Download or read book Vibration Analysis and Intelligent Control of Flexible Rotor Systems Using Smart Materials written by Lawrence Atepor and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Flexible rotor-bearing system stability is a very important subject impacting the design, control, maintenance and operating safety. As the rotor bearing-system dynamic nonlinearities are significantly more prominent at higher rotating speeds, the demand for better performance through higher speeds has rendered the use of linear approaches for analysis both inadequate and ineffective. To address this need, it becomes important that nonlinear rotor-dynamic responses indicative of the causes of nonlinearity, along with the bifurcated dynamic states of instabilities, be fully studied. The objectives of this research are to study rotor-dynamic instabilities induced by mass unbalance and to use smart materials to stabilise the performance of the flexible rotor-system. A comprehensive mathematical model incorporating translational and rotational inertia, bending stiffness and gyroscopic moment is developed. The dynamic end conditions of the rotor comprising of the active bearing-induced axial force is modelled, the equations of motion are derived using Lagrange equations and the Rayleigh-Ritz method is used to study the basic phenomena on simple systems. In this thesis the axial force terms included in the equations of motion provide a means for axially directed harmonic force to be introduced into the system. The Method of Multiple Scales is applied to study the nonlinear equations obtained and their stabilities. The Dynamics 2 software is used to numerically explore the inception and progression of bifurcations suggestive of the changing rotor-dynamic state and impending instability. In the context of active control of flexible rotors, smart materials particularly SMAs and piezoelectric stack actuators are introduced. The application of shape memory alloy (SMA) elements integrated within glass epoxy composite plates and shells has resulted in the design of a novel smart bearing based on the principle of antagonistic action in this thesis. Previous work has shown that a single SMA/composite active bearing can be very effective in both altering the natural frequency of the fundamental whirl mode as well as the modal amplitude. The drawback with that design has been the disparity in the time constant between the relatively fast heating phase and the much slower cooling phase which is reliant on forced air, or some other form of cooling. This thesis presents a modified design which removes the aforementioned existing shortcomings. This form of design means that the cooling phase of one half, still using forced air, is significantly assisted by switching the other half into its heating phase, and vice versa, thereby equalising the time constants, and giving a faster push-pull load on the centrally located bearing; a loading which is termed Â'antagonisticÂ' in this present dissertation. The piezoelectric stack actuator provides an account of an investigation into possible dynamic interactions between two nonlinear systems, each possessing nonlinear characteristics in the frequency domain. Parametric excitations are deliberately introduced into a second flexible rotor system by means of a piezoelectric exciter to moderate the response of the pre-existing mass-unbalance vibration inherent to the rotor. The intended application area for this SMA/composite and piezoelectric technologies are in industrial rotor systems, in particular very high-speed plant, such as small light pumps, motor generators, and engines for aerospace and automotive application.

Download or read book Vibration Control Systems Utilizing Smart Materials Actuators written by Seung-Bok Choi and published by . This book was released on 2016 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, considerable attention has been focused on vibration control technology using "smart" or "intelligent" materials, which have inherently actuating and sensing capabilities. Typically these materials are employed to the vibration control of lumped parameter systems or distributed parameter structures by controlling the mass-distribution, stiffness change and the dissipation change. This may be accomplished by semi-active control or active control methods associated with the smart material actuators. Among many candidates of smart materials, magneto-rheological materials and piezoelectric materials are frequently adopted for vibration control. Magneto-rheological fluid and elastomer are especially utilized for vibration control of lumped parameter systems such as automotive damper, while the piezoelectric materials are used for vibration control of flexible distributed parameter structures with salient characteristics, such as fast response time. This book can be used as a textbook for graduate students or as a reference book for potential researchers who are interested in vibration control utilizing new methods associated with smart materials actuators. This book will provide some novel insights for advanced vibration control technology to many readers.

Download or read book Sustainable Education and Development Making Cities and Human Settlements Inclusive Safe Resilient and Sustainable written by Joseph N. Mojekwu and published by Springer Nature. This book was released on 2022-01-01 with total page 826 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents papers from the 10th Applied Research Conference in Africa (ARCA), showcasing the latest research on education and inclusive, safe, resilient, and sustainable communities. The conference is focused on applied research discussion and its dissemination, developing understanding about the role of research and researchers in the development of the continent. Education is a key driver to transform lives, build peace, eradicate poverty and drive sustainable development in Africa. Researchers face large challenges to making a meaningful contribution to the development of Africa. It is a continent where research can at time be not viewed directly related to development. The aim of the Applied Research Conference in Africa is to provide a platform for capacity building and networking among researchers in Africa. The proceedings is focussed on applied research, its discussion and dissemination and will be if interest to researchers, professors, graduate students, policymakers and professionals in industry.

Download or read book Inverse Dynamics Problems written by Hamed Kalhori and published by MDPI. This book was released on 2021-06-15 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: The inverse dynamics problem was developed in order to provide researchers with the state of the art in inverse problems for dynamic and vibrational systems. Contrasted with a forward problem, which solves for the system output in a straightforward manner, an inverse problem searches for the system input through a procedure contaminated with errors and uncertainties. An inverse problem, with a focus on structural dynamics, determines the changes made to the system and estimates the inputs, including forces and moments, to the system, utilizing measurements of structural vibration responses only. With its complex mathematical structure and need for more reliable input estimations, the inverse problem is still a fundamental subject of research among mathematicians and engineering scientists. This book contains 11 articles that touch upon various aspects of inverse dynamic problems.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Intelligent Materials and Structures written by Haim Abramovich and published by Walter de Gruyter GmbH & Co KG. This book was released on 2016-09-12 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intelligent Materials and Structures provides exceptional insights into designing intelligent materials and structures for special applications in engineering. The author introduces the fundamental materials science involved in research endeavors and simultaneously reviews the current state-of-the-art of intelligent materials and structures. Separate chapters are devoted to the thorough examination of theory and application of laminated composite materials, Piezoelectricity, Shape Memory Alloys, Electro- and Magnetorheological fluids as well as Magneto- and Electrostrictive materials. Each chapter contains numerous equations and figures describing theories, models and behavior of the intelligent material discussed. Special attention is paid to applications of intelligent materials to various structures in the aerospace and medical sector, piezoelectric motors as well as piezoelectric and electromagnetic energy harvesting. Contents: Introduction to Intelligent Materials and Structures Laminated Composite Materials Piezoelectricity Shape Memory Alloys Electrorheological and Magnetorheological Fluids Magnetostrictive and Electrostrictive Materials Applications of Intelligent Materials in Structures Energy Harvesting using Intelligent Materials Index

Download or read book Proceedings of the ASME Conference on Smart Materials Adaptive Structures and Intelligent Systems written by and published by . This book was released on 2009 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fourth NASA Workshop on Computational Control of Flexible Aerospace Systems Part 2 written by and published by . This book was released on 1991 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vibrations of Rotating Machinery written by Osami Matsushita and published by Springer. This book was released on 2017-05-22 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book opens with an explanation of the vibrations of a single degree-of-freedom (dof) system for all beginners. Subsequently, vibration analysis of multi-dof systems is explained by modal analysis. Mode synthesis modeling is then introduced for system reduction, which aids understanding in a simplified manner of how complicated rotors behave. Rotor balancing techniques are offered for rigid and flexible rotors through several examples. Consideration of gyroscopic influences on the rotordynamics is then provided and vibration evaluation of a rotor-bearing system is emphasized in terms of forward and backward whirl rotor motions through eigenvalue (natural frequency and damping ratio) analysis. In addition to these rotordynamics concerning rotating shaft vibration measured in a stationary reference frame, blade vibrations are analyzed with Coriolis forces expressed in a rotating reference frame. Other phenomena that may be assessed in stationary and rotating reference frames include stability characteristics due to rotor internal damping and instabilities due to asymmetric shaft stiffness and thermal unbalance behavior.

Download or read book Active Vibration Noise Control Design Towards Performance Limit written by Jiqiang Wang and published by Springer Nature. This book was released on 2022-08-22 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is motivated by the pivotal issue: what is the performance limit of active control and energy harvesting? It aims to develop systematic design methodologies with a “visualization technique” where the performance limit can be readily determined solely based on visual inspections. Modern technological systems have evolved toward high speed, heavy load, lightweight, flexible operation and extreme conditions, as demonstrated in aerospace, marine, transportation and manufacturing industries. The associated vibration and noise issues have become such problematic that they may significantly confine the performance of the systems, to say the discomfort at least. Through the geometric representation of the performance specifications, fundamental issues such as (1) the existence of feasible controllers; (2) the optimality of controllers; (3) the performance limit of controllers; (4) compromisability among the performance specifications; (5) the synthesis of controllers; and (6) the influence of constraints on optimal solutions can all be resolved within the proposed framework. The state of the art is thus refined with a new approach complementary to those optimization-based routines, where extra effort would have to be exercised to disclose the compromisability of performance specifications. The proposed book will result in a new design methodology—performance limit-oriented active control. It was initiated by the author with the project “Active Control for Performance Limit” (ACPL). A series of fundamental results are obtained and will be disseminated in this book. The results are verified through extensive numerical demonstrations and are expected to provide useful guidance for practical engineering in the vibration and noise industry and research.

Download or read book Active Vibration Control of Flexible Rotors Using Magnetic Bearings written by Randall Allen Bartlett and published by . This book was released on 1984 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Active vibration control of flexible rotor systems using angular electro magnetic dampers written by Irvin Redmond and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Smart Helicopter Rotors written by Ranjan Ganguli and published by Springer. This book was released on 2015-12-16 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exploiting the properties of piezoelectric materials to minimize vibration in rotor-blade actuators, this book demonstrates the potential of smart helicopter rotors to achieve the smoothness of ride associated with jet-engined, fixed-wing aircraft. Vibration control is effected using the concepts of trailing-edge flaps and active-twist. The authors’ optimization-based approach shows the advantage of multiple trailing-edge flaps and algorithms for full-authority control of dual trailing-edge-flap actuators are presented. Hysteresis nonlinearity in piezoelectric stack actuators is highlighted and compensated by use of another algorithm. The idea of response surfaces provides for optimal placement of trailing-edge flaps. The concept of active twist involves the employment of piezoelectrically induced shear actuation in rotating beams. Shear is then demonstrated for a thin-walled aerofoil-section rotor blade under feedback-control vibration minimization. Active twist is shown to be significant in reducing vibration caused by dynamic stall. The exposition of ideas, materials and algorithms in this monograph is supported by extensive reporting of results from numerical simulations of smart helicopter rotors. This monograph will be a valuable source of reference for researchers and engineers with backgrounds in aerospace, mechanical and electrical engineering interested in smart materials and vibration control. Advances in Industrial Control aims to report and encourage the transfer of technology in control engineering. The rapid development of control technology has an impact on all areas of the control discipline. The series offers an opportunity for researchers to present an extended exposition of new work in all aspects of industrial control.

Download or read book Vibration Engineering and Technology of Machinery written by Jyoti K. Sinha and published by Springer. This book was released on 2014-08-14 with total page 1110 pages. Available in PDF, EPUB and Kindle. Book excerpt: The VETOMAC-X Conference covered a holistic plethora of relevant topics in vibration and engineering technology including condition monitoring, machinery and structural dynamics, rotor dynamics, experimental techniques, finite element model updating, industrial case studies, vibration control and energy harvesting, and signal processing. These proceedings contain not only all of the nearly one-hundred peer-reviewed presentations from authors representing more than twenty countries, but also include six invited lectures from renowned experts: Professor K. Gupta, Mr W. Hahn, Professor A.W. Lees, Professor John Mottershead, Professor J.S. Rao, and Dr P. Russhard. This work is of interest to researchers and practitioners alike, and is an essential book for most of libraries of higher academic institutes.

Download or read book Test and Theory for Robust Active Vibration Control of Rotor Bearing Systems Utilizing Piezoelectric Actuators written by Shankar Jagannathan and published by . This book was released on 1993 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Piezoelectric Vibration Energy Harvesting written by Sajid Rafique and published by Springer. This book was released on 2017-11-03 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: The electromechanical coupling effect introduced by piezoelectric vibration energy harvesting (PVEH) presents serious modeling challenges. This book provides close-form accurate mathematical modeling and experimental techniques to design and validate dual function PVEH vibration absorbing devices as a solution to mitigate vibration and maximize operational efficiency. It includes in-depth experimental validation of a PVEH beam model based on the analytical modal analysis method (AMAM), precisely identifying electrical loads that harvest maximum power and induce maximum electrical damping. The author's detailed analysis will be useful for researchers working in the rapidly emerging field of vibration based energy harvesting, as well as for students investigating electromechanical devices, piezoelectric sensors and actuators, and vibration control engineering.

Download or read book Research in Progress written by and published by . This book was released on 1992 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: