analysis. Over 80 problems are included with answers and worked solutions to most. This book provides engineering students, designers and professional engineers with a detailed insight into the principles involved in the analysis and damping of structural vibration while presenting a sound theoretical basis for further study. Suitable for students of engineering to first degree level and for designers and practising engineersNumerous worked examplesClear and easy to follow
Download or read book Gas Turbine Engineering Handbook written by Meherwan P. Boyce and published by Elsevier. This book was released on 2017-09-01 with total page 956 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Gas Turbine Engineering Handbook has been the standard for engineers involved in the design, selection, and operation of gas turbines. This revision includes new case histories, the latest techniques, and new designs to comply with recently passed legislation. By keeping the book up to date with new, emerging topics, Boyce ensures that this book will remain the standard and most widely used book in this field. The new Third Edition of the Gas Turbine Engineering Hand Book updates the book to cover the new generation of Advanced gas Turbines. It examines the benefit and some of the major problems that have been encountered by these new turbines. The book keeps abreast of the environmental changes and the industries answer to these new regulations. A new chapter on case histories has been added to enable the engineer in the field to keep abreast of problems that are being encountered and the solutions that have resulted in solving them. Comprehensive treatment of Gas Turbines from Design to Operation and Maintenance. In depth treatment of Compressors with emphasis on surge, rotating stall, and choke; Combustors with emphasis on Dry Low NOx Combustors; and Turbines with emphasis on Metallurgy and new cooling schemes. An excellent introductory book for the student and field engineers A special maintenance section dealing with the advanced gas turbines, and special diagnostic charts have been provided that will enable the reader to troubleshoot problems he encounters in the field The third edition consists of many Case Histories of Gas Turbine problems. This should enable the field engineer to avoid some of these same generic problems
Download or read book Improving Compressed Air System Performance written by and published by U.S. Department of Energy. This book was released on with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Principles of Animal Locomotion written by R. McNeill Alexander and published by Princeton University Press. This book was released on 2006-03-19 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: How can geckoes walk on the ceiling and basilisk lizards run over water? What are the aerodynamic effects that enable small insects to fly? What are the relative merits of squids' jet-propelled swimming and fishes' tail-powered swimming? Why do horses change gait as they increase speed? What determines our own vertical leap? Recent technical advances have greatly increased researchers' ability to answer these questions with certainty and in detail. This text provides an up-to-date overview of how animals run, walk, jump, crawl, swim, soar, hover, and fly. Excluding only the tiny creatures that use cilia, it covers all animals that power their movements with muscle--from roundworms to whales, clams to elephants, and gnats to albatrosses. The introduction sets out the general rules governing all modes of animal locomotion and considers the performance criteria--such as speed, endurance, and economy--that have shaped their selection. It introduces energetics and optimality as basic principles. The text then tackles each of the major modes by which animals move on land, in water, and through air. It explains the mechanisms involved and the physical and biological forces shaping those mechanisms, paying particular attention to energy costs. Focusing on general principles but extensively discussing a wide variety of individual cases, this is a superb synthesis of current knowledge about animal locomotion. It will be enormously useful to advanced undergraduates, graduate students, and a range of professional biologists, physicists, and engineers.
