Pub Date : 2022-12-29DOI: 10.20535/2521-1943.2022.6.3.265948
D. Dzhulii, V. Maiboroda, Oleksii Burikov
The paper presents the study of the influence of the process of magneto-abrasive machining (MAM) on the characteristics of the surface layers of flat surfaces of parts made of ferromagnetic material U9 by machining with end-type heads based on high-power permanent magnets that form a magneto-abrasive tool of the "brush" type. For estimation of the influence of the process of magneto-abrasive machining on the surface layer, the parameters of surface hardness were analyzed after the machining of test samples with different powders and under different modes. The degree of influence of the MAM on the surface, both in terms of the hardness of the surface layer and the deformation of samples due to compressive residual stresses arising as a result of machining, was studied. The estimation of the state of the surface layer was performed by the change in hardness after machining, the magnitude of the degree of hardening, to some extent, by the parameters of roughness. The control of changes in internal residual stresses formed in the surface layers of samples due to the interaction of powder particles with the surface during machining was carried out according to the degree of their deformation after MAM. It was found that due to MAM, internal compressive stresses of 30–100 MPa arise in the near-surface layer of the material of the samples, while the magnitude of the stresses varied in inverse dependency, that is, with an increase in the working gap, in the vast majority of cases, a decrease in the magnitude of the stresses was observed. It was shown that the depth of the hardened layer under different machining conditions is up to 200 µm or more, and the strengthening coefficient varies from 10 to 40%.
{"title":"Influence of magneto-abrasive machining on the characteristics of the surface layer of flat parts","authors":"D. Dzhulii, V. Maiboroda, Oleksii Burikov","doi":"10.20535/2521-1943.2022.6.3.265948","DOIUrl":"https://doi.org/10.20535/2521-1943.2022.6.3.265948","url":null,"abstract":"The paper presents the study of the influence of the process of magneto-abrasive machining (MAM) on the characteristics of the surface layers of flat surfaces of parts made of ferromagnetic material U9 by machining with end-type heads based on high-power permanent magnets that form a magneto-abrasive tool of the \"brush\" type. For estimation of the influence of the process of magneto-abrasive machining on the surface layer, the parameters of surface hardness were analyzed after the machining of test samples with different powders and under different modes. The degree of influence of the MAM on the surface, both in terms of the hardness of the surface layer and the deformation of samples due to compressive residual stresses arising as a result of machining, was studied. The estimation of the state of the surface layer was performed by the change in hardness after machining, the magnitude of the degree of hardening, to some extent, by the parameters of roughness. The control of changes in internal residual stresses formed in the surface layers of samples due to the interaction of powder particles with the surface during machining was carried out according to the degree of their deformation after MAM. It was found that due to MAM, internal compressive stresses of 30–100 MPa arise in the near-surface layer of the material of the samples, while the magnitude of the stresses varied in inverse dependency, that is, with an increase in the working gap, in the vast majority of cases, a decrease in the magnitude of the stresses was observed. It was shown that the depth of the hardened layer under different machining conditions is up to 200 µm or more, and the strengthening coefficient varies from 10 to 40%.","PeriodicalId":32423,"journal":{"name":"Mechanics and Advanced Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44887173","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 : 2022-12-29DOI: 10.20535/2521-1943.2022.6.3.264786
I. Taranenko
At design of high-loaded units of engineering objects, especially such as articles of aero-space engineering, the problem of creation of reliable joints between metal and composite articles having predefined strength and ability to fulfill given functions appears. Development and grounding of selection of structural-manufacturing solutions of “metal-composite” joints with transversal fastening elements is selected as the objective of studying. As the object for studying possible structural-manufacturing solutions of “metal-composite” joints that use transversal fastening elements which are embedded to composite and attached to metal article or produced on its surface. Three types of fastening micro-elements are considered, i.e. pyramidal monolithic, cylindrical and sheet-formed, also different technologies of fastening elements production are considered too. Mass of typical flat article with micro-pins at given load-carrying ability of “metal-composite joint” was esti-mated for above-mentioned types of micro-fasteners. Such quantitative indexes of manufacturability as labor-intensity and energy consumption of fastening elements production were considered as results of studies. Approach to comparison methods of fastening elements manufacturing is suggested. This approach is based on analysis of correspondent numerical specific indexes of labor-intensity and energy consumption. These indexes are com-pared for micro-pins which are assumed to be produced of aluminum, titanium alloys and stainless steels. Distinctive feature of suggested model of analysis is taking into consideration both main and auxiliary techno-logical operations, which influence significantly on manufacturing labor-intensity and duration. Process of classical milling with cylindrical and disc mills is compared with up-to-date methods of electro-erosion cutting with wire. Recommendations for selection shape, type and arrangement scheme of micro-fasteners on article surface and exact manufacturing process of micro-pins production at given material are formulated as conclusions.
{"title":"Application of erosion dimensional treatment methods for creation transversal fasteners in “metal-composite” joints","authors":"I. Taranenko","doi":"10.20535/2521-1943.2022.6.3.264786","DOIUrl":"https://doi.org/10.20535/2521-1943.2022.6.3.264786","url":null,"abstract":"At design of high-loaded units of engineering objects, especially such as articles of aero-space engineering, the problem of creation of reliable joints between metal and composite articles having predefined strength and ability to fulfill given functions appears.\u0000Development and grounding of selection of structural-manufacturing solutions of “metal-composite” joints with transversal fastening elements is selected as the objective of studying.\u0000As the object for studying possible structural-manufacturing solutions of “metal-composite” joints that use transversal fastening elements which are embedded to composite and attached to metal article or produced on its surface. Three types of fastening micro-elements are considered, i.e. pyramidal monolithic, cylindrical and sheet-formed, also different technologies of fastening elements production are considered too.\u0000Mass of typical flat article with micro-pins at given load-carrying ability of “metal-composite joint” was esti-mated for above-mentioned types of micro-fasteners.\u0000Such quantitative indexes of manufacturability as labor-intensity and energy consumption of fastening elements production were considered as results of studies.\u0000Approach to comparison methods of fastening elements manufacturing is suggested. This approach is based on analysis of correspondent numerical specific indexes of labor-intensity and energy consumption. These indexes are com-pared for micro-pins which are assumed to be produced of aluminum, titanium alloys and stainless steels.\u0000Distinctive feature of suggested model of analysis is taking into consideration both main and auxiliary techno-logical operations, which influence significantly on manufacturing labor-intensity and duration. Process of classical milling with cylindrical and disc mills is compared with up-to-date methods of electro-erosion cutting with wire.\u0000Recommendations for selection shape, type and arrangement scheme of micro-fasteners on article surface and exact manufacturing process of micro-pins production at given material are formulated as conclusions.","PeriodicalId":32423,"journal":{"name":"Mechanics and Advanced Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45314492","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 : 2022-12-29DOI: 10.20535/2521-1943.2022.6.3.267250
V. Lavrinenko, V. Solod
The issue of energy efficiency of machining processes has been the focus of attention for the last 50 years. This is due to the fact that in comparison with other industries, metallurgy and mechanical engineering are characterized by a high level of energy intensity of products. Analysis of available in the literature indicators of energy costs of processing processes and determination of consistent data from these indicators. Establishing an analytical relationship between the grinding energy and the energy required for melting the finishing material. It is determined that the cutting energy of the material during chip formation is close to the energy required for melting the metal, and the excess amount of spent grinding energy is spent on friction between the chips and the grinding wheel. It is shown that in the literature there are data on the energy consumption of different treatments: turning - 2 kJ/cm3, milling - 9 kJ/cm3, grinding - 60 kJ/cm3, electrospark treatment - 3000 kJ/cm3. At the same time, the specific energy consumption of steel grinding is 60 kJ/cm3. And the specific heat of fusion of steel is 0.64 kJ/cm3. As a result, 100 times more heat is pumped into the steel during grinding than is needed to melt it. That is, there is a contradiction. To find ways to resolve this contradiction, it is more accurate to estimate the specific energy consumption of diamond-abrasive machining of superhard materials through additional consideration, in addition to productivity and effective machining power, wear of the working layer of the wheel.
{"title":"Analysis of Available Data and Estimation of Energy Supply of Mechanical Processing","authors":"V. Lavrinenko, V. Solod","doi":"10.20535/2521-1943.2022.6.3.267250","DOIUrl":"https://doi.org/10.20535/2521-1943.2022.6.3.267250","url":null,"abstract":"The issue of energy efficiency of machining processes has been the focus of attention for the last 50 years. This is due to the fact that in comparison with other industries, metallurgy and mechanical engineering are characterized by a high level of energy intensity of products.\u0000Analysis of available in the literature indicators of energy costs of processing processes and determination of consistent data from these indicators.\u0000Establishing an analytical relationship between the grinding energy and the energy required for melting the finishing material.\u0000It is determined that the cutting energy of the material during chip formation is close to the energy required for melting the metal, and the excess amount of spent grinding energy is spent on friction between the chips and the grinding wheel. It is shown that in the literature there are data on the energy consumption of different treatments: turning - 2 kJ/cm3, milling - 9 kJ/cm3, grinding - 60 kJ/cm3, electrospark treatment - 3000 kJ/cm3. At the same time, the specific energy consumption of steel grinding is 60 kJ/cm3. And the specific heat of fusion of steel is 0.64 kJ/cm3. As a result, 100 times more heat is pumped into the steel during grinding than is needed to melt it. That is, there is a contradiction.\u0000To find ways to resolve this contradiction, it is more accurate to estimate the specific energy consumption of diamond-abrasive machining of superhard materials through additional consideration, in addition to productivity and effective machining power, wear of the working layer of the wheel.","PeriodicalId":32423,"journal":{"name":"Mechanics and Advanced Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41486180","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 : 2022-12-29DOI: 10.20535/2521-1943.2022.6.3.269900
O. Salenko, S. Klimenko, Vadum Orel, Volodymyr Kholodny, Natalya Gavrushkevich
The principles of creating hybrid processing processes based on the functional approach are given. The base of this approach, its theoretical aspects are given in the first part of the article. The practical application of the approaches is reflected in specific scientific and technical problems in the problem of high-quality cleaning of the surface from various adhesive coatings, the use of methods for obtaining holes and perforations in workpieces from metals and composite materials, as well as in the problem of contour cutting of plates from superhard sintered materials. It is shown that the use of a functionally oriented approach makes it possible to identify such combinations of force and energy effects that make it possible to process even those materials that are considered difficult to process or not machinable. Samples of cleaned surfaces, cuts of superhard materials, holes in honeycomb systems of aerospace engineering are presented.
{"title":"Using the functional approach in the development of hybrid processes in engineering: practical aspects","authors":"O. Salenko, S. Klimenko, Vadum Orel, Volodymyr Kholodny, Natalya Gavrushkevich","doi":"10.20535/2521-1943.2022.6.3.269900","DOIUrl":"https://doi.org/10.20535/2521-1943.2022.6.3.269900","url":null,"abstract":"The principles of creating hybrid processing processes based on the functional approach are given. The base of this approach, its theoretical aspects are given in the first part of the article. The practical application of the approaches is reflected in specific scientific and technical problems in the problem of high-quality cleaning of the surface from various adhesive coatings, the use of methods for obtaining holes and perforations in workpieces from metals and composite materials, as well as in the problem of contour cutting of plates from superhard sintered materials. It is shown that the use of a functionally oriented approach makes it possible to identify such combinations of force and energy effects that make it possible to process even those materials that are considered difficult to process or not machinable.\u0000Samples of cleaned surfaces, cuts of superhard materials, holes in honeycomb systems of aerospace engineering are presented.\u0000 ","PeriodicalId":32423,"journal":{"name":"Mechanics and Advanced Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44237982","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 : 2022-12-29DOI: 10.20535/2521-1943.2022.6.3.269897
V. Kaliuzhnyi, Leyla Aliieva, Oleksandr Yarmolenko, S. Sytnyk
The work is devoted to researching a new method of hot direct-reverse extrusion of hollow conical products from high-carbon steel and determinated parameters for technological design. The considered method makes it possible to obtain in one step hollow products with different wall thickness in height, while the wall thickness in the upper part of the product can be greater than the thickness in the bottom part. The dimensions of the initial workpiece are determined by modeling using the finite element method, which ensures the simultaneous flow of metal in the forward and reverse directions during the process of forming the product, which reduces the deformation force. The use of this method also leads to a decrease in the heating of the deforming tool due to a decrease in the contact area of the deformed workpiece with the tool. The strain rate is determined to ensure the temperature interval of extrusion. The dependencies of the force of extrusion, removal of the punch from the deformed workpiece, pushing the product out of the matrix on the movement of the corresponding tool are established. The final shape and dimensions of the product with the distribution of temperature and deformations were found. For the maximum amount of extrusion force, the distributions of specific forces on the contacting surfaces of the punch, matrix, ejector and stress on the volume of the deformed workpiece were found. According to the obtained data, the technology of direct-reverse extrusion can be developed and implemented on universal press equipment, which has high productivity due to the reduction of the number of stamping steps. The design of the stamp for extruding products of certain sizes with forced cooling of the matrix is given.
{"title":"Hot extrusion of high carbon steel cone hollow products","authors":"V. Kaliuzhnyi, Leyla Aliieva, Oleksandr Yarmolenko, S. Sytnyk","doi":"10.20535/2521-1943.2022.6.3.269897","DOIUrl":"https://doi.org/10.20535/2521-1943.2022.6.3.269897","url":null,"abstract":"The work is devoted to researching a new method of hot direct-reverse extrusion of hollow conical products from high-carbon steel and determinated parameters for technological design. The considered method makes it possible to obtain in one step hollow products with different wall thickness in height, while the wall thickness in the upper part of the product can be greater than the thickness in the bottom part. The dimensions of the initial workpiece are determined by modeling using the finite element method, which ensures the simultaneous flow of metal in the forward and reverse directions during the process of forming the product, which reduces the deformation force. The use of this method also leads to a decrease in the heating of the deforming tool due to a decrease in the contact area of the deformed workpiece with the tool. The strain rate is determined to ensure the temperature interval of extrusion. The dependencies of the force of extrusion, removal of the punch from the deformed workpiece, pushing the product out of the matrix on the movement of the corresponding tool are established. The final shape and dimensions of the product with the distribution of temperature and deformations were found. For the maximum amount of extrusion force, the distributions of specific forces on the contacting surfaces of the punch, matrix, ejector and stress on the volume of the deformed workpiece were found. According to the obtained data, the technology of direct-reverse extrusion can be developed and implemented on universal press equipment, which has high productivity due to the reduction of the number of stamping steps. The design of the stamp for extruding products of certain sizes with forced cooling of the matrix is given.\u0000 ","PeriodicalId":32423,"journal":{"name":"Mechanics and Advanced Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48815387","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 : 2022-12-29DOI: 10.20535/2521-1943.2022.6.3.262805
Marianna Dyman, A. Moltasov, Serhii Kaliuzhnyi
As it was mentioned in the first part of this work, to determine the modulus of elasticity of one of the layers of a double-layer beam during bending, it is necessary to know the modulus of elasticity of the other layer and the bending stiffness of the entire section. Therefore, the purpose of the presented part of the work is to experimentally establish the specified characteristics of coated samples of rectangular cross-section and substrate without coating during three-point bending. The results of experimental studies of elastic-geometric characteristics during bending of samples with coatings of VT1-00 and KTC-110 alloys, applied to a substrate of VT6 alloy by microplasma sputtering, with different degrees of porosity, are presented. Analytical calculations of the modulus of elasticity of the specified coatings were carried out, the results of which make it possible to establish the general regularities of its change depending on their degree of porosity.
{"title":"Calculation and experimental procedure for determining the modulus of elasticity of porous coatings on a substrate during bending. Part 2. Experimental research","authors":"Marianna Dyman, A. Moltasov, Serhii Kaliuzhnyi","doi":"10.20535/2521-1943.2022.6.3.262805","DOIUrl":"https://doi.org/10.20535/2521-1943.2022.6.3.262805","url":null,"abstract":"As it was mentioned in the first part of this work, to determine the modulus of elasticity of one of the layers of a double-layer beam during bending, it is necessary to know the modulus of elasticity of the other layer and the bending stiffness of the entire section. Therefore, the purpose of the presented part of the work is to experimentally establish the specified characteristics of coated samples of rectangular cross-section and substrate without coating during three-point bending. The results of experimental studies of elastic-geometric characteristics during bending of samples with coatings of VT1-00 and KTC-110 alloys, applied to a substrate of VT6 alloy by microplasma sputtering, with different degrees of porosity, are presented. Analytical calculations of the modulus of elasticity of the specified coatings were carried out, the results of which make it possible to establish the general regularities of its change depending on their degree of porosity.","PeriodicalId":32423,"journal":{"name":"Mechanics and Advanced Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46006381","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 : 2022-12-29DOI: 10.20535/2521-1943.2022.6.3.264783
M. Bobyr
The work proposes and substantiates a type of phenomenal criterion of composite material destruction at the stage of macro crack origination. It considers damageability and two mechanisms of destruction: tearing and slice. It describes that as parameter of damageability it can be taken specific energy of extra stresses or specific energy of diffusion. For proportionate and complex processes of metallic materials loading they result equally in practice. Methodologies of respective energetic parameters search are described. It is set threshold value of stress in the element of construction during the reach of it it is necessary to consider an accumulation of damage. It is described the methodology that describes interconnection between anisotropy factors and components of damage tensor.
{"title":"Criterion of the limit state of composites materials","authors":"M. Bobyr","doi":"10.20535/2521-1943.2022.6.3.264783","DOIUrl":"https://doi.org/10.20535/2521-1943.2022.6.3.264783","url":null,"abstract":"The work proposes and substantiates a type of phenomenal criterion of composite material destruction at the stage of macro crack origination. It considers damageability and two mechanisms of destruction: tearing and slice. It describes that as parameter of damageability it can be taken specific energy of extra stresses or specific energy of diffusion. For proportionate and complex processes of metallic materials loading they result equally in practice. Methodologies of respective energetic parameters search are described. It is set threshold value of stress in the element of construction during the reach of it it is necessary to consider an accumulation of damage. It is described the methodology that describes interconnection between anisotropy factors and components of damage tensor.","PeriodicalId":32423,"journal":{"name":"Mechanics and Advanced Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41961863","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 : 2022-12-29DOI: 10.20535/2521-1943.2022.6.3.268515
Oleksii Ishchenko, M. Kryshchuk
In case for nuclear power plants long-term service operation over their design life, it is necessary to calculate reactor pressure vessel (RPV) strength and durability acknowledgment (static strength, strength under cyclic and seismic loads, brittle fracture resistance (BFR) include) the as one of the most important NPP structure. Usually, according to the brittle strength assessment, RPV resource is determined, that is, time of its subsequent safe operation. The purpose of this work is assessed BFR RPV at potential emergency accidents (EA) using the Ukrainian warm pre-stress approach. The calculated thermohydrodynamic parameters at EA were used to calculate the stress-strain state of the developed reactor finite element (FE) model. For researching, the most indicative scenarios were selected: where reactor is cooled at a high pressure. In RPV FE model cracks are modeled at the most dangerous places - welds and nozzle. Stress intensity factor (SIF) distribution along crack front and temperature for the most dangerous accidents in terms of BFR are presented in figures. Brittle strength condition is ensured during the nuclear power plants service operation for up to 60 years, which is more than 1.5 times more than the oldest Ukrainian power plant with VVER-1000. For some emergency accidents, warm pre-stress really significantly increased RPV safety margin, but for the most dangerous accidents, the results are the same as without taking into account WPS.
{"title":"Safety margin determination of the nuclear power plant reactor pressure vessel with taking into account warm pre-stress effect","authors":"Oleksii Ishchenko, M. Kryshchuk","doi":"10.20535/2521-1943.2022.6.3.268515","DOIUrl":"https://doi.org/10.20535/2521-1943.2022.6.3.268515","url":null,"abstract":"In case for nuclear power plants long-term service operation over their design life, it is necessary to calculate reactor pressure vessel (RPV) strength and durability acknowledgment (static strength, strength under cyclic and seismic loads, brittle fracture resistance (BFR) include) the as one of the most important NPP structure. Usually, according to the brittle strength assessment, RPV resource is determined, that is, time of its subsequent safe operation. The purpose of this work is assessed BFR RPV at potential emergency accidents (EA) using the Ukrainian warm pre-stress approach. The calculated thermohydrodynamic parameters at EA were used to calculate the stress-strain state of the developed reactor finite element (FE) model. For researching, the most indicative scenarios were selected: where reactor is cooled at a high pressure. In RPV FE model cracks are modeled at the most dangerous places - welds and nozzle. Stress intensity factor (SIF) distribution along crack front and temperature for the most dangerous accidents in terms of BFR are presented in figures. Brittle strength condition is ensured during the nuclear power plants service operation for up to 60 years, which is more than 1.5 times more than the oldest Ukrainian power plant with VVER-1000. For some emergency accidents, warm pre-stress really significantly increased RPV safety margin, but for the most dangerous accidents, the results are the same as without taking into account WPS.","PeriodicalId":32423,"journal":{"name":"Mechanics and Advanced Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48718267","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 : 2022-12-29DOI: 10.20535/2521-1943.2022.6.3.263541
I. Orynyak, J. Bai, I. Kostiushko
The principally new method of selected exact solutions, SES, for plate vibration based on fundamental solutions of Voigt is suggested. In contrast to similar known methods, it employs the frequency dependent functions for both space coordinates. The sets of exact solutions which depends on some arbitrary chosen parameters are constructed. This allows to choose any number of exact solutions, while the required number of them depends on the boundary conditions which should satisfy in considered collocation points. The efficiency of method is demonstrated for the most unfavorable case of all sides clamped rectangular plate. Nevertheless, the accuracy is quite satisfactory for first six natural frequencies even for relatively small number of collocation boundary points, and testify about big prospects as to application for complex structures, different geometries, various boundary conditions. Additionally two variants of the Galerkin method are realized and compared. First one, employs the exponential functions, while the second one –the very popular beam functions. The calculation results show the superiority of first variant as in technical realization as in accuracy, and in further applications in structural mechanics.
{"title":"Applications of randomly selected sets of exact Voight's solutions for vibration of thin plates","authors":"I. Orynyak, J. Bai, I. Kostiushko","doi":"10.20535/2521-1943.2022.6.3.263541","DOIUrl":"https://doi.org/10.20535/2521-1943.2022.6.3.263541","url":null,"abstract":"The principally new method of selected exact solutions, SES, for plate vibration based on fundamental solutions of Voigt is suggested. In contrast to similar known methods, it employs the frequency dependent functions for both space coordinates. The sets of exact solutions which depends on some arbitrary chosen parameters are constructed. This allows to choose any number of exact solutions, while the required number of them depends on the boundary conditions which should satisfy in considered collocation points. \u0000The efficiency of method is demonstrated for the most unfavorable case of all sides clamped rectangular plate. Nevertheless, the accuracy is quite satisfactory for first six natural frequencies even for relatively small number of collocation boundary points, and testify about big prospects as to application for complex structures, different geometries, various boundary conditions. \u0000Additionally two variants of the Galerkin method are realized and compared. First one, employs the exponential functions, while the second one –the very popular beam functions. The calculation results show the superiority of first variant as in technical realization as in accuracy, and in further applications in structural mechanics.","PeriodicalId":32423,"journal":{"name":"Mechanics and Advanced Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45384912","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 : 2022-12-29DOI: 10.20535/2521-1943.2022.6.3.266603
V. Kovalev, Wei Chenyu
Modern moving objects containing large volumes of liquid need to ensure stability on the movement trajectory, reliability of control during maneuvers, as well as the ability to predict and prevent extreme movement conditions. The presented article provides review materials devoted to the research results into inertial flows of viscous incompressible fluid in tanks with internal damping baffles. In order to exert force on resonant excitations from the liquid side and to compensate for the instabilities of moving objects, the analysis and design of rational structures of influence means on currents is carried out. Among the most effective means of damping should be noted rigid internal baffles of various designs installed in tanks in the most likely areas where instabilities and sources of excitation of resonant fluid movements may occur. Flat rigid partitions, profiled permeable damping surfaces, perforated and retaining elements, enslavers of liquid due to surface tension forces, etc., require comprehensive and detailed study and analysis.
{"title":"The structure of viscous liquid internal flows in tanks with damping baffles","authors":"V. Kovalev, Wei Chenyu","doi":"10.20535/2521-1943.2022.6.3.266603","DOIUrl":"https://doi.org/10.20535/2521-1943.2022.6.3.266603","url":null,"abstract":"Modern moving objects containing large volumes of liquid need to ensure stability on the movement trajectory, reliability of control during maneuvers, as well as the ability to predict and prevent extreme movement conditions. The presented article provides review materials devoted to the research results into inertial flows of viscous incompressible fluid in tanks with internal damping baffles. In order to exert force on resonant excitations from the liquid side and to compensate for the instabilities of moving objects, the analysis and design of rational structures of influence means on currents is carried out.\u0000Among the most effective means of damping should be noted rigid internal baffles of various designs installed in tanks in the most likely areas where instabilities and sources of excitation of resonant fluid movements may occur. Flat rigid partitions, profiled permeable damping surfaces, perforated and retaining elements, enslavers of liquid due to surface tension forces, etc., require comprehensive and detailed study and analysis.","PeriodicalId":32423,"journal":{"name":"Mechanics and Advanced Technologies","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42158630","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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