Swirling flows of fluids and gases are an integral part of many complex flows which are widely encountered in nature and technology. The working process of numerous technical devices (cyclones, vortex combustion chambers, air separators, gas and steam turbines, electric machines and generators, etc.) is generally determined by the laws of hydrodynamics and heat exchange of rotating flows. The problem of deriving general laws for a turbulent flow in the field of centrifugal forces provokes considerable scientific interest since it belongs to an underdeveloped field of hydromechanics. Therefore, mathematical modeling of swirling turbulent flows is still an urgent problem. In this paper, a comparative analysis of the advanced turbulence models for the Taylor -Couette flow is carried out. For this purpose, the linear turbulence models (SARC and SST-RC), the Reynolds stress method SSG/LRR-RSM-w2012, and a two-fluid model are used. The results obtained using these models are compared with each other and with known experimental data and direct numerical simulation results. The numerical results calculated with the use of turbulence models for the Taylor-Couette flow confirm that almost all the models adequately describe velocity profiles. However, they yield different turbulent viscosity values and, as a result, different friction coefficients. A comparison of the numerical results shows that the friction coefficient calculated using a two-fluid turbulence model is the closest to that obtained experimentally.
{"title":"Comparison of advanced turbulence models for the Taylor-Couette flow","authors":"Z. Malikov, F. K. Nazarov, M. Madaliev","doi":"10.17223/19988621/78/10","DOIUrl":"https://doi.org/10.17223/19988621/78/10","url":null,"abstract":"Swirling flows of fluids and gases are an integral part of many complex flows which are widely encountered in nature and technology. The working process of numerous technical devices (cyclones, vortex combustion chambers, air separators, gas and steam turbines, electric machines and generators, etc.) is generally determined by the laws of hydrodynamics and heat exchange of rotating flows. The problem of deriving general laws for a turbulent flow in the field of centrifugal forces provokes considerable scientific interest since it belongs to an underdeveloped field of hydromechanics. Therefore, mathematical modeling of swirling turbulent flows is still an urgent problem. In this paper, a comparative analysis of the advanced turbulence models for the Taylor -Couette flow is carried out. For this purpose, the linear turbulence models (SARC and SST-RC), the Reynolds stress method SSG/LRR-RSM-w2012, and a two-fluid model are used. The results obtained using these models are compared with each other and with known experimental data and direct numerical simulation results. The numerical results calculated with the use of turbulence models for the Taylor-Couette flow confirm that almost all the models adequately describe velocity profiles. However, they yield different turbulent viscosity values and, as a result, different friction coefficients. A comparison of the numerical results shows that the friction coefficient calculated using a two-fluid turbulence model is the closest to that obtained experimentally.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"25 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90866658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mikhail Selikhovkin, A. Akhmadieva, I. Zhukov, E. Marchenko, A. Khrustalyov
In this paper, the study of the effect of diamond nanoparticles on the structure and mechanical properties of the Mg-Ca-Zn magnesium alloy. The influence of diamond nanoparticles concentration amount of 0.1 wt. % in the structure of alloy Mg-Ca-Zn, the ultimate tensile strength increases from 294 up to 332 MPa, the elongation value increases from 22 % up to 27 % and the yield strength increases from 66 up to 75 MPa in the tested samples. Nanoparticles in magnesium alloy do not change the hardness of the alloy. The introduction of diamond nanoparticles into the magnesium alloy increased the Zn concentration from 4 % to 4.7 % and the Ca concentration from 1 % to 1.3 %. It is found that the introduction of the nanodiamond particles into a magnesium melt contributes to a decrease in the average grain size from ~ 100 to 64 pm in the obtained castings and, as a result, to an increase in the mechanical properties.
{"title":"Investigation of the effect of diamond nanoparticles on the structure and mechanical behavior of Mg-Ca-Zn alloy","authors":"Mikhail Selikhovkin, A. Akhmadieva, I. Zhukov, E. Marchenko, A. Khrustalyov","doi":"10.17223/19988621/79/13","DOIUrl":"https://doi.org/10.17223/19988621/79/13","url":null,"abstract":"In this paper, the study of the effect of diamond nanoparticles on the structure and mechanical properties of the Mg-Ca-Zn magnesium alloy. The influence of diamond nanoparticles concentration amount of 0.1 wt. % in the structure of alloy Mg-Ca-Zn, the ultimate tensile strength increases from 294 up to 332 MPa, the elongation value increases from 22 % up to 27 % and the yield strength increases from 66 up to 75 MPa in the tested samples. Nanoparticles in magnesium alloy do not change the hardness of the alloy. The introduction of diamond nanoparticles into the magnesium alloy increased the Zn concentration from 4 % to 4.7 % and the Ca concentration from 1 % to 1.3 %. It is found that the introduction of the nanodiamond particles into a magnesium melt contributes to a decrease in the average grain size from ~ 100 to 64 pm in the obtained castings and, as a result, to an increase in the mechanical properties.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"119 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81755647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a theoretical study of quick methods for determining the aerodynamic characteristics of fixed-wing unmanned aerial vehicles (UAVs). The purpose of the research is to create tools for aircraft shape optimization problems. The developed analytical techniques allow one to determine aerodynamic lift and drag coefficients as well as the efficiency characteristics based on the aircraft general characteristics. Other properties that can be derived are the wing shape parameters, the take-off mass, the structural mass, and the required characteristics of the propulsion and power supply system according to the specified flight performance characteristics. The use of these techniques for discrete points with aerodynamic characteristics obtained numerically or experimentally allows one to extrapolate the results to the entire range of operating angles of attack. As a result, the stages of conceptual and preliminary design of UAVs can be passed in a shorter span of time. Two UAVs have been designed in Tomsk State University with the use of the proposed techniques. The first is the preliminary designed UAV Prototype-2E; the second is the Prototype-2T UAV, which has been fully designed and then manufactured. The data calculated with these techniques on a SKIF Cyberia supercomputer in Tomsk State University are compared with the results of numerical simulations implemented in OpenFOAM and ANSYS Fluent. Good agreement of the results is revealed.
{"title":"Determination of aerodynamic characterisitcs of fixed-wing unmanned aerial vehicle by analytical techniques","authors":"Kuatbay Ismailov","doi":"10.17223/19988621/78/9","DOIUrl":"https://doi.org/10.17223/19988621/78/9","url":null,"abstract":"This paper presents a theoretical study of quick methods for determining the aerodynamic characteristics of fixed-wing unmanned aerial vehicles (UAVs). The purpose of the research is to create tools for aircraft shape optimization problems. The developed analytical techniques allow one to determine aerodynamic lift and drag coefficients as well as the efficiency characteristics based on the aircraft general characteristics. Other properties that can be derived are the wing shape parameters, the take-off mass, the structural mass, and the required characteristics of the propulsion and power supply system according to the specified flight performance characteristics. The use of these techniques for discrete points with aerodynamic characteristics obtained numerically or experimentally allows one to extrapolate the results to the entire range of operating angles of attack. As a result, the stages of conceptual and preliminary design of UAVs can be passed in a shorter span of time. Two UAVs have been designed in Tomsk State University with the use of the proposed techniques. The first is the preliminary designed UAV Prototype-2E; the second is the Prototype-2T UAV, which has been fully designed and then manufactured. The data calculated with these techniques on a SKIF Cyberia supercomputer in Tomsk State University are compared with the results of numerical simulations implemented in OpenFOAM and ANSYS Fluent. Good agreement of the results is revealed.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"3 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77778107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Reynolds equations are solved with account for inertial forces in a plane wedge-shaped layer using the Slezkin-Targ method. The analytical expressions determining the dimensionless longitudinal velocity, hydrodynamic pressure, and total pressure force as functions of the lubricating Reynolds number and dimensionless parameter of the problem are obtained. A new method for solving the Reynolds equations is proposed accounting for inertial forces and avoiding averaging the inertial terms with respect to the gap height. The numerical analysis of the proposed method shows that in the first and second approximations, the deviations for the total hydrodynamic pressure force in a plane wedge-shaped layer differ little from each other in the considered range of the lubricating Reynolds number for varying dimensionless parameter of the problem, but exceed the deviation obtained using the Slezkin-Targ method. The coincidence of the first approximation with the second one gives ground to believe that the proposed method is more accurate for calculating the total hydrodynamic pressure force in the fluid flow occurring in a plane wedge-shaped layer.
{"title":"Pressure calculation for a fluid flowing in a plane wedge-shaped layer with account for inertial forces","authors":"P. V. Kaurov","doi":"10.17223/19988621/79/6","DOIUrl":"https://doi.org/10.17223/19988621/79/6","url":null,"abstract":"The Reynolds equations are solved with account for inertial forces in a plane wedge-shaped layer using the Slezkin-Targ method. The analytical expressions determining the dimensionless longitudinal velocity, hydrodynamic pressure, and total pressure force as functions of the lubricating Reynolds number and dimensionless parameter of the problem are obtained. A new method for solving the Reynolds equations is proposed accounting for inertial forces and avoiding averaging the inertial terms with respect to the gap height. The numerical analysis of the proposed method shows that in the first and second approximations, the deviations for the total hydrodynamic pressure force in a plane wedge-shaped layer differ little from each other in the considered range of the lubricating Reynolds number for varying dimensionless parameter of the problem, but exceed the deviation obtained using the Slezkin-Targ method. The coincidence of the first approximation with the second one gives ground to believe that the proposed method is more accurate for calculating the total hydrodynamic pressure force in the fluid flow occurring in a plane wedge-shaped layer.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"17 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78333418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Classical mechanics of deformable bodies is based on the continuity hypothesis. However, many structural elements are made of porous materials. Porous natural materials (soil, rocks) have invariable porosity. Porous synthetic materials (ceramics, concrete, graphite, and pressed powder metals) have controlled porosity. To calculate the strength and hardness of the structure, the material is assumed to be conditionally continuous with the adjusted porosity. Nowadays, there are many available works presenting mechanical characteristics of materials with different porosities. This paper proposes a new class of problems in mechanics of deformable solids. Considering a low arch stability problem, which is important in construction practice, the problem of optimal arch design is solved by controlling the properties of the material. The solution to the problem of stability of the low arch made of porous material is presented. The flat arch with a rectangular crosssection is exposed to equally distributed loading. The near-rational law of the porosity distribution over the cross-section is used. The load is considered as a random variable. The solution to the problem is obtained using the theory of stationary random processes. A comparative analysis of the reliability and material consumption is carried out for the arch with continuous and porous sections. The calculation shows that the porous structure of the arch reduces the material consumption by 13.3% without stability and reliability losses.
{"title":"A stability problem for a low-height curvilinear porous arch under random loading","authors":"S. Shlyakhov, Elvira F. Krivulina","doi":"10.17223/19988621/79/14","DOIUrl":"https://doi.org/10.17223/19988621/79/14","url":null,"abstract":"Classical mechanics of deformable bodies is based on the continuity hypothesis. However, many structural elements are made of porous materials. Porous natural materials (soil, rocks) have invariable porosity. Porous synthetic materials (ceramics, concrete, graphite, and pressed powder metals) have controlled porosity. To calculate the strength and hardness of the structure, the material is assumed to be conditionally continuous with the adjusted porosity. Nowadays, there are many available works presenting mechanical characteristics of materials with different porosities. This paper proposes a new class of problems in mechanics of deformable solids. Considering a low arch stability problem, which is important in construction practice, the problem of optimal arch design is solved by controlling the properties of the material. The solution to the problem of stability of the low arch made of porous material is presented. The flat arch with a rectangular crosssection is exposed to equally distributed loading. The near-rational law of the porosity distribution over the cross-section is used. The load is considered as a random variable. The solution to the problem is obtained using the theory of stationary random processes. A comparative analysis of the reliability and material consumption is carried out for the arch with continuous and porous sections. The calculation shows that the porous structure of the arch reduces the material consumption by 13.3% without stability and reliability losses.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"118 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79520655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Imomnazarov, Abdulhamid E. Kholmurodov, A. Omonov
In applied problems related to propagation of elastic waves, it is often necessary to take into account porosity, fluid saturation of the media, and the hydrodynamic background. Real geological media are multiphase, electrically conductive, fractured, porous, etc. When propagating, seismic waves dissipate due to the absorption of energy. In this paper, the wave propagation process occurs in terms of partial densities of phases, stress tensor, pore pressure, and velocities of the corresponding phases. In the first section, for completeness, the presentation presents a quasilinear system of equations of the poroelasticity theory [1-3]. In the second section, the corresponding linear system of equations of the poroelasticity theory for a homogeneous medium is obtained. In the third section, we construct a fundamental solution for the system of equations of the poroelasticity theory obtained in the second section. In the final section, the inverse poroelasticity problem of determining the distributed source in a half-space using additional information about the free surface mode is considered.
{"title":"Direct and inverse dynamic problems of poroelasticity","authors":"K. Imomnazarov, Abdulhamid E. Kholmurodov, A. Omonov","doi":"10.17223/19988621/75/8","DOIUrl":"https://doi.org/10.17223/19988621/75/8","url":null,"abstract":"In applied problems related to propagation of elastic waves, it is often necessary to take into account porosity, fluid saturation of the media, and the hydrodynamic background. Real geological media are multiphase, electrically conductive, fractured, porous, etc. When propagating, seismic waves dissipate due to the absorption of energy. In this paper, the wave propagation process occurs in terms of partial densities of phases, stress tensor, pore pressure, and velocities of the corresponding phases. In the first section, for completeness, the presentation presents a quasilinear system of equations of the poroelasticity theory [1-3]. In the second section, the corresponding linear system of equations of the poroelasticity theory for a homogeneous medium is obtained. In the third section, we construct a fundamental solution for the system of equations of the poroelasticity theory obtained in the second section. In the final section, the inverse poroelasticity problem of determining the distributed source in a half-space using additional information about the free surface mode is considered.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"36 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82196058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of this work is to develop the method of boundary states for the class of torsion problems as applied to transversely isotropic elastic bodies of revolution. Efforts, displacements, or a combination of both are used as twisting conditions at the border. Proceeding from the general solution to the problem of cross section warping, the basis of the space of internal states is formed. The search for an internal state is reduced to the study of the boundary state isomorphic to it. The solution is a Fourier series. The proposed technique is implemented in solving the first main problem for a body in the form of a truncated cone; the second main problem for a circular cylinder; and the main mixed problem for a non-canonical body of revolution. The solution was verified and the calculation accuracy was assessed. The obtained characteristics of the elastic field have a polynomial form. The elastic field in each problem satisfies the specified boundary conditions in the form of their distribution over the surface and does not satisfy them only in the integral sense.
{"title":"Boundary state method in solving torsion problems for transversely isotropic bodies of revolution","authors":"D. A. Ivanychev","doi":"10.17223/19988621/75/7","DOIUrl":"https://doi.org/10.17223/19988621/75/7","url":null,"abstract":"The aim of this work is to develop the method of boundary states for the class of torsion problems as applied to transversely isotropic elastic bodies of revolution. Efforts, displacements, or a combination of both are used as twisting conditions at the border. Proceeding from the general solution to the problem of cross section warping, the basis of the space of internal states is formed. The search for an internal state is reduced to the study of the boundary state isomorphic to it. The solution is a Fourier series. The proposed technique is implemented in solving the first main problem for a body in the form of a truncated cone; the second main problem for a circular cylinder; and the main mixed problem for a non-canonical body of revolution. The solution was verified and the calculation accuracy was assessed. The obtained characteristics of the elastic field have a polynomial form. The elastic field in each problem satisfies the specified boundary conditions in the form of their distribution over the surface and does not satisfy them only in the integral sense.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"59 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84336598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Afonin, V. G. Butov, Victor A. Solonenko, A. A. Yashchuk, Andrey A. Yakushev
This paper presents the results of numerical simulation of the processes in a two-chamber plasma generator of the pulsed MHD generator running on combustion products of a combined pyrotechnic fuel with afterburning in air oxygen. A mixture of Mg powder (a fuel) and KNO3 powder (an oxidizer and a source of the easily ionized additive) is chosen as a pyrotechnic fuel. The considered plasma generator includes a gas generator and an afterburner. Multicomponent combustion products of the selected pyrotechnic fuel contain solid particles of MgO and gaseous Mg. Within the afterburner, the unburnt Mg is burned up in the presence of air oxygen, forming MgO liquid particles. The proposed mathematical model allows one to numerically investigate all the processes occurring in a plasma generator of an MHD generator with an afterburner and to obtain the required data for determining the shape of the accelerating nozzle and the relevant parameters for calculations in the MHD channel.
{"title":"A Study of processes in a plasma generator of the pulsed MHD generator running on a combined pyrotechnic fuel","authors":"A. Afonin, V. G. Butov, Victor A. Solonenko, A. A. Yashchuk, Andrey A. Yakushev","doi":"10.17223/19988621/78/5","DOIUrl":"https://doi.org/10.17223/19988621/78/5","url":null,"abstract":"This paper presents the results of numerical simulation of the processes in a two-chamber plasma generator of the pulsed MHD generator running on combustion products of a combined pyrotechnic fuel with afterburning in air oxygen. A mixture of Mg powder (a fuel) and KNO3 powder (an oxidizer and a source of the easily ionized additive) is chosen as a pyrotechnic fuel. The considered plasma generator includes a gas generator and an afterburner. Multicomponent combustion products of the selected pyrotechnic fuel contain solid particles of MgO and gaseous Mg. Within the afterburner, the unburnt Mg is burned up in the presence of air oxygen, forming MgO liquid particles. The proposed mathematical model allows one to numerically investigate all the processes occurring in a plasma generator of an MHD generator with an afterburner and to obtain the required data for determining the shape of the accelerating nozzle and the relevant parameters for calculations in the MHD channel.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"66 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80226411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Promakhov, A. Matveev, N. Schulz, V. Bakhmat, F. Dronov, Timur E. Turanov
Due to mechanical properties, Inconel family alloys are proven to be functional materials that are used at elevated temperatures in chemically aggressive environments and under high loads. Development of additive technologies has revealed a potential of these alloys as an initial powder raw material for additive manufacturing machines. In this work, the application of metal matrix composite materials in a direct laser growing technology is studied. The technology of self-propagating high-temperature synthesis is used to manufacture the composite material. The study results show that the application of metal matrix materials in the technology of direct laser growing allows one to increase wettability of ceramic particles by a matrix metal. As a result, the quality of particle-matrix borders is improved, the porosity is decreased, and the uniformity of the distribution of particles in the matrix is increased. The structure of the obtained materials is represented by Inconel 625 matrix alloy and inclusions of TiB2 ceramics. The average size of the ceramic particles is less than 300 nm. It is shown that adding to Inconel 625 powder of a composite metal matrix SHS powder of NiTi-TiB2 in an amount of 5 wt% leads to an increase in the microhardness of the material by 1.5 times relative to the materials obtained from pure Inconel 625. At the same time, there is an increase in the ultimate strength of the materials up to 920 MPa and a decrease in the ductility by 15% relative to the samples made of pure Inconel 625 alloy.
{"title":"A study of the structure and properties of the metal matrix composite materials obtained by a method of direct laser growing","authors":"V. Promakhov, A. Matveev, N. Schulz, V. Bakhmat, F. Dronov, Timur E. Turanov","doi":"10.17223/19988621/77/10","DOIUrl":"https://doi.org/10.17223/19988621/77/10","url":null,"abstract":"Due to mechanical properties, Inconel family alloys are proven to be functional materials that are used at elevated temperatures in chemically aggressive environments and under high loads. Development of additive technologies has revealed a potential of these alloys as an initial powder raw material for additive manufacturing machines. In this work, the application of metal matrix composite materials in a direct laser growing technology is studied. The technology of self-propagating high-temperature synthesis is used to manufacture the composite material. The study results show that the application of metal matrix materials in the technology of direct laser growing allows one to increase wettability of ceramic particles by a matrix metal. As a result, the quality of particle-matrix borders is improved, the porosity is decreased, and the uniformity of the distribution of particles in the matrix is increased. The structure of the obtained materials is represented by Inconel 625 matrix alloy and inclusions of TiB2 ceramics. The average size of the ceramic particles is less than 300 nm. It is shown that adding to Inconel 625 powder of a composite metal matrix SHS powder of NiTi-TiB2 in an amount of 5 wt% leads to an increase in the microhardness of the material by 1.5 times relative to the materials obtained from pure Inconel 625. At the same time, there is an increase in the ultimate strength of the materials up to 920 MPa and a decrease in the ductility by 15% relative to the samples made of pure Inconel 625 alloy.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"33 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75424237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
When developing new circumlunar satellite systems for various purposes, it is necessary to know the dynamic features of various regions of circumlunar space. It is noted that one of the main features of the dynamics of artificial Moon satellites (AMS) is the increase in the eccentricity of their orbits. It is known that such orbital evolution of objects can be caused by resonant perturbations. In this regard, the purpose of this paper is to study the influence of secular and half-secular resonances occurring on the AMS. The results are obtained by means of the processing of data from an extensive numerical experiment to study the orbital evolution of the uniformly distributed circumlunar objects moving in the range of large semi-axes from 1911.8 to 26070 km and with inclinations from 0 to 180°. The study of the influence of secular and half-secular resonances on the orbital evolution of the AMS is carried out using numerical and analytical techniques. Both techniques have advantages and disadvantages and are used in the study. Maps of secular and half-secular resonances are of great practical importance. They clearly demonstrate the areas of influence of secular resonances on the orbital evolution of circumlunar objects depending on the initial values of the semimajor axis and inclination of the orbits of objects. The analysis of each particular resonance consists in the revealing of a resonant characteristic type, which is determined by the nature of the change in a critical argument: libration - stable resonance, libration/circulation - unstable resonance, and circulation - no resonance. To estimate the whole range of the influence of resonances on the AMS dynamics, maps of their overlaps are built. The maps allow one to determine areas with significant influence of the resonances on the orbital evolution of circumlunar objects. The obtained results show that the reason for a large increase in the eccentricity in a vast area of circumlunar orbital space is the presence of the stable apsidal resonance of the Kozai-Lidov type.
{"title":"Analysis of a dynamic structure of secular resonances in circumlunar orbital space","authors":"N. Popandopulo, A. Aleksandrova, T. Bordovitsyna","doi":"10.17223/19988621/77/9","DOIUrl":"https://doi.org/10.17223/19988621/77/9","url":null,"abstract":"When developing new circumlunar satellite systems for various purposes, it is necessary to know the dynamic features of various regions of circumlunar space. It is noted that one of the main features of the dynamics of artificial Moon satellites (AMS) is the increase in the eccentricity of their orbits. It is known that such orbital evolution of objects can be caused by resonant perturbations. In this regard, the purpose of this paper is to study the influence of secular and half-secular resonances occurring on the AMS. The results are obtained by means of the processing of data from an extensive numerical experiment to study the orbital evolution of the uniformly distributed circumlunar objects moving in the range of large semi-axes from 1911.8 to 26070 km and with inclinations from 0 to 180°. The study of the influence of secular and half-secular resonances on the orbital evolution of the AMS is carried out using numerical and analytical techniques. Both techniques have advantages and disadvantages and are used in the study. Maps of secular and half-secular resonances are of great practical importance. They clearly demonstrate the areas of influence of secular resonances on the orbital evolution of circumlunar objects depending on the initial values of the semimajor axis and inclination of the orbits of objects. The analysis of each particular resonance consists in the revealing of a resonant characteristic type, which is determined by the nature of the change in a critical argument: libration - stable resonance, libration/circulation - unstable resonance, and circulation - no resonance. To estimate the whole range of the influence of resonances on the AMS dynamics, maps of their overlaps are built. The maps allow one to determine areas with significant influence of the resonances on the orbital evolution of circumlunar objects. The obtained results show that the reason for a large increase in the eccentricity in a vast area of circumlunar orbital space is the presence of the stable apsidal resonance of the Kozai-Lidov type.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"121 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75485326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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