Author: P. LadePublisher:
ISBN:
Category :
Languages : en
Pages : 18
Book Description
Experimental Study of Factors Controlling Instability of Frictional Materials
Experimental Study of Factors Controlling Instability of Frictional Materials
Author: P. LadePublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
The objectives of the experimental investigations being reported here were to further study the factors that control the stability and instability of frictional materials. The study is divided into two parts: (1) Conditions for Instability, in which a coarse sand was tested at a total of three void ratios to study effects of density as well as additional aspects of instability of granular materials. These experiments were conducted in high pressure triaxial equipment (cell pressures up to 70 MPa). (2) Creep in Sand, in which a fundamental study of creep and relaxation of granular materials was performed, because time-dependent behavior has considerable influence on the stability of granular materials. The sand employed in the experiments had weak, easily crushed grains, which typically exhibit considerable creep. The experiments were performed under drained conditions in order to maintain a constant stress state. Various stress states were used to study whether the plastic potential can be used for prediction of the relative magnitudes of the inelastic creep strain increments, and to examine the effect of creep on the outward movement of the plastic yield surface. This in turn will control the conditions for instability.
Experimental Study of Nonassociated Flow and Instability of Frictional Materials. Attachment
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 774
Book Description
This study presents the results of an extensive experimental investigation of granular materials at high pressures. Among the many types of experiments performed are drained and undrained triaxial compression and extension tests with an overall confining pressure range of 0.25 to 68.9 MPa. One-dimensional compression tests up to 900 MPa axial stress level were also performed. Major topics that were studied include: strain localization in triaxial extension tests; drained and undrained stress-strain and strength behavior from low to high pressures in triaxial extension and compression; instability of granular materials at high pressures in triaxial compression and extension; the determination of Skempton's pore pressure parameter B at high pressures; strain rate effects of granular materials at high pressures in drained and undrained conditions; examination of the effective stress principle at high pressures; particle breakage at high pressures; behavior of sands in one-dimensional compression tests at very high pressures; determination of values of k sub o, the coefficient of earth pressure at rest, at high pressures; evaluation of the elastic modulus and Poisson's ratio at high pressure levels; and correlations of high pressure soil behavior with stress-dilatancy, critical state, and input energy.
Energy Research Abstracts
Author: Bifurcations, Instabilities and Degradations in Geomaterials
Author: Richard WanPublisher: Springer Science & Business Media
ISBN: 3642182844
Category : Science
Languages : en
Pages : 366
Book Description
Geomaterials exhibit complex but rich mechanical behaviour with a variety of failure modes ranging from diffuse to localized deformation depending on stress, density, microstructure, and loading conditions. These failure modes are a result of an instability of material and/or geometric nature that can be studied within the framework of bifurcation theory. Degradation is another related phenomenon arising from cyclic loading, ageing, weathering, chemical attack, and capillary effects, among others. The methodology of analyzing the various types of instabilities is crucial in the adequate modelling and safe design of numerous problems in geomechanics. The present volume contains a sampling of enlarged versions of papers presented at the International Workshop on Bifurcation and Degradations in Geomaterials (IWBDG 2008) held in Lake Louise, Alberta, Canada, May 28-31, 2008. These papers capture the state-of-the-art in the specialized field of geomechanics and contemporary approaches to solving the central issue of failure. Some engineering applications are presented in the areas of energy resource extraction and soil-machine interaction.
Friction Surface Phenomena
Author: G.P. ShpenkovPublisher: Elsevier
ISBN: 0080875939
Category : Science
Languages : en
Pages : 359
Book Description
This monograph summarises results of research in some surface phenomena, observed in mechanical treatment and friction. In particular the book is devoted to urgent problems of the science of friction and wear and provides insight into the mechanism of the phenomena that cause, on the one hand, anomalously low coefficients of friction and wear (the so-called selective transfer) and on the other, dramatic damages of the surface layers during sliding (hydrogen wear of metals). The nature of metal interaction during sliding in selective transfer and hydrogen wear modes is analysed in detail. Furthermore results of studies concerned with certain aspects of phenomena appearing in the process of influencing contacting surfaces and with detecting the relationship between the observed characteristics and behavior of investigated materials in the process of mechanical treatment and friction are presented. The principle followed is to combine varied experimental facts, physical concepts and investigation methods, which at first sight appear to be unrelated, and using this approach to determine general rules. Chapter one provides the reader with a general understanding of fundamental surface phenomena which provide the background to their dynamic interaction in mechanical treatment and under friction. Chapter two deals with the laws governing influence of mechanical effects on the surface. The third chapter presents the fundamentals of the selective transfer theory under friction. Other chapters deal with the possibilities of the Mössbauer electron spectroscopy method, widely used in physics for solving tribology problems, the influence of external electromotive force sources on contact resistance and friction pairs' wear, and hydrogen wear of metals under friction.
Scientific and Technical Aerospace Reports
Author: Design Practices
Author: SAE Transmission/Axle/Driveline Forum CommitteePublisher: SAE International
ISBN: 0768075319
Category : Technology & Engineering
Languages : en
Pages : 771
Book Description
Since the mid-20th Century, automatic transmissions have benefited drivers by automatically changing gear ratios, freeing the driver from having to shift gears manually. The automatic transmission's primary job is to allow the engine to operate in its speed range while providing a wide range of output (vehicle) speeds automatically. The transmission uses gears to make more effective use of the engine's torque and to keep the engine operating at an appropriate speed. For nearly half a century, Design Practices: Passenger Car Automatic Transmissions has been the “go-to” handbook of design considerations for automatic transmission industry engineers of all levels of experience. This latest 4th edition represents a major overhaul from the prior edition and is arguably the most significant update in its long history. In summary, the authors have put together the most definitive handbook for automatic transmission design practices available today. Virtually all existing chapters have been updated and improved with the latest state-of-the-art information and many have been significantly expanded with more detail and design consideration updates; most notably for torque converters and start devices, gears/splines/chains, bearings, wet friction, one-way clutch, pumps, seals and gaskets, and controls. All new chapters have also been added, including state-of-the-art information on: • Lubrication • Transmission fluids • Filtration • Contamination control Finally, details about the latest transmission technologies—including dual clutch and continuously variable transmissions—have been added.
Highway Safety Literature
Author: A Study of Experiments Covering the Factors Affecting the Coefficient of Friction, and a Proposed Outline for a Further Test of These Factors
Author: George Andrew HawkinsPublisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 0
Book Description