Трение и износ, 1997, Vol.18, No.2

Трение и износ, 1997, Vol.18, No.2

ТРЕНИЕ И ИЗНОС
Международный научный журнал
Издатель: Институт механики металлополимерных систем им. В.А. Белого НАН Беларуси, Гомель, Беларусь

Том 18, номер 2; март-апрель, 1997

СОДЕРЖАНИЕ

СТАТЬИ

Balakin V. A.
Friction in man's walking. pp. 141--146
Summary: Various diagrams of contact are considered between man's feet and support in making steps. It is shown why a man falls backwards or sideways in walking on a slippery support. The requirements are justified to shoe's soles used for walking on the slippery support.

Petrokovets M. I., Myshkin N. K., Chizhik S. A.
Some statistical models of frictional contact. pp. 147--154
Summary: Contact is discussed of real surfaces with a broad scale range of asperities. Results of simulation are presented of rough contact with adhesion. Real contact area is shown to be governed by adhesion parameter which is characterized by a relation of surface force and pull-off force of surfaces in contact.

Vasiljev Yu.N., Fugol V. A.
Structural and energy theory of friction of solids. pp. 155--162
Summary: A thermodynamic system is considered comprising two bodies in frictional contact. In the cycle involving formation of the contact, its movement over the crystallite and disruption after intersecting the boundary of the crystallite variations of the potential is demonstrated to be DG = 0. Once the contact has been formed, system's surface reduces by the doubled actual contact area. This is accompanied by heat dissipation: -DG = D WE = 2A_rE= dq, whereas DG = 0 when the contact moves over the crystallite. Disruption of the contact results in a rise of the thermodynamic potential, for which purpose a work A = DG = 2A_rE should be expended. Therefore, the specific adhesion is t₀ = 2E/L. The share of work done by the friction force to produce debris is b = 6nIE/PL. Within the measurement error, the experimental and calculated friction parameters are in agreement for some metals, carbon-based materials and polyethylene.

Chichinadze A. V., Kokonin S. S., Braun Ye. D., Matveev A. A.
Theoretical and experimental prediction of performance of multiple-disc aircraft brakes. pp. 163--173
Summary: Different combinations of materials are used in multiple-disc aircraft brakes. Stability and fluctuations of braking torque (friction coefficient) should be at the specified level, the braking is consistent and efficient, and the brake efficiency should be as high as possible to provide gradual braking and maximum wear life. Test-calculation method is proposed to assess the friction pair at the stage of design. The method is based on the theory of thermal dynamics and simulation of contact at dry friction and boundary lubrication. Particular attention is paid to the influence of the number and design of slots on rotating and stationary discs and their optimal amount in the pack.

Komarovskii I. A., Zharov I. A.
Wear simulation in wheel flange--roil pair by rollers with lateral slippage. pp. 174--180
Summary: Wear tests with rollers at lateral slippage has allowed us to identify four types of wear and to recognize the conditions when they appear. It was established that the results of modelling can be applied to side surfaces of real contact between wheel flange and rail providing the scale factor is taken into account.

Chernovol M. I., Solovykh E. K.
Calculation of solid-lubricant film thickness at friction of the composite polymer-metal coating. pp. 181--186
Summary: The article deals with the mechanism of friction of the composite polymer-metal coating. On the basis of the solution of the combined problem of heat conduction and thermoelasticity for a two-layer cylinder the calculation of the thickness of the film being formed on the friction surface of a heterogeneous antifriction material has been carried out. The testing of the theory has been performed.

Dzhanakhmedov A. Kh.
Tribological problems of oil and gas equipment. pp. 187--193
Summary: The results of field and lab analyses, experimental studies of wear resistance of parts and units of various oil and gas equipment are reviewed with the consideration of the effects of hydrogen sulfide, carbon dioxide, and abrasives containing in the crude product. Basic criteria of the failure mechanism of tribosystems are established for various conditions of operation.

Grigoriev A. Ya.
Condition monitoring of lubricated friction pair by debris morphology and neural network. pp. 194--200
Summary: In this work, an evaluation was made to prove the possibility of employing neural net method for debris classification and monitoring the process of a lubricated contact pair. We trained a neural net to define wear severity into two class from morphology features of wear debris. Following procedures were used for this purpose. First, the shape of wear particles were characterized by Fourier descriptors. The Fourier descriptors were considered as coordinates of a point in multidimensional feature space. A set of points form a cluster, and its location and structure depend on the morphology of wear particles and current conditions of the contact system. A distance distribution between the debris in the feature space was used to represent the cluster location. Second we train a back-propagation neural net. For training neural net, we used the distance distribution that corresponded to the different stage of wear process as an input vector and encoded the wear rate as a desired response. The network was then further trained until the desired error goal achieved. Finally, we tested the trained neural net. The ability of neural net method to monitor wear has been shown.

Evdokimova A. N.
Effect of environment and alternating strain on wear and hardening of steel surface layers at high-speed friction. pp. 201--204
Summary: Wear resistance and hardening are discussed at high-speed unidirectional and reciprocating friction of low-carbon steel in various gases and oils. It is shown experimentally that wear can be controlled by selecting the ambient medium. Conditions can be provided for white-layer formation which is not found in low-carbon steels usually. It is revealed that with the white layers appeared, the wear is lower at reciprocating sliding than at unidirectional one. If the white layers do not form then an opposite situation takes place. The above effect is proposed for friction hardening of machine components.

Grib V. V., Gdanskii N. I.
Calculation of friction losses in planetary-lantem gear-trains. pp. 205--212
Summary: A technique is proposed to predict friction losses in planetary gear-trains with epicyclic-lantern meshing. The technique takes into account clearances in kinematic pairs and mutual shift of links under load. Using symmetric arrangement of satellites as an example, we deduce conditions of force contact in kinematic pairs and equations for reactions at links. Moreover, a method of calculating load-carrying capacity of the gear-train is developed. Power loss factor and efficiency of the reducer are estimated.

Broide Z. S., Larin M. L., Marchenko E. A.
Structural and tribological aspects of development of "Silico" wear-resistant composite coatings. pp. 213--217
Summary: Processes running in production of multicomponent diffusion coatings by chemical-thermal treatment are discussed. The analysis of structure and tribological behavior of Silico composite coatings is presented.

Gamulya G. D., Vvedenskii Yu. V., Yukhno T. P.
Prediction of service performance of solid-lubricant coatings at friction in vacuum. pp. 218--223
Summary: On the basis of the present understanding of wear mechanism of solid-lubricant coatings at friction in vacuum there are developed the experimental and calculation methods for determining load-carrying capacity and mild wear limits, as well as predicting the service life of friction pairs with solid-lubricant coatings. The method is discussed for condition monitoring of the processing technology in production of tribological materials.

Markova L. V., Kirpichenko Yu. E., Kholodilov O. V.
Portable optomagnetic detector and its application to wear monitoring. pp. 224--228
Summary: An optomagnetic technique and device for wear monitoring is described. Optomagnetic delector (OMD) is shown to monitor wear by analyzing debris formed in friction. Comparison of the OMD and particle quantifier (PQ) is given.

Astapchik S. A., Panteleenko F. I., Lisovskii A. L., Sorogovets V. I.
Investigation of wear resistance of hardened sliding friction pairs. pp. 229--234
Summary: An internal combustion engine (ICE) crankshaft -- bushing pair was investigated. An optimal wear-resistant coating material and efficient method to apply it to ICE journal with further machining was found. An optimal hardness and roughness of the crankshaft surface were determined at which the sliding pair has the highest wear resistance. The technique for restoring ICE crankshaft combining plasma facing, laser and ultrasonic treatment is proposed.

Ginzburg B. M., Tochil'nikov D. G., Bulatov V. P.
Effect of fullerene C₆₀ upon steel-on-steel sliding at boundary lubrication. pp. 235--239
Summary: The influence of fullerene C₆₀ as additive to industrial oil was investigated at sliding friction of steel on steel. The oils with additives of C₆₀ powder (1--5 wt.%) has shown only a weak trend to decrease the friction coefficient in comparison with the base oil. However the antiwear and antiscoring properties of the oils with C₆₀ additives have shown the great improvement comparing to the base oil. In particular, the wear volume decreases two to ten times and the interval of the permissible loador pressure has widened by a factor of 1.5--2.0.

Boltushkin V. I., Goltsev V. P., Goltsev M. V.
Effect of compositions of ion-plasma coatings upon their tribological behavior. pp. 240--243
Summary: Protective coatings based on the Ti--Zr--N nitride system were applied by combining plasma fluxes. Variations of the modes of application have yielded coatings with different concentrations of components. The pattern of wear of the coatings has been investigated in order to identify optimal concentrations to achieve the least wear.

Novitskii V. G., Tikhonovich V. I., Kalchuk N. A.
Fluid erosion of chromium steels 110X15 and 110X15MБ recommended for through flow portions of hop mills. pp. 244--248
Summary: The effect of the original structure of steels 110X15 and 110X15MБ upon their resistance to fluid erosion has been investigated. The steels with the martensite structure have manifested the highest wear resistance in water. Steel 110X14MБ has manifested the maximum resistance in the beer due to the equal concentrations of martensite and austenite in the original structure.

Ershov B. I., Andrianov D. N.
Experimental investigation of fluid leakages in small annular clearances. pp. 249--253
Summary: Behavior of leakages in small annular clearances (5...25 µm) depending on pressure is described by the known formulas. At relatively low pressures the leakages measured agree with calculated values and disagree with them at high pressures. The experiment carried out for a piston pair at two different clearances indicates that the processes running in a thin fluid layer beyond the limits of the initial working pressures (10...20 MPa) at small annular clearances require sophisticated theoretical justification.

Gromakovskii D. G., Kolerov O. K., Logvinov A. N., Tregub B. I.
Estimation of failure activation energy in metals and alloys by their microhardness. pp. 254--257
Summary: It is described the technique for estimating activation energy in metals and alloys failure by their microhardness developed in Samara State Engineering University. It is shown that activation energy and structural-sensitive coefficient of life kinetic level can be estimated reliably by standard microhardness meters equipped with a heater.

ОБЗОРЫ

Krasnov A. P., Gribova I. A., Chumayevskaya A. N.
Chemical structures of polymers and tribochemical transformations in polymers and filled systems. pp. 258--279
Summary: Publications are reviewed relating to the identification of some regularities in relationships between the chemical structures of the repeating unit, the macromolecular chain (linear, branched, crosslinked structures), deviations in structure of repeating unit and structure of polymer bodies, polymer mixtures, tribochemical transformations in polymers, filled systems and the frictional behavior (the friction coefficient and wear) typical for different classes of polymers, such as carbochain, carbocyclochain, heterochain and heterocyclochain polymers.

Drozdova E. Yu.,Yudin E.G.
Some aspects of tribology progress in Japan. pp. 280--284
Summary: Publications in the area of space tribology, ecotribology, novel tribomaterials, sliding bearings with ferrofluids, contact hydromechanics, stepless frictional transmissions have been reviewed. A harmonized progress of experimental and theoretical research supported by sophisticated instruments, hardware, and software is described. Fundamental and applied research is oriented at industries and is highly effective. It is concluded that there are strong efforts in Japan to expand tribological research and to promote its quality.

ЛЮДИ НАУКИ

Mark I. Petrokovets (To 60th anniversary). pp. 285--286

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