Download or read book Energy Flow Regulation Through Built up Structures Toward Wave Guiding and Vibration Damping written by Shilong Li and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The overarching goal of structural dynamic analysis is usually to facilitate regulation of energy flows in terms of vibration and acoustic wave transmission. Such regulation of vibratory energy flows can yield effective designs of vibration suppression, energy harvesting, and vibration/wave based health monitoring, etc. This dissertation research employs the concept of built-up structure, i.e., constructing secondary oscillatory sub-systems and incorporating them into the underlying host structure to realize new ways of energy flow regulation. In particular, we propose to develop three distinct designs of sub-systems to realize unusual wave transmission and to dramatically improve damping performance, i.e., electro-mechanical local scatter for wave guiding, multi-field adaptive metasurfacing, and cantilevered coupling design to enhance energy dissipation. The first built-up sub-system design is based on the electro-mechanical local coupling, aiming at realizing adaptive elastic metasurfaces capable of arbitrarily manipulating refracted wave energy. By adjusting the negative capacitances properly, accurately formed, discontinuous phase profiles along the elastic metasurfaces can be achieved. Based on different phase profiles, anomalous refractions, planar focal lenses, self-accelerating beams and source illusion can be realized on the transmitted elastic wave energy. The second sub-system, multi-field adaptive metasurfacing, combines the membrane-type acoustic metasurface with piezoelectric integration able to tune the initial stress on the membrane with different voltages such that different resonant frequencies of the membranes can be realized to accomplish proper phase profiles along metasurfaces. Applications, such as acoustic cloaking, are illustrated to feature the acoustic wave energy manipulation. To dissipate the vibrational energy, tuned mass particle damper is designed based on cantilevered coupling, where the particle damping mechanism is integrated into a tuned mass damper configuration. The essential idea is to utilize the tuned mass damper configuration as a motion magnifier to amplify the energy dissipation capability of particle damper. While these built-up sub-system designs are distinctly different, they share the common feature that, by properly adjusting the sub-system oscillatory effects, the impedance at the region of interest of the host structure can be altered as desired. Consequently, effective energy flow regulations are realized. The outcome of this research can directly benefit vibration control and structural health monitoring.

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 2015 with total page 0 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 Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Passive Vibration Control of Structures written by Suhasini Madhekar and published by CRC Press. This book was released on 2022-05-05 with total page 597 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research in vibration response control deals not only with prevention of catastrophic failures of structures during natural or accidental/manmade hazards but also ensures the comfort of occupants through serviceability. Therefore, the focus of this book is on the theory of dynamic response control of structures by using different kinds of passive vibration control devices. The strategies used for controlling displacement, velocity, and acceleration response of structures such as buildings, bridges, and liquid storage tanks under the action of dynamic loads emanating from earthquake, wind, wave, and so forth are detailed. The book: Explains fundamentals of vibration response control devices and their practical applications in response mitigation of structures exposed to earthquake, wind, and wave loading Offers a comprehensive overview of each passive damper, its functioning, and mathematical modeling in a dynamical system Covers practical aspects of employing the passive control devices to some of the benchmark problems that are developed from existing buildings and bridges in different countries worldwide Includes MATLAB® codes for determining the dynamic response of single degree of freedom (SDOF) and multi-degree of freedom (MDOF) systems along with computational models of the passive control devices This book is aimed at senior undergraduate students, graduate students, and researchers in civil, earthquake, aerospace, automotive, mechanical engineering, engineering dynamics, and vibration control, including structural engineers, architects, designers, manufacturers, and other professionals.

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 Piezoelective Semi active Networks for Structural Vibration Damping with Energy Redistribution written by Dan Wu and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural vibration control is an important issue and has received considerable research attention in many industry applications. Researches investigated various approaches to reduce undesirable vibrations. The smart materials can control and suppress vibration in an efficient and “intelligent” way without causing much additional weight. The majority of research in smart damping materials has focused on the control of composite structure using embedded or bonded piezoelectric transducers. The advantages of piezoelectric materials include high achievable bandwidth, compactness, lightness, easy implementation and good electromechanical coupling characteristics, thus making them appropriate for actuators and sensors applications. Recently, a non-linear semi-passive vibration control technique, so-called Synchronized Switch Damping (SSD), has been developed. SSD technique relies on a cumulative build-up of the voltage resulting from the continuous switching of the piezoelectric voltage and it was shown that the performance is strongly related to this total voltage amplitude available. Based on SSD techniques, a new global approach for improved vibration damping of smart structure, based on global energy redistribution by means of a network of piezoelectric elements is proposed in this thesis. The objective of this work is to propose a new approach to increase the piezoelectric voltage (also related to the damping operative energy) in order to improve the damping performance. In the proposed semi-active approach, the extra energy used to improve this voltage is gathered on the various modes of the structure using an interconnected piezoelectric element network. Two original network topologies are developed for transferring energy. One is named SSDT for “Synchronized Switch Damping by energy Transfer”. The second is defined as SSDD for “Synchronized Switch Damping with Diode”. Performance evaluations and comparisons are performed on a model representative of a clamped plate equipped with piezoelectric elements in the case of multimodal motion. Compared to the Modal-SSDI method used as a baseline, simulation results and a global theoretical model are proposed demonstrating the relationship between the achievable damping improvement and the ratio of transferred energy to the structure mechanical energy, thus proving the capability of a network of piezoelectric elements for global energy management and redistribution in order to improve the vibration damping of smart structures.

Download or read book Structural Vibration Damping with Synchronized Energy Transfer Between Piezoelectric Patches written by Kaixiang Li and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced materials such as carbon fiber, composite materials et al. are more and more used in modern industry. They make the structures lighter and stiffer. However, they bring vibration problems. Researchers studied numerous methods to eliminate the undesirable vibrations. These treatments are expected to be a compact, light, intellectual and modular system. Recently, a nonlinear technique which is known as Synchronized Switch Damping (SSD) technique was proposed. These techniques synchronously switched when structure got to its displacement extremes that leading to a nonlinear voltage on the piezoelectric elements. This resulting voltage showed a time lag with the piezoelectric strain thus causing energy dissipation. Based on the developed SSD techniques, a new synchronized switch damping e.g. Synchronized Switch Damping with Energy Transfer (SSDET) was proposed in this document. This method damped the vibration by using the energy from other vibrating form. The objectives of the work reported in this document were threefold. The first one consisted of introduction of SSDET principle and developing its control law. This part aimed at establishing the mathematical model and verifying the proposed method by mathematical tools. Then, the experimental validations were carried out. Three experiments with different configurations demonstrated that SSDET can be implemented not only between structures but also vibrating modes in one structure. A SSDET scheme with multi-patches was also investigated for improving the damping. Finally, a bidirectional SSDET concept was introduced based on the original SSDET technique. This technique be regarded as a multimode control SSDET. Since it privileged the target vibration while keeps a decent control effect on the source vibration.

Download or read book The Experimental Measurement of Flexural Wave Power Flow in Structures written by W. Redman-White and published by . This book was released on 1984 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: When attempting to control vibration in structures, it is often desirable to be able to identify significant paths of vibration transmission from sources through the structure to some point of interest. In pursuance of this objective, consideration of vibration amplitudes at various points is of little help, since stationary waves my be present giving rise to large amplitudes whilst little power is being transmitted. The concept of wave intensity is therefore necessary, and is defined as the power flow per unit width of cross section area (in a uniform plate) and is measurable as a vector quantity at a given point. In beams, where wave propagation is in one dimension only, the power flowing through the total cross section is considered. If it is possible to obtain repeated measurements of intensity at many points on a structure, then a pattern of power flow may be identified. Here, only power carried by flexural waves is considered; this is generally the most important, and is theoretically more difficult to measure than power due to other wave types.

Download or read book Energy Research Abstracts written by and published by . This book was released on 1978 with total page 982 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Mechanics in Structural Engineering written by F.Y. Cheng and published by Elsevier. This book was released on 1999-02-16 with total page 413 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Second Sino-US Symposium Workshop on Recent Advancement of Computational Mechanics in Structural Engineering was held between May 25-28, 1998, in Dalian, China. The objectives were: to share the insights and experiences gained from recent developments in theory and practice; to assess the current state of knowledge in various topic areas of mechanics and computational methods and to identify joint research opportunities; to stimulate future cooperative research and to develop joint efforts in subjects of common needs and interests; to build and to strengthen the long-term bilateral scientific relationship between academic and professional practicing communities.Topics discussed covered the entire field of computational structural mechanics. These topics have advanced broad applications in the engineering practice of modern structural analysis, design and construction of buildings and other structures, and in natural hazard mitigation.

Download or read book Multimodal Vibration Damping of Structures Coupled to Their Analogous Piezoelectric Networks written by Boris Lossouarn and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural vibrations can be reduced by benefiting from the electromechanical coupling that is offered by piezoelectric materials. In terms of passive damping, piezoelectric shunts allow converting the vibration energy into electrical energy. Adding an inductor in the circuit creates an electrical resonance due to the charge exchanges with the piezoelectric capacitance. By tuning the resonance of the shunt to the natural frequency of the mechanical structure, the equivalent of a tuned mass damper is implemented. This strategy is extended to the control of a multimodal structure by increasing the number of piezoelectric patches. These are interconnected through an electrical network offering modal properties that approximate the behavior of the structure to control. This multi-resonant network allows the simultaneous control of multiple mechanical modes. An adequate electrical topology is obtained by discretizing the mechanical structure and applying the direct electromechanical analogy. The analogous network shows inductors and transformers, whose numbers and values are chosen according to the frequency band of interest. After focusing on the design of suitable magnetic components, the passive control strategy is applied to the damping of one-dimensional structures as bars or beams. It is then extended to the control of thin plates by implementing a two-dimensional analogous network.

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 NEHRP Recommended Provisions National Earthquake Hazards Reduction Program for Seismic Regulations for New Buildings and Other Structures Commentary written by United States. Federal Emergency Management Agency and published by . This book was released on 2001 with total page 468 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 Vibration Problems in Structures written by Hugo Bachmann and published by Birkhäuser. This book was released on 2012-12-06 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Authors: Hugo Bachmann, Walter J. Ammann, Florian Deischl, Josef Eisenmann, Ingomar Floegl, Gerhard H. Hirsch, Günter K. Klein, Göran J. Lande, Oskar Mahrenholtz, Hans G. Natke, Hans Nussbaumer, Anthony J. Pretlove, Johann H. Rainer, Ernst-Ulrich Saemann, Lorenz Steinbeisser. Large structures such as factories, gymnasia, concert halls, bridges, towers, masts and chimneys can be detrimentally affected by vibrations. These vibrations can cause either serviceability problems, severely hampering the user's comfort, or safety problems. The aim of this book is to provide structural and civil engineers working in construction and environmental engineering with practical guidelines for counteracting vibration problems. Dynamic actions are considered from the following sources of vibration: - human body motions, - rotating, oscillating and impacting machines, - wind flow, - road traffic, railway traffic and construction work. The main section of the book presents tools that aid in decision-making and in deriving simple solutions to cases of frequently occurring "normal" vibration problems. Complexer problems and more advanced solutions are also considered. In all cases these guidelines should enable the engineer to decide on appropriate solutions expeditiously. The appendices of the book contain fundamentals essential to the main chapters.

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1044 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Variable Speed Pumping written by Europump & the Hydraulic Europump & the Hydraulic Insti and published by Elsevier. This book was released on 2004-06-10 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prepared by industry experts from the pump, motor and drive industries under the auspices of Europump and the Hydraulic Institute, this reference book provides a comprehensive guide to variable speed pumping.It includes technical descriptions of pumping systems and their components, and guides the reader through the evaluation of different speed control options.Case studies help illustrate the life cycle cost savings and process improvements that appropriate variable speed pumping can deliver.·Authoritative, global reference to Variable Speed Pumping, by Europump and the Hydraulic Institute·Combines the technical knowledge of pump, motor and control systems in one guide·Brings together all the concepts, metrics and step-by-step decision-making support you need to help you decide which VSD strategies are most appropriate·Will help you design and specify pumping applications that minimise life-cycle costs