2 edition of Frictional heating due to asperity interaction of elastohydrodynamic line-contact surfaces found in the catalog.
Frictional heating due to asperity interaction of elastohydrodynamic line-contact surfaces
Bankim C Majumdar
by National Aeronautics and Space Administration, Scientific and Technical Information Branch, For sale by the National Technical Information Service] in Washington, D.C, [Springfield, Va
Written in English
|Statement||Bankim C. Majumdar and Bernard J. Hamrock|
|Series||NASA technical paper -- 1882|
|Contributions||Hamrock, Bernard J, Lewis Research Center, United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch|
|The Physical Object|
|Pagination||20 p. :|
|Number of Pages||20|
A new model was developed for the simulation of the friction coefficient in lubricated sliding line contacts. A half-space-based contact algorithm was linked with a numerical elasto-hydrodynamic lubrication solver using the load-sharing concept. The model was compared with an existing asperity-based friction model for a set of theoretical simulations. Depending on the load and surface. number and type of asperity interactions and on the complex role played by insulating films, principally oxides, which form on the sliding surfaces. The Division of Heat Between Sliding Solids. The division of heat during sliding and the magnitude of the flash temperatures have been investigated theoretically by Blok  and Jaeger .
A statistical approach is used to obtain the heat generation rate due to one asperity and employed to develop the equation for generation of heat rate between two rough surfaces. This heat rate formulation between the two rough surfaces has been incorporated into the 2D lumped parameter model of disk pair in dry friction developed by Elhomani. The problem of the wear of an elastic coating due to a rigid body sliding over the coating surface and heating due to contact friction has been considered. The solution of the quasi-static problem has been constructed in the form of a series over eigenvalues. The area of unstable solutions of the problem, where the thermoelastic instability of a sliding contact takes place, has been determined.
This heat generation is shown to be significant compared to frictional heating even at relatively large slide-to-roll ratios. Parametric studies show that the ratio of asperity-plastic-deformation heating to frictional heating is sensitive to slide-to-roll ratio, hardness and surface finish but insensitive to contact load, rolling velocity and. Elastohydrodynamic Lubrication (EHL) is commonly known as a mode of fluid-film lubrication in which the mechanism of hydrodynamic film formation is enhanced by surface elastic deformation and lubricant viscosity increase due to high pressure. It has been an active and challenging field of research since the s.
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G Due to Asperity Interaction of Elastohydrodynamic Line-Contact Surfaces,' I c. 1 '.,\. Bankim C. Majumdar the predominant thermal energy source is frictional dissipation due to asperity interaction. Frictional heating in the thin-film zone increases the temperature and consequently decreases the viscosity of.
Get this from a library. Frictional heating due to asperity interaction of elastohydrodynamic line-contact surfaces. [Bankim C Majumdar; Bernard J Hamrock; Lewis Research Center.; United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch.].
Frictional heating occurs at the interface between the wire and the die, and thus a radial temperature gradient is established. The gradient is, as noted previously, rather short-lived, and by the time the wire reaches a distance L eq, downstream from the die exit, the contribution of frictional heating will have equilibrated to the frictional work set forth in Equation Frictional heating due to asperity interaction of elastohydrodynamic line-contact surfaces / By Bankim C.
Majumdar, Bernard J. Hamrock, Lewis Research Center. and United States. National Aeronautics and Space Administration.
Slightly higher stress levels developed at asperity exit than at entry due to the asperity interaction with the EHL pressure spike. The directions of σ 1 are indicated with arrows in the bottom part of Fig.
4 c. Note that the arrows point in both directions of the principal stress. development of TEI involves the interaction of frictional heating, surface deformation, and wear, and its avoidance requires an understanding of those three phenomena and their interaction.
• In addition to the effects noted above, excessive surface temperatures can contribute to the operational failure of many tribological Size: KB. E.M. Kopalinsky, P.L.B. Oxley, in Tribology Series, An asperity interaction model is given in which the frictional force results from the pushing of waves of plastically deforming material in the softer surface ahead of asperities on the harder surface.
Evidence is presented to show that the lubrication at the hard asperity-wave interface is elastohydrodynamic in nature. H. Khan, P. SinhaEffect of inter-asperity cavitation on thermal elastohydrodynamic lubrication of infinite line contact rough surfaces Int J Surf Sci Eng, 5 (2) (), pp./IJSURFSE thermal due to the frictional heating between the contact surfaces.
ﬁ xed surface interaction section, l, surface asperity changes longer under the sliding contact condition. A numerical solution of an elastohydrodynamic lubrication (EHL) contact between two long, rough surface cylinders is obtained. A theoretical solution of pressure distribution, elastohydrodynamic load, and film thickness for given speeds and for lubricants with pressure-dependent viscosity, material properties of cylinders, and surface roughness parameters is made by simultaneous solution of an.
These factors include asperity contact pressure, surface traction, and subsurface stress under elastohydrodynamic lubrication (EHL) conditions. Transient effects occur in gears due to the motion of surface roughness relative to the contact.
These relative velocities are different for the two surfaces according to the distance from the pitch point. Frictional behaviour of mixed Elasto-hydrodynamic lubrication (EHL) arises from the coupling of the lubricant fluid and asperity interaction frictions.
Due to the difficulties in modelling. The paper presents the numerical solution of line contact thermal elastohydrodynamic lubrication (EHL) with bio-based lubricant. The model comprises Reynolds equation, film thickness, load balance. Due to failure of oil film, asperity interaction of mating surfaces increases which would result in high frictional heating.
The contact temperature is calculated using the real/asperity area of contact and boundary coefficient of friction for the regions where lubricant breakdown occurs. the frictional heating for solids with arbitrary thermal properties.
The theory is applied to rubber friction on road surfaces and we take into account that the frictional energy is partly produced inside the rubber due to the internal friction of rubber and in a thin (nanometer) interfacial layer at.
Surfaces of mechanical components under combined rolling and sliding motions may be subjected to accelerated contact fatigue failure due to increased number of microscopic stress cycles and. We now consider the temperature increase due to the frictional interaction in the area of contact (sometimes denoted as the adhesive rubber-counter surface contribution to the friction).
In this case we expect the dissipated frictional energy to be localized in a thin layer of nanometer thickness d at the sliding interface. pressure and the load carried by interacting surface asperities.
Asperity interactions are often integrated non-Newtonian Reynolds equation for an elastohydrodynamic line contact problem. The Author’s ISS-ISN test results have been a bit more shocking.
Phantaslube ® ISS-ISN technology has reported anywhere from 10 – 50% improvements in fuel economy in on-road, real-world testing. Recent over-the-road (OTR) semi truck testing yielded a reported % improvement in fuel economy during a 1,+ mile, 8 U.S.
state, evaluation run. Further, detailed interferometer data of.  Heat flow measurements along much of the San Andreas fault (SAF) constrain the apparent coefficient of friction (μapp) of the fault to.
Asperity interactions are often integrated using rough surface contact models. For example, Gelinck and Schipper [ 24 ] presented a mixed lubrication mathematical model, capable of simulating lubrication regime transitions for a line contact problem based on the load-sharing method.The problem of the movement of a fluid in an elastohydrodynamic contact is examined in cases of high pressures, high displacement velocities, and low characteristic times, taking into account the nonlinear properties of the fluid — dependence of viscosity on pressure, temperature, and displacement velocity.
Simple asymptotic formulas are obtained.Asperity contact pressure is determined by the interaction of two mating surfaces. The applied load is carried out by the lubricant film and the contacted asperities. FFT techniques are utilized to calculate the surface displacement (forward problem) by convolution and the asperity contact pressure (inverse problem) by deconvolution for non.