Download or read book Theoretical and Experimental Investigation on Friction in Lubricated Line Contacts with Different Materials and Textures in Presence of Wear written by and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wear and Contact Mechanics II written by Luis Rodríguez-Tembleque and published by Trans Tech Publications Ltd. This book was released on 2016-02-15 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Special topic volume with invited peer reviewed papers only
Download or read book Advances in Italian Mechanism Science written by Vincenzo Niola and published by Springer Nature. This book was released on 2020-08-19 with total page 902 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the proceedings of the 3rd International Conference of IFToMM ITALY, held online on September 9-11, 2020. It includes peer-reviewed papers on the latest advances in mechanism and machine science, discussing topics such as biomechanical engineering, computational kinematics, the history of mechanism and machine science, gearing and transmissions, multi-body dynamics, robotics and mechatronics, the dynamics of machinery, tribology, vibrations, rotor dynamics and vehicle dynamics. A valuable, up-to-date resource, it offers an essential overview of the subject for scientists and practitioners alike, and will inspire further investigations and research.
Download or read book Investigation of Dynamic Friction in Lubricated Surfaces written by Hanuman Rachoor and published by . This book was released on 1995 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research reported in this dissertation is concerned with the development of friction models for lubricated contacts. A few analytical models have been developed to investigate the friction under dynamic velocity conditions. In this study, two different tribological situations such as conformal and non-conformal contacts have been chosen. Friction modeling covers boundary, mixed and full fluid film friction regions. A new theory based on the elastic properties of the surface materials, and fluid film properties of the lubricant at the contact has been developed to determine the dynamic friction in boundary, mixed and full hydrodynamic lubrication regions. In the full fluid film lubrication region, friction has been determined from the lubrication principles based on the tribological situation, i.e., hydrodynamic lubrication theory for a short journal bearing and elastohydrodynarnic lubrication theory for a line contact. A conformal contact formed by a short journal bearing operating in the region where hydrodynamic lubrication theory is valid has been considered to develop a model. The model is simulated for unidirectional as well as bi-directional sinusoidal velocity oscillations for various frequencies. Simulation resulted in a phase lag in the fiction and hysteresis in ftiction versus velocity (f vs. U) curves. The results obtained for unidirectional velocity oscillations indicate qualitative agreement with experimental work on lubricated line contact by Hess and Soom (1990). Results for bi-directional oscillations also show phase lag in friction and similar hysteresis in f vs U curves. In addition to the hysteresis, results for the bi-directional velocity oscillations show a discontinuity in friction at velocity reversals. These results have been verified experimentally. A special apparatus to measure the friction has been designed and built by using a sleeve bearing. Experiments have been conducted to measure friction under various velocity conditions, and the results have been used to determine the coefficients required to simulate the analytical model. The analytical model has been simulated for the above coefficients and the results have been compared with the friction measurements. The comparison shows similar hysteresis in f vs U curves for uni-directional and bi-directional velocity oscillations. However, the friction behavior of the apparatus during bi-directional oscillations differs in the magnitude of the discontinuity (step function) at velocity reversals. The above analytical friction model developed for the hydrodynamic short journal bearing has been extended to investigate the effect of resisting forces on the dynamic friction behavior at low speed. Resistance forces include sliding friction as well as the presliding friction Dahl effect. The Dahl effect is due to elastic deformation of the compliance in the system before the force reaches the breakaway magnitude when sliding initiates. In this study, stiffness of the asperities as well as elastic support have been considered. Simulation results of the model for uni-directional velocity oscillations are in qualitative agreement with earlier experimental work. Simulation of the model for bi-directional velocity oscillations shows that the discontinuity at velocity reversals has been replaced by a line with slope. This work indicates that the stiffness, of the elastic compliance can play a significant role in replacing the discontinuity. The above concepts of friction modeling has been extended for a non-conformal contact formed with a cylindrical surface sliding over a flat surface operating on elastohydrodynamic lubrication theory. In this model, elastohydrodynamic lubrication theory has been used to determine the friction in full fluid film region. Simulation results of this model for uni-directional as well as bi-directional sinusoidal velocity oscillations indicate a similar phase lag in the friction and hysteresis in f vs. U curves as observed in the earlier models. Results of the present investigation indicate that the instantaneous friction is not only a function of the instantaneous velocity, but it is also a function of previous velocity or velocity history. These models can be improved with the aid of more experimental work. Also, these models can be extended for stick-slip analysis and for friction compensation.
Download or read book Interfacial Mechanics written by Jane Wang and published by CRC Press. This book was released on 2019-12-06 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the characteristics of material contact and lubrication at tribological interfaces is of great importance to engineering researchers and machine designers. Traditionally, contact and lubrication are separately studied due to technical difficulties, although they often coexist in reality and they are actually on the same physical ground. Fast research advancements in recent years have enabled the development and application of unified models and numerical approaches to simulate contact and lubrication, merging their studies into the domain of Interfacial Mechanics. This book provides updated information based on recent research progresses in related areas, which includes new concepts, theories, methods, and results for contact and lubrication problems involving elastic or inelastic materials, homogeneous or inhomogeneous contacting bodies, using stochastic or deterministic models for dealing with rough surfaces. It also contains unified models and numerical methods for mixed lubrication studies, analyses of interfacial frictional and thermal behaviors, as well as theories for studying the effects of multiple fields on interfacial characteristics. The book intends to reflect the recent trends of research by focusing on numerical simulation and problem solving techniques for practical interfaces of engineered surfaces and materials. This book is written primarily for graduate and senior undergraduate students, engineers, and researchers in the fields of tribology, lubrication, surface engineering, materials science and engineering, and mechanical engineering.
Download or read book Theoretical and experimental results on friction for line contacts in mixed and elastohydrodynamic lubrication regimes written by Roberto Bassani and published by . This book was released on 1999 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Tribology written by Michael M. Khonsari and published by John Wiley & Sons. This book was released on 2017-10-02 with total page 670 pages. Available in PDF, EPUB and Kindle. Book excerpt: Insightful working knowledge of friction, lubrication, and wear in machines Applications of tribology are widespread in industries ranging from aerospace, marine and automotive to power, process, petrochemical and construction. With world-renowned expert co-authors from academia and industry, Applied Tribology: Lubrication and Bearing Design, 3rd Edition provides a balance of application and theory with numerous illustrative examples. The book provides clear and up-to-date presentation of working principles of lubrication, friction and wear in vital mechanical components, such as bearings, seals and gears. The third edition has expanded coverage of friction and wear and contact mechanics with updated topics based on new developments in the field. Key features: Includes practical applications, homework problems and state-of-the-art references. Provides presentation of design procedure. Supplies clear and up-to-date information based on the authors’ widely referenced books and over 500 archival papers in this field. Applied Tribology: Lubrication and Bearing Design, 3rd Edition provides a valuable and authoritative resource for mechanical engineering professionals working in a wide range of industries with machinery including turbines, compressors, motors, electrical appliances and electronic components. Senior and graduate students in mechanical engineering will also find it a useful text and reference.
Download or read book Friction and Wear written by Giovanni Straffelini and published by Springer. This book was released on 2015-04-03 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the basic concepts of contact mechanics, friction, lubrication, and wear mechanisms, providing simplified analytical relationships that are useful for quantitative assessments. Subsequently, an overview on the main wear processes is provided, and guidelines on the most suitable design solutions for each specific application are outlined. The final part of the text is devoted to a description of the main materials and surface treatments specifically developed for tribological applications and to the presentation of tribological systems of particular engineering relevance. The text is up to date with the latest developments in the field of tribology and provides a theoretical framework to explain friction and wear problems, together with practical tools for their resolution. The text is intended for students on Engineering courses (both bachelor and master degrees) who must develop a sound understanding of friction, wear, lubrication, and surface engineering, and for technicians or professionals who need to solve tribological problems in their work.
Download or read book Wear and Contact Mechanics II written by Luis Rodríguez-Tembleque and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This special topic volume is a compilation of works contributed by experts from the international scientific community in the field of Wear and Contact Mechanics. The papers presented in this volume cover different aspects of the current areas of research in Wear and Contact Mechanics using new innovative theoretical, experimental and computational approaches. Numerical formulations are based on the finite element method (FEM) or the boundary element method (BEM) and their variants, i.e., Isogeometric analysis, p-version of finite elements and symmetric Galerkin boundary elements. A number of topics are addressed, such as computational wear and contact modeling with Isogeometric dual mortar methods, treatment of nonmatching interfaces, node-to-surface contact formulations for high-order elements and 3D problems, elastic-plastic contact between hard metal particles, friction in lubricated line contacts, running-in wear and fretting wear computing, frictional contact problems between viscoelastic-solids, frictional indentation of functionally graded materials (FGM), electro-elastic contact modeling, estimation of contact parameters in finite element analysis and high technological applications, as auxetic microstructures modeling and duct-concrete contact interface in high curvature post-tensioned tanks.
Download or read book Rheological Effects on Friction in Elastohydrodynamic Lubrication written by Edward G. Trachman and published by . This book was released on 1973 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical and experimental investigation is presented of the friction in a rolling and sliding elastohydrodynamic lubricated contact. The rheological behavior of the lubricant is described in terms of two viscoelastic models. These models represent the separate effects of non-Newtonian behavior and the transient response of the fluid. A unified description of the non-Newtonian shear rate dependence of the viscosity is presented as a new hyperbolic liquid model. The transient response of viscosity, following the rapid pressure rise encountered in the contact, is described by a compressional viscoelastic model of the volume response of a liquid to an applied pressure step. The resulting momentum and energy equations are solved by an iterative numerical technique, and a friction coefficient is calculated. The experimental study was performed, with two synthetic paraffinic lubricants, to verify the friction predictions of the analysis. The values of friction coefficient from theory and experiment are in close agreement.
Download or read book Interdisciplinary Approach to the Lubrication of Concentrated Contacts written by P. M.. Ku and published by . This book was released on 1970 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Contact Mechanics and Friction written by Valentin L. Popov and published by Springer. This book was released on 2017-03-10 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: This application-oriented book introduces readers to the associations and relationships between contact mechanics and friction, providing them with a deeper understanding of tribology. It addresses the related phenomena of contacts, adhesion, capillary forces, friction, lubrication, and wear from a consistent point of view. The author presents (1) methods for rough estimates of tribological quantities, (2) simple and general methods for analytical calculations, and (3) the crossover into numerical simulation methods, the goal being to convey a consistent view of tribological processes at various scales of magnitude (from nanotribology to earthquake research). The book also explores the system dynamic aspects of tribological systems, such as squeal and its suppression, as well as other types of instabilities and spatial patterns. It includes problems and worked-out solutions for the respective chapters, giving readers ample opportunity to apply the theory to practical situations and to deepen their understanding of the material discussed. The second edition has been extended with a more detailed exposition of elastohydrodynamic lubrication, an updated chapter on numerical simulation methods in contact mechanics, a new section on fretting in the chapter on wear, as well as numerous new exercises and examples, which help to make the book an excellent reference guide.
Download or read book Dynamical Contact Problems with Friction written by Walter Sextro and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this book is to describe an efficient procedure to model dynamical contact problems with friction. This procedure is applied to different practical problems and validated by experiments. Friction contacts are used to transmit forces or to dissipate energy. Examples for dynamical engineering systems with friction are brakes, machine tools, motors, turbines, bearings or wheel-rail systems. A better understanding of friction phenomena can result in improvements like the reduction of noise and maintenance costs, increased life time of machines and improved energy efficiency. Dependent on the features of the friction contact, different contact models and solution methods are applied.
Download or read book An Experimental Investigation on Fricton and Scuffing Failure of Lubricated Point Contacts written by Sai Goutham Soma and published by . This book was released on 2015 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scuffing failure is a catastrophic thermal failure mode induced by the extreme surface temperature of the contacting components. As two mechanical elements roll against each other with high sliding motion, the frictional heat flux elevates the surface temperature to exceed the critical limit, resulting in the welding of the surfaces. The relative motion then tears the welded surfaces apart, causing the damage. Scuffing failure has been an important failure mode for rolling machine elements such as bearings and gears in aerospace applications, owing to the very high operating speeds. Recently, this failure mode has extended to the automotive field, where the power density of the transmission system has been continuously increasing. Employing a two-disk contact set-up, this experimental study investigates the scuffing load carrying capacity of two new alloys, which are paired with the lubricant of the Mil-PRF-23699 turbine fluid, in comparison to the baseline material of AISI 5120, under different speed conditions. The variations of the friction coefficient with the sliding are also quantified for all the three alloy-lubricant pairs under various load and speed conditions. It is observed that the new materials failed to improve the scuffing performance with the lubricant and the operating conditions considered. It is suggested to use a different additive package in the lubricant, which may be more effective for the formation of the protective tribo-film along the new material surfaces. It is also suggested to extend the operating speed range for higher speed applications.
Download or read book Contact Mechanics and Friction of Elastic Solids on Hard and Rough Substrates written by Boris Lorenz and published by Forschungszentrum Jülich. This book was released on 2012 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Friction and Wear From Elementary Mechanisms to Macroscopic Behavior written by Valentin L. Popov and published by Frontiers Media SA. This book was released on 2019-08-21 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Friction and the interaction of surfaces can usually be felt at the scale of the contacting bodies. Indeed, phenomena such as the frictional resistance or the occurrence of wear can be observable with plain eye, but to characterize them and in order to make a prediction, a more detailed understanding at smaller scales is often required. These can include individual roughness peaks or single molecule interactions. In this Research Topic, we have gathered a collection of articles representing the state of the art in tribology’s endeavor to bridge the gap between nano scale elementary research and the macroscopic behavior of contacting bodies. These articles showcase the breadth of questions related to the interaction of micro and macro scale and give examples of successful transfer of insights from one to the other. We are delighted to present this Research Topic to the reader with the hope that it will further inspire and stimulate research in the field.
Download or read book Fundamentals of Fluid Film Lubrication written by Bernard J. Hamrock and published by CRC Press. This book was released on 2004-03-15 with total page 794 pages. Available in PDF, EPUB and Kindle. Book excerpt: Specifically focusing on fluid film, hydrodynamic, and elastohydrodynamic lubrication, this edition studies the most important principles of fluid film lubrication for the correct design of bearings, gears, and rolling operations, and for the prevention of friction and wear in engineering designs. It explains various theories, procedures, and equations for improved solutions to machining challenges. Providing more than 1120 display equations and an introductory section in each chapter, Fundamentals of Fluid Film Lubrication, Second Edition facilitates the analysis of any machine element that uses fluid film lubrication and strengthens understanding of critical design concepts.
