Abstract Recently, textured surfaces have been used to enhance the performance of tribological systems. This paper examines the effect of textured surfaces on hole-entry spherical hybrid journal bearings operated using magnetorheological (MR) fluid. The different geometric shapes of textured surfaces, including spherical, rectangular, and conical, have been selected for numerical analysis. Next-generation design for tribological systems based on MR fluid lubrication emphasizes dynamic performance. MR fluid responds quickly, and its rheological characteristics can be simply adjusted. The present paper also deals with the non-Newtonian behavior of MR fluid on the bearing performance characteristics parameters. The finite element method is used to solve the modified Reynolds equation. The findings of numerical simulation show that the application of textured surfaces and MR fluid improves the values of minimum fluid film thickness and stability of the bearing.
{"title":"Performance analysis of textured spherical hybrid journal bearings operated with magneto-rheological fluid","authors":"Adesh Kumar Tomar, Satish Chandra Sharma, Krishnkant Sahu","doi":"10.1115/1.4063495","DOIUrl":"https://doi.org/10.1115/1.4063495","url":null,"abstract":"Abstract Recently, textured surfaces have been used to enhance the performance of tribological systems. This paper examines the effect of textured surfaces on hole-entry spherical hybrid journal bearings operated using magnetorheological (MR) fluid. The different geometric shapes of textured surfaces, including spherical, rectangular, and conical, have been selected for numerical analysis. Next-generation design for tribological systems based on MR fluid lubrication emphasizes dynamic performance. MR fluid responds quickly, and its rheological characteristics can be simply adjusted. The present paper also deals with the non-Newtonian behavior of MR fluid on the bearing performance characteristics parameters. The finite element method is used to solve the modified Reynolds equation. The findings of numerical simulation show that the application of textured surfaces and MR fluid improves the values of minimum fluid film thickness and stability of the bearing.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135824316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rahul Gupta, Tarun Nanda, O. P. Pandey, Varun Singhal, Sandeep Bansal, Ravi Shankar Raman
Abstract In this work, high temperature tribological characteristics of ilmenite reinforced LM13 aluminium alloy based composites (AMCs) and boron carbide reinforced AMCs are compared. Stir-cast composites were processed using boron carbide (CDP) and ilmenite (NDP) particles separately as reinforcements. Particle size range was 106–125 μm and reinforcement levels were 5, 10, and 15 wt.% for both types of composites. Both composites exhibited uniform distribution of reinforced particles and grain refinement. Compared to the LM13 base alloy, NDP composite containing 15 wt.% reinforcement showed significant improvement in hardness (57%), coefficient of friction (57%), mild-to-severe wear transition temperature, average steady-state wear rate (49%), and coefficient of thermal expansion (55%). CDP-15 composite showed slightly better properties than NDP-15 composite. Microstructure refinement, increased dimensional stability, formation of oxide layer, and formation of tribo-layer due to reinforcement of the ceramic fillers were the main reasons for improvement in properties of processed AMCs. SEM-EDS of wear tracks-debris showed abrasive/delamination wear as the main mechanisms for materials loss. The research showed that the low-cost ilmenite particles can substitute for the very costly boron carbide particles as reinforcements in AMCs used for dry sliding wear applications under high operating temperatures-applied load conditions of the order of 300°C-49 N.
{"title":"Comparison of tribological characteristics of LM13/B4C and LM13/ilmenite composites at high temperature conditions","authors":"Rahul Gupta, Tarun Nanda, O. P. Pandey, Varun Singhal, Sandeep Bansal, Ravi Shankar Raman","doi":"10.1115/1.4063811","DOIUrl":"https://doi.org/10.1115/1.4063811","url":null,"abstract":"Abstract In this work, high temperature tribological characteristics of ilmenite reinforced LM13 aluminium alloy based composites (AMCs) and boron carbide reinforced AMCs are compared. Stir-cast composites were processed using boron carbide (CDP) and ilmenite (NDP) particles separately as reinforcements. Particle size range was 106–125 μm and reinforcement levels were 5, 10, and 15 wt.% for both types of composites. Both composites exhibited uniform distribution of reinforced particles and grain refinement. Compared to the LM13 base alloy, NDP composite containing 15 wt.% reinforcement showed significant improvement in hardness (57%), coefficient of friction (57%), mild-to-severe wear transition temperature, average steady-state wear rate (49%), and coefficient of thermal expansion (55%). CDP-15 composite showed slightly better properties than NDP-15 composite. Microstructure refinement, increased dimensional stability, formation of oxide layer, and formation of tribo-layer due to reinforcement of the ceramic fillers were the main reasons for improvement in properties of processed AMCs. SEM-EDS of wear tracks-debris showed abrasive/delamination wear as the main mechanisms for materials loss. The research showed that the low-cost ilmenite particles can substitute for the very costly boron carbide particles as reinforcements in AMCs used for dry sliding wear applications under high operating temperatures-applied load conditions of the order of 300°C-49 N.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135994077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Li Jiaxue, Jin Wenrui, Zhang Zhigang, Lv Xiaoxiao, Zhang Tao
Abstract The working characteristics of wet clutches have an important impact on the safety performance of vehicles. In order to obtain the thermoelastic instability characteristics of wet clutch separate plate, a finite element modeling method is proposed. The temperature field calculation model of separate plate and its thermo-hydro-mechanical coupling relationship are constructed. The distribution law of high temperature hot spots on the surface of separate plate is obtained and the thermoelastic instability mechanism is revealed. Effectiveness of the simulation model is verified by road test, and surface topography of separate plate is observed by scanning electron microscope. A thermoelastic instability calculation model considering different material parameters is established. The temperature field distribution law is reviewed under different elastic modulus, specific heat capacity, thermal conductivity and thermal expansion coefficient. Results show that increasing the specific heat capacity and thermal conductivity of the separate plate, decreasing the elastic modulus and thermal expansion coefficient can improve the stability of the system. The thermal conductivity and thermal expansion coefficient have important effects on the thermoelastic instability. The specific heat capacity has a certain effect, and the elastic modulus' effect is the least. The research results of this paper can provide theoretical support for optimizing the structure of wet clutch and improving the stability of the system.
{"title":"Analysis on effects of material parameters on thermoelastic instability of separate plate in wet clutch","authors":"Li Jiaxue, Jin Wenrui, Zhang Zhigang, Lv Xiaoxiao, Zhang Tao","doi":"10.1115/1.4063812","DOIUrl":"https://doi.org/10.1115/1.4063812","url":null,"abstract":"Abstract The working characteristics of wet clutches have an important impact on the safety performance of vehicles. In order to obtain the thermoelastic instability characteristics of wet clutch separate plate, a finite element modeling method is proposed. The temperature field calculation model of separate plate and its thermo-hydro-mechanical coupling relationship are constructed. The distribution law of high temperature hot spots on the surface of separate plate is obtained and the thermoelastic instability mechanism is revealed. Effectiveness of the simulation model is verified by road test, and surface topography of separate plate is observed by scanning electron microscope. A thermoelastic instability calculation model considering different material parameters is established. The temperature field distribution law is reviewed under different elastic modulus, specific heat capacity, thermal conductivity and thermal expansion coefficient. Results show that increasing the specific heat capacity and thermal conductivity of the separate plate, decreasing the elastic modulus and thermal expansion coefficient can improve the stability of the system. The thermal conductivity and thermal expansion coefficient have important effects on the thermoelastic instability. The specific heat capacity has a certain effect, and the elastic modulus' effect is the least. The research results of this paper can provide theoretical support for optimizing the structure of wet clutch and improving the stability of the system.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":"40 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135994795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In hydrodynamic lubrication problems, the presence of step structures on the surface can cause discontinuities in the film thickness. This article proposes two models for solving the two-dimensional Reynolds equation with film thickness discontinuity using the finite difference method (FDM). In model I, the film thickness variable is defined at the center of the mesh grids, allowing the Reynolds equation to be reformulated in a weak form that eliminates the singularity of film thickness discontinuity and satisfies the flow continuity condition at the film thickness discontinuity region. By considering the step boundary on the surface as the interface, model II is constructed based on the immersed interface method, turning the hydrodynamic lubrication problem into a classical interface problem. The jump conditions across the interface are derived in accordance with the continuous flow requirement. A phase-field function is adopted to describe the interface on the uniform rectangular mesh grids. Numerical experiments are conducted to assess the accuracy and capabilities of the two proposed models for analyzing a step-dimple-textured sealing. The results demonstrate that both modified FDM models can effectively address the thickness discontinuity issue. Model II achieves second-order accuracy for the pressure distribution when dealing with curved interfaces based on Cartesian grids, whereas model I demonstrates first-order accuracy. Both the proposed models exhibit superior accuracy compared to the traditional second-order central FDM when dealing with curved interfaces. Moreover, the performance of model II is further assessed by simulating lubrication problems with complex groove shapes, and the results indicate its flexibility in addressing thickness discontinuity problems with complex curve interface.
{"title":"Modified finite difference methods for Reynold equation with film thickness discontinuity","authors":"Qiang He, Fengming Hu, Weifeng Huang, Yang Hu, Guohui Cong, Yixun Zhang","doi":"10.1115/1.4063442","DOIUrl":"https://doi.org/10.1115/1.4063442","url":null,"abstract":"Abstract In hydrodynamic lubrication problems, the presence of step structures on the surface can cause discontinuities in the film thickness. This article proposes two models for solving the two-dimensional Reynolds equation with film thickness discontinuity using the finite difference method (FDM). In model I, the film thickness variable is defined at the center of the mesh grids, allowing the Reynolds equation to be reformulated in a weak form that eliminates the singularity of film thickness discontinuity and satisfies the flow continuity condition at the film thickness discontinuity region. By considering the step boundary on the surface as the interface, model II is constructed based on the immersed interface method, turning the hydrodynamic lubrication problem into a classical interface problem. The jump conditions across the interface are derived in accordance with the continuous flow requirement. A phase-field function is adopted to describe the interface on the uniform rectangular mesh grids. Numerical experiments are conducted to assess the accuracy and capabilities of the two proposed models for analyzing a step-dimple-textured sealing. The results demonstrate that both modified FDM models can effectively address the thickness discontinuity issue. Model II achieves second-order accuracy for the pressure distribution when dealing with curved interfaces based on Cartesian grids, whereas model I demonstrates first-order accuracy. Both the proposed models exhibit superior accuracy compared to the traditional second-order central FDM when dealing with curved interfaces. Moreover, the performance of model II is further assessed by simulating lubrication problems with complex groove shapes, and the results indicate its flexibility in addressing thickness discontinuity problems with complex curve interface.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134948053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yixin Zhang, Wei Pan, Shujiang Chen, Yongtao Zhang, Changhou Lu
Abstract The dynamic performance of the hydraulic system depends on the dynamic characteristics of the servo valve. In this article, the control characteristics of the piezoelectric servo valve are studied theoretically and experimentally. The mathematical model of the system is established by considering the influence of the piezoelectric servo valve, the influence of the pipeline, and the interaction between them. The frequency response characteristics of the system and the influence of the pipeline parameters on the control characteristics of the system are discussed. The simulation results are compared with the experimental results to verify the accuracy and efficiency of the piezoelectric servo valve dynamic model established in this article.
{"title":"Mathematical modeling and experimental characterization of the piezoelectric servo valve system","authors":"Yixin Zhang, Wei Pan, Shujiang Chen, Yongtao Zhang, Changhou Lu","doi":"10.1115/1.4063210","DOIUrl":"https://doi.org/10.1115/1.4063210","url":null,"abstract":"Abstract The dynamic performance of the hydraulic system depends on the dynamic characteristics of the servo valve. In this article, the control characteristics of the piezoelectric servo valve are studied theoretically and experimentally. The mathematical model of the system is established by considering the influence of the piezoelectric servo valve, the influence of the pipeline, and the interaction between them. The frequency response characteristics of the system and the influence of the pipeline parameters on the control characteristics of the system are discussed. The simulation results are compared with the experimental results to verify the accuracy and efficiency of the piezoelectric servo valve dynamic model established in this article.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":"300 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134948206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thomas Russell, Farshid Sadeghi, Young Sup Kang, Isidoro Mazzitelli
Abstract A six degrees-of-freedom Dynamic Bearing Model (DBM) was modified to include a novel cage pocket lubrication model. The motion of the cage was determined using the finite difference method to solve for the pressure generation and resultant forces inside of each cage pocket at each time step of the dynamic model. The computational domain of the finite difference model was designed to reflect the specific cage pocket geometry of four common cage designs. Additionally, a bearing cage friction test rig was utilized to characterize the lubrication state inside of each cage. Experiments were performed that reveal the relationship between cage shape, ball speed, and relative ball – cage position. Specifically, information on the occurrence of kinematic starvation, the speed dependent evacuation of oil from a cage pocket, was collected for use as an input condition to the dynamic bearing model. An inverse distance weighting scheme was utilized to predict starvation parameters for a general ball position inside of the cage pocket. Results from the dynamic simulation reveal new knowledge on the effect of cage geometry and lubrication on dynamic behavior. The inclusion of lubrication effects inside of the cage pocket reduces the median contact force between the balls and cage pocket and improves the stability of the predicted cage motion.
{"title":"The Influence of Cage Pocket Lubrication on the Simulation of Deep Groove Ball Bearing Cage Motion","authors":"Thomas Russell, Farshid Sadeghi, Young Sup Kang, Isidoro Mazzitelli","doi":"10.1115/1.4063624","DOIUrl":"https://doi.org/10.1115/1.4063624","url":null,"abstract":"Abstract A six degrees-of-freedom Dynamic Bearing Model (DBM) was modified to include a novel cage pocket lubrication model. The motion of the cage was determined using the finite difference method to solve for the pressure generation and resultant forces inside of each cage pocket at each time step of the dynamic model. The computational domain of the finite difference model was designed to reflect the specific cage pocket geometry of four common cage designs. Additionally, a bearing cage friction test rig was utilized to characterize the lubrication state inside of each cage. Experiments were performed that reveal the relationship between cage shape, ball speed, and relative ball – cage position. Specifically, information on the occurrence of kinematic starvation, the speed dependent evacuation of oil from a cage pocket, was collected for use as an input condition to the dynamic bearing model. An inverse distance weighting scheme was utilized to predict starvation parameters for a general ball position inside of the cage pocket. Results from the dynamic simulation reveal new knowledge on the effect of cage geometry and lubrication on dynamic behavior. The inclusion of lubrication effects inside of the cage pocket reduces the median contact force between the balls and cage pocket and improves the stability of the predicted cage motion.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135696521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ajith Kurian Baby, Rajendrakumar PK, Deepak Lawrence K
Abstract Uncertainty analyses can improve the reliability and validity of the assessment of friction and wear rate of tribo-systems. This work analyses the various sources of uncertainty in the estimation of friction and wear rate of liner-ring pairs using a linear reciprocating tribometer (LRT) as per the analytical method suggested by Guide to the Expression of Uncertainty in Measurement (GUM) and simulation approach using Monte Carlo Simulation (MCS) method. The uncertainty analysis was conducted by performing sliding wear experiments using a hypereutectic Al-Si cylinder liner specimen against the chrome-coated piston ring as the counter specimen. The experiments were performed to mimic the engine's condition under a boundary layer lubrication regime. The Type A and Type B uncertainty components of the tribo system, such as uncertainty involved in the measurement of mass, linear dimensions of the specimen, radius of the specimen, normal force, stroke length and frictional force, were evaluated to study their influence on the assessment of the friction and wear rate. The probability density function of all these uncertainty sources were simulated using MCS approach to compute the 95% coverage interval for friction and wear rate directly. The variation in absolute value between the coverage interval limits computed by the GUM framework and predicted by the Monte Carlo method for wear rate was 11.83%, and for friction coefficient, it was 12.005%.
{"title":"Uncertainty Analysis of Friction and Wear Rate of Cylinder Liner- Piston Ring Tribo Pair under Boundary Lubrication Conditions","authors":"Ajith Kurian Baby, Rajendrakumar PK, Deepak Lawrence K","doi":"10.1115/1.4063623","DOIUrl":"https://doi.org/10.1115/1.4063623","url":null,"abstract":"Abstract Uncertainty analyses can improve the reliability and validity of the assessment of friction and wear rate of tribo-systems. This work analyses the various sources of uncertainty in the estimation of friction and wear rate of liner-ring pairs using a linear reciprocating tribometer (LRT) as per the analytical method suggested by Guide to the Expression of Uncertainty in Measurement (GUM) and simulation approach using Monte Carlo Simulation (MCS) method. The uncertainty analysis was conducted by performing sliding wear experiments using a hypereutectic Al-Si cylinder liner specimen against the chrome-coated piston ring as the counter specimen. The experiments were performed to mimic the engine's condition under a boundary layer lubrication regime. The Type A and Type B uncertainty components of the tribo system, such as uncertainty involved in the measurement of mass, linear dimensions of the specimen, radius of the specimen, normal force, stroke length and frictional force, were evaluated to study their influence on the assessment of the friction and wear rate. The probability density function of all these uncertainty sources were simulated using MCS approach to compute the 95% coverage interval for friction and wear rate directly. The variation in absolute value between the coverage interval limits computed by the GUM framework and predicted by the Monte Carlo method for wear rate was 11.83%, and for friction coefficient, it was 12.005%.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135696528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuanlong Cao, Hao kaiyuan, Jiahui Fan, Hang Zhang, Hanqing Guan, Kai Feng
Abstract Shape memory alloy (SMA)-gas foil bearings (SMA-GFBs) are novel gas bearings constituted of top foil, SMA springs and housing. The radial clearance, stiffness and damping coefficients of SMA-GFBs can be controlled by the bearing temperature which is determined by the electric heating of SMS springs and the cooling air. A 3D thermohydrodynamic model (THD) with the consideration of the conduction and convection of top foil, bearing housing and hollow rotor and heat energy of heated SMA springs is presented to simulate the temperature distribution of SMA-GFBs at different rotational speeds, heating powers and cooling flows. A test rig is built to measure the SMA-GFB temperature and to validate the effectiveness of the theoretical model and circumferential cooling mode. Parametric studies are conducted with different speeds, heating powers and cooling flows. Heat transfer ratios of rotor and substructure are also compared. Compared with the temperature difference of bearing temperature in the circumferential or axial direction, the influence of rotational speed and cooling flow on bearing temperature is very obvious. The phase transition process of SMA spring can be controlled by adjusting the rotor speed and the cooling flow reasonably, and then the temperature characteristics of SMA-GFB can be changed. The temperature generated by compressed gas film and heated SMA springs and cooling mode can be adjust to validate the feasibility of active changing the performance of bearing-rotor system.
{"title":"Thermohydrodynamic Analysis of a Controllable Stiffness Foil Bearing with Shape Memory Alloy Springs: Experimental Tests and Theoretical Predictions","authors":"Yuanlong Cao, Hao kaiyuan, Jiahui Fan, Hang Zhang, Hanqing Guan, Kai Feng","doi":"10.1115/1.4063441","DOIUrl":"https://doi.org/10.1115/1.4063441","url":null,"abstract":"Abstract Shape memory alloy (SMA)-gas foil bearings (SMA-GFBs) are novel gas bearings constituted of top foil, SMA springs and housing. The radial clearance, stiffness and damping coefficients of SMA-GFBs can be controlled by the bearing temperature which is determined by the electric heating of SMS springs and the cooling air. A 3D thermohydrodynamic model (THD) with the consideration of the conduction and convection of top foil, bearing housing and hollow rotor and heat energy of heated SMA springs is presented to simulate the temperature distribution of SMA-GFBs at different rotational speeds, heating powers and cooling flows. A test rig is built to measure the SMA-GFB temperature and to validate the effectiveness of the theoretical model and circumferential cooling mode. Parametric studies are conducted with different speeds, heating powers and cooling flows. Heat transfer ratios of rotor and substructure are also compared. Compared with the temperature difference of bearing temperature in the circumferential or axial direction, the influence of rotational speed and cooling flow on bearing temperature is very obvious. The phase transition process of SMA spring can be controlled by adjusting the rotor speed and the cooling flow reasonably, and then the temperature characteristics of SMA-GFB can be changed. The temperature generated by compressed gas film and heated SMA springs and cooling mode can be adjust to validate the feasibility of active changing the performance of bearing-rotor system.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134913964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhe Wu, Yuying Zhang, Yang Xu, Desuan Jie, R. Jackson
The flash temperature in the sliding frictional contact between micro asperities has an important influence on the frictional characteristics of advanced functional ceramics. In this paper, the elastic sliding frictional contact of single three-dimensional micron/submicron scale asperity pair is considered. A three-dimensional finite element model (FEM) for fully coupled thermal-stress analysis of sliding contact of SiC/Al2O3 asperity pair is developed. An empirical correction factor for contact characteristics is obtained based on the FEM results. The FEM results show that, compared with the Hertz theoretical solution, the contact area becomes smaller and the contact pressure becomes larger in the case of sliding contact with large deformation. The flash temperature has a negative correlation with the composite radius of asperity pair, and a positive correlation with the interference depth and sliding speed. Using Hertz theory, parabolic distributed heat source, Fourier heat conduction law, and the newly-proposed correction factor, a semi-analytical model of flash temperature during the elastic frictional sliding between two single asperities is established. The relative difference between the flash temperature predicted by the established semi-analytical model and the FEM model is less than 1.2%. The relative difference decreases with the increasing interference depth. This work is of valuable reference for studying the frictional heat related issues of advanced ceramics.
{"title":"Modeling of Flash Temperature for Elastic Sliding Contact of Single Micro-Asperity Pair","authors":"Zhe Wu, Yuying Zhang, Yang Xu, Desuan Jie, R. Jackson","doi":"10.1115/1.4063334","DOIUrl":"https://doi.org/10.1115/1.4063334","url":null,"abstract":"\u0000 The flash temperature in the sliding frictional contact between micro asperities has an important influence on the frictional characteristics of advanced functional ceramics. In this paper, the elastic sliding frictional contact of single three-dimensional micron/submicron scale asperity pair is considered. A three-dimensional finite element model (FEM) for fully coupled thermal-stress analysis of sliding contact of SiC/Al2O3 asperity pair is developed. An empirical correction factor for contact characteristics is obtained based on the FEM results. The FEM results show that, compared with the Hertz theoretical solution, the contact area becomes smaller and the contact pressure becomes larger in the case of sliding contact with large deformation. The flash temperature has a negative correlation with the composite radius of asperity pair, and a positive correlation with the interference depth and sliding speed. Using Hertz theory, parabolic distributed heat source, Fourier heat conduction law, and the newly-proposed correction factor, a semi-analytical model of flash temperature during the elastic frictional sliding between two single asperities is established. The relative difference between the flash temperature predicted by the established semi-analytical model and the FEM model is less than 1.2%. The relative difference decreases with the increasing interference depth. This work is of valuable reference for studying the frictional heat related issues of advanced ceramics.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47804117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bing-qing Wang, Xiaoxuan Li, X.-L. Peng, Yuntang Li, Yuan Chen, Jie Jin
Thermoelastohydrodynamic (TEHD) mixed lubrication characteristics of a step combined rod seal under high pressure and high speed conditions are analyzed in this article. A novel TEHD mixed lubrication model for combined rod seals is innovatively established from the perspective of “seal-film-rod” system for the first time. Parameterized studies are conducted to evaluate the thermal effect on seal behavior with the comparison of isothermal elastohydrodynamic (EHD) lubrication analysis. Numerical results show that the interface friction heat is quite remarkable and mainly concentrated on the sealing lip especially in high pressure and speed cases. With the increasing of sealed pressure or rod speed, the temperature rise becomes more obvious and has a more significant impact on the sealing performance. The excessively rising temperature will even exceed the melting point of the sealing material, causing thermal damage.
{"title":"Thermoelastohydrodynamic mixed lubrication of combined rod seals operating at high pressures and speeds: mathematical modeling and numerical analysis","authors":"Bing-qing Wang, Xiaoxuan Li, X.-L. Peng, Yuntang Li, Yuan Chen, Jie Jin","doi":"10.1115/1.4063267","DOIUrl":"https://doi.org/10.1115/1.4063267","url":null,"abstract":"\u0000 Thermoelastohydrodynamic (TEHD) mixed lubrication characteristics of a step combined rod seal under high pressure and high speed conditions are analyzed in this article. A novel TEHD mixed lubrication model for combined rod seals is innovatively established from the perspective of “seal-film-rod” system for the first time. Parameterized studies are conducted to evaluate the thermal effect on seal behavior with the comparison of isothermal elastohydrodynamic (EHD) lubrication analysis. Numerical results show that the interface friction heat is quite remarkable and mainly concentrated on the sealing lip especially in high pressure and speed cases. With the increasing of sealed pressure or rod speed, the temperature rise becomes more obvious and has a more significant impact on the sealing performance. The excessively rising temperature will even exceed the melting point of the sealing material, causing thermal damage.","PeriodicalId":17586,"journal":{"name":"Journal of Tribology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49529408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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