Трение и износ, 1997, Vol.18, No.5

Трение и износ, 1997, Vol.18, No.5

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

Том 18, номер 5; сентябрь-октябрь, 1997

СОДЕРЖАНИЕ

СТАТЬИ

Kuzmin N. N., Feldshtein I. V.
Dynamics of chaos in friction. pp. 571--577
Summary: Poor reproducibility of experiments and high sensitivity of their results to test conditions have been observed repeatedly. The cases are well-known when the same tribosystems operating under similar conditions demonstrate service lives different by orders of magnitude. This paper presents results of theoretical and experimental study of dynamic behavior of tribosystem. The results show that the behavior is governed by inherent features of the system, and not just random external action.

Evtushenko A. A., Ivanik E. G., Gorbacheva N. V.
The influence of convective cooling on the temperature and stress state at braking. pp. 578--587
Summary: A method is proposed for predicting the transient temperature field and its associated quasi-stationary thermal stresses which occur due to heat generation at braking with constant deceleration. The convective heat exchange with environment is taken into account.

Serdobintsev Yu. P., Ivannikov A. V.
Prediction of wear rate for precision friction pairs of production equipment. pp. 588--594
Summary: Relationships were obtained to predict wear rate and service life of sliding guides with account for machine tool use, time of idle motion, and other factors. The relationships started from assumption of the same wear of real pair and its model. They are true for guides operating at constant pressure profile during wear.

Nazarov A. D.
Influence of total unbalanced mass of crank mechanism parts on wear of crankshaft main bearings and engine life. pp. 595--602
Summary: Fundamentals and technique were developed for estimating an influence of total unbalanced mass of crank mechanism parts on the late and uniformity of wear of main journals, upper and lower main linings, on a rise of mean clearance and its coefficient of nonuniformity in crankshaft main bearings, as well as on engine life. It was demonstrated that during service or accelerated bench tests we can restrict our study of the influence to a rise of mean clearance and nonuniformity coefficient of clearance. In this case the time and cost needed for testing decrease 2.7--3.4 times.

Zernin M. V.
Simulation of damage in sliding bearing based on failure criterion. Part 2. Finite element models of lubricant flow. pp. 603--611
Summary: A subroutine library of various contact finite elements is devised to simulate different regions of the contact zone based on various models of liquid, boundary, and unlubricated friction. The library will serve to solve a problem for the bearing whose different portions of contact operate under different conditions of lubrication. Two-dimensional finite element models of the liquid laminar flow between two surfaces are described in detail. Suitable finite elements of the first order with three and four nodes and of the second order with eight and nine nodes are constructed.

Korochkina T. V., Meshkov V. V.
Stress state analysis of moving precision contacts in pump under dynamic loading. Part II. Distributor disc -- thrust bearing. pp. 612--617
Summary: With the finite element method a stress state is evaluated of the rubbing precision components of axial-piston pump operating at high velocities and various loads. A dependence of stress arising from impact load on time and friction force is obtained. The most dangerous domains of high stresses are defined. Based on the results of the analysis, the recommendations are elaborated to improve the design and choice of materials of a tribosystem with the goal of enhancing its performance.

Konchits V. V., Kim Ch. K.
Heating of contact spots by electric current. Part 2. pp. 618--625
Summary: Experimental data are demonstrated relating to the regularities of current passage and heat liberation in static contacts with thin tunnel-conductive surface films. The results have been analyzed from the point of view of simulation of heating conditions in the contact zone when electric current is passed. It is demonstrated that current passage through the contact is accompanied by the appearance of a channel (bridge) with elevated conductivity, even in extremely thin films. It leads to the localization of the Joule heat predominantly in the vicinity of the appearing bridge excluding regular heating of the contact area. The parameters are evaluated of the appearing bridges for several situations.

Dzhilavdary I. Z., Rusak A. A.
Direct measurement of small forces and coefficients of friction. pp. 626--630
Summary: A new method for measurement of low friction is described. It is based on the registration of free pendulum acceleration when passing the equilibrium point. Its theory and an estimate of instrumental and systematic errors are presented. A dependence of the friction torque on rotational speed is studied experimentally for an instrument rolling bearing. It is concluded that the method.

Zharov I. A., Konkova T. E.
Steady wear of rubbing bodies. pp. 631--635
Summary: A problem on shape of mating bodies which is formed at their rubbing is formulated. The methods of its attack are advanced.

Balakin V. A., Galai Ye. I.
Thermal conditions for electric train brake at speed control of block pressing force. pp. 636--642
Summary: This is discussed the problem of thermal conditions in the block--wheel contact zone in case of urgent braking at speed control of normal load. The formulas are derived for calculating the coefficient of heat flow distribution, heat layer thickness, temperature fields in block and wheel, as well as temperature fluctuation amplitude on the wheel rolling surface.

Ryzhov Ye. V., Sakalo V. I., Khokhlov V. M.
Wear at boundary lubrication. pp. 643--646
Summary: New technique and formulas for predicting wear at elastic contact are proposed which can be used in design of friction pairs of different machines and mechanisms. Calculated results are in good agreement with well-known experimental data.

Dmitrieva T. V., Sirovatka L. A., Bortnitskii V. I.
Study of thermo- and tribodestruction of some nitrogen- and sulfur-containing compounds. pp. 647--654
Summary: Mass-spectrometry has been employed to investigate the compositions of volatile products and the intensity of their liberation during tribodestruction of urea, thiourea, thiosemicarbazide and potassium rhodanide as potential modifiers of metallic surfaces during their thermochemical and mechanochemical treatment. It has been established that the time and intensity of liberation of the volatile products during tribodestruction reach their maxima in sequence urea, thiourea and thiosemicarbazide in accordance with their thermal stability.

Burya A. I., Arlamova N. T., Burya A. A., Ilyushenok V. V., Cherskii I. N.
Investigation of service characteristics of low-filled phenylone. pp. 655--662
Summary: The influence of ultradispersed fillers based on silicon nitrides on thermal, mechanical and tribological properties of composites based on aromatic polyamide Phenylone C-2 was investigated. Filler contents of 0.2--5.0 mas.% are shown to produce high mechanical properties, wear-resistance, and low coefficient of friction.

Krasnov A. P., Fedorova L. S., Gribova I. A., Afonicheva O. V.
Tribochemical processes in coatings based on blends of cross-linked polymers. pp. 663--668
Summary: The properties of antifrictional coatings based on blends of polyaminoimide and ureaformaldellyde oligomer were investigated. Nonadditive enhancing of tribochemical characteristics was observed. High antifrictional properties of coatings based on copolymer of polyaminoimide and ureaformaldehyde oligomer are related to special character of tribochemical degradation involving active decomposition of ureaformaldehyde component and high stability of polyaminoimide one. Similar behavior of the polymer blends at friction is mainly caused by two factors: the difference in components thermal stability and higher adhesion to filler and underlying material.

Zaitsev A. L., Pleskachevskii Yu. M., Kirilenko V. P.
Chemophysical processes induced by friction between ethylene glycol, iron and its oxides. pp. 669--677
Summary: It has been endeavored to identify chemophysical processes during friction under boundary lubrication conditions by investigating the thermoactivated reactions of ethylene glycol with metallic iron and oxide compounds. Thermogravimetry and pyrolytic mass-spectrometry have revealed a relationship between the conditions of frictional interactions and the presence of predominantly oxide or hydroxide films on the metallic surface inducing various chemophysical processes. Decarboxylation and destruction of multiatomic alcohol are typical for the friction over the oxidized iron surface. Friction on the metal coated with a layer of hydroxide is accompanied by the appearance of surface alcoholates followed by their transformation into other stabler compounds and by the processes of dehydration, destruction and oxidation.

Kozak N. V., Kosyanchuk L. F., Nizelskii Yu. N., Gorbatenko A. N.
Thermal characteristics of epoxy and polyisocyanate compositions as possible binders for brake materials. pp. 678--682
Summary: The results are given of analysis of thermal characteristics of oligoepoxyether and polyiso-cyanate-based polymer systems as possible binders for brake materials as well as characteristics of brake blocks made on their base. The investigation performed indicates the improvement of friction material thermal stability when using the binders in question.

Evdokimova A. N.
Improvement of tribological performance of tin bronze by applying high-speed alternating friction. pp. 683--686
Summary: Possibility is shown of improving the tribological performance of tin bronze treated by friction with alternating strain and supply of various lubricants into the contact zone.

Potekha V. L.
Application of harmonic analysis to tribological tests of materials. pp. 687--693
Summary: Cyclic variation ill tribological parameters of rubber-metallic tribosystems was revealed experimentally. A method is proposed how to present and analyze experimental data by the correlation squares. It is demonstrated that the test results can be presented in the form of harmonic series (trigonometric polynomials). As it follows from the harmonic analysis, parameters of the series are influenced by surface roughness of the steel shaft being a part of the tribosystem. These parameters can be used to predict wear of tribosystems.

ОБЗОРЫ

Rodnenkov V. G.
Investigation of tribological behavior of liquid crystals. Part III. Applications of liquid crystals in tribosystems. pp. 694--705
Summary: Applications of liquid crystals in various real friction units are described and their effectiveness as components of water-and oil-based coolant-lubricants is demonstrated. Liquid crystals reduce the run-in period of internal combustion engines and manifest high wear resistance. Applications of liquid crystals for correction of human articular pathologies are illustrated.

КОРОТКИЕ СООБЩЕНИЯ

Gaivoronskii A. A., Rastikhin A. V., Kareva A. A.
Effect of thickness of the copper undercoating upon the shear stress in steel -- hard alloy couples under high contact loads. pp. 706--707
Summary: The effect of thickness of the copper undercoating upon the shear stress at start and in motion of copper - hard alloy couples has been evaluated experimentally for various lubricating materials.

ХРОНИКА

News of the International Tribology Council. p. 708.

КАЛЕНДАРЬ КОНФЕРЕНЦИЙ. pp. 709--710.

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