The low service performance and sudden failure characteristics of coated self-lubricating spherical plain bearings (SPBs) limit their engineering application prospects. In the current study, two new self-lubricating coatings types were applied to the bearing contact surfaces. The bearings were compared and investigated using life tests. Furthermore, the wear failure mechanism was investigated. The results show that self-lubricating coatings improved the service performance of the traditional bearings with manganese phosphate coating. Among them, double-sided coated bearings had the best service performance and life. More interestingly, the torque and temperature rise signal curves will show a notable signal downstage before the signal mutation stage. The large-area and complete mixed friction transfer film on the contact surfaces was the main reason for the signal downstage. Moreover, the failure mechanism changed from abrasive wear to adhesive wear and fatigue wear with the increment of load. This study results preliminarily verify the performance improvement of high-performance coatings and provide a theoretical reference for further breaking through the engineering application bottleneck of coated self-lubricating SPBs.
{"title":"A new coated self-lubricating spherical plain bearing with high performance and excellent security","authors":"Yunfan Liu, Guozheng Ma, Lina Zhu, Cuihong Han, Zhen Li, Bin Zhang, Haichao Zhao, Haidou Wang, Shuying Chen","doi":"10.1177/13506501231203034","DOIUrl":"https://doi.org/10.1177/13506501231203034","url":null,"abstract":"The low service performance and sudden failure characteristics of coated self-lubricating spherical plain bearings (SPBs) limit their engineering application prospects. In the current study, two new self-lubricating coatings types were applied to the bearing contact surfaces. The bearings were compared and investigated using life tests. Furthermore, the wear failure mechanism was investigated. The results show that self-lubricating coatings improved the service performance of the traditional bearings with manganese phosphate coating. Among them, double-sided coated bearings had the best service performance and life. More interestingly, the torque and temperature rise signal curves will show a notable signal downstage before the signal mutation stage. The large-area and complete mixed friction transfer film on the contact surfaces was the main reason for the signal downstage. Moreover, the failure mechanism changed from abrasive wear to adhesive wear and fatigue wear with the increment of load. This study results preliminarily verify the performance improvement of high-performance coatings and provide a theoretical reference for further breaking through the engineering application bottleneck of coated self-lubricating SPBs.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135536767","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 : 2023-09-27DOI: 10.1177/13506501231203032
Huiyi Yang, Yang Xu, Chao Xu
Due to inherent nonlinear stiffness and damping characteristics, dry friction interfaces have a significant impact on the dynamics of jointed structures. When two surfaces are brought into purely normal contact, contact pressure distribution is of high concern. This work focused on the statistics of the contact pressure distribution between a rough surface and a smooth rigid plane, which provides new insight into the interface contact behaviour. First, the fractal rough surface is generated using the Weierstrass–Mandelbrot function with measured roughness parameters. With meshed rough surfaces, an elastic–plastic finite element contact analysis is performed to determine the contact pressure distribution. Then, the results of contact pressure are statistically analysed. The effects of roughness and contact load on contact area, contact stiffness and mean contact pressure are thoroughly investigated. The probability distribution of contact pressure is determined by fitting a continuous function using a twofold Weibull mixture model. The proposed probability distribution function is found to be capable of describing contact pressure. The contact pressure distribution is affected by the surface fractal characteristics and evolves with the contact load.
{"title":"A statistics view of contact pressure distribution for normal contact of fractal surfaces","authors":"Huiyi Yang, Yang Xu, Chao Xu","doi":"10.1177/13506501231203032","DOIUrl":"https://doi.org/10.1177/13506501231203032","url":null,"abstract":"Due to inherent nonlinear stiffness and damping characteristics, dry friction interfaces have a significant impact on the dynamics of jointed structures. When two surfaces are brought into purely normal contact, contact pressure distribution is of high concern. This work focused on the statistics of the contact pressure distribution between a rough surface and a smooth rigid plane, which provides new insight into the interface contact behaviour. First, the fractal rough surface is generated using the Weierstrass–Mandelbrot function with measured roughness parameters. With meshed rough surfaces, an elastic–plastic finite element contact analysis is performed to determine the contact pressure distribution. Then, the results of contact pressure are statistically analysed. The effects of roughness and contact load on contact area, contact stiffness and mean contact pressure are thoroughly investigated. The probability distribution of contact pressure is determined by fitting a continuous function using a twofold Weibull mixture model. The proposed probability distribution function is found to be capable of describing contact pressure. The contact pressure distribution is affected by the surface fractal characteristics and evolves with the contact load.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135537322","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 : 2023-09-20DOI: 10.1177/13506501231201894
Siwei Dai, Jianchun Fan, Siqi Yang
When studying the erosion behavior of fracturing pipelines, it is inevitable to consider the exacerbating effect of fluctuating internal pressure on pipeline erosion damage. Therefore, an erosion experimental apparatus capable of applying fluctuating tensile loads to specimens was developed to investigate the erosion rate of 35CrMo steel at different average tensile stresses (0–500 MPa), impact angles (15–90°), flow velocity (7.5–20 m/s), and experimental times (10–60 min), and to analyze the erosion damage mechanism under fluctuating loads by observing the microstructure within the erosion scars using scanning electron microscope. The results indicated that erosion rate increased up to 36.84% compared to that without loading under the same erosion condition. Erosion rate increased up to 822.00% when velocity increased from minimum to maximum. Under fluctuating loads, the deepest part of the erosion scar cracked first and the specimen eventually fractured completely along with its entire width, demonstrating that the newly established experimental conditions can well reproduce the sudden bursting phenomenon common to high-pressure pipelines that erode under harsh conditions. The fracture of the specimen shows laminar structure, which is a typical damage feature resulting from the combined effect of a great number of tensile stress cycles and erosion wear.
{"title":"Experimental study of erosion behavior under fluctuating tensile loads","authors":"Siwei Dai, Jianchun Fan, Siqi Yang","doi":"10.1177/13506501231201894","DOIUrl":"https://doi.org/10.1177/13506501231201894","url":null,"abstract":"When studying the erosion behavior of fracturing pipelines, it is inevitable to consider the exacerbating effect of fluctuating internal pressure on pipeline erosion damage. Therefore, an erosion experimental apparatus capable of applying fluctuating tensile loads to specimens was developed to investigate the erosion rate of 35CrMo steel at different average tensile stresses (0–500 MPa), impact angles (15–90°), flow velocity (7.5–20 m/s), and experimental times (10–60 min), and to analyze the erosion damage mechanism under fluctuating loads by observing the microstructure within the erosion scars using scanning electron microscope. The results indicated that erosion rate increased up to 36.84% compared to that without loading under the same erosion condition. Erosion rate increased up to 822.00% when velocity increased from minimum to maximum. Under fluctuating loads, the deepest part of the erosion scar cracked first and the specimen eventually fractured completely along with its entire width, demonstrating that the newly established experimental conditions can well reproduce the sudden bursting phenomenon common to high-pressure pipelines that erode under harsh conditions. The fracture of the specimen shows laminar structure, which is a typical damage feature resulting from the combined effect of a great number of tensile stress cycles and erosion wear.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136313560","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 : 2023-09-16DOI: 10.1177/13506501231201692
Xin Pei, Wanyou Yang
A new contact model of finite-length crowned roller bearing, capable of handling lubrication, eccentric load, and misalignment situations, is established in this study. Simulation results of interface pressure, film thickness distribution, flash temperature, and subsurface stress can be obtained with different speeds, misalignment angles, load eccentricity, and roller trimming parameters. It is found that edge trimming can greatly reduce the stress concentration at the edge, and there are optimal trimming parameters to minimize the concentrated stress under normal load and eccentric load. When the eccentric load exceeds a certain angle, the increase in the maximum stress can be very large, which may lead to premature failure of the interface. Meanwhile, the staggering velocity caused by the misalignment of the roller axis also has a certain influence on the distribution of the lubricating film.
{"title":"Investigation of the misalignment and modification for crown roller contacts under mixed lubrication","authors":"Xin Pei, Wanyou Yang","doi":"10.1177/13506501231201692","DOIUrl":"https://doi.org/10.1177/13506501231201692","url":null,"abstract":"A new contact model of finite-length crowned roller bearing, capable of handling lubrication, eccentric load, and misalignment situations, is established in this study. Simulation results of interface pressure, film thickness distribution, flash temperature, and subsurface stress can be obtained with different speeds, misalignment angles, load eccentricity, and roller trimming parameters. It is found that edge trimming can greatly reduce the stress concentration at the edge, and there are optimal trimming parameters to minimize the concentrated stress under normal load and eccentric load. When the eccentric load exceeds a certain angle, the increase in the maximum stress can be very large, which may lead to premature failure of the interface. Meanwhile, the staggering velocity caused by the misalignment of the roller axis also has a certain influence on the distribution of the lubricating film.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135308619","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 : 2023-09-16DOI: 10.1177/13506501231201693
Ravi Prakash Sharma, Mukesh Kumar, Ashiwani Kumar
This research work investigates the physical, mechanical, thermal, thermo-mechanical, and dry sliding wear characteristics of hybrid flyash particulates (F-class; 0 – 20 wt.% at the step of 5%)–basalt fibres (chopped; fixed 10 wt.%) reinforced polyamide 66 polymer composites fabricated using the twin screw extruder and injection moulding machine. Taguchi's design of experiment optimization approach is used for parameter optimization of the dry sliding wear process, followed by analysis of variance analysis. Further, the hybrid AHP-R method is used for ranking optimization based on the performance metrics. It is observed that the composition having 15 wt.% flyash particulates optimizes overall performance metrics, hence recommended for industrial parts fabrications. It has an experimental density of 1.23 g/cc, voids content of 5.93%, water absorption of 4.21%, tensile strength of 110.73 MPa, flexural strength of 146.72 MPa, Rockwell hardness of 62.44 HRM, fracture toughness of 4.17 MPa√m, impact strength of 2.06 J, the thermal conductivity of 1.24 W/mK, and specific wear rate of 7.55 × 10 −4 mm 3 /Nm. The overall subjective ranking of the hybrid polymer composites attunes with the objective ranking by the hybrid AHP-R method.
{"title":"Ranking analysis of flyash – basalt fibre – polyamide 66 polymer composites based on the mechanical and sliding wear performance metrics using hybrid AHP-R method","authors":"Ravi Prakash Sharma, Mukesh Kumar, Ashiwani Kumar","doi":"10.1177/13506501231201693","DOIUrl":"https://doi.org/10.1177/13506501231201693","url":null,"abstract":"This research work investigates the physical, mechanical, thermal, thermo-mechanical, and dry sliding wear characteristics of hybrid flyash particulates (F-class; 0 – 20 wt.% at the step of 5%)–basalt fibres (chopped; fixed 10 wt.%) reinforced polyamide 66 polymer composites fabricated using the twin screw extruder and injection moulding machine. Taguchi's design of experiment optimization approach is used for parameter optimization of the dry sliding wear process, followed by analysis of variance analysis. Further, the hybrid AHP-R method is used for ranking optimization based on the performance metrics. It is observed that the composition having 15 wt.% flyash particulates optimizes overall performance metrics, hence recommended for industrial parts fabrications. It has an experimental density of 1.23 g/cc, voids content of 5.93%, water absorption of 4.21%, tensile strength of 110.73 MPa, flexural strength of 146.72 MPa, Rockwell hardness of 62.44 HRM, fracture toughness of 4.17 MPa√m, impact strength of 2.06 J, the thermal conductivity of 1.24 W/mK, and specific wear rate of 7.55 × 10 −4 mm 3 /Nm. The overall subjective ranking of the hybrid polymer composites attunes with the objective ranking by the hybrid AHP-R method.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135308621","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}
This study applied a MoS 2 coating layer on the surface of 100Cr6 bearing steel balls through high-temperature sintering and tested and evaluated the modified friction pair. Compared to the unmodified friction pair, the MoS 2 coating treatment significantly improved the self-lubricating property of the friction pair, reduced the friction coefficient of the friction pair by 0.05, maximum wear depth was reduced by 32% during the test cycle and prolonged the retention time of the PTFE transfer film at the friction interface. After modification, the wear mechanism of the friction pair changed from abrasive wear to fatigue wear and then to slight adhesive wear. Results indicate that MoS 2 coating has great application prospects in improving the tribological properties and operational reliability of spherical plain bearings.
{"title":"Influence of MoS<sub>2</sub> coating treatment on the damage behaviour of the self-lubricating friction pair of spherical plain bearings","authors":"Fatao Zong, Xiaoqiang Yang, Deqiang Tan, Qiang Ye, Yue Hu, Qiang He, Wenfeng Yang, Huiying Gao","doi":"10.1177/13506501231201689","DOIUrl":"https://doi.org/10.1177/13506501231201689","url":null,"abstract":"This study applied a MoS 2 coating layer on the surface of 100Cr6 bearing steel balls through high-temperature sintering and tested and evaluated the modified friction pair. Compared to the unmodified friction pair, the MoS 2 coating treatment significantly improved the self-lubricating property of the friction pair, reduced the friction coefficient of the friction pair by 0.05, maximum wear depth was reduced by 32% during the test cycle and prolonged the retention time of the PTFE transfer film at the friction interface. After modification, the wear mechanism of the friction pair changed from abrasive wear to fatigue wear and then to slight adhesive wear. Results indicate that MoS 2 coating has great application prospects in improving the tribological properties and operational reliability of spherical plain bearings.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135740766","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: 10.1177/13506501231201202
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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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}
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