Download or read book Non linear Vibration Control of Long Flexible Structures Employing Inter modal Energy Transfer modal Damping written by James E. May and published by . This book was released on 2009 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In the not too distant past, the design philosophy for tall civil structures could be summarized as LARGE MASS-LARGE STIFFNESS. The information age has brought about advances in material science and design technologies that provide the means to explore and construct high-reaching, expansive and much lighter-duty geometries. Current design trends require not only extensive strength-based engineering, but also carefully executed motion-based analysis. Tall, flexible civil structures have long been known to be prone to low frequency transverse vibrations. To further complicate matters, the associated natural damping properties are small leading to drawn out settling times. Motion-based augmentations offer enabling solutions. This research develops, evaluates and demonstrates a modal-based motion control strategy that may be viable for a select grouping of flexible structures. 'Modal Damping' exploits damping mechanisms inherent in structures by capitalizing on distinctive dynamic properties existing among the structures vibration modes. An automated, non-linear control scheme was developed to transfer energy from the fundamental vibration mode, where most vibration energy of the civil structures of interest resides, to higher order modes where vibration impedance was shown to be more effective. To achieve this objective, Modal Damping employs motion control forces self-powered by the redistribution of fundamental mode kinetic energy making the strategy highly efficient. The Modal Damping concept was developed and analyzed via dynamic simulation. The analytical findings were then applied to design an experimental model that was constructed and utilized to conduct a concept demonstration and evaluation."--Abstract.

Download or read book Vibration Control of Active Structures written by André Preumont and published by Springer. This book was released on 2018-02-10 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook is an introduction to the dynamics of active structures and to the feedback control of lightly damped flexible structures; the emphasis is placed on basic issues and simple control strategies that work. Now in its fourth edition, more chapters have been added, and comments and feedback from readers have been taken into account, while at the same time the unique premise of bridging the gap between structure and control has remained. Many examples, covering a broad field of applications from bridges to satellites and telescopes, and problems bring the subject to life and take the audience from theory to practice. The book has 19 chapters dealing with some concepts in structural dynamics; electromagnetic and piezoelectric transducers; piezoelectric beam, plate and truss; passive damping with piezoelectric transducers; collocated versus non-collocated control; active damping with collocated systems; vibration isolation; state space approach; analysis and synthesis in the frequency domain; optimal control; controllability and observability; stability; applications; tendon control of cable structures; active control of deformable mirrors for Adaptive Optics and large earth-based and space telescopes; and semi-active control. The book concludes with an exhaustive bibliography and index. This book is intended for structural engineers who want to acquire some background in vibration control, and for control engineers who are dealing with flexible structures. It can be used as a textbook for a graduate course on vibration control or active structures. A solutions manual is available through the publisher to teachers using this book as a textbook.

Download or read book Experimental Investigation of Vibration Damping in Linear and Nonlinear Vibration written by Giovanni Ferrari and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The main tool for the dynamic analysis of continuous structures is today modal analysis, which applies to lightly dampened structures undergoing small amplitude vibrations. Vibration energy in real structures is always partially lost because of internal material dissipation, Coulomb friction, interaction with fluids and even in presence of passive and active dampers. This dissipation is integrated in modal analysis by the use of a modal damping ratio for each normal vibration mode. A linear viscous or equivalent damping model underlies the use of modal damping ratios and preserves mode superposition in the study. The use of modal damping in linear vibrations is also practically profitable, as real structures tend to show small damping values that vary with the natural modes. However, the estimation of modal damping ratios is impossible a priori, and experimental measurement is necessary. Modern design practices are imposing the use of thin lightweight structures, often in contact with fluids, which easily undergo large amplitude vibrations; stricter safety regulations, in turn, may require the estimate of vibration amplitudes closer to resonance. In these cases, modal parameters remain valid with very good approximation, freeing the industry from the adoption of more complex theories. Modal damping, however, cannot be extended to nonlinear large amplitude vibration: as soon as vibration amplitudes exceed the characteristic dimension of the system, the prediction of vibration amplitude fails altogether. Even under the assumption of stationary vibrations, experimentally determined damping values appear dependent not only on the normal mode of vibration, but also on the vibration amplitude. Provided the availability of suitable know-how, it was decided to undertake a wide experimental characterization of the trend of damping values of thin walled shells and plates during large amplitude forced vibrations, bridging the lack of relevant literature. In order to give general character to this experimental activity, several cases were taken into account: metallic materials, composites and rubbers, in presence and in absence of fluid-structure interaction. The increasingly common smart materials and smart structures, composites for which vibration damping is tuned according to the designer's wish, feature active or semi-active damping. In presence of fluids and active elements, damping can grow to large values or can instead destabilize the system by feeding, not removing, energy. The study of modal damping in case of active vibration amplitude mitigation was therefore included as well. Through this wide range of experiments, a better comprehension of nonlinear damping was sought empirically. Since no other means were available for geometrically nonlinear vibrations, modal damping was applied unchanged to match with experimental results the vibration amplitude predicted by nonlinear models at one specific resonance. As expected, the values had to be changed to reproduce the vibration amplitude given by different force levels of stepped-sine excitation. The dependence on excitation amplitude seemed to follow an auspicious trend across a wide range of cases. Furthermore, different expressions of damping in the nonlinear field were used with respect to the traditional viscous (modal) damping formulation. This is particularly suitable for specific materials (e.g. elastomers showing a viscoelastic behavior) or configurations. Relevant experimental results, however, were not more general than the ones obtained employing modal damping, which indicates the great complexity of the problem. Actually, some evidence seemed to suggest that the equivalent values of damping in the nonlinear field are also influenced by the energy transfers between vibration modes. While damping has been seldom or never investigated previously in case of internal resonances, an estimate of its values in this situation led to additional insight." --

Download or read book Vibration Control of Active Structures written by A. Preumont and published by Springer Science & Business Media. This book was released on 2002-09-30 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book consists of 14 chapters. Chapters 2 and 3 are devoted to the dynamics of active structures; the open loop transfer functions are derived from the constitutive equations; the discussion includes active trusses with piezoelectric struts, and beams and shells with embedded laminar piezoelectric actuators and sensors. Chapters 4 and 5 discuss the virtues of collocated actuator/sensor configurations and how they can be exploited to develop active damping with guaranteed stability. Chapter 6 addresses vibration isolation for one and 6 d.o.f. Chapter 7 discusses optimal control for SISO systems with symmetric root locus. Chapter 8 discusses the design tradeoffs for SISO systems in the frequency domain, including the Bode amplitude/phase relationship. Chapter 9 provides a more general discussion of optimal control using of optimal control using the Riccati equation; spillover is examined. Chapters 10 and 11 review briefly the concepts of controllability, observability and stability. Chapter 12 discusses the semi-active control, including some materials on magneto-rheological fluids. Chapter 13 describes various practical applications to active damping, precision positioning and vibroacoustics, and chapter 14 discusses the active damping of cable- structures.

Download or read book Light Metals Advances in Research and Application 2012 Edition written by and published by ScholarlyEditions. This book was released on 2012-12-26 with total page 1913 pages. Available in PDF, EPUB and Kindle. Book excerpt: Light Metals—Advances in Research and Application: 2012 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Light Metals. The editors have built Light Metals—Advances in Research and Application: 2012 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Light Metals in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Light Metals—Advances in Research and Application: 2012 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.

Download or read book Vibration Control of Flexible Structures Using Nonlinear Devices written by Srinivasa Rao Chavakula and published by . This book was released on 1995 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Composite Structures written by I.H. Marshall and published by Springer. This book was released on 1991-09-30 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers contained herein were presented at the Sixth International Conference on Composite Structures (ICCS/6) held at Paisley College, Scotland in September 1991. The Conference was organised and sponsored by Paisley College. It was co-sponsored by Scottish Enterprise, the National Engineering Laboratory, the US Army Research, Development and Standardisation Group-UK, Strathclyde Regional Council and Renfrew District Council. It forms a natural and ongoing progression from the highly successful ICCS/1/2/3/4 and 5 held at Paisley in 1981, 1983, 1985, 1987 and 1989 respectively. As we enter the final decade of this century many organisations throughout the world are adopting a prophetic role by attempting to forecast future scientific advances and their associated impact on mankind. Although some would argue that to do so is folly, without such futuristic visionaries the world would be that much poorer. IntelJigent speculation based on research trends and historical advances, rather than fanciful theories, breathes a healthy air of enthusiasm into the scientific community. Surely this is the very oxygen necessary to ignite the fir~s of innovation and invention amongst pioneers of research.

Download or read book Enhanced Self powered Vibration Damping of Smart Structures by Modal Energy Transfer written by Zhen Wang and published by . This book was released on 2020 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a context of embedded structures, the next challenge is to develop an efficient, energetically autonomous vibration control technique. Synchronized Switch Damping techniques (SSD) have been demonstrated interesting properties in vibration control with a low power consumption. For compliant or soft smart structures, modal control is a promising way as specific modes can be targetted. This Ph-D work examines a novel energy transfer concept and design of simultaneous energy harvesting and vibration control on the same host structure. The basic idea is that the structure is able to extract modal energy from the chosen modes, and utilize this harvested energy to suppress the target modes via modal control method. We propose here a new technique to enhance the classic SSD circuit due to energy harvesting and energy transfer. Our architecture called Modal Synchronized Switching Damping and Harvesting (Modal SSDH) is composed of a harvesting circuit (Synchronized Switch Harvesting on Inductor SSHI), a Buck-Boost converter and a vibration modal control circuit (SSD). Various alternatives of our SSDH techniques were proposed and simulated. A real smart structure is modeled and used as specific case to test the efficiency of our concept. Piezoelectric sensors and actuators are taken as active transducers, as they develop the direct and inverse effects useful for the energy harvesting and the vibration damping. Optimization are running out and the basic design factors are discussed in terms of energy transfer. Simulations, carried out under bi-harmonic and noise excitation, underline that our new SSDH concept is efficient and robust. Our technique improve the damping effect of semi-active method compared to classic SSD method thanks to the use of harvested modal energy.

Download or read book Technology for Large Space Systems written by and published by . This book was released on 1986 with total page 674 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 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Linear Nonlinear and Networked based Vibration Control of Smart Flexible Structures written by Ehsan Omidi and published by . This book was released on 2015 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flexible structures are one of the most frequently used elements in different systems. They can be easily shaped to any desired form, they are light-weight, relatively inexpensive, and they have the required mechanical properties for many applications. In many cases, implementation of these systems requires real-time (active) application of a force or a moment to guarantee the required performance. Also sometimes, real-time measurement of the deflections in these systems is needed to measure a property or a parameter. To address these needs, flexible structures have been taken to a different level by enhancing them with smart materials. One of the most frequently used smart materials for flexible structures are piezoelectric layers. The result is a smart flexible structure which can provide a measurement of its deflections, and/or its displacement can be actively controlled. Active control of smart structures is one of the most important topics in this field. Using active control, a desired level of vibration can be induced in the structure, or undesired vibration can be eliminated. Additionally, deflection measurement in flexible smart structures can be improved alongside current developments in other sensing devices. To this end in this dissertation, several new control techniques have been proposed for active vibration control of flexible smart structures based on the method of positive feedback, in addition to decentralized measurement and control using novel networked-based consensus techniques. The methodologies developed in this dissertation are listed as: 0́Ø Multimode Modified Positive Position Feedback 0́Ø Modified Positive Velocity Feedback 0́Ø Hybrid Positive Feedback 0́Ø Spatial Modified Positive Position Feedback 0́Ø Multi Positive Feedback 0́Ø Nonlinear Modified Positive Position Feedback 0́Ø Nonlinear Integral Resonant Controller 0́Ø Nonlinear Integral Positive Position Feedback 0́Ø Optimal consensus observer design for piezo-active smart structures 0́Ø Consensus-based multi-piezoelectric microcantilever sensor 0́Ø Leader-follower based consensus vibration controller 0́Ø Consensus Positive Position Feedback The mentioned approaches which are designed for sensing and control of smart flexible structures are numerically and/or experimentally investigated, and their strengths and weaknesses in each case are thoroughly discussed. This dissertation provides a useful reference for engineers who seek to implement smart structures, and inspires them to develop and apply novel techniques in this field.

Download or read book Vibration Control of Nonlinear Flexible Structures written by I.R. Astrachan and published by . This book was released on 1987 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Harmonic Balance for Nonlinear Vibration Problems written by Malte Krack and published by Springer. This book was released on 2019-03-23 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph presents an introduction to Harmonic Balance for nonlinear vibration problems, covering the theoretical basis, its application to mechanical systems, and its computational implementation. Harmonic Balance is an approximation method for the computation of periodic solutions of nonlinear ordinary and differential-algebraic equations. It outperforms numerical forward integration in terms of computational efficiency often by several orders of magnitude. The method is widely used in the analysis of nonlinear systems, including structures, fluids and electric circuits. The book includes solved exercises which illustrate the advantages of Harmonic Balance over alternative methods as well as its limitations. The target audience primarily comprises graduate and post-graduate students, but the book may also be beneficial for research experts and practitioners in industry.

Download or read book Technology for Large Space Systems A Bibliography with Indexes supplement 20 written by United States. National Aeronautics and Space Administration. Scientific and Technical Information Division and published by . This book was released on 1989 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Large Space Structures Systems in the Space Station Era written by and published by . This book was released on 1990 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Space Station Systems written by and published by . This book was released on 1987 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: