and Computational Methods

Rubric: "01.02.00 Mechanics"

doi: 10.18698/2309-3684-2015-1-6782

The article presents a suggested method of numerical finite-element solving the ‘hole ovalization’ problem. This method can be applied for experimental development of advanced aviation materials with the aim of determining structure element resistance against deforming with stress concentrators, mainly, connectors. The method is based on three-dimensional finite element solution of the problem of lastoplastic deformation of plates with a hole under crushing. It is appropriate for reduction of xperimental studies and replacing them by the numerical experiments. The Ilyushin model of small lastoplastic deformations has been used. The results of numerical simulation of a threedimensional stress-strain state of elastoplastic plates under crushing are presented as well as results of experimental nvestigations of deforming plates of Al-alloy 163. It is shown that the results of numerical and experimental modeling for deforming plates under crushing agree quite well.

Dimitrienko Y., Gubareva E., Sborschikov S., Erasov V., Yakovlev N. Computational modeling and experimental investigation of elastic-plastic plates deforming under crushing. Маthematical Modeling and Coтputational Methods, 2015, №1 (5), pp. 67-82

doi: 10.18698/2309-3684-2017-1-7890

The research examines the planar and three-dimensional problems of an ice cover perturbed by a point pulse source localized in the depth of an infinitely deep liquid. We studied the ice cover of different thickness and carried out numerical study of its perturbations by sources located at different depths. The main attention is paid to the ice cover perturbations that arise directly above the source.

Savin A., Gorlova N., Strunin P. Numerical simulation of the point pulse source impact in a liquid on the ice cover. Маthematical Modeling and Coтputational Methods, 2017, №1 (13), pp. 78-90

doi: 10.18698/2309-3684-2016-3-2432

In this article we suggest a method for calculating the dynamic stability of a cylindrical shell with its axial compressive time-varying load, and cyclic axial load, which varies according to a certain law. As an example, we consider the axial load, changing linearly and the cyclic load, which varies according to the harmonic law. To show the cyclic load, we use Ince — Strutt diagram, defining the stable and unstable regions of the shell fluctuations.

Dubrovin V., Butina T. Simulation of dynamic stability of a cylindrical shell under cyclic axial impact. Маthematical Modeling and Coтputational Methods, 2016, №3 (11), pp. 24-32

doi: 10.18698/2309-3684-2014-2-115126

During the last decades we are witnessing climate changes. Scientists assume global warming to be the result of man-generated increase of green house gases in the atmosphere, the most important one being СО2. The article deals with the problem and describes cutting-edge solutions for stabilising climate. The research makes use of a seasonal global combined threedimensional hydrodynamic model of climate. This model of climate includes model of the World Ocean with real depths and configuration of continents, model of evolution of sea ice and energy — moisture balance model of the atmosphere. The first stage covers estimation of climate change through 2100 following IPCC A2 СО2 increase scenario. The calculations yield rise of average annual surface temperature of the atmosphere by 3,5 С. A number of calculations have been made to estimate possibility of stabilising climate at the level of 2010 by means of controlled release of sulphate aerosol into stratosphere. The aerosol will reflect and disperse a part of the coming solar radiation. We have calculated concentration (albedo) of the aerosol from 2010 to 2100 which will enable us to stabilise the average annual temperature of the surface layer of atmosphere. We have shown that by this way it is impossible to achieve the seasonal uniform approximation to the existing climate, although it is possible to significantly reduce the greenhouse warming effect. Provided that the aerosol is distributed evenly in space in stratosphere, we can stabilize the average annual temperature of the atmosphere, herewith in middle and low latitudes the climate will be colder by 0,1…0,2 С and in high latitudes it will be warmer by 0,2…1,2 С. Besides, these differences are essentially seasonal in nature, they increase in winter. If we stop releasing the aerosol in 2080 the average annual global temperature of the atmosphere will rise, reaching the former value without the aerosol by the year 2100.

Parkhomenko V. Modelling global climate stabilisation by controlled emission of stratospheric aerosol. Маthematical Modeling and Coтputational Methods, 2014, №2 (2), pp. 115-126

doi: 10.18698/2309-3684-2016-3-3352

Modification of Pohlhausen method is developed. It allows for quick and effective heat transfer distribution over the blunt body surfaces. Calculations were done. Their results are described in comparison with the numerical solution of a problem within the framework of Navier — Stokes equations.

Kotenev V., Bulgakov V., Ozhgibisova Y. Modification of Pohlhausen method for calculating heat transfer on blunt bodies. Маthematical Modeling and Coтputational Methods, 2016, №3 (11), pp. 33-52

doi: 10.18698/2309-3684-2014-4-7487

The article describes performed simulation of force action on streamlined horizontal elements of engineering structures in the upper layer of sharply stratified flow associated with the generation of waves at the interface between the liquid layers. We obtained an integral representation of the wave drag and lift, made numerical calculations for a real marine environment. The conditions under which there is a significant increase in the hydrodynamic reactions on streamlined structural elements were revealed.

Vladimirov I., Korchagin N., Savin A. Simulation of wave action on horizontal structure elements in the upper layer of stratified flow. Маthematical Modeling and Coтputational Methods, 2014, №4 (4), pp. 74-87

doi: 10.18698/2309-3684-2015-2-4657

The article describes a method for calculating the dynamic stability of cylindrical shell under axial compressive time-varying load. The case of linearly varying load was con-sidered as an example.

Dubrovin V., Butina T. Modeling of the dynamic stability of a cylindrical shell under the axial compressive load. Маthematical Modeling and Coтputational Methods, 2015, №2 (6), pp. 46-57

doi: 10.18698/2309-3684-2016-4-1733

We obtained a mathematical model for determining the parameters of longitudinal selfoscillations, excited in the pressure gas flow at local flow heat supply. In our research we established that under certain conditions the gas heat supply alters the flow hydraulic characteristics, creating the "negative" resistance effect. In this case, the self-oscillation excitation is possible even with the monotonically decreasing supercharger pressure characteristic.

Basok B., Gotsulenko V. Simulation of pressure gas flow self-oscillation excited by heat supply. Маthematical Modeling and Coтputational Methods, 2016, №4 (12), pp. 17-33

doi: 10.18698/2309-3684-2017-1-2231

The study tested a model of a layered hierarchically constructed composite, whose structure has a morphology similar to fractal formation. In our research we developed an algorithm for studying the interaction of an alternating electric field with a fractal composite, as well as a software package that allows simulating fractal characteristics of the composite under study and calculating the electrical parameters of the composite medium. Moreover, we studied the boundaries of the developed model application: the maxand min-dimensions of the composite, at which fractal properties appear. We investigated the frequency dependences of the permittivity of a fractal composite.

The results of the research can be used in designing the materials with predefined electrophysical parameters and characteristics, as well as in developing the elements and devices that possess absorbing and selective properties.

Korchagin S., Terin D., Klinaev Y. Simulating a fractal composite and studying its electrical characteristics. Маthematical Modeling and Coтputational Methods, 2017, №1 (13), pp. 22-31