ANALYSIS OF THE GENERAL EQUATIONS OF THE TRANSVERSE VIBRATION OF A PIECEWISE UNIFORM VISCOELASTIC PLATE

This article discusses the analysis of the general equations of the transverse vibration of a piecewise homogeneous viscoelastic plate obtained in the “Oscillation of inlayer plates of constant thickness” [1]. In the present work on the basis of a mathematical method, the approached theory of fluctuation of the two-layer plates, based on plate consideration as three dimensional body, on exact statement of a three dimensional mathematical regional problem of fluctuation is stood at the external efforts causing cross-section fluctuations. The general equations of fluctuations of piecewise homogeneous viscoelastic plates of the constant thickness, described in work [1], are difficult on structure and contain derivatives of any order on coordinates x, y and time t and consequently are not suitable for the decision of applied problems and carrying out of engineering calculations. For the decision of applied problems instead of the general equations it is expedient to use confidants who include this or that final order on derivatives. The classical equations of cross-section fluctuation of a plate contain derivatives not above 4th order, and for piecewise homogeneous or two-layer plates the elementary approached equation of fluctuation is the equation of the sixth order. On the basis of the analytical decision of a problem the general and approached decisions of a problem are under construction, are deduced the equation of fluctuation of piecewise homogeneous two-layer plates taking into account rigid contact on border between layers, and also taking into account mechanical and rheological properties of a material of a plate. The received theoretical results for the decision of dynamic problems of cross-section fluctuation of piecewise homogeneous two-layer plates of a constant thickness taking into account viscous properties of their material allow to count more precisely the is intense-deformed status of plates at non-stationary external loadings.

MODELING THE HYDRAULIC CHARACTERISTICS OF DRAIN VALVE AND BURST FITTING OF AN AIRCRAFT ACCIDENT-RESISTANT FUEL SYSTEM

The article discusses methods for determining the hydraulic resistance of units of an accident-resistant fuel system. A detailed description of the need to create such fuel systems for modern helicopters is given. The development of such systems today is impossible without the use of the method of mathematical modeling, which allows to qualitatively solve problems arising in the design process. To obtain accurate research results, it is necessary to have a complete description of all elements and assemblies of the system. Methods for determining the hydraulic characteristics of AFS elements using the drag coefficient, reference literature and CFD codes are considered. As the investigated AFS units, a drain valve and burst fitting were studied in the article. A hydraulic calculation of these AFS elements ware performed, the simulation results are presented in the ANSYS CFX software package. Also as the calculation results of bursting fitting, the pressure distribution fields of full and static pressure, velocity and streamlines are also shown. An experimental setup for validating the results obtained using the mathematical modeling method is considered, as well as a methodology for conducting a full-scale experiment to determine the hydraulic resistance of the unit. Materials have been prepared for inclusion in a one-dimensional mathematical model of an accident-resistant fuel system.

KINEMATIC FEATURES OF THE LAPPING PROCESS AND DETERMINATION OF ITS BASIC PARAMETERS

This paper discusses the kinematic characteristics of lapping process and the main parameters of the process. It was determined that the influencing degree of technological parameters to the forming surface and processes. It was projected the construction of the lapping head for processing of internal cylindrical surfaces, scheme of the lapping operation and graphic description of the forces influencing. The relationships between the axial, radial and tangential cutting forces and the effect of the combined force thereof are determined in order to ensure the necessary surface pressure. During the analysis geometric and mathematical relationships were obtained. The extracted analytical expressions can be realized by further experimental researches and can be used in engineering calculations of technological parameters of processing by lapping. Angular velocity, friction force, linear velocity, also the length of the tactile curve and the radius of the part can be considered the main kinematic and dynamic parameters of the process that the formation of the surface, also the course of the process depends on these parameters. Depending on the kinematic parameters, the wear nature of the tool changes and this changes the linear and angular velocities, which have a significant impact on the accuracy, quality and productivity of processing. When examining the technological capabilities of the process, the nature of the movement between the part and the grinding tool, also changes in cutting speed are often considered as a main factor. Analytical expressions were obtained to determine the main parameters of the process, taking into account the kinematic characteristics of the friction process. These expressions can be used in engineering calculations and allow to determine the optimal values of the processing mode. In order to obtain the required micrometric surface cleanliness and measurement accuracy, correlation relationships were established between the main parameters of the process, equations of the equilibrium system of shear forces were compiled and analytical expressions were obtained based on the analysis of kinematic and dynamic properties of the system.

REDUCED MODEL OF PLASMA DISCHARGE CONTROL IN TOKAMAK WITH IRON CORE

A reduced model has been developed to describe the time evolution of a discharge in an iron core tokamak, taking into account the nonlinear behavior of the ferromagnetic during the discharge. The calculation of the discharge scenario and program regime in the tokamak is formulated as an inverse problem - the optimal control problem. The methods for solving the problem are compared and the analysis of the correctness and stability of the control problem is carried out. A model of “quasi-optimal” control is proposed, which allows one to take into account real power sources. The discharge scenarios are calculated for the T-15 tokamak with an iron core.

A STUDY OF CARBON NANOTUBES ENERGETICS USING ORBITAL FREE METHOD IN THE FRAME-WORK OF THE DENSITY FUNCTIONAL THEORY

Dependence of the binding energy of carbon atoms in nanotubes on the tube diameter is studied. The full-electron orbital free modeling method, developed by us in the framework of the density functional theory, was used for calculation of the binding energy. Nanotubes of limited lengths with the armchair ends were investigated. The tube diameter D, was varied from 0,68 nm up to 1,50 nm; numbers of included atoms were changed from 80 up to 320. Three sets of tubes were studied: the tube length was 0,87 nm in the first set, 1,36 nm in second set, and 1,86 nm in the third set. For the first set the energy minimum (-7.50 eV) was found at Dmin = 1,22 nm, for the second set (-7.62 eV) at Dmin = 1.00 nm, and for the third set (-8.01 eV) at Dmin = 1.06 eV.

THE MECHANISM OF ANOMALY OF CHARGED PARTICLES BEFORE THE EARTHQUAKE

Some mechanisms are considered in the form of analysis of the propagation and origin of charged particles involved in acting forces in energy transfer processes that lead to a highly deformed seismically active state and create the necessary conditions for the occurrence of an earthquake. The results of monitoring the registration of charged particles of radioactive radiation of the earth’s crust for the purpose of earthquake forecasting are analyzed. During monitoring, responses to the origin of an event - an earthquake-are observed in the behavior of charged particles, which are located on remote parts of the earth’s crust relative to the place where charged particles are registered. In this case, wide horizons of the earth’s crust are involved, where tectonic disturbances are developed, covering not only the deep layers of the earth’s crust, but also the sections that appear in the upper parts. These tectonic disturbances can be considered as through-current channels that facilitate the transfer of energy from great depths. On the earth’s surface, the behavior of charged particles should be considered within the framework of the action of geomagnetic and atmospheric electricity fields. These fields at the earth’s surface are a carrier field that provides a special transfer of not only energy and matter. Thus, the propagation of charged particle flows over considerable distances from the epicenter of earthquakes can be caused by the carrier fields of deep change processes.

MANAGEMENT MODELS OF DATA COLLECTION PROCESSES IN IOT NETWORKS WITH THE DYNAMIC STRUCTURE

The collection of data from the network with dynamic structure is a complex process that must be performed with considering of security, energy efficiency and latency requirements. To determine the optimal data collection models that meet the stated requirements, the authors analyzed models and methods of data collection in dynamic networks, as well as management processes of data collection. The study allows to determine the most effective technologies for data collection in dynamic networks, which include Fog technologies and clustering technologies. Based on the analysis, the authors have developed the model for data collection managment, which allows to construct and rebuild the structures of data collection models in accordance with the requirements and conditions of data collection. The developed approaches and principles were successfully implemented in practice: a system of data collection was tested for the crane complexes, which is designed to work at production sites. In general, the study allows to identify methods and tools that effectively solve the problems of data collection in the networks with dynamic structure, and to demonstrate the solution of these problems in practice.

INFLUENCE OF THE BASICITY INDEX ON WELDING ELECTRODE COATINGS ON THEIR WELDING AND TECHNOLOGICAL PROPERTIES

At this article presented the results of researches on studying of influence of basicity index BI of the electrode coating and the Melting Temperature Tm of the slag of electrode coatings consisting of a two-component CaO-SiO2 oxide system and ore-mineral raw materials of the Republic of Uzbekistan on the welding and technological properties of the welding electrodes. The relationship between these indicators was determined, the strength of linear correlation of which was estimated using the coefficient of determination R2. The influence of the BI value on such properties of the welding electrode as the breaking length of the arc, the formation of the deposited metal, and the formation of a visor or cover at the end of the electrode is established. Based on the research results, recommendations for the basicity index BI of the electrode coating were identified, which can be used in the development of electrode coating compositions for their effective impact on the welding and technological properties of welding electrodes.

https://urvak.ru/articles/compu-8014-vypusk-3-analiz-obshchego-uravneniya-po/

In article occurrence of earthquakes and mountain blows and their communication by volcanic processes occurring in a kernel is analyzed. Mathematical modeling is resulted, uniting occurring processes in a kernel, occurrence Р-longitudinal shock waves and the S-intensity before earthquakes. In the given work it is considered, how by means of mathematical modeling it is possible to create model of occurring events and to untangle communication of seismic signatures of pushes arising from seismic processes. Such method of modeling will allow to create the three dimensional image of earth crust and to show in interaction of tectonic plates as the forces creating and pushing the formed break change in due course. For this purpose it is necessary to enter the seismic given districts that the model corresponded to supervision of how the plate is deformed to and during time, and after earthquake. It will help to draw conclusions on what forces operate on plate border - plates and as it is deformed, handing over the fluctuation information outside and as in things in common one plate dives into a hot viscous cloak of the Earth. In it to a floor the fused layer firm breeds exude and behave in the unexpected image, therefore the understanding of general dynamics of a status of a kernel can help to define communication between pressure along a break before earthquake. The problem of influence of mobile loadings on layers arises from a kernel of the earth a striking power of boiling magma, a surface top a piecewise homogeneous two-layer plate-plate the running wave along a x axis with constant speed V0 normal loading extends. The blows which are starting with a kernel of the Earth from an event volcanism, creating running waves in earth crust it is described by the total formula (17). The mathematical concept of interpretation can be applied to concept of occurring events of a kernel of definition of striking power P-waves, intensity S-waves and places at forecasting of natural accidents for the Earth.

THE CONCEPT OF FUEL SYSTEM’S MATHEMATICAL MODELING BASED ON CERTIFICATION REQUIREMENTS

The article discusses the concept of fuel system’s mathematical modeling based on certification requirements. A detailed description of the safety of aircraft operation, taking into account the standard of airworthiness, and methods for conformity assessment of certification has also been presented. The development concept modeling is not possible to without a methodology to construct an integrated mathematical model which presents a solution using a one-dimensional and three-dimensional functioning model. The combined calculation in a one-dimensional and three-dimensional setting allows the modulating of the refuelling process with drainage system, signaling and centralized fuelling management process. Also as the calculation results of simulation of fuel flow from tanks when one pump fails are shown. Dynamic simulation of fuel production from tanks for calculation of static change fuel static moment and geometric modelling of non-working and non-poured remainder also presented. The article analysed fuel system requirements. This conformity can be met using a complex of mathematical modeling tools.