Download or read book Thermoelastic instabilities in sliding contact written by Thomas A. Dow and published by . This book was released on 1972 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoelastic instability in rubbing contact is shown to be a consequence of the interaction of frictional heating, thermal expansion, conduction of heat from the contact zone, and wear. It manifests itself as a departure of the pressure distribution from a nominally uniform magnitude, as a result of the amplification of small disturbances. Such an instability is investigated here for two models of surface contact; (a) one-dimensional pin model and (b) two-dimensional blade model. The effects of materials, friction coefficients, severity of wear and sliding speed are delineated with respect to disturbance amplification or damping. The long-term growth of a disturbance is described and the resulting hot spot motion is explained. (Author).
Download or read book Thermoelastic Instability in a Seal Like Configuration written by Ralph A. Burton and published by . This book was released on 1973 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report comprises five independent studies leading progressively to an understanding of the thermoelastic behavior of sliding contacts. To be specific it deals with a seal-like configuration consisting of two tubes, contacting end to end. The effects of materials variation, oxide films and initial departures from flatness are investigated; and, as will be shown, the conditions under which surface contact departs from its initial state are delineated. The ultimate high-sliding-speed configuration of isolated contact patches separated by non contacting surfaces is treated, and both contact temperature of the patches and leakage in the gaps between are dealt with analytically. To the extent that the simplified geometry and materials choices represent real seals, the analytical results lead toward design criteria for practical applications. (Author).
Download or read book Transient Thermomechanical Deformation of Point Contacts Sliding with Dry Friction written by Hang-Seng Ng and published by . This book was released on 2009 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: The non-linear finite element program Abaqus will be used to simulate transient contact of a steel sphere sliding with friction against a rigid plane. The contact conditions include elastic and elastic/plastic deformation of the sphere. Both isothermal and thermomechanical conditions, i.e. with and without frictional heating are included. The contact radius, pressure distribution and temperature are tracked. From parametric studies, varying load, friction coefficient and material properties, dimensionless relationships will be developed. Comparison between the numerical studies and theoretical work under stricter conditions are made, where possible. Elastic and thermoelastic simulations agree with theory, although thermoelastic instabilities are found under conditions, where they are not normally expected. Under isothermal elastic/plastic conditions, the contact area during static load and sliding is larger than in the elastic case. Under thermoelasto-plastic sliding, we find interactions between thermomechanical instabilities (shrinking of the contact patch), thermal softening and plastic deformation, generally yielding contact sizes that may be somewhat larger than either the thermoelastic or the isothermal elastoplastic cases. We also find unexpected pressure and temperature distributions, even where contact sizes and pressure are close to the Hertzian, thermoelastic or elasto-plastic conditions. The thermomechanical elastic-plastic results can only be obtained by computational approach.
Download or read book Friction and Instabilities written by J.A.C. Martinis and published by Springer. This book was released on 2014-05-04 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book addresses instability and bifurcation phenomena in frictional contact problems. The treatment of this subject has its roots in previous studies of instability and bifurcation in elastic, thermoelastic or elastic-plastic bodies, and in previous mathematical, mechanical and computational studies of unilateral problems. The salient feature of this book is to put together and develop concepts and tools for stability and bifurcation studies in mechanics, taking into account the inherent non-smoothness and non-associativity (non-symmetry) of unilateral frictional contact laws. The mechanical foundations, the mathematical theory and the computational algorithms for such studies are developed along six chapters written by the lecturers of a CISM course. Those concepts and tools are illustrated not only with enlightening academic examples but also with some demanding industrial applications, related, namely, to the automotive industry.
Download or read book Thermoelastic Instability of Frictional Contacts written by Ralph A. Burton and published by . This book was released on 1970 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a study of the stability of frictional contact of elastic solids. To be specific, the problem is to determine when surface pressure or temperature distributions will be damped, or when they will be amplified by the thermal, frictional and elastic interactions of the surfaces. This effort will shed light on the behavior of numerous lubricated and unlubricated sliding systems such as seals, bearings, and piston rings. It should lead to design criteria in terms of materials and operating parameters. The present report is concerned with two phases of the study: (1) a discrete model of surface contact, and (2) a continuous thin-blade model of surface contact. The first sheds light on the processes at work, and analysis of it leads to a 'thermal vibration' equation with a damping coefficient which may be either negative or positive depending upon the specific operating conditions. The second model provides a more complete treatment of the thermoelastic interactions at work in continuous bodies. The work reported carries the analysis up through the derivation of a pair of algebraic equations involving the materials and operating parameters of the system. Because of the complex relationships involved, further work will be required to determine all of their implications. (Author).
Download or read book Thermoelastic Phenomena in Lubricated Sliding Contact written by Barunendra N. Banerjee and published by . This book was released on 1977 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lubricated sliding motion is studied for thermoelastic effects, notably an instability that causes large thermoelastic deformation of a nominally flat surface. A configuration similar to a face seal is used, with one face consisting of a thermal conductor and the other of an insulator. The roles of the pertinent parameters and material properties are delineated. Simple equation is given for the threshold of thermoelastic instability when both faces are initially flat. For the case of an initially wavy conducting face, the model for viscous heating envisages a full, coherent film on the one hand and, on the other, a broken film with zero heating in the cavitation zones. For both models, the continuous thermoelastic deformation of the conducting face, with changing sliding speed, is discussed and criteria for the onset of instability are presented. Experiments are reported to corroborate the findings of the theoretical analyses. (Author).
Download or read book Thermoelastic Effects in Sliding Systems written by A. L. Kistler and published by . This book was released on 1981 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Northwestern high speed rubbing apparatus has been modified to remove certain ambiguities in output data interpretation. Some experiments have been carried out with the modified apparatus, and data on friction, temperature, and contact resistance have been obtained for a graphite-steel contact region. No thermoelastic instability effects were observed over a speed range of 70M/sec. (Author).
Download or read book Thermoelastic Instabilities in Brakes and Clutches written by Essam Ali Al-Bahkali and published by . This book was released on 2003 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Role of Thermoelastic Effects in the Scuffing Failure of Rolling Sliding EHD Contacts written by R. R. Johnson and published by . This book was released on 1988 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt: A two-dimensional numerical solution of the thermal Reynolds', elasticity, and energy equations resulted in predictions of the flow velocities and temperatures within the lubricant film between a crown roller and a rotating shaft. The results showed a good agreement with previously measured experimental data on the surface temperatures in an EHD contact and on the resulting frictional torques for both rolling and sliding. A pressure and temperature dependent viscosity was assumed for the synthetic paraffinic hydrocarbon used in the experiments. This model allowed an evaluation of the relative importance of the generation, viscous dissipation, and compression terms in the energy equation at different stations along the mid-film line of contact. Based on the insight about the relative importance of terms as found in the numerical simulation, convenient expressions were developed for an approximate method of predicting the mid-film temperature and sliding friction force. The influence of thermal expansion of the contact between a crowned surface in sliding contact with a rotating cylindrical surface was included in a model of thermoelastic instability to predict the onset of scuffing failure. The simplified approach assumed a heat balance between the generation from friction and the heat conducted into the cylinders. (RH).
Download or read book Thermoelastic Instabilities in Automotive Disk Brakes and Clutches written by Yun-Bo Yi and published by . This book was released on 2001 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis and Simulation of Contact Problems written by Peter Wriggers and published by Springer Science & Business Media. This book was released on 2006-08-15 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: This carefully edited book offers a state-of-the-art overview on formulation, mathematical analysis and numerical solution procedures of contact problems. The contributions collected in this volume summarize the lectures presented by leading scientists in the area of contact mechanics, during the 4th Contact Mechanics International Symposium (CMIS) held in Hannover, Germany, 2005.
Download or read book Transient Solution of a Thermoelastic Instability Problem Using a Reduced Order Model written by Abdullah M. Al-Shabibi and published by . This book was released on 2002 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Frictionally excited Thermoelastic Instability in Automotive Disk Brakes written by Kwangjin Lee and published by . This book was released on 1993 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nonsmooth Dynamics of Contacting Thermoelastic Bodies written by Jan Awrejcewicz and published by Springer Science & Business Media. This book was released on 2008-12-10 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is devoted to an intensive study in contact mechanics, treating the nonsmooth dynamics of contacting bodies. Mathematical modeling is illustrated and discussed in numerous examples of engineering objects working in different kinematic and dynamic environments. Topics covered in five self-contained chapters examine non-steady dynamic phenomena which are determined by key factors: i.e., heat conduction, thermal stresses, and the amount of wearing. New to this monograph is the importance of the inertia factor, which is considered on par with thermal stresses. Nonsmooth Dynamics of Contacting Thermoelastic Bodies is an engaging accessible practical reference for engineers (civil, mechanical, industrial) and researchers in theoretical and applied mechanics, applied mathematics, physicists, and graduate students.
Download or read book Thermoelastic Deformations written by D. Iesan and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: The theory of thermoelasticity studies the interaction between thermal and mechan ical fields in elastic bodies. This theory is of interest both for the mathematical and technical point of view. Intense interest has been shown recently in this field owing to the great practical importance of dynamical effects in aeronautics, nu clear reactors, and its potential importance in cryogenic applications. This work is concerned mainly with basic problems of the theory of thermoelasticity. Ther moelasticity of polar materials and the theories of thermoelasticity with finite wave speeds are not considered here. The reader interested in these subjects will find a full account in the works of Nowacki [280], Chandrasekharaiah [60] and Ignaczak [195]. Our purpose in this work is to present a systematic treatment of some results established in the theory of thermoelasticity. On the whole, the subject matter is directed towards recent developments. Chapter 1 is concerned mainly with the development of the fundamental equa tions of the theory of thermoelasticity. The kinematics and primitive concepts associated with the basic principles are developed and emphasized only to the ex tent that they are needed in our treatment of the subject. Chapter 2 is devoted to a study of linear thermoelastic deformations for prestressed bodies. We have at tempted to isolate those conceptual and mathematical difficulties which arise over and above those inherent in the problems concerned with unstressed bodies.
Download or read book Thermoelastic Contact Stability Analysis written by Chuan Li and published by . This book was released on 1998 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Trends and Developments in Automotive System Engineering written by Marcello Chiaberge and published by BoD – Books on Demand. This book was released on 2011-01-08 with total page 681 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last few years the automobile design process is required to become more responsible and responsibly related to environmental needs. Basing the automotive design not only on the appearance, the visual appearance of the vehicle needs to be thought together and deeply integrated with the power developed by the engine. The purpose of this book is to try to present the new technologies development scenario, and not to give any indication about the direction that should be given to the research in this complex and multi-disciplinary challenging field.
