Pub Date : 2023-09-11DOI: 10.1177/13506501231201202
Kun Chen, Xiaofei Wei, Qinglin Zhang
The discrete element method was used to simulate the friction process of copper-based graphite composite materials in order to analyze the influence of pore structure on the solid lubricants migration in metal-based self-lubricating materials. And the near-surface pore volume evolution was considered in the simulation. The simulation results showed that the graphite particle motion depth and the migration channel increased gradually and tended to stable during friction. The near-surface pore structure has an important influence on the graphite migration and the tribological properties of the composite: the larger the migration channel was, the greater the graphite migration speed was; with the increase in migration channel, the graphite average critical migration depth decreased first then increased, the number of the film-forming particles first increased and then decreased; the greater the migration channel volume was, the more worn particles number were. The numerical simulation was confirmed by experimental analysis on a self-made in-situ observation tribometer, the experimental results were consistent with the numerical simulation results.
{"title":"Effect of the near-surface pore volume evolution on graphite migration of copper-based graphite composite during friction","authors":"Kun Chen, Xiaofei Wei, Qinglin Zhang","doi":"10.1177/13506501231201202","DOIUrl":"https://doi.org/10.1177/13506501231201202","url":null,"abstract":"The discrete element method was used to simulate the friction process of copper-based graphite composite materials in order to analyze the influence of pore structure on the solid lubricants migration in metal-based self-lubricating materials. And the near-surface pore volume evolution was considered in the simulation. The simulation results showed that the graphite particle motion depth and the migration channel increased gradually and tended to stable during friction. The near-surface pore structure has an important influence on the graphite migration and the tribological properties of the composite: the larger the migration channel was, the greater the graphite migration speed was; with the increase in migration channel, the graphite average critical migration depth decreased first then increased, the number of the film-forming particles first increased and then decreased; the greater the migration channel volume was, the more worn particles number were. The numerical simulation was confirmed by experimental analysis on a self-made in-situ observation tribometer, the experimental results were consistent with the numerical simulation results.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136023768","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}
Pub Date : 2023-09-11DOI: 10.1177/13506501231186284
Junjie Lu, Changsheng Zhu, Daixing Lu
The failure of the plug valve seal may result in dangerous accidents in the production and transportation process of petroleum and chemical products. In the paper at hand, the operating life of the plug valve is studied in the opening–closing process. The adhesion wear between the sealing surface of the plug valve is numerically studied in micro-scale, and the contact force between the sealing surface is balanced with the internal flow field of the plug valve and the deformation force between the set screw and the spool. The internal flow field of the plug valve in opening–closing process is calculated by finite element method. The deformation coupling model between the set screw and the spool is built to analyze the structure and the mechanics of the plug valve. Then, a leakage identification algorithm based on auto-correlation function is implemented for analyzing contact stress of the plug valve's sealing surfaces after wear. Finally, taking plug valve F-2 ISO-STANDARD as an example, the force of turbulent flow field on the spool is calculated during the closing process. Results show, that while the maximum contact stress increases, the pressure decreases, and the displacement trajectory of spool increases. The operating life decreases by increasing the roughness of the spool sealing surface. The model proposed provides a new practical method to evaluate the operating life of the plug valve, which is a good guidance for the design of the valve.
{"title":"Numerical study on sealing performance after wear of plug valve during opening–closing process","authors":"Junjie Lu, Changsheng Zhu, Daixing Lu","doi":"10.1177/13506501231186284","DOIUrl":"https://doi.org/10.1177/13506501231186284","url":null,"abstract":"The failure of the plug valve seal may result in dangerous accidents in the production and transportation process of petroleum and chemical products. In the paper at hand, the operating life of the plug valve is studied in the opening–closing process. The adhesion wear between the sealing surface of the plug valve is numerically studied in micro-scale, and the contact force between the sealing surface is balanced with the internal flow field of the plug valve and the deformation force between the set screw and the spool. The internal flow field of the plug valve in opening–closing process is calculated by finite element method. The deformation coupling model between the set screw and the spool is built to analyze the structure and the mechanics of the plug valve. Then, a leakage identification algorithm based on auto-correlation function is implemented for analyzing contact stress of the plug valve's sealing surfaces after wear. Finally, taking plug valve F-2 ISO-STANDARD as an example, the force of turbulent flow field on the spool is calculated during the closing process. Results show, that while the maximum contact stress increases, the pressure decreases, and the displacement trajectory of spool increases. The operating life decreases by increasing the roughness of the spool sealing surface. The model proposed provides a new practical method to evaluate the operating life of the plug valve, which is a good guidance for the design of the valve.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136024558","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}
Pub Date : 2023-09-10DOI: 10.1177/13506501231198569
Cheng Xiong, Bo Xu, Zhongwen Huang, Zhenqian Chen
In the present study, a multiphysics simulation model was established to evaluate the effects of the fluid-thermal-structural interaction on the performance of multifoil gas lubrication thrust bearing. The thermal and elastic deformation mechanisms of multifoil bearings were studied in detail, and the effects of the preload ratio and foil structural parameters on the bearing performance were analyzed. The results show that the preload ratio determines the performance of the multifoil thrust bearing. A small preload helps the bearing maintain a low lift-off speed, whereas a large preload is helpful in improving the bearing load capacity. The thickness of the foil has a significant effect on the gas film pressure distribution and the down foil thickness plays a leading role in the load capacity.
{"title":"The fluid-thermal-structural interaction analysis of a new multifoil aerodynamic thrust bearings","authors":"Cheng Xiong, Bo Xu, Zhongwen Huang, Zhenqian Chen","doi":"10.1177/13506501231198569","DOIUrl":"https://doi.org/10.1177/13506501231198569","url":null,"abstract":"In the present study, a multiphysics simulation model was established to evaluate the effects of the fluid-thermal-structural interaction on the performance of multifoil gas lubrication thrust bearing. The thermal and elastic deformation mechanisms of multifoil bearings were studied in detail, and the effects of the preload ratio and foil structural parameters on the bearing performance were analyzed. The results show that the preload ratio determines the performance of the multifoil thrust bearing. A small preload helps the bearing maintain a low lift-off speed, whereas a large preload is helpful in improving the bearing load capacity. The thickness of the foil has a significant effect on the gas film pressure distribution and the down foil thickness plays a leading role in the load capacity.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136072986","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}
Pub Date : 2023-09-04DOI: 10.1177/13506501231197877
Chang Li, Shuangjiu Deng, Xinxue Chen, Xing Han
The IN625 laser cladding is extensively utilized in the sectors of aviation, navigation, petroleum, and chemical engineering, among others. When the cladding layer is exposed to harsh environments for extended periods, it is prone to fatigue delamination, pitting corrosion, and other detrimental effects, which jeopardize the performance of the workpiece. Quantitatively elucidating the corrosion failure mechanisms of the cladding layer can provide essential insights for enhancing its service life. This study focuses on investigating the evolution mechanism of pitting corrosion pits on the surface of the cladding layer in a corrosive environment. A numerical model for pitting corrosion in the IN625 cladding layer is established to reveal the transient variations in corrosion rate and electrode potential. The results indicate that the concentration changes of Cl − , Na + , and Ni 2+ in the corrosion pits follow the sequence of Cl − > Ni 2+ > Na + . The pH value in the corrosion pits gradually decreases from the top to the bottom, while the corrosion rate at the top of the pits exhibits minimal variation. As the corrosion rate increases, the pits continue to deepen. Based on electrochemical corrosion experiments conducted on the CS310 M electrochemical workstation between the substrate and the cladding layer, it is determined that the corrosion current density of the IN625 cladding layer is reduced by two orders of magnitude compared to the QT600 substrate, resulting in a 395.5-fold decrease in the corrosion rate. The IN625 cladding layer significantly enhances the corrosion resistance of the substrate.
{"title":"Numerical simulation and experimental study on pitting damage of IN625 laser cladding layer","authors":"Chang Li, Shuangjiu Deng, Xinxue Chen, Xing Han","doi":"10.1177/13506501231197877","DOIUrl":"https://doi.org/10.1177/13506501231197877","url":null,"abstract":"The IN625 laser cladding is extensively utilized in the sectors of aviation, navigation, petroleum, and chemical engineering, among others. When the cladding layer is exposed to harsh environments for extended periods, it is prone to fatigue delamination, pitting corrosion, and other detrimental effects, which jeopardize the performance of the workpiece. Quantitatively elucidating the corrosion failure mechanisms of the cladding layer can provide essential insights for enhancing its service life. This study focuses on investigating the evolution mechanism of pitting corrosion pits on the surface of the cladding layer in a corrosive environment. A numerical model for pitting corrosion in the IN625 cladding layer is established to reveal the transient variations in corrosion rate and electrode potential. The results indicate that the concentration changes of Cl − , Na + , and Ni 2+ in the corrosion pits follow the sequence of Cl − > Ni 2+ > Na + . The pH value in the corrosion pits gradually decreases from the top to the bottom, while the corrosion rate at the top of the pits exhibits minimal variation. As the corrosion rate increases, the pits continue to deepen. Based on electrochemical corrosion experiments conducted on the CS310 M electrochemical workstation between the substrate and the cladding layer, it is determined that the corrosion current density of the IN625 cladding layer is reduced by two orders of magnitude compared to the QT600 substrate, resulting in a 395.5-fold decrease in the corrosion rate. The IN625 cladding layer significantly enhances the corrosion resistance of the substrate.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135402742","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}
Pub Date : 2023-09-03DOI: 10.1177/13506501231198287
A. C. Opia, M. Abdollah, A. H. Kameil, S. Syahrullail, Audu Ibrahim Ali, Stanly Chinedu Mama, Abdelgade Agilah Saleh, Ahmed Sule, Charles N. Johnson
An investigation on lubricating oil rheological behavior and tribological effect on sliding contact was conducted. The study employed organic polymer Eichhornia Crassipes carboxymethyl cellulose (EC-CMC) polymer as additive in corn oil (CO) and sunflower oil (SFO). The experiment was performed using high frequency reciprocating rig (HFRR). Analysis on viscosity behavior was done with three samples of EC-CMC concentration (0.5 wt.%, 1 wt.%, and 1.5 wt.%) under 100 ml volume of base CO and SFO samples. Rheological studies on the polymer concentrations show good results with 0.5 wt.%, 1 wt.%, and 1.5 wt.%, but indicated optimal on 1 wt.% EC-CMC especially from temperature beyond 100°C for the two selected lubricants. Under friction and wear analysis, the test was conducted using 1 wt.% EC-CMC. The base lubricants CO and SFO yielded coefficient of friction and wear scar diameter of 0.087, 11.2 × 10−6 mm3/N/m and 0.080, 10.5 × 10−6 mm3/N/m, respectively. During the testing, the use of 1 wt.% EC-CMC blended SFO gives lower coefficient of friction than CO both at base state and inclusion with additive. This yielded COF reduction by 22.5% and 13.8% for 1 wt.% EC-CMC + SFO and 1 wt.% EC-CMC + CO, respectively, but gives better reduction under SAE-5W-30. The analysis concluded that application of 1 wt.% concentration of EC-CMC in base oil lubricant for both SFO and CO significantly enhanced the properties. The utilization of this sustainable product certainly will contribute in solving global pollution challenges.
{"title":"Tribological performance evaluation of organic polymer as additives in vegetable oil using steel materials","authors":"A. C. Opia, M. Abdollah, A. H. Kameil, S. Syahrullail, Audu Ibrahim Ali, Stanly Chinedu Mama, Abdelgade Agilah Saleh, Ahmed Sule, Charles N. Johnson","doi":"10.1177/13506501231198287","DOIUrl":"https://doi.org/10.1177/13506501231198287","url":null,"abstract":"An investigation on lubricating oil rheological behavior and tribological effect on sliding contact was conducted. The study employed organic polymer Eichhornia Crassipes carboxymethyl cellulose (EC-CMC) polymer as additive in corn oil (CO) and sunflower oil (SFO). The experiment was performed using high frequency reciprocating rig (HFRR). Analysis on viscosity behavior was done with three samples of EC-CMC concentration (0.5 wt.%, 1 wt.%, and 1.5 wt.%) under 100 ml volume of base CO and SFO samples. Rheological studies on the polymer concentrations show good results with 0.5 wt.%, 1 wt.%, and 1.5 wt.%, but indicated optimal on 1 wt.% EC-CMC especially from temperature beyond 100°C for the two selected lubricants. Under friction and wear analysis, the test was conducted using 1 wt.% EC-CMC. The base lubricants CO and SFO yielded coefficient of friction and wear scar diameter of 0.087, 11.2 × 10−6 mm3/N/m and 0.080, 10.5 × 10−6 mm3/N/m, respectively. During the testing, the use of 1 wt.% EC-CMC blended SFO gives lower coefficient of friction than CO both at base state and inclusion with additive. This yielded COF reduction by 22.5% and 13.8% for 1 wt.% EC-CMC + SFO and 1 wt.% EC-CMC + CO, respectively, but gives better reduction under SAE-5W-30. The analysis concluded that application of 1 wt.% concentration of EC-CMC in base oil lubricant for both SFO and CO significantly enhanced the properties. The utilization of this sustainable product certainly will contribute in solving global pollution challenges.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"39 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75365451","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}
Pub Date : 2023-09-03DOI: 10.1177/13506501231198288
Yifei Li
The present work is dedicated to investigating both characteristics of the vortex-induced excitation and the displacement impedance and also weakening the micro-vibration for the aerostatic bearing with orifice type restrictor. Firstly, the numerical simulation is conducted to study the characteristics of the vortex flow in the frequency domain. Further, the displacement impedance is investigated based on an approximate model; the effects of bearing parameters on displacement impedance are also discussed. It is found that the vortex-induced excitation is the dynamic load acting on the floating device, while the displacement impedance reflects the capability of the bearing to withstand the dynamic load. Hence, it is necessary to enhance the displacement impedance for micro-vibration reduction in the bearing. Moreover, the design problem corresponding to the micro-vibration reduction is formulated, and the design optimization is carried out under several given bearing loads. Optimization results show that the micro-vibration can be reduced by increasing the displacement impedance and decreasing the Reynolds number in the flow field. The optimization process can provide an efficient way for reducing the micro-vibration in engineering application.
{"title":"Investigation of micro-vibration reduction method based on dynamic performance analysis of aerostatic bearing","authors":"Yifei Li","doi":"10.1177/13506501231198288","DOIUrl":"https://doi.org/10.1177/13506501231198288","url":null,"abstract":"The present work is dedicated to investigating both characteristics of the vortex-induced excitation and the displacement impedance and also weakening the micro-vibration for the aerostatic bearing with orifice type restrictor. Firstly, the numerical simulation is conducted to study the characteristics of the vortex flow in the frequency domain. Further, the displacement impedance is investigated based on an approximate model; the effects of bearing parameters on displacement impedance are also discussed. It is found that the vortex-induced excitation is the dynamic load acting on the floating device, while the displacement impedance reflects the capability of the bearing to withstand the dynamic load. Hence, it is necessary to enhance the displacement impedance for micro-vibration reduction in the bearing. Moreover, the design problem corresponding to the micro-vibration reduction is formulated, and the design optimization is carried out under several given bearing loads. Optimization results show that the micro-vibration can be reduced by increasing the displacement impedance and decreasing the Reynolds number in the flow field. The optimization process can provide an efficient way for reducing the micro-vibration in engineering application.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"41 1","pages":"2074 - 2087"},"PeriodicalIF":2.0,"publicationDate":"2023-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78534088","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}
Pub Date : 2023-09-01DOI: 10.1177/13506501231198571
Thi-Na Ta, J. Horng
In this study, the synergistic effects of methyltrioctylammonium bis(trifluoromethylsulfonyl)imide [N1888] [NTf2] ionic liquid (IL) with zinc dialkyldithiophosphate (ZDDP) and zinc oxide (ZnO) nanoparticles (NPs) as hybrid additives in a circulation oil for steel–steel contacts at different temperatures. The wear test results indicated that the additions of single additives (IL, ZDDP, and ZnO NPs) could enhance the tribological performance of the circulation oil. Among these additives, the IL exhibited the most effective at the same weight concentration blended into the tested oil. The mixture of IL and ZDDP showed superior friction-reducing and wear-reducing properties compared to the IL + ZnO formulation. The hybrid additive formulation consisting of 0.5 wt% IL, 0.25 wt% ZDDP, and 0.25 wt% ZnO NPs exhibited excellent tribological properties at higher temperatures in the boundary lubrication regime. Analysis using scanning electron microscopy/energy dispersive X-ray reveals that all single additives contribute to the formation of a tribofilm wear mechanism. However, the role of ZnO NPs in the hybrid additive conditions was changed from the most likely tribosintering effect to the most likely nano bearing effect at 100 °C. The interactions among IL, ZDDP, and NPs examined in this study can provide fundamental insights for the development of future lubricants.
{"title":"Evaluation of tribological behavior of a circulation oil with ionic liquid and hybrid additives","authors":"Thi-Na Ta, J. Horng","doi":"10.1177/13506501231198571","DOIUrl":"https://doi.org/10.1177/13506501231198571","url":null,"abstract":"In this study, the synergistic effects of methyltrioctylammonium bis(trifluoromethylsulfonyl)imide [N1888] [NTf2] ionic liquid (IL) with zinc dialkyldithiophosphate (ZDDP) and zinc oxide (ZnO) nanoparticles (NPs) as hybrid additives in a circulation oil for steel–steel contacts at different temperatures. The wear test results indicated that the additions of single additives (IL, ZDDP, and ZnO NPs) could enhance the tribological performance of the circulation oil. Among these additives, the IL exhibited the most effective at the same weight concentration blended into the tested oil. The mixture of IL and ZDDP showed superior friction-reducing and wear-reducing properties compared to the IL + ZnO formulation. The hybrid additive formulation consisting of 0.5 wt% IL, 0.25 wt% ZDDP, and 0.25 wt% ZnO NPs exhibited excellent tribological properties at higher temperatures in the boundary lubrication regime. Analysis using scanning electron microscopy/energy dispersive X-ray reveals that all single additives contribute to the formation of a tribofilm wear mechanism. However, the role of ZnO NPs in the hybrid additive conditions was changed from the most likely tribosintering effect to the most likely nano bearing effect at 100 °C. The interactions among IL, ZDDP, and NPs examined in this study can provide fundamental insights for the development of future lubricants.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"38 1","pages":"2059 - 2073"},"PeriodicalIF":2.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74014898","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}
Although nanosilver particles are commonly used as oil lubrication additives, their mechanism for improving lubrication at the atomic scale remains unclear. This article explains how the performance of a pentaerythritol oleate lubrication system can be improved using silver nanoparticles through molecular dynamics simulation. Additionally, tribological tests were conducted using a reciprocating friction and wear testing machine. The relative concentrations and simulated shear conformation revealed that silver nanoparticles underwent deformation under shear stress and fractured at the interlayer slip. This resulted in the formation of a deposited film that spread over both the top and bottom Fe layers. We characterized the interaction between pentaerythritol oleate molecular chains and Fe layers by analyzing interfacial interaction energies, mean square displacements, and self-diffusion coefficients. Our findings indicate that the presence of silver nanoparticles improves both the adsorption of pentaerythritol oleate molecular chains onto the Fe layer and their diffusion behavior. The results of tribological tests indicate that adding silver nanoparticles significantly reduces friction coefficient and frictional wear across various lubrication conditions. The addition of silver nanoparticles at different loads and temperatures resulted in varying reductions in the coefficient of friction and wear. At a load of 20 N and a temperature of 298 K, the coefficient of friction decreased by 9%, and wear decreased by 31%. When the load was reduced to 2 N while maintaining a temperature of 298 K, the coefficient of friction decreased by 8% and wear decreased significantly by 84%. Finally, at a load of 20 N but with an increased temperature to 373 K, there was a larger reduction in the coefficient of friction (23%) compared to wear (50%). The film-formation mechanism of improved lubrication by silver nanoparticles was verified through tribological tests and simulations.
{"title":"Mechanisms of friction and wear reduction by nanosilver additives to base oil: Molecular dynamics simulation and experimental study","authors":"Peng Chen, Ningning Hu, Songquan Wang, Tianchi Chen, Da-hang Li, Kaijun Wang, Xiuhe Zhang","doi":"10.1177/13506501231196930","DOIUrl":"https://doi.org/10.1177/13506501231196930","url":null,"abstract":"Although nanosilver particles are commonly used as oil lubrication additives, their mechanism for improving lubrication at the atomic scale remains unclear. This article explains how the performance of a pentaerythritol oleate lubrication system can be improved using silver nanoparticles through molecular dynamics simulation. Additionally, tribological tests were conducted using a reciprocating friction and wear testing machine. The relative concentrations and simulated shear conformation revealed that silver nanoparticles underwent deformation under shear stress and fractured at the interlayer slip. This resulted in the formation of a deposited film that spread over both the top and bottom Fe layers. We characterized the interaction between pentaerythritol oleate molecular chains and Fe layers by analyzing interfacial interaction energies, mean square displacements, and self-diffusion coefficients. Our findings indicate that the presence of silver nanoparticles improves both the adsorption of pentaerythritol oleate molecular chains onto the Fe layer and their diffusion behavior. The results of tribological tests indicate that adding silver nanoparticles significantly reduces friction coefficient and frictional wear across various lubrication conditions. The addition of silver nanoparticles at different loads and temperatures resulted in varying reductions in the coefficient of friction and wear. At a load of 20 N and a temperature of 298 K, the coefficient of friction decreased by 9%, and wear decreased by 31%. When the load was reduced to 2 N while maintaining a temperature of 298 K, the coefficient of friction decreased by 8% and wear decreased significantly by 84%. Finally, at a load of 20 N but with an increased temperature to 373 K, there was a larger reduction in the coefficient of friction (23%) compared to wear (50%). The film-formation mechanism of improved lubrication by silver nanoparticles was verified through tribological tests and simulations.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"330 1","pages":"2002 - 2013"},"PeriodicalIF":2.0,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84739271","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}
Pub Date : 2023-08-25DOI: 10.1177/13506501231196355
H. Baş, Y. E. karabacak
Additive manufacturing is a rapidly developing technology that enables the production of complex parts with intricate geometries. Self-lubricating radial bearings are one of the machine elements that can be produced using additive manufacturing. In this research, we present a machine learning-based approach to model the friction coefficient and friction torque in self-lubricating radial bearings manufactured by additive manufacturing using polyether ether ketone (PEEK), polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), and nylon. The proposed approach includes different machine learning models (artificial neural networks, support vector machines, regression trees, linear regression models) that utilize experimental data to predict the coefficient of friction and friction torque of different types of radial bearings. Experimental data were obtained by performing tribological tests on self-lubricating radial bearings under various operating conditions. The results reveal that the machine learning models are successful in predicting the friction coefficient and friction torque in self-lubricating radial bearings with high accuracy. The approach can be utilized to optimize the design and performance of self-lubricating radial bearings manufactured using additive manufacturing.
{"title":"Prediction of friction coefficient and torque in self-lubricating polymer radial bearings produced by additive manufacturing: A machine learning approach","authors":"H. Baş, Y. E. karabacak","doi":"10.1177/13506501231196355","DOIUrl":"https://doi.org/10.1177/13506501231196355","url":null,"abstract":"Additive manufacturing is a rapidly developing technology that enables the production of complex parts with intricate geometries. Self-lubricating radial bearings are one of the machine elements that can be produced using additive manufacturing. In this research, we present a machine learning-based approach to model the friction coefficient and friction torque in self-lubricating radial bearings manufactured by additive manufacturing using polyether ether ketone (PEEK), polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), and nylon. The proposed approach includes different machine learning models (artificial neural networks, support vector machines, regression trees, linear regression models) that utilize experimental data to predict the coefficient of friction and friction torque of different types of radial bearings. Experimental data were obtained by performing tribological tests on self-lubricating radial bearings under various operating conditions. The results reveal that the machine learning models are successful in predicting the friction coefficient and friction torque in self-lubricating radial bearings with high accuracy. The approach can be utilized to optimize the design and performance of self-lubricating radial bearings manufactured using additive manufacturing.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":"51 1","pages":"2014 - 2038"},"PeriodicalIF":2.0,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88418406","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}
Pub Date : 2023-08-13DOI: 10.1177/13506501231194201
S. Yan, T. Lai, Yingke Gao, Mingzhe Liu, Yu Hou
Spiral-grooved thrust bearing (SGTB) is one of the important kinds of supporting component in high-speed rotating devices. The high shearing rate of SGTB can produce a large amount of viscous dissipative heat, which causes a temperature rise. Dynamic pressure effect induces pressure variation in the herringbone SGTB (HSGTB). When liquid hydrogen (LH2) is used as a lubricant, cavitation caused by lower pressure and higher temperature can result in lubrication failure. Especially, the cavitation of LH2 is more prone to occur because of its small temperature difference between the triple point and critical point, and the smaller supercooling degree. The influence of thermal properties on the phase transition process of LH2 is more significant. In this paper, the thermal and mechanical performance of three different structures of LH2 lubricated SGTB is compared by considering viscous dissipative heat. Herringbone SGTB is proposed for better performance and feasibility of its application in LH2 lubrication. The static performances of HSGTB such as load capacity, friction torque, cavitation rate, average temperature, and heat flux have been evaluated numerically by introducing the cryogenic cavitation model. The orthogonal sampling method and range analysis are used to optimize the HSGTB structure. Compared with the original HSGTB, cavitation rate and temperature rise are significantly suppressed in the optimized HSGTB. In addition, the load capacity is also improved effectively at high rotational speed, which is expected to be applied to high-speed centrifugal pumps.
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