To show dynamic properties of a motorized spindle at high speed, C01 type motorized spindle bearing-rotor system is used as a study object, and the dynamic model of the bearing-rotor system is established. The method to analyze vibration characteristics of motorized spindles by power flow is proposed, and it is found that the vibration energy is not necessarily considerable at the position where the vibration displacement response is significant. Finally, the system vibration energy distribution under different bearing stiffness is analyzed. The power flow method can analyze the dynamic characteristics of the bearing-rotor system in terms of energy distribution.
{"title":"Research on vibration characteristics of motorized spindle at high speed based on power flow","authors":"Yudong Bao, Zhentao Zhou, Linkai Wu, Ye Dai","doi":"10.15632/jtam-pl/175498","DOIUrl":"https://doi.org/10.15632/jtam-pl/175498","url":null,"abstract":"To show dynamic properties of a motorized spindle at high speed, C01 type motorized spindle bearing-rotor system is used as a study object, and the dynamic model of the bearing-rotor system is established. The method to analyze vibration characteristics of motorized spindles by power flow is proposed, and it is found that the vibration energy is not necessarily considerable at the position where the vibration displacement response is significant. Finally, the system vibration energy distribution under different bearing stiffness is analyzed. The power flow method can analyze the dynamic characteristics of the bearing-rotor system in terms of energy distribution.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"19 12","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139010394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Laboratory study of the dynamic fracture in pre-drilled boreholes and the associated host rock behaviours","authors":"Cheng Guo Zhang, Xuebin Gu, Weiyao Guo, Xufei Gong, Hengyu Fang, He Huang","doi":"10.15632/jtam-pl/175127","DOIUrl":"https://doi.org/10.15632/jtam-pl/175127","url":null,"abstract":"","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"2 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138584754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To analyze the dynamic stall of multistage axial compressors, a three-dimensional unsteady numerical model is established based on the body force model. For a two-stage axial compressor with a clean inlet, the calculated maximum steady static pressure rise coefficient is only 0.1% different compared with the experimental data. The characteristic frequency of the dynamic stall evolution basically agrees with the experimental results, which proves the effectiveness of the model. For the compressor with a combined radial-circumferential total pressure inlet distortion, the predictions preliminarily verify the ability of the model for qualitative description of the flow instability process with the complex inlet distortion.
{"title":"Unsteady body force model for rotating stall in axial compressor with various inlet conditions","authors":"Jin Guo","doi":"10.15632/jtam-pl/174960","DOIUrl":"https://doi.org/10.15632/jtam-pl/174960","url":null,"abstract":"To analyze the dynamic stall of multistage axial compressors, a three-dimensional unsteady numerical model is established based on the body force model. For a two-stage axial compressor with a clean inlet, the calculated maximum steady static pressure rise coefficient is only 0.1% different compared with the experimental data. The characteristic frequency of the dynamic stall evolution basically agrees with the experimental results, which proves the effectiveness of the model. For the compressor with a combined radial-circumferential total pressure inlet distortion, the predictions preliminarily verify the ability of the model for qualitative description of the flow instability process with the complex inlet distortion.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"79 7","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138604723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper is devoted to a clamped sandwich beam with an individual functionally graded core under a uniformly distributed load. A non-linear shear deformation theory is developed with consideration of the classical shear stress formula for beams. Two differential equations of the equilibrium of the beam are obtained based on the principle of stationary total potential energy. The shear effect function and the relative deflection line of the beam are determined. Moreover, a numerical FEM model (Ansys system) of this beam is elaborated. Detailed calculations of exemplary beams are realised using two methods, analytical and numerical FEM.
{"title":"Bending of a sandwich beam with an individual functionally graded core","authors":"Krzysztof Magnucki, Krzysztof Sowiński","doi":"10.15632/jtam-pl/174698","DOIUrl":"https://doi.org/10.15632/jtam-pl/174698","url":null,"abstract":"This paper is devoted to a clamped sandwich beam with an individual functionally graded core under a uniformly distributed load. A non-linear shear deformation theory is developed with consideration of the classical shear stress formula for beams. Two differential equations of the equilibrium of the beam are obtained based on the principle of stationary total potential energy. The shear effect function and the relative deflection line of the beam are determined. Moreover, a numerical FEM model (Ansys system) of this beam is elaborated. Detailed calculations of exemplary beams are realised using two methods, analytical and numerical FEM.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":" 32","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138620649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, a piezoelectric phononic crystal beam at the nanoscale has been mechanically modeled by using the surface piezoelectric theory. The band gap has been calculated by the plane wave expansion method and the band gap structure picture has been analyzed. The influence of electromechanical coupling effects, surface effects and geometry on the band gap properties are discussed separately. This study contributes positively to the design and active control of nanoelectromechanical systems.
{"title":"Ultrahigh frequency vibration control in a piezoelectric phononic crystal beam at the nanoscale considering surface effects","authors":"Zexin Zhang, Denghui Qian, Long Ren, Qi Wang","doi":"10.15632/jtam-pl/174870","DOIUrl":"https://doi.org/10.15632/jtam-pl/174870","url":null,"abstract":"In this paper, a piezoelectric phononic crystal beam at the nanoscale has been mechanically modeled by using the surface piezoelectric theory. The band gap has been calculated by the plane wave expansion method and the band gap structure picture has been analyzed. The influence of electromechanical coupling effects, surface effects and geometry on the band gap properties are discussed separately. This study contributes positively to the design and active control of nanoelectromechanical systems.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"15 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139236457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.55787/jtams.23.53.4.348
A BSTRACT : Mathematical model of the deformation and drainage of film between interacting drops is presented in the case when dispersed or continuous phases are viscoelastic fluids. The model is based on the assumptions of a gentle collision at small Reynolds numbers and small deformation at small capillary numbers. It consists of lubrication approximation in the film and creeping flow equation in the dispersed phase. The equations in the continuous and dispersed phases are coupled by continuity of the velocity and stress boundary conditions at the interface. Generalizations of the Maxwell-type rheological constitutive relation are used to model the viscoelastic effects: upper-convected Maxwell model in the drop and fractional Maxwell model in the film phase. Predictions of the effect of the extra elastic stresses on the film drainage are given.
{"title":"MATHEMATICAL MODELING OF THE EFFECT OF VISCOELASTICITY ON THE FILM DRAINAGE BETWEEN INTERACTING DROPS","authors":"","doi":"10.55787/jtams.23.53.4.348","DOIUrl":"https://doi.org/10.55787/jtams.23.53.4.348","url":null,"abstract":"A BSTRACT : Mathematical model of the deformation and drainage of film between interacting drops is presented in the case when dispersed or continuous phases are viscoelastic fluids. The model is based on the assumptions of a gentle collision at small Reynolds numbers and small deformation at small capillary numbers. It consists of lubrication approximation in the film and creeping flow equation in the dispersed phase. The equations in the continuous and dispersed phases are coupled by continuity of the velocity and stress boundary conditions at the interface. Generalizations of the Maxwell-type rheological constitutive relation are used to model the viscoelastic effects: upper-convected Maxwell model in the drop and fractional Maxwell model in the film phase. Predictions of the effect of the extra elastic stresses on the film drainage are given.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"27 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135272396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.55787/jtams.23.53.4.404
A BSTRACT : The paper presents statistical analysis of air pollutants in the Bulgarian part of trans-border BG–RO area. Air contamination charcteristics and norms are also presented and commented in the present survey. Ecological monitoring system in the BG–RO trans-border area is described. Particulate matter (PM), nitrogen dioxide (NO 2 ) and ground-level ozone (O 3 ) , are now generally recognised as the three pollutants that most significantly affect human health. Because of this, further in the paper concentration levels of these three pollutants are statistically studied, based on official monitoring data. Re-sults are graphically presented and commented. Ambient air quality in the BG–RO trans-borer area is better today than it was two decades ago, but despite improvements, pollutant levels still show significant adverse effects on human health and the environment. To improve air quality in the future, it will be necessary to increase the use of ”green” and more efficient technologies in terms of thermal insulation of buildings, as well as the use of alternative sources of fuel in the household and transport, use of best available technology in the industry, green roofs in urban areas and more. Also it is nessessary more precise mathematical modeling of the data series, which take into account more factors to be developed and used for better understanding and forecasting the air contamination processes.
{"title":"AIR POLLUTION STUDY FOR BULGARIAN PART OF BULGARIA-ROMANIA TRANS-BORDER AREA","authors":"","doi":"10.55787/jtams.23.53.4.404","DOIUrl":"https://doi.org/10.55787/jtams.23.53.4.404","url":null,"abstract":"A BSTRACT : The paper presents statistical analysis of air pollutants in the Bulgarian part of trans-border BG–RO area. Air contamination charcteristics and norms are also presented and commented in the present survey. Ecological monitoring system in the BG–RO trans-border area is described. Particulate matter (PM), nitrogen dioxide (NO 2 ) and ground-level ozone (O 3 ) , are now generally recognised as the three pollutants that most significantly affect human health. Because of this, further in the paper concentration levels of these three pollutants are statistically studied, based on official monitoring data. Re-sults are graphically presented and commented. Ambient air quality in the BG–RO trans-borer area is better today than it was two decades ago, but despite improvements, pollutant levels still show significant adverse effects on human health and the environment. To improve air quality in the future, it will be necessary to increase the use of ”green” and more efficient technologies in terms of thermal insulation of buildings, as well as the use of alternative sources of fuel in the household and transport, use of best available technology in the industry, green roofs in urban areas and more. Also it is nessessary more precise mathematical modeling of the data series, which take into account more factors to be developed and used for better understanding and forecasting the air contamination processes.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"27 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135272394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.55787/jtams.23.53.4.319
The aim of this study is to perform a stability analysis of a thermo-capillary flow in a steady-state evaporating/condensing liquid layer applying the statistical rate theory expression for the mass flux across the interface. In the general mass, momentum and energy balance equations, the effects of gravity, temperature gradients in the surface tension, the interfacial momentum and energy loss due to the net mass flux are taken into account. Assuming a non-deformable surface and low dynamic viscosity and thermal conductivity of the vapor, the stability problem of the liquid phase is separated from that for the vapor. The exact solution is found and the dispersion relationship is solved numerically for water. The numerical results show that the interfacial instability mode always takes place in spite of the direction of the mass flux across the interface. The main physical reason for this kind of instability is the strong dependence of the mass flux on the vapor pressure predicted from the statistical rate theory. Other internal instability modes are described as a function of the Rayleigh and Marangoni numbers. The stability diagrams are discussed in the light of the available experiments for controllable water steady-state evaporation and condensation.
{"title":"STABILITY OF LIQUID-VAPOR INTERFACE AT STEADY-STATE EVAPORATION AND CONDENSATION","authors":"","doi":"10.55787/jtams.23.53.4.319","DOIUrl":"https://doi.org/10.55787/jtams.23.53.4.319","url":null,"abstract":"The aim of this study is to perform a stability analysis of a thermo-capillary flow in a steady-state evaporating/condensing liquid layer applying the statistical rate theory expression for the mass flux across the interface. In the general mass, momentum and energy balance equations, the effects of gravity, temperature gradients in the surface tension, the interfacial momentum and energy loss due to the net mass flux are taken into account. Assuming a non-deformable surface and low dynamic viscosity and thermal conductivity of the vapor, the stability problem of the liquid phase is separated from that for the vapor. The exact solution is found and the dispersion relationship is solved numerically for water. The numerical results show that the interfacial instability mode always takes place in spite of the direction of the mass flux across the interface. The main physical reason for this kind of instability is the strong dependence of the mass flux on the vapor pressure predicted from the statistical rate theory. Other internal instability modes are described as a function of the Rayleigh and Marangoni numbers. The stability diagrams are discussed in the light of the available experiments for controllable water steady-state evaporation and condensation.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135272415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.55787/jtams.23.53.4.424
A BSTRACT : In this work, the possibilities of the magnetosheath-magneto-sphere model for describing the plasma parameters in the magnetosheath are demonstrated. We consider the problem of a flow around a body (the Earth’s magnetosphere) with two movable boundaries – the bow shock (BS) and the magnetopause (MP). The grid-characteristic method is applied to describe an ideal gas flow in the transition region (magnetosheath). A theoretical finite element model and the semi-empirical Tsyganenko model are used to describe the magnetic field in the magnetosphere. The model allows a self-consistent determination of the magnetosheath boundaries for a given momentary state of the solar wind. For these input parameters the three-dimensional solution in the transition region is calculated. An analysis of the ion flux was made based on the model and the data measured by the Interball-1 satellite in several cases of magnetosheath crossings. The advantages and limitations of the model for describing the magnetosheath flow are analyzed.
{"title":"ION FLUX IN THE MAGNETOSHEATH: RESULTS FROM GAS-DYNAMIC MODELLING AND INTERBALL-1 MEASUREMENTS","authors":"","doi":"10.55787/jtams.23.53.4.424","DOIUrl":"https://doi.org/10.55787/jtams.23.53.4.424","url":null,"abstract":"A BSTRACT : In this work, the possibilities of the magnetosheath-magneto-sphere model for describing the plasma parameters in the magnetosheath are demonstrated. We consider the problem of a flow around a body (the Earth’s magnetosphere) with two movable boundaries – the bow shock (BS) and the magnetopause (MP). The grid-characteristic method is applied to describe an ideal gas flow in the transition region (magnetosheath). A theoretical finite element model and the semi-empirical Tsyganenko model are used to describe the magnetic field in the magnetosphere. The model allows a self-consistent determination of the magnetosheath boundaries for a given momentary state of the solar wind. For these input parameters the three-dimensional solution in the transition region is calculated. An analysis of the ion flux was made based on the model and the data measured by the Interball-1 satellite in several cases of magnetosheath crossings. The advantages and limitations of the model for describing the magnetosheath flow are analyzed.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135272393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.55787/jtams.23.53.4.389
A BSTRACT : Complex flow instabilities including wall slip and shear banding occur in many industrial applications, such as in polymer extrusion processes, thus affecting the throughput and the quality of the final product. The modelling of rheological data is a key point when studying different polymeric flows. The present survey incorporates three different ways to model the shear stress of shear thinning polymers as nonlinear functions of shear stress: generalized Newtonian model (Carreau-Yasuda model), wall shear slipping and banding with yield (Herschel–Bulkley model). Based on these models, the flow in the nozzle tube of a 3D printer is analyzed by a numerical model and two analytical models: the classical Weissenberg–Rabinowitsch–Mooney (WRM) model with slip; a simple model in three different regions in the tube (including yield, parabolic and band, which match their boundaries). The real data of measured shear stress by a plate–plate rheometer for three nanocomposites is used to compare the three models. The experimentally measured flow rates during the extrusion of the same nanocomposites are used to give insight into the corresponding flow structures in the nozzle tube.
{"title":"MODELLING OF POLYMER FLOW INSTABILITIES WITH APPLICATION TO 3D PRINTING","authors":"","doi":"10.55787/jtams.23.53.4.389","DOIUrl":"https://doi.org/10.55787/jtams.23.53.4.389","url":null,"abstract":"A BSTRACT : Complex flow instabilities including wall slip and shear banding occur in many industrial applications, such as in polymer extrusion processes, thus affecting the throughput and the quality of the final product. The modelling of rheological data is a key point when studying different polymeric flows. The present survey incorporates three different ways to model the shear stress of shear thinning polymers as nonlinear functions of shear stress: generalized Newtonian model (Carreau-Yasuda model), wall shear slipping and banding with yield (Herschel–Bulkley model). Based on these models, the flow in the nozzle tube of a 3D printer is analyzed by a numerical model and two analytical models: the classical Weissenberg–Rabinowitsch–Mooney (WRM) model with slip; a simple model in three different regions in the tube (including yield, parabolic and band, which match their boundaries). The real data of measured shear stress by a plate–plate rheometer for three nanocomposites is used to compare the three models. The experimentally measured flow rates during the extrusion of the same nanocomposites are used to give insight into the corresponding flow structures in the nozzle tube.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135272399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：