Trenie i Iznos (Friction and Wear), 2002, Vol.23, No.1

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Trenie i Iznos (Friction and Wear), 2002, Vol.23, No.1

FRICTION AND WEAR (Trenie i Iznos)
International Scientific Journal
Published by The V.A.Biely Institute of Mechanics of Metal-Polymer Systems of the National Academy of Sciences of Belarus, Gomel, Republic of Belarus

Volume 23, Number 1; January--February, 2002

ARTICLES

Drozdov Yu. N.
Solution of triboengineering problems for the Moon. pp. 5--9

Summary: Space missions to the moon are expected to resume and expand in the 21st century. Habitable moon settlements are expected to appear with production, astrophysical, mining, maintenance facilities and services. Space missions launched from the moon require less energy than from the earth; therefore it is attractive to construct launching pads there. National importance is attached to the program of moon exploration in China. The experience of designing and operation of moon engineering systems shows the intricacy of achieving and maintaining reliable performance of friction units. In the 60s of the last century the tribological experimental and theoretical studies for lunar conditions have been performed with highly fruitful results for space and Earth.

Dmitriev N.N.
Movement of the disk and the ring over the plane with anistropic friction. pp. 10--15

Summary: The problem is analyzed how the disk and the ring move over the plane in case of anisotropic friction. The law of friction takes into account the mutual orientation of contacting surface in the friction pair.

Sorokatyi R.V.
Modeling the behavior of tribosystems using the method of triboelements. pp. 16--22

Summary: A method of triboelements is disclosed used for modeling the behavior of tribosystems. The method is based on the application of Markov random processes. An example is shown how a tribocontact problem is solved with this method.

Nasibov N.A.
Dynamics of migration of a material point over a nonsmooth curve. pp. 23--26

Summary: A dynamic friction problem is analyzed. Migration of a material point (a particle) over a nonsmooth random-shaped spatial curve is studied. The linear law of sliding friction is used to generalize the solution. Variations of the kinetic energy due to the force of friction work function are considered. The Amonton and Coulomb law of friction are considered as special cases. The necessary calculation dependencies are derived.

Zharov I.A., Voronin I.N.
Calculation of temperature fields adjacent to contact spots between wheel -- rail pairs in rolling and sliding. pp. 27--34

Summary: A formula has been derived to calculate the temperature on the surface of a semispace during boundary friction of the third kind. It is shown that changes of temperature on the spot of contact with the rail can serve to alter the mechanical characteristics of wheel and rail steels. Ways how to reduce temperature rises are demonstrated.

Balakin V.A., Sergienko V.P., Lysenok Yu.V.
Heat conditions of operation of car brakes when driving downslope. pp. 35--40

Summary: Formulas to calculate average temperature increments in the car brakes are proposed when driving downslope with variable modes of engine operation. The results of calculation of heat loading as a function of braking conditions are analyzed,

Akhverdiev K.C., Melnikova E.P.
Non-isothermal flow of lubricating coolant between the surfaces of tools and blanks exposed to perturbation pressure. pp. 41--46

Summary: A mathematical model has been elaborated how the lubricating coolant flows during finishing operations. An exact self-similarity solution of the problem of predicting the perturbation pressure of the medium between the rough blank surface and tool moving with a definite speed. Regularities have been established how the roughness of the blank changes with the account of the initial difference between the temperatures of the tool and the blank, internal heat generation causing local pressure variations. The obtained solutions allow to predict surface roughness at a specified roughness and vice versa at a specified perturbation pressure.

Baranov V.M., Kudryavtsev E.M., Sarychev G.A., Stopyra A.Z.
Modification of statistical characteristics of friction surfaces in the process of running-in. pp. 47--59

Summary: A method of proposed how to calculate changes of statistical characteristics of friction surface in the process of running-in. Fatigue failure of the tallest microprojections is assumed to occur when surfaces run-in. A relationship has been established between the typical time when microprojections destroy and statistical characteristics of friction surfaces and parameters describing multicycle fatigue of coupled materials. An expression has been derived how the probability density of the heights of projections on contacting surfaces change in time. Calculations have revealed that running-in smoothes friction surfaces and strongly decelerates the rate of changes of the dispersity of the heights of projections. Pressure stabilizes, dispersion of pressure over actual contact spots reduces. It is proposed to assume the time of running in as the time after which the dispersion of projection heights practically ceases to change.

Tochilnikov D.G., Ginzburg B.M.
The effect of fulleren black on the friction of fluoroplastics at rest during elastic contact with steel without any lubricating material. pp. 60--63

Summary: Introduction of 1% fulleren black into the Ô-4 fluoroplastic and fluoroplastic Ô-4K20 composite reduces noticeably the friction coefficient at rest by reducing the molecular component of the force of friction governing energy losses at the initial moment of sliding of surfaces in case of an elastic contact between polymers and steel.

Abdrashitov E.F., Ponomarev A.N.
Study of the surface structure of plasma modified rubbers. pp. 64--71

Summary: The surface structures of original and plasma modified siloxane rubbers have been studied at different stages of modification using the techniques of electron and infrared microscopy. It has been established that the relief of a plasma treated rubber article is produced by a specific effect of the discharge on the various ingredients included into the compositions of rubbers. Plasma treatment produces a transition layer on the rubber surface containing fluorocarbon groups and products of plasma oxidative destruction of the rubber surface. The coating has the appearance offlakes with typical dimensions of scores of microns. Rubber becomes destroyed and the sealing fails due to the appearance of caverns along the friction track under the effect of the "roll-over" mechanism.

Krasnov A.P., Tokareva N.V., Popov V.K., Houdle S., Morley C., Afonicheva O.V.
The role of tribochemical processes during friction of super high molecular polyethylene impregnated with a silver organic compound. pp. 72--77

Summary: Friction of SHMPE with silver particles impregnated into the surface layer from a silver organic complex in the CO; atmosphere has been studied. It is shown that treatment ofSHMPE specimens in the supercritical atmosphere plays a dominating role in improving the triboengineering characteristics during their friction over Ti and a Ti-- Al alloy, even without introducing the silver organic complex. It has been established that introduction of silver particles affects the extent of tribooxidation of the polymer.

Kadolich Zh.V., Pinchuk L.S., Tsvetkova E.A.
The mechanism of friction of a microporous material from superhighmolecular polyethylene. pp. 78--81

Summary: The results of tribological tests of hip joint endoprosthetic devises are analyzed using ajoint friction simulator. The polymeric couple consisted of a polymeric superhighmolecular polyethylene liner with a microporous layer and CoCrMo-alloy or alumosilicate ceramic ball heads. It is established that the moment of friction on the metallic counterbody changes sinusoidally in time. Friction strongly reduces when the specimen is lubricated with a fluid compared with the reference superhighmolecular polyethylene specimens.

Tsvetkov Yu.N., Tretyakov D.V.
Some features of plastic deformation of metallic materials during cavitation wear. pp. 82--87

Summary: Wear of an aluminium alloy by cavitation has been studied. It has been established that the layer hardened by cavitation becomes continuously thicker during the accumulative (incubation) period of cavitation wear. The maximum dependence of the thickness of the hardened layer depends on the duration of cavitation and corresponds to the completion of the accumulation period. It is shown that the maximum thickness of the surface layer hardened during the accumulation period changes leapwise when the amplitude of oscillations of the concentrator of the magnetostrictive vibrator increases. The mechanisms of cavitation effects and wear under various conditions of tests are analyzed.

Tolstoy A.V., Pushkin S.O.
Improving wear resistance of gear pumps by relieving friction units hydraulically. pp. 88--92

Summary: A pump has been designed allowing to employ the principle of hydraulic relieving of friction units more effectively. The proposed method of calculation of the components of counterpressure voids allows to reduce pressure in the contact between shafts and sleeves. The proposed modifications in the design allow to improve the wear resistance of bearing units 6-7 compared with a standard pump.

Vlasov V.M., Zelenko V.K., Zhigunov K.V., Ivankin I.S.
Triboengineering characteristics of nicotitrated structural steels. pp. 93--99

Summary: The effect of the composition of saturating ammonia and endogas mixtures on the triboengineering characteristics of structural steels has been investigated after the steels undergo combined chemothermal treatment. It is shown that the latter produces carbon nitride coatings 15--25 µm thick with a microhardness 750¸930 HV depending on the concentration of nitrogen in the saturating atmosphere. It has been revealed that nicotitrated coatings should best be treated at temperatures 650 °C in the superheated molybdenum oxide vapor atmosphere.

Rusin N.M., Kang S.B.
The effect of contact pressure on the process of equichannel angular extrusion of materials. Part I. Extrusion of samples without coatings. pp. 100--104

Summary: The effect of contact friction on he shapes of aluminum alloy specimens and distribution of deformation in the material during equichannel angular extrusion have been studied. It is demonstrated that a lubricating material effectively reduces the total force of compaction, yet the pattern of plastic flow remains non-homogenous because the design features of press tools used to implement this method of extrusion determine the flow.

MEN OF SCIENCE

Nikolai Semenovich Penkin. p. 105

Irina Alexandrovna Gribova. p. 106

CONGRATULATIONS

Avtandil Vissarionovich Chichinadze. p. 107

NEW BOOKS. p. 107

OBITUARY

Fedor Romanovich Gekker. pp. 108--109

CONFERENCE CALENDAR. p. 110

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