Том 46, № 1 (2017)

A forecasting model of the remaining lifetime of a diagnosed oil and gas pipeline is suggested depending on the strength reliability factor: the survival probability when the breaking point, pressure, diameter and wall thickness are regularly distributed, and the remaining lifetime is subject to a Weilbull two-parameter distribution.

The article provides the results of structural calculation of cooling of a nickel mold of continuous casting machine for cylindrical billets, superheated to 180°C with water at a density of the supplied heat flow of 1.5–3.3 MW/m². The novelty of the work has been confirmed by a patent for an invention.

This work is devoted to studying the compression of cavitation bubbles by viscous liquid and the rate of steam compression in it within a wide range of Reynolds numbers. The influence of heat conductivity in bubble, the compressibility of liquid and evaporation/condensation on the surface of the bubble have been studied. It has been shown that the maximal pressure inside of the bubble increases sharply in a small neighborhood of some critical value with growth in the Reynolds number. This critical value is close to the one established by Zababakhin, which separates regimes of the bubble collapse in incompressible liquid for finite and infinite times.

Bending oscillations of walls of conduit on Winkler foundation under the influence of pulsating flow of viscous liquid have been studied. The statement and solution of hyper-elasticity problem have allowed analytical expressions for channel wall bends and pressure in liquid to be defined, as well as the distribution functions for bend amplitudes and pressures along the channel to be plotted. The performed calculations showed the significant impact of taking into consideration the elastic compliance of the channel foundation on the bend amplitude of channel walls and pressure in the channel. The obtained results present the possibilities of studying the dynamic processes conditioned by the interactions of elastic structural elements with viscous liquid in hydraulic drives, assemblies, and devices.

The article proposes criteria and methods for estimating the adaptive properties of mechanical systems, such as sliding bearings, worm gears, and internal combustion engines. The examples of estimating the adaptation effects under the conditions of using the film-forming lubricants have been given.

The research results of experimental aluminum alloys intended for the possible replacement of costly bronzes in the friction units of railway transport have been presented. The preliminary selection of alloys was carried out by the sclerometry technique on the criterion of relative shear strength as more informative compared with microcutting contact stress. The tribotechnical tests of selected alloys were performed by the three-finger scheme, which simulates the work of supporting the sliding bearing. In principle, the test results confirmed the possibility of using these alloys as substitutes for bronze. The structure and chemical composition of surface both the original samples and the samples after testing was studied. The influence of the alloy’s chemical composition on the tribological properties of investigated alloys has been revealed.

In this paper the problem of optimizing a distribution of carbon fiber content in hybrid glass/carbon fiber reinforced (GFRP/CFRP) structural elements of plane, statically determinate regular elastic truss structure is discussed. A modification of genetic algorithm combined with the method of mathematical induction is proposed. A criterion of structural materials cost minimization while satisfying elastic strength requirements is used as an optimality criterion.

This article suggests a method of controlling an artificial arm by foot and leg action. The functional design of a wrist with pneumatic bellows that are controlled by contact sensors installed on inner soles has been presented. A remote-control system has been developed for ease of manipulation. A workable artificial arm model has been made that allows differently shaped objects to be gripped.

The touch-sensitive direct-filling dispenser, in which the dose is defined by the distance between the sensor of the position of the free-floating piston located on the external side of the measuring sleeve, has been described. The factors that most significantly affect the dosing errors have been analyzed. The results of the experimental study of the dosing accuracy that depend on the pressure in the product pipeline and dispenser control algorithm have been given.