Download or read book Effect of Sliding Friction on Spur and Helical Gear Dynamics and Vibro acoustics written by Song He and published by . This book was released on 2008 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This study examines the salient effects of sliding friction on spur and helical gear dynamics and associated vibro-acoustic sources. First, new dynamic formulations are developed for spur and helical gear pairs based on a periodic description of the contact point and realistic mesh stiffness. Difficulty encountered in existing discontinuous models is overcome by characterizing a smoother transition during the contact. Frictional forces and moments now appear as either excitations or periodically-varying parameters, since the frictional force changes direction at the pitch point/line. These result in a class of periodic ordinary differential equations with multiple and interacting coefficients. Predictions match well with a benchmark finite element/contact mechanics code and/or experiments. Second, new analytical solutions are constructed which provide an efficient evaluation of the frictional effect and a more plausible explanation of dynamic interactions in multiple directions. Both single- and multi-term harmonic balance methods are utilized to predict dynamic mesh loads, friction forces and pinion/gear displacements. Such semi-analytical solutions explain the presence of higher harmonics in gear noise and vibration due to exponential modulations of periodic parameters. This knowledge also analytically reveals the effect of the tooth profile modification in spur gears under the influence of sliding friction. Further, the Floquet theory is applied to obtain closed-form solutions of the dynamic response for a helical gear pair, where the frictional effect is quantified by an effective piecewise stiffness function. Analytical predictions are validated using numerical simulations. Third, an improved source-path-receiver vibro-acoustic model is developed to quantify the effect of sliding friction on structure-borne noise. Interfacial bearing forces are predicted for the spur gear source sub-system given two whine excitations (static transmission error and sliding friction). A computational model of the gearbox, with embedded bearing stiffness matrices, is developed to characterize the motilities of structural paths. Radiated sound pressure is then estimated by using the Rayleigh integral method and a substitute source technique. Predicted pressures match well with measured noise data over a range of operating torques. In particular, the proposed vibro-acoustic model quantifies the contribution of sliding friction, which could be significant when the transmission error is minimized through tooth modifications.
Download or read book Dynamic Analysis of Sliding Friction in Rotorcraft Geared Systems written by and published by . This book was released on 2005 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive study has examined the key effects of sliding friction in spur and helical gear dynamic models, vibro-acoustic sources and geared system responses. First, many dynamic phenomena that emerge due to the interactions between time-varying mesh stiffness, sliding friction and/or surface finish are successfully formulated. Second, new multi-degree-of-freedom models considering both torsional and translational dynamics of spur and helical gear pairs have been developed. These include time-varying mesh stiffness, sliding friction excitation and shaft/bearing compliances. Line-of-action and off-line-of-action motion predictions, based on the lumped gear dynamic models, match well with a benchmark finite element/contact mechanics code. Third, new mathematical models have been proposed to examine structure-borne and air-borne noise that should arise due to surface asperities as a function of operating speed and surface finish. Fourth, mobility type frequency response studies of the system vibro-acoustic characteristics provide new insights into dynamic forces at the bearings and sound radiation. Fifth, two sets of experimental studies at ARL/NASA Glenn were conducted. Gear noise source and lumped system models match well with experiments on ARL/NASA spur gears. Finally, a set of helical gears has been designed that clearly isolate the effects of sliding friction. Suggestions for future research are included.
Download or read book Advances in Acoustics and Vibration III written by Nabih Feki and published by Springer Nature. This book was released on 2021-05-29 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book provides readers with a snapshot of recent research and industrial trends in field of industrial acoustics and vibration. Each chapter, accepted after a rigorous peer-review process, reports on a selected, original piece of work presented and discussed at the Third International Conference on Acoustics and Vibration (ICAV2021), which was organized by the Tunisian Association of Industrial Acoustics and Vibration (ATAVI) and held online on March 15-16, 2021, from Sfax, Tunisia. The contributions cover advances in both theory and practice in a variety of subfields, such as: smart materials and structures; fluid-structure interaction; structural acoustics as well as computational vibro-acoustics and numerical methods. Further topics include: engines control, noise identification, robust design, flow-induced vibration and many others. This book provides a valuable resource for both academics and professionals dealing with diverse issues in applied mechanics. By combining advanced theories with industrial issues, it is expected to facilitate communication and collaboration between different groups of researchers and technology users.
Download or read book Mobility Analysis of a Spur Gear Pair and the Examination of Sliding Friction written by Allison Holub and published by . This book was released on 2005 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Linear vibro-acoustic models of a geared system are developed to comparatively examine the effect of the static transmission error and sliding friction excitations. Mobility synthesis is applied to a spur gear pair system with six degrees-of-freedom, describing only the line-of-action dynamics. The frequency responses are validated using direct inversion for assumed transmission error excitation. Simplified analytical expressions for natural frequencies and dynamic bearing forces are derived using the mobility model and compared to the work presented by Steyer (1987). The transmission error and sliding friction sources are compared in terms of the gear mesh harmonic amplitudes predicted by a computer program called Load Distribution Program. To simplify the friction excitation, an empirical equation describing a variable coefficient of friction, as a function of roll angle, is employed and then a mean value of the coefficient is obtained for various operating conditions. An eight degree-of-freedom model incorporating the off-line-of-action direction is also developed for the spur gear pair, in which the friction force excitation is assumed to act externally with a given amplitude for all frequencies. Using this model, the dynamic bearing forces are evaluated in both the line-of-action and off-line-of-action directions. A simple noise prediction model for the gearbox based on experimentally measured structural-acoustic transfer functions is presented. The sound pressure levels are predicted at the gear mesh harmonics to examine the role of the static transmission error and sliding friction excitations. The predictions are qualitatively compared to measurements performed at NASA Glenn Research Center as well.
Download or read book Vibro acoustic characterstics of sliding friction in geared rotor systems Ph D Ohio State University 2001 Gear Dynamics and Gear Noise Research Laboratory written by Manish Vaishya and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 1006 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of Mechanical Design written by and published by . This book was released on 2007 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of the Impact of Random Spacing Errors on the Transmission Error of Spur and Helical Gear Pairs written by Muhammad Nevin Anandika and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Noise and vibration performance of a gear system is critical in any industry. Vibrations caused by the excitations at the gear meshes propagate to the transmission housing to cause noise, while also increasing gear tooth stresses to degrade durability. As such, gear engineers must seek gear designs that are nominally quiet with low vibration amplitudes. tudes. They must also ensure that this nominal performance is robust in the presence of various manufacturing errors. This thesis research aims at an experimental investigation of the influence of one type of manufacturing error, namely random tooth spacing errors, on the vibratory responses of spur and helical gear pairs. For this purpose, families of spur and helical gear test specimens having intentionally induced, tightly controlled random spacing error sequences are fabricated. These specimens are paired and assembled in various ways to achieve different sequences of composite spacing errors. Static and dynamic motion transmission error measurements from these tests are compared to the baseline case of “no error” gear to quantify the impact of random spacing errors on the dynamic response. These comparisons show that there is a significant, quantifiable impact of random spacing errors on both spur and helical gear dynamics. In general, vibration amplitudes of gear pairs having random spacing errors are higher than those of the corresponding no-error gear pairs. In the frequency domain, gears having random spacing errors exhibit broad-band spectra with significant non-mesh harmonics, pointing to potential noise quality issues.
Download or read book Proceedings of IncoME V CEPE Net 2020 written by Dong Zhen and published by Springer Nature. This book was released on 2021-05-15 with total page 949 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume gathers the latest advances, innovations and applications in the field of condition monitoring, plant maintenance and reliability, as presented by leading international researchers and engineers at the 5th International Conference on Maintenance Engineering and the 2020 Annual Conference of the Centre for Efficiency and Performance Engineering Network (IncoME-V & CEPE Net-2020), held in Zhuhai, China on October 23-25, 2020. Topics include vibro-acoustics monitoring, condition-based maintenance, sensing and instrumentation, machine health monitoring, maintenance auditing and organization, non-destructive testing, reliability, asset management, condition monitoring, life-cycle cost optimisation, prognostics and health management, maintenance performance measurement, manufacturing process monitoring, and robot-based monitoring and diagnostics. The contributions, which were selected through a rigorous international peer-review process, share exciting ideas that will spur novel research directions and foster new multidisciplinary collaborations.
Download or read book Effect of Operating Conditions on Gearbox Noise written by and published by . This book was released on 1992 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low-contact-ratio spur gears were tested in the NASA gear-noise rig to study the noise radiated from the top of the gearbox The measured sound power from the gearbox top was obtained from a near-field acoustic intensity scan taken at 63 nodes just above the surface. The sound power was measured at a matrix of 45 operating speeds and torque levels. Results are presented in the form of a spectral speed map and as plots of sound power versus torque (at constant speed) and as sound power versus speed (at constant torque). Because of the presence of vibration modes, operating speed was found to have more impact on noise generation than torque level. A NASA gear dynamics code was used to compute the gear tooth dynamic overload at the same 45 operating conditions used for the experiment. Similar trends were found between the analytical results for dynamic tooth overload and experimental results for sound power. Dynamic analysis may be used to design high-quality gears with profile relief optimized for minimum dynamic load and noise. Gear noise; Spur gears; Acoustic intensity; Sound power.
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 The Automotive Transmission Book written by Robert Fischer and published by Springer. This book was released on 2015-05-11 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents essential information on systems and interactions in automotive transmission technology and outlines the methodologies used to analyze and develop transmission concepts and designs. Functions of and interactions between components and subassemblies of transmissions are introduced, providing a basis for designing transmission systems and for determining their potentials and properties in vehicle-specific applications: passenger cars, trucks, buses, tractors and motorcycles. With these fundamentals the presentation provides universal resources for both state-of-the-art and future transmission technologies, including systems for electric and hybrid electric vehicles.
Download or read book Gear Noise and Vibration written by J. Derek Smith and published by CRC Press. This book was released on 2003-04-08 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on over 40 years of consultation and teaching experience, Gear Noise and Vibration demonstrates logical gear noise and vibration approaches without the use of complex mathematics or lengthy computation methods. The second edition offers new and extended discussions on high- and low-contact ratio gears, lightly loaded gears, planetary and spli
Download or read book Design and Modeling of Mechanical Systems written by Mohamed Haddar and published by Springer Science & Business Media. This book was released on 2013-03-12 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 5th International Congress on Design and Modeling of Mechanical Systems (CMSM) was held in Djerba, Tunisia on March 25-27, 2013 and followed four previous successful editions, which brought together international experts in the fields of design and modeling of mechanical systems, thus contributing to the exchange of information and skills and leading to a considerable progress in research among the participating teams. The fifth edition of the congress (CMSM ́2013), organized by the Unit of Mechanics, Modeling and Manufacturing (U2MP) of the National School of Engineers of Sfax, Tunisia, the Mechanical Engineering Laboratory (MBL) of the National School of Engineers of Monastir, Tunisia and the Mechanics Laboratory of Sousse (LMS) of the National School of Engineers of Sousse, Tunisia, saw a significant increase of the international participation. This edition brought together nearly 300 attendees who exposed their work on the following topics: mechatronics and robotics, dynamics of mechanical systems, fluid structure interaction and vibroacoustics, modeling and analysis of materials and structures, design and manufacturing of mechanical systems. This book is the proceedings of CMSM ́2013 and contains a careful selection of high quality contributions, which were exposed during various sessions of the congress. The original articles presented here provide an overview of recent research advancements accomplished in the field mechanical engineering.
Download or read book Vibro impact Dynamics written by Albert C. J. Luo and published by John Wiley & Sons. This book was released on 2012-11-29 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents a systematic view of vibro-impact dynamics based onthe nonlinear dynamics analysis Comprehensive understanding of any vibro-impact system iscritically impeded by the lack of analytical tools viable forproperly characterizing grazing bifurcation. The authors establishvibro-impact dynamics as a subset of the theory of discontinuoussystems, thus enabling all vibro-impact systems to be explored andcharacterized for applications. Vibro-impact Dynamics presents an original theoreticalway of analyzing the behavior of vibro-impact dynamics that can beextended to discontinuous dynamics. All topics are logicallyintegrated to allow for vibro-impact dynamics, the central theme,to be presented. It provides a unified treatment on the topicwith a sound theoretical base that is applicable to both continuousand discrete systems Vibro-impact Dynamics: Presents mapping dynamics to determine bifurcation and chaos invibro-impact systems Offers two simple vibro-impact systems with comprehensivephysical interpretation of complex motions Uses the theory for discontinuous dynamical systems ontime-varying domains, to investigate the Fermi-oscillator Essential reading for graduate students, university professors,researchers and scientists in mechanical engineering.
Download or read book Fundamentals of Multibody Dynamics written by Farid Amirouche and published by Springer Science & Business Media. This book was released on 2007-05-24 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook – a result of the author’s many years of research and teaching – brings together diverse concepts of the versatile tool of multibody dynamics, combining the efforts of many researchers in the field of mechanics.
Download or read book Vibration based Condition Monitoring written by Robert Bond Randall and published by John Wiley & Sons. This book was released on 2011-03-25 with total page 409 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Without doubt the best modern and up-to-date text on the topic, wirtten by one of the world leading experts in the field. Should be on the desk of any practitioner or researcher involved in the field of Machine Condition Monitoring" Simon Braun, Israel Institute of Technology Explaining complex ideas in an easy to understand way, Vibration-based Condition Monitoring provides a comprehensive survey of the application of vibration analysis to the condition monitoring of machines. Reflecting the natural progression of these systems by presenting the fundamental material and then moving onto detection, diagnosis and prognosis, Randall presents classic and state-of-the-art research results that cover vibration signals from rotating and reciprocating machines; basic signal processing techniques; fault detection; diagnostic techniques, and prognostics. Developed out of notes for a course in machine condition monitoring given by Robert Bond Randall over ten years at the University of New South Wales, Vibration-based Condition Monitoring: Industrial, Aerospace and Automotive Applications is essential reading for graduate and postgraduate students/ researchers in machine condition monitoring and diagnostics as well as condition monitoring practitioners and machine manufacturers who want to include a machine monitoring service with their product. Includes a number of exercises for each chapter, many based on Matlab, to illustrate basic points as well as to facilitate the use of the book as a textbook for courses in the topic. Accompanied by a website www.wiley.com/go/randall housing exercises along with data sets and implementation code in Matlab for some of the methods as well as other pedagogical aids. Authored by an internationally recognised authority in the area of condition monitoring.
