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Geometrical modeling of geodesic lines on computer gears in Novikov transmission

100%

Nikitenko O. , Kernytskyy I. , Kovalova G. , Kalinin A.

tom Vol. 32

65--71

The theory of geodesic lines according to the authors is of interest from an applied point of view. Since the movement of many types of mechanical systems, as well as bodies or particles in gravitational or electromagnetic fields, in a continuous medium often occur along trajectories that can be considered as geodesic of certain spaces or surfaces. When two surfaces are conjugated, the line of their contact is also geodesic. This property can be used to design conjugated cyclic helical surfaces that occur in Novikov's gearing. In this paper, the equation of the geodesic line for such surfaces is obtained by minimizing the length of the curve. To confirm the obtained results, several geodesic lines were built in the graphic editor, the beginning of which was at point P (2, 0, 0), and computer models of Novikov gears with geodesic lines applied to them were also presented.

Teoria linii geodezyjnych jest interesująca z praktycznego punktu widzenia. Ruch w wielu typach układów mechanicznych, a także ruch ciał lub cząstek w polach grawitacyjnych lub elektromagnetycznych często odbywa się wzdłuż trajektorii, które można uznać za przestrzenne lub powierzchniowe linie geodezyjne. W trakcie kontaktu dwóch powierzchni linia ich styku jest również geodezyjna. Ta własność może być wykorzystana do projektowania sprzężonych cyklicznych powierzchni śrubowych, które występują w przekładni Novikova. W niniejszym artykule równanie linii geodezyjnej dla takich powierzchni otrzymano metodą minimalizacji długości krzywej jako funkcjonału. W celu potwierdzenia uzyskanych wyników, w edytorze graficznym, skonstruowano kilka linii geodezyjnych. Ponadto przedstawiono modele komputerowe przekładni Novikova z zastosowanymi do nich liniami geodezyjnymi.

Prospects of electrosleep therapy devices for long-distance drivers

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Kernytskyy I. , Storchun Y. , Yakovenko Y. , Horbay O. , Humenuyk R. , Sholudko Y.

tom Vol. 29, No. 4

454--460

Accomulated exhaustion is a fairly common problem for long-distance truck and bus drivers on international routes. In case of uncompensated exhaustion, the driver is unable to overcome the resulting attention violations with will effort, which increases the probability of errors and accidents. The last claim is confirmed by the increase in the number of incidents after 7 h and especially 10 h of work. To overcome this problem, it is necessary to stop and fall asleep for a short time. Recovery comes in about 10–15 min of relaxation. The source of stimulation of the brain is weak impulse current, which causes sleep of varying depth and duration. Clinical studies have shown that the strongest impact is on pulses with a duration of approximately 0.3– –0.5 ms and a frequency of repetition ranging from 0.5–2 to 80–100 Hz. Current levels are typically between 50 and 5 mA. Transcranial electrotherapy is considered to stimulate endorphin production and affect the hypothalamus, causing changes in neurohormonal regulatory mechanisms and reticular formation of the brain stem. The reticular formation is involved in many behavioral reactions and has a significant impact on body functioning and thought processes. The aim of this work was to determine correlation between human brain biorhythms and electrosleep device signal by calculating mutual correlation. For this purpose, the model in MATLAB Simulink environment was developed. The encephalogram was processed using the EEGLAB tool to remove artifacts. A model in the MATLAB Simulink environment was developed to evaluate the effect of the signal characteristics of electrosleep therapy devices on brain biorhythms, with the help of which correlation coefficients were calculated.

Dynamic properties of screw-bolts connections of sowing machine

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Snitynskyy V. , Kernytskyy I. , Diveyev B. , Horbay O. , Burtak V. , Humenyuk R.

2019

tom Vol. 28, No. 4

584--593

A vehicle is a complicated system under the influence of vibration caused by an inequality of the road surface, variable speed, unbalance of the rotating elements. The main factors influencing the relaxation of threaded connections (TC) are the amplitude, frequency and gradient of vibration. Although the frequencies of these oscillations are distributed over a wide range, the general effects of dynamic loading on bolted connections are similar. Main effects: (1) loosening the nut/bolt and (2) failure due to fatigue failure. The analysis of the technological process of agricultural machinery shows that the main external factors influencing their work are the profile of the surface of the field, the hardness and moisture of the soil, the speed of the unit, the instability of the engine, the traction of the wheels of the tractor and others. To study the integrity of TC, which is tested on the stand, consider the design scheme of nonlinear oscillations of the design in the presence of gaps in the TC. The study was conducted in two modes of movement of the drill: with tightened bolts and weakened bolts. For the survey, the method of spectral analysis of multidimensional periodically non-stationary random signals was used. In the process of testing, the dynamic loading of bolted joints installed on the respective knots and components of the drill was evaluated. From the conducted research it follows that the maximum vibrations acting on the TC of the drill may be in the vicinity of high-frequency resonances of TC. In parallel, nonlinear mathematical models of the oscillations of the seeder and the weakened TC were developed. The theoretical results qualitatively correspond to the experimental data.