Pub Date : 2023-04-01DOI: 10.17804/2410-9908.2023.2.019-040
I. Emelyanov
An approach based on the method of virtual elements is used to solve the contact problem for a thin shell of revolution lying on a rigid foundation. In this case, the surface of the base has a shape inconsistent with the surface of the shell. The method makes it possible to determine the contact area and the contact pressure from the contact area unknown in two coordinate directions. Since the contact area is not known in advance, the problem is structurally nonlinear. A thin isotropic shell is described by the classical theory based on the Kirchhoff–Love hypotheses. The base is taken absolutely rigid, but with the presence of an elastic gasket. The shell equations are integrated by S. K. Godunov’s method of discrete orthogonalization. To determine the forces of interaction between the shell and the base, a mixed method of structural mechanics is used. With this aim in view, the maximum possible contact area is discretized by virtual rectangular elements. A constant value of the contact pressure is assumed on each element obtained in this area, and the contact pressure is assumed to be zero on the elements in the area where the shell leaves the base. Based on the assumptions, a system of linear algebraic equations is constructed, which determines the contact pressure and deflection of the shell circumference axis. Since the shell can move away from the base, iterative procedures are applied to search for the real contact area, which depends on the geometric and elastic parameters of the shell and the magnitude of the external load. As an example, the contact interaction of a cylindrical shell (part of the shell of a tank car) lying on a rigid base with a gasket is considered. It is shown how the contact area and contact pressure change depending on the rigidity of the gasket and the difference between the radii of the shell and the base (inconsistency in the shape of the surfaces).
采用虚元法求解刚性基础上旋转薄壳的接触问题。在这种情况下，底座的表面具有与壳体表面不一致的形状。该方法使得从两个坐标方向上未知的接触面积确定接触面积和接触压力成为可能。由于事先不知道接触面积，所以问题在结构上是非线性的。基于Kirchhoff-Love假设的经典理论描述了薄的各向同性壳。该基地是采取绝对刚性，但有一个弹性垫片的存在。利用S. K. Godunov的离散正交法对壳方程进行积分。为了确定壳与基础之间的相互作用力，采用了结构力学的混合方法。为此，采用虚矩形元对最大可能接触面积进行离散。假定在该区域得到的每个单元的接触压力为恒定值，并且假定壳体离开底座区域的单元的接触压力为零。在此基础上，构造了一套确定壳周轴接触压力和挠度的线性代数方程组。由于壳体可以远离底座，因此应用迭代程序来搜索实际接触面积，这取决于壳体的几何和弹性参数以及外部载荷的大小。作为一个例子，考虑了一个圆柱形壳体(油罐车壳体的一部分)与垫片放在刚性基座上的接触相互作用。它显示了接触面积和接触压力是如何变化的，这取决于垫片的刚度和外壳半径与底座之间的差异(表面形状的不一致)。
{"title":"Applying the method of virtual elements to solving contact problems of shells of revolution interacting with surfaces of inconsistent shape","authors":"I. Emelyanov","doi":"10.17804/2410-9908.2023.2.019-040","DOIUrl":"https://doi.org/10.17804/2410-9908.2023.2.019-040","url":null,"abstract":"An approach based on the method of virtual elements is used to solve the contact problem for a thin shell of revolution lying on a rigid foundation. In this case, the surface of the base has a shape inconsistent with the surface of the shell. The method makes it possible to determine the contact area and the contact pressure from the contact area unknown in two coordinate directions. Since the contact area is not known in advance, the problem is structurally nonlinear. A thin isotropic shell is described by the classical theory based on the Kirchhoff–Love hypotheses. The base is taken absolutely rigid, but with the presence of an elastic gasket. The shell equations are integrated by S. K. Godunov’s method of discrete orthogonalization. To determine the forces of interaction between the shell and the base, a mixed method of structural mechanics is used. With this aim in view, the maximum possible contact area is discretized by virtual rectangular elements. A constant value of the contact pressure is assumed on each element obtained in this area, and the contact pressure is assumed to be zero on the elements in the area where the shell leaves the base. Based on the assumptions, a system of linear algebraic equations is constructed, which determines the contact pressure and deflection of the shell circumference axis. Since the shell can move away from the base, iterative procedures are applied to search for the real contact area, which depends on the geometric and elastic parameters of the shell and the magnitude of the external load. As an example, the contact interaction of a cylindrical shell (part of the shell of a tank car) lying on a rigid base with a gasket is considered. It is shown how the contact area and contact pressure change depending on the rigidity of the gasket and the difference between the radii of the shell and the base (inconsistency in the shape of the surfaces).","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"110 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83655036","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}
Pub Date : 2023-02-01DOI: 10.17804/2410-9908.2023.1.024-040
Yu. V. Khudorozhkova, S. M. Zadvorkin, S. V. Burov, I. Kamantsev
The study of the applicability of magnetic and optical methods to the detection of prefracture zones under fatigue degradation of structural materials is exemplified by the 09G2S steel. The regularities of changes in the signal of an attached fluxgate gradiometer with the increasing number of loading cycles have been revealed; namely, significant changes in the gradiometer readings on individual specimen surface areas prove to result from the formation of fracture zones. The change in the value of the coefficient of correlation among the speckle images is studied at different stages of cyclic testing. Speckle image heterogeneity is shown to appear due to fracture nucleation. Thus, the applicability of magnetic and speckle-interferometric methods to detecting prefracture zones in objects under cyclic loading is substantiated.
{"title":"Detection of prefracture zones in structural materials by magnetic and optical methods","authors":"Yu. V. Khudorozhkova, S. M. Zadvorkin, S. V. Burov, I. Kamantsev","doi":"10.17804/2410-9908.2023.1.024-040","DOIUrl":"https://doi.org/10.17804/2410-9908.2023.1.024-040","url":null,"abstract":"The study of the applicability of magnetic and optical methods to the detection of prefracture zones under fatigue degradation of structural materials is exemplified by the 09G2S steel. The regularities of changes in the signal of an attached fluxgate gradiometer with the increasing number of loading cycles have been revealed; namely, significant changes in the gradiometer readings on individual specimen surface areas prove to result from the formation of fracture zones. The change in the value of the coefficient of correlation among the speckle images is studied at different stages of cyclic testing. Speckle image heterogeneity is shown to appear due to fracture nucleation. Thus, the applicability of magnetic and speckle-interferometric methods to detecting prefracture zones in objects under cyclic loading is substantiated.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88225877","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}
Pub Date : 2023-02-01DOI: 10.17804/2410-9908.2023.1.006-016
S. Smirnov, I. Veretennikova, D. Konovalov, N. Michurov, V. Osipova, A. Pestov
The aim of this study is to investigate the mechanical properties of coatings based on ED-20 epoxy resin, manufactured with polyethylenepolyamine or polyamidepolyamine used as hardeners. Instrumented indentation with a Berkovich triangular pyramid is used to determine the mechanical properties. Indentation hardness, reduced elastic modulus, and creep at a given holding time are used as the characteristic parameters. The results testify that the mechanical properties of the epoxy coatings made with different hardeners differ significantly from each other and demonstrate different behaviors.
{"title":"Effect of hardeners on the mechanical properties of epoxy coatings based on ED-20 resin","authors":"S. Smirnov, I. Veretennikova, D. Konovalov, N. Michurov, V. Osipova, A. Pestov","doi":"10.17804/2410-9908.2023.1.006-016","DOIUrl":"https://doi.org/10.17804/2410-9908.2023.1.006-016","url":null,"abstract":"The aim of this study is to investigate the mechanical properties of coatings based on ED-20 epoxy resin, manufactured with polyethylenepolyamine or polyamidepolyamine used as hardeners. Instrumented indentation with a Berkovich triangular pyramid is used to determine the mechanical properties. Indentation hardness, reduced elastic modulus, and creep at a given holding time are used as the characteristic parameters. The results testify that the mechanical properties of the epoxy coatings made with different hardeners differ significantly from each other and demonstrate different behaviors.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87080461","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}
Pub Date : 2023-02-01DOI: 10.17804/2410-9908.2023.1.017-023
V. V. Struzhanov, A. Chaikin
A problem on the fracture of a thin-walled spherical vessel affected by increasing internal pressure is formulated. The material properties both in the stage of hardening and in the stage of softening (prefracture) are described. The mathematics of the catastrophe theory is used to write down the equilibrium equations and to find the critical value of pressure, at which the vessel fails.
{"title":"Fracture of a thin-walled spherical vessel affected by internal pressure","authors":"V. V. Struzhanov, A. Chaikin","doi":"10.17804/2410-9908.2023.1.017-023","DOIUrl":"https://doi.org/10.17804/2410-9908.2023.1.017-023","url":null,"abstract":"A problem on the fracture of a thin-walled spherical vessel affected by increasing internal pressure is formulated. The material properties both in the stage of hardening and in the stage of softening (prefracture) are described. The mathematics of the catastrophe theory is used to write down the equilibrium equations and to find the critical value of pressure, at which the vessel fails.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85553126","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}
Pub Date : 2023-02-01DOI: 10.17804/2410-9908.2023.1.054-064
L. F. Koroleva, R. Savrai, E. Prosviryakov, V. A. Kostarev, S. V. Pavlyshko, P. V. Kostarev
The paper studies the polishing power of a tribochemically active abrasive material based on a solid solution of iron and aluminum oxides, as well as a solid solution of aluminum and iron oxides modified by zirconium oxide and yttrium oxide additives, and the tribotechnical properties of a lubricant doped with these abrasive materials. The modified Al2O3·Fe2O3·ZrO2·Y2O3 powders prove to have an essentially higher polishing power producing a considerably lower surface roughness than that of the unmodified Al2O3·Fe2O3 powder. By varying the content of the modifying oxides, one can change the tribochemical activity of the abrasive powder and select the best composition depending on the material to be polished. The addition of these abrasive powders is shown to have an essential effect on the tribotechnical properties of the lubricant for the wheel–rail contact. The laboratory testing of the lubricant compositions suggests their effective applicability to the wheel–rail contact.
{"title":"The effect of abrasive additives on the tribotechnical properties of lubricants for the wheel–rail system","authors":"L. F. Koroleva, R. Savrai, E. Prosviryakov, V. A. Kostarev, S. V. Pavlyshko, P. V. Kostarev","doi":"10.17804/2410-9908.2023.1.054-064","DOIUrl":"https://doi.org/10.17804/2410-9908.2023.1.054-064","url":null,"abstract":"The paper studies the polishing power of a tribochemically active abrasive material based on a solid solution of iron and aluminum oxides, as well as a solid solution of aluminum and iron oxides modified by zirconium oxide and yttrium oxide additives, and the tribotechnical properties of a lubricant doped with these abrasive materials. The modified Al2O3·Fe2O3·ZrO2·Y2O3 powders prove to have an essentially higher polishing power producing a considerably lower surface roughness than that of the unmodified Al2O3·Fe2O3 powder. By varying the content of the modifying oxides, one can change the tribochemical activity of the abrasive powder and select the best composition depending on the material to be polished. The addition of these abrasive powders is shown to have an essential effect on the tribotechnical properties of the lubricant for the wheel–rail contact. The laboratory testing of the lubricant compositions suggests their effective applicability to the wheel–rail contact.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"71 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86129070","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}
Pub Date : 2023-02-01DOI: 10.17804/2410-9908.2023.1.041-053
L. Goruleva, E. Prosviryakov
A family of exact solutions to the Navier–Stokes equations is constructed to describe nonuniform two-dimensional fluid motions. The superposition of the main unidirectional flow with the secondary flow is considered. The secondary flow is determined by suction or injection through permeable boundaries. This class of exact solutions is obtained by multiplicative and additive separation of variables. The flow of a viscous incompressible fluid is described by a polynomial of the horizontal (longitudinal) coordinate. The polynomial coefficients are functions of the vertical (transverse) coordinate and time. They are determined by a chain of homogeneous and inhomogeneous parabolic partial differential equations with a convective term. In the case of a steady flow, it is described by a system of ordinary differential equations with constant coefficients. An algorithm for integrating a system of ordinary differential equations for studying the steady motion of a viscous fluid is presented. In this case, all the functions defining the velocity are quasipolynomials since the system of ordinary differential equations has an Euler-form exact solution.
{"title":"Exact solutions to the Navier–Stokes equations for describing inhomogeneous isobaric vertical vortex fluid flows in regions with permeable boundaries","authors":"L. Goruleva, E. Prosviryakov","doi":"10.17804/2410-9908.2023.1.041-053","DOIUrl":"https://doi.org/10.17804/2410-9908.2023.1.041-053","url":null,"abstract":"A family of exact solutions to the Navier–Stokes equations is constructed to describe nonuniform two-dimensional fluid motions. The superposition of the main unidirectional flow with the secondary flow is considered. The secondary flow is determined by suction or injection through permeable boundaries. This class of exact solutions is obtained by multiplicative and additive separation of variables. The flow of a viscous incompressible fluid is described by a polynomial of the horizontal (longitudinal) coordinate. The polynomial coefficients are functions of the vertical (transverse) coordinate and time. They are determined by a chain of homogeneous and inhomogeneous parabolic partial differential equations with a convective term. In the case of a steady flow, it is described by a system of ordinary differential equations with constant coefficients. An algorithm for integrating a system of ordinary differential equations for studying the steady motion of a viscous fluid is presented. In this case, all the functions defining the velocity are quasipolynomials since the system of ordinary differential equations has an Euler-form exact solution.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84530581","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}
Pub Date : 2022-12-01DOI: 10.17804/2410-9908.2022.6.095-106
L. Goruleva, S. M. Zadvorkin, A. N. Mushnikov
The changes in the phase composition and electromagnetic properties of the 321N chromium-nickel austenitic steel under plastic deformation by uniaxial tension are studied. As strain increases from 0 to 0.37, the content of ferromagnetic α′-martensite in the steel increases monotonically to 60%. The electrical resistivity and the initial magnetic permeability increase monotonically by factors of 1,25 and 18, respectively. To monitor the strain state and the content of α'-martensite in products made of the 321N steel, it is preferable to use initial magnetic permeability rather than electrical resistance. The skin layer thickness of the deformed 321N steel for frequencies from 5 to 1000 kHz is calculated from the experimental values of initial magnetic permeability and electrical resistivity. Eddy current diagnostics of the state of the surface of products made of this steel, hardened by surface plastic deformation, is proposed to be performed at frequencies ranging between 100 and 200 kHz.
{"title":"Effect of plastic deformation on the phase composition and electromagnetic characteristics of the 321N austenitic steel (08Kh18N10T)","authors":"L. Goruleva, S. M. Zadvorkin, A. N. Mushnikov","doi":"10.17804/2410-9908.2022.6.095-106","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.6.095-106","url":null,"abstract":"The changes in the phase composition and electromagnetic properties of the 321N chromium-nickel austenitic steel under plastic deformation by uniaxial tension are studied. As strain increases from 0 to 0.37, the content of ferromagnetic α′-martensite in the steel increases monotonically to 60%. The electrical resistivity and the initial magnetic permeability increase monotonically by factors of 1,25 and 18, respectively. To monitor the strain state and the content of α'-martensite in products made of the 321N steel, it is preferable to use initial magnetic permeability rather than electrical resistance. The skin layer thickness of the deformed 321N steel for frequencies from 5 to 1000 kHz is calculated from the experimental values of initial magnetic permeability and electrical resistivity. Eddy current diagnostics of the state of the surface of products made of this steel, hardened by surface plastic deformation, is proposed to be performed at frequencies ranging between 100 and 200 kHz.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77761324","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}
Pub Date : 2022-12-01DOI: 10.17804/2410-9908.2022.6.065-075
A. Chumaevsky, A. Panfilov, K. Kalashnikov, A. Zykova, T. Kalashnikova, A. Vorontsov, S. Nikonov, E. Moskvichev, V. Semenchuk, V. Е. Rubtsov, E. Kolubaev
Samples of composite materials based on BrAMts9-2 bronze with the introduction of the Udimet500 and Inconel625 nickel alloys were obtained by wire-feed electron-beam technology. The studies show that the structures of composites formed during printing, although fairly similar due to the same base of the alloys, have different features due to different combinations of alloying elements. The mechanical properties of the samples with the introduction of up to 15 % of the Udimet500 alloy are higher than those of the samples of the second material. With the introduction of 25 % of a nickel alloy, the strength is higher for the composite material samples with the introduction of the Inconel625 alloy. The microhardness of the samples with the introduction of 5 % of a nickel alloy is identical, the introduction of large volumes of a nickel alloy leads to the implementation of greater hardness in the samples with the introduction of the Inconel625 alloy due to the higher content of refractory materials. Relative elongation after rupture varies insignificantly for the samples of both types.
{"title":"Production of metal matrix composites based on aluminum-manganese bronze and nickel alloys by wire feed electron-beam additive manufacturing","authors":"A. Chumaevsky, A. Panfilov, K. Kalashnikov, A. Zykova, T. Kalashnikova, A. Vorontsov, S. Nikonov, E. Moskvichev, V. Semenchuk, V. Е. Rubtsov, E. Kolubaev","doi":"10.17804/2410-9908.2022.6.065-075","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.6.065-075","url":null,"abstract":"Samples of composite materials based on BrAMts9-2 bronze with the introduction of the Udimet500 and Inconel625 nickel alloys were obtained by wire-feed electron-beam technology. The studies show that the structures of composites formed during printing, although fairly similar due to the same base of the alloys, have different features due to different combinations of alloying elements. The mechanical properties of the samples with the introduction of up to 15 % of the Udimet500 alloy are higher than those of the samples of the second material. With the introduction of 25 % of a nickel alloy, the strength is higher for the composite material samples with the introduction of the Inconel625 alloy. The microhardness of the samples with the introduction of 5 % of a nickel alloy is identical, the introduction of large volumes of a nickel alloy leads to the implementation of greater hardness in the samples with the introduction of the Inconel625 alloy due to the higher content of refractory materials. Relative elongation after rupture varies insignificantly for the samples of both types.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"140 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90405100","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}
Pub Date : 2022-12-01DOI: 10.17804/2410-9908.2022.6.016-024
Y. Reutov
The paper reports the results of an experimental study of the work of a surface eddy current transducer in terms of detecting and testing metal loss under one-sided access conditions. The transducer consists of an exciting coil and a microchip Hall-effect transducer placed in it. The phase shift of the voltage from the Hall probe output relative to the current in the exciting coil, measured by a digital phase meter, is used as an informative parameter. The experiments were carried out on a package of duralumin plates. It is shown that, when the thickness of the duralumin test object is 12.5 mm, a fairly linear transformation of metal loss from 0 to 50 % at a frequency of 640 Hz is possible. The results can be useful in the development of devices for detecting metal corrosion losses in non-ferromagnetic objects with a thickness of tens of millimeters under one-sided access conditions.
{"title":"A surface eddy current transducer for metal loss detection","authors":"Y. Reutov","doi":"10.17804/2410-9908.2022.6.016-024","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.6.016-024","url":null,"abstract":"The paper reports the results of an experimental study of the work of a surface eddy current transducer in terms of detecting and testing metal loss under one-sided access conditions. The transducer consists of an exciting coil and a microchip Hall-effect transducer placed in it. The phase shift of the voltage from the Hall probe output relative to the current in the exciting coil, measured by a digital phase meter, is used as an informative parameter. The experiments were carried out on a package of duralumin plates. It is shown that, when the thickness of the duralumin test object is 12.5 mm, a fairly linear transformation of metal loss from 0 to 50 % at a frequency of 640 Hz is possible. The results can be useful in the development of devices for detecting metal corrosion losses in non-ferromagnetic objects with a thickness of tens of millimeters under one-sided access conditions.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83305715","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}
Pub Date : 2022-12-01DOI: 10.17804/2410-9908.2022.6.046-064
V. Pegov, I. Moshkin
The paper provides an experimental study of a multiphase flow around models in a large high-speed hydrodynamic tunnel with a vertical working section. Experimental dependences of drag coefficients on the cavitation number for vertical cavities are obtained. The results of cavitation flow around bodies of revolution in a vertically descending fluid flow are considered. A methodology for calculating the shape of vertical cavities under the slender-body theory is proposed. Relationships suitable for engineering evaluation are obtained for very long cavities. Numerical simulation of underwater motion is performed with models moving vertically in a nonstationary cavitation flow. The hydrodynamic loads can be evaluated through the determination of the nonstationary boundaries of a gas cavity and a linear load on a water-flown aft. The predicted results are compared with the experimental data. Validation and verification are performed by comparing the analysis results with the experimental data. The applicability of the proposed method to the determination of the hydrodynamic parameters of vehicles under multiphase flow is demonstrated.
{"title":"Studying multiphase flow around a vehicle moving freely to the water surface","authors":"V. Pegov, I. Moshkin","doi":"10.17804/2410-9908.2022.6.046-064","DOIUrl":"https://doi.org/10.17804/2410-9908.2022.6.046-064","url":null,"abstract":"The paper provides an experimental study of a multiphase flow around models in a large high-speed hydrodynamic tunnel with a vertical working section. Experimental dependences of drag coefficients on the cavitation number for vertical cavities are obtained. The results of cavitation flow around bodies of revolution in a vertically descending fluid flow are considered. A methodology for calculating the shape of vertical cavities under the slender-body theory is proposed. Relationships suitable for engineering evaluation are obtained for very long cavities. Numerical simulation of underwater motion is performed with models moving vertically in a nonstationary cavitation flow. The hydrodynamic loads can be evaluated through the determination of the nonstationary boundaries of a gas cavity and a linear load on a water-flown aft. The predicted results are compared with the experimental data. Validation and verification are performed by comparing the analysis results with the experimental data. The applicability of the proposed method to the determination of the hydrodynamic parameters of vehicles under multiphase flow is demonstrated.","PeriodicalId":11165,"journal":{"name":"Diagnostics, Resource and Mechanics of materials and structures","volume":"108 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74647648","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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