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NECESSATY OF QUALITATIVE TRIBOSYSTEMS DEVELOPMENT FOR OUTER SPACE
Drozdov, Yuri. N ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 1999 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.1999 No.-
It is stated the particularity of friction units operation in deep space: absence of the oxidising atmosphere, the vacuum presence, the sublimation of materials elements, heightened evaporability of lubricants, the heat density, high gradient of temperatures, the space radiation, the zero gravity, the micrometeorites influence, the effect of vibratory and impact loads at start and landing stages of space vehicles, the complication of the liquid oils application. What with comparatively limited energetic resources of autonomous space systems, seeking for the minimisation of mass and dimensional characteristics, the obstructivity of the repair(the maintenance) advisable at the design stage to determine expectable energy losses, the reliability of tribological systems. Inapprehension of the problem relevance leads to breakdowns and catastrophes in space.
Drozdov, A.D.,Al-Mulla, A.,Gupta, R.K. Techno-Press 2012 Advances in materials research Vol.1 No.4
Results of isothermal torsional oscillation tests are reported on melts of linear low density polyethylene and isotactic polypropylene. Prior to rheological tests, specimens were annealed at various temperatures ranging from $T_a$ = 180 to $310^{\circ}C$ for various amounts of time (from 30 to 120 min). Thermal treatment induced degradation of the melts and caused pronounced decreases in their molecular weights. With reference to the concept of transient networks, constitutive equations are developed for the viscoelastic response of polymer melts. A melt is treated as an equivalent network of strands bridged by junctions (entanglements and physical cross-links). The time-dependent response of the network is modelled as separation of active strands from and merging of dangling strands with temporary nodes. The stress-strain relations involve three adjustable parameters (the instantaneous shear modulus, the average activation energy for detachment of active strands, and the standard deviation of activation energies) that are determined by matching the dependencies of storage and loss moduli on frequency of oscillations. Good agreement is demonstrated between the experimental data and the results of numerical simulation. The study focuses on the effect of molecular weight of polymer melts on the material constants in the constitutive equations.
THE BASICS OF LIFE CALCULATION OF CYLINDER PLAIN JOURNAL BEARING BY WEAR CRITERION
Drozdov, Y.N.,Kovalenko, E.V. ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 1999 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.1999 No.-
An algorithm for the calculation of the durability of cylinder plain bearings is developed on the basis of the wear equation obtained by the methods of similarity theory and the analysis of dimensions. The equation contains a number of dimensionless complexes describing mechanical, thermal and chemical properties of bodies in contact.
REFINED MATHEMATICAL MODEL OF A BINARY GAS BEARING IN WIDE RANGE OF KNUDSEN NUMBERS
Drozdov, Y.N.,Yemelyanov, I.A. 경북대학교 트라이볼로지연구소 2001 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.2001 No.-
The experimental technique for high strength yarn's cut resistance measurement was proposed Transverse cut tests at various angles of cutter blade inclination were performed on Zylon, Kevlar and Spectra yarns to evaluate the cut resistance of high strength fabrics and to investigate the failure mechanism involved in the cutting process. The effects of blade angle of inclination on the yarn's cut resistance were presented. In tests with a utility blade ( 2 ㎛ radius of curvature), Zylon required 4 times as much energy per linear density than other two materials, for cut-through at 0° angle of inclination. This fracture energy decreased sharply with increased inclination angle, as did the strain corresponding to the initiation of fiber failure.
PREDICTION OF WEAR OF RUBBING BODIES ON THE BASE OF A THEORETICAL-INVARIANT METHOD
Drozdov, Yu. N.,Ignatieva, Z.V. ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 2000 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.2000 No.-
A theoretical-invariant method of friction units service life prediction is developed based on the combining some deterministic and probabilistic approaches to the problem of surface failure taking into consideration a number of mechanical, physico-chemical, thermal aspects of contact interaction of rubbing bodies.
CONTACT STRESSES IN PLAIN BEARINGS
Drozdov, Y.N.,Ushakov, B.N. ENGINEERING TRIBOLOGY RESEARCH INSTITUTE KYUNGPOOK 1998 INTERNATIONAL SYMPOSIUM ON HIGH PERFORMANCE OF TRI Vol.1998 No.-
A calculation-experimental method of contact stress analysis in plain bearings is reported. The method is based on a hybrid use of the finite element method and photoelasticity. The results of contact pressure and contact angle determination in hinge joints as functions of magnitude and direction of load are presented. Contact stress distributions in three-dimensional machine elements with plain bearings have been investigated taking account of real deformations. Some directions of improvement for contact stress distribution and increase of wear service life and reliability are discussed.
Yu. N. Drozdov 한국트라이볼로지학회 2002 한국트라이볼로지학회 학술대회 Vol.2002 No.10
In XXI century it is necessary to expect the recommencement and development of activities on mastering the Moon. In the long term it is construction of manned lunar bases with industrial, astrophysical, procuring, repair equipment and services. Interplanetary flights from the Moon demand smaller power expenditures, than from the Earth, therefore it is favourable to use its surface for the construction of space-vehicle launching sites. Flights of devices in libration points in the system "Earth - Moon" are considered. Experience of engineering system creation for the Moon displays the great complexity in provision of serviceability and reliability of friction units. Open friction units should operate under following conditions on the Moon: pressure of environment (vacuum) p < 10?¹? ㎩; wide range of temperature change +150℃ ...-l70℃; high evaporability of lubricants; influence of temperature gradients and warping of constructions; sublimation of elements of constructional materials; irradiation of different physical nature; effect of micrometeorites; reduced gravitation; influence of abrasive particles of lunar ground; requirements on minimization of size and weight characteristics of a construction (high tension); undesirability (impossibility) of application of liquid and plastic lubricants; vibration, shock, acoustic loadings during start and landings to the Earth; difficulties in repair-regenerative operations in conditions of the Moon etc. Adhesive interaction of conjugated surfaces is the principal reason of possible failures of rubbed units on the Moon. In the research of the Moon automatic interplanetary stations of "Luna" (USSR), "Surveyer", "Apollo" (USA) series were used. Stations executed functions of flying, landing, artificial satellites of the Moon, moon-rovers and manned spacecrafts such as "Apollo". The experimental-theoretical researches carried out in the sixtieth years on tribology for conditions of the Moon appeared to be rather useful to engineering of an outer space exploration and the decision of complex problems for the friction units operating in extreme conditions on the Earth. For the creation of highly loaded friction units for the long service life on the Moon it is required not only to use accumulated experience and designed technologies, but also to carry out wide scientific research.