The fastener clips of the high-speed railway may fracture due to accumulated fretting damage, posing a hazard to train operation safety. To investigate the evolution mechanism of fretting wear characteristics of high-speed railway fastener clips, this paper conducted fretting wear tests on 60Si2MnA steel used for clips and analyzed the fretting wear characteristics under different number of fretting cycles (N). The results indicate that as N increases, the friction coefficient rises initially, then falls, slightly rises again, and eventually stabilizes. Furthermore, the surface wear volume and depth of 60Si2MnA steel material increase continuously, and its fretting wear mechanism undergoes a transformation. Specifically, at 20,000 cycles, surface plastic deformation primarily causes material damage. While at 40,000 cycles, an oxide plastic deformation layer appears on the material surface, where adhesive wear and oxidation wear become the primary wear mechanisms. When N increases to 80,000, plastic strain accumulates continually on the material surface, causing the oxide plastic deformation layer in the outer contact area to break and detach gradually. Adhesive wear transforms into abrasive wear, cracks occur inside the material, and fatigue wear becomes a significant wear mechanism. This study fills the research gap in the fretting wear evolution mechanism of 60Si2MnA steel.
高速铁路的扣件卡箍可能会因累积的烧损而断裂，对列车运行安全造成危害。为了探究高速铁路扣件卡箍摩擦磨损特性的演变机理，本文对用于卡箍的 60Si2MnA 钢进行了摩擦磨损试验，分析了不同摩擦循环次数（N）下的摩擦磨损特性。结果表明，随着 N 的增加，摩擦系数从最初的上升，到下降，再到略微上升，最终趋于稳定。此外，60Si2MnA 钢材料的表面磨损量和磨损深度不断增加，其摩擦磨损机理也发生了转变。具体来说，在 20000 次循环时，表面塑性变形是造成材料损坏的主要原因。当循环次数达到 40,000 次时，材料表面出现氧化塑性变形层，粘着磨损和氧化磨损成为主要的磨损机制。当 N 值增加到 80,000 时，塑性应变在材料表面不断累积，导致外接触区域的氧化塑性变形层逐渐破裂和脱落。粘着磨损转变为磨料磨损，材料内部出现裂纹，疲劳磨损成为一种重要的磨损机制。本研究填补了 60Si2MnA 钢摩擦磨损演变机理方面的研究空白。
{"title":"Fretting wear characteristics evolution mechanism of 60Si2MnA steel for high-speed railway fastener clips","authors":"Yong Zeng, Zhan Qin, Chao Su, Ziyue Zeng, Shihang Xu, Guixiang Zhang, Pingdi Ren","doi":"10.1177/13506501241233347","DOIUrl":"https://doi.org/10.1177/13506501241233347","url":null,"abstract":"The fastener clips of the high-speed railway may fracture due to accumulated fretting damage, posing a hazard to train operation safety. To investigate the evolution mechanism of fretting wear characteristics of high-speed railway fastener clips, this paper conducted fretting wear tests on 60Si2MnA steel used for clips and analyzed the fretting wear characteristics under different number of fretting cycles (N). The results indicate that as N increases, the friction coefficient rises initially, then falls, slightly rises again, and eventually stabilizes. Furthermore, the surface wear volume and depth of 60Si2MnA steel material increase continuously, and its fretting wear mechanism undergoes a transformation. Specifically, at 20,000 cycles, surface plastic deformation primarily causes material damage. While at 40,000 cycles, an oxide plastic deformation layer appears on the material surface, where adhesive wear and oxidation wear become the primary wear mechanisms. When N increases to 80,000, plastic strain accumulates continually on the material surface, causing the oxide plastic deformation layer in the outer contact area to break and detach gradually. Adhesive wear transforms into abrasive wear, cracks occur inside the material, and fatigue wear becomes a significant wear mechanism. This study fills the research gap in the fretting wear evolution mechanism of 60Si2MnA steel.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141706681","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 : 2024-06-07DOI: 10.1177/13506501241259225
T. V. Albuquerque de Freitas, Rômulo do Nascimento Rodrigues, Camilo A Santos Costa, Roberto de Araujo Bezerra, Vanessa Vieira Gonçalves, Mateus H Cardoso Maciel
Squeal is a noise problem that affects all types of automotive brake systems and may affect the health of the population living in heavy traffic areas. Parameters such as pressure, friction, and Young’s Modulus are crucial in determining brake noise generation. Notably, wear on rubbing surfaces emerges as a key contributor to squeal, affecting the overall brake system functionality and necessitating frequent maintenance and parts replacement. This study conducted a detailed analysis of the influence of material and operational factors on squeal generation, specifically examining their relationship with friction wear in motorcycle disc brakes. To achieve this goal, a parametric study was conducted using finite element analysis software ANSYS. Thus, the study involved subjecting the geometry to static and modal analyses to verify the generation of unstable modes. Additionally, two models were built to analyze the influence of wear on noise: one with Archard wear activated, which calculated the worn volume, and another with this option disabled. The results of the study suggest that wear is a crucial parameter that must be considered in numerical models, given its significant impact on stability attributes. Moreover, since material and operational parameters play a substantial role in generating squeal noise, this study provides valuable insights into the causes and effects of brake noise, offering practical recommendations for mitigating this common problem in motorcycle disc brakes. The model developed also serves as foundational framework for configuring simulations for similar systems, automotive or train disc brake, to study the noise and lifespan of pads.
{"title":"Parametric analysis of the relationship between squeal and friction wear in motorcycle disc brakes","authors":"T. V. Albuquerque de Freitas, Rômulo do Nascimento Rodrigues, Camilo A Santos Costa, Roberto de Araujo Bezerra, Vanessa Vieira Gonçalves, Mateus H Cardoso Maciel","doi":"10.1177/13506501241259225","DOIUrl":"https://doi.org/10.1177/13506501241259225","url":null,"abstract":"Squeal is a noise problem that affects all types of automotive brake systems and may affect the health of the population living in heavy traffic areas. Parameters such as pressure, friction, and Young’s Modulus are crucial in determining brake noise generation. Notably, wear on rubbing surfaces emerges as a key contributor to squeal, affecting the overall brake system functionality and necessitating frequent maintenance and parts replacement. This study conducted a detailed analysis of the influence of material and operational factors on squeal generation, specifically examining their relationship with friction wear in motorcycle disc brakes. To achieve this goal, a parametric study was conducted using finite element analysis software ANSYS. Thus, the study involved subjecting the geometry to static and modal analyses to verify the generation of unstable modes. Additionally, two models were built to analyze the influence of wear on noise: one with Archard wear activated, which calculated the worn volume, and another with this option disabled. The results of the study suggest that wear is a crucial parameter that must be considered in numerical models, given its significant impact on stability attributes. Moreover, since material and operational parameters play a substantial role in generating squeal noise, this study provides valuable insights into the causes and effects of brake noise, offering practical recommendations for mitigating this common problem in motorcycle disc brakes. The model developed also serves as foundational framework for configuring simulations for similar systems, automotive or train disc brake, to study the noise and lifespan of pads.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141370659","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 : 2024-06-06DOI: 10.1177/13506501241259898
B. Cui, Ping Chen, Boshen Liu, Yuanqi Zhao, Jiaqi Zheng
The black-water regulating valve is very easy to be damaged due to the erosion of the key components, such as valve spool and valve seat. This work presents the failure analysis of the spool and seat of regulating valve in the black-water treatment system. Scanning electron microscopy and X-ray energy-dispersive spectrometer were used to detect the morphology and chemical compositions of failure valve samples. The computational fluid dynamics method was also adopted to simulate the medium flow characteristics in black-water regulating valve. The results show that most erosion areas of the valve occur at the spool-seat throttle zone. The erosion profile is mainly manifested in plastic deformation pits, cutting abrasions, furrows, pinhole pits and impact pits. The particles and cavitation bubbles move toward the throttle zone driven by black-water medium, causing particles impact and bubbles collapse. The particle flow velocity in the throttle zone of the valve is between 50 and 175 m/s, while the maximum velocity can reach 175 m/s. The valve suffered severe particle erosion and cavitation erosion under the particle impact and bubble collapse, finally resulting in its failure.
黑水调节阀很容易因阀芯和阀座等关键部件的侵蚀而损坏。本研究对黑水处理系统中调节阀的阀芯和阀座进行了失效分析。采用扫描电子显微镜和 X 射线能量色散光谱仪检测失效阀门样品的形态和化学成分。此外，还采用计算流体动力学方法模拟了黑水调节阀中介质的流动特性。结果表明，阀门的大部分侵蚀区域发生在阀芯-阀座节流区。冲蚀剖面主要表现为塑性变形凹坑、切削擦伤、沟槽、针孔凹坑和冲击凹坑。颗粒和气蚀气泡在黑水介质的驱动下向节流区移动，造成颗粒撞击和气泡破裂。阀门节流区的颗粒流速在 50 至 175 m/s 之间，最大流速可达 175 m/s。在颗粒冲击和气泡崩溃的作用下，阀门受到严重的颗粒侵蚀和气蚀，最终导致阀门失效。
{"title":"Failure analysis and numerical simulation of the regulating valve with particle erosion and cavitation erosion in the black-water treatment system","authors":"B. Cui, Ping Chen, Boshen Liu, Yuanqi Zhao, Jiaqi Zheng","doi":"10.1177/13506501241259898","DOIUrl":"https://doi.org/10.1177/13506501241259898","url":null,"abstract":"The black-water regulating valve is very easy to be damaged due to the erosion of the key components, such as valve spool and valve seat. This work presents the failure analysis of the spool and seat of regulating valve in the black-water treatment system. Scanning electron microscopy and X-ray energy-dispersive spectrometer were used to detect the morphology and chemical compositions of failure valve samples. The computational fluid dynamics method was also adopted to simulate the medium flow characteristics in black-water regulating valve. The results show that most erosion areas of the valve occur at the spool-seat throttle zone. The erosion profile is mainly manifested in plastic deformation pits, cutting abrasions, furrows, pinhole pits and impact pits. The particles and cavitation bubbles move toward the throttle zone driven by black-water medium, causing particles impact and bubbles collapse. The particle flow velocity in the throttle zone of the valve is between 50 and 175 m/s, while the maximum velocity can reach 175 m/s. The valve suffered severe particle erosion and cavitation erosion under the particle impact and bubble collapse, finally resulting in its failure.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141378599","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 : 2024-06-06DOI: 10.1177/13506501241258284
P. Samanta, N. C. Murmu, M. Khonsari
Foil bearings are considered to be an excellent fit for a range of high-temperature applications. However, they are susceptible to collapse as a result of thermoelastic instability (TEI). This study introduces a novel approach to enhance passive cooling by adding fins to the surface of the hollow journal cylinder. The effect of enhanced heat transport on the thermoelastic evolution of the bearing surface is thoroughly explored. Furthermore, the critical speed of a foil bearing is derived after taking into account the effect of fins. This affordable method enables the designer to increase the threshold speed of TEI and guard against foil-bearing failure.
{"title":"A new thermal management method for reducing thermoelastic growth of an air foil bearing","authors":"P. Samanta, N. C. Murmu, M. Khonsari","doi":"10.1177/13506501241258284","DOIUrl":"https://doi.org/10.1177/13506501241258284","url":null,"abstract":"Foil bearings are considered to be an excellent fit for a range of high-temperature applications. However, they are susceptible to collapse as a result of thermoelastic instability (TEI). This study introduces a novel approach to enhance passive cooling by adding fins to the surface of the hollow journal cylinder. The effect of enhanced heat transport on the thermoelastic evolution of the bearing surface is thoroughly explored. Furthermore, the critical speed of a foil bearing is derived after taking into account the effect of fins. This affordable method enables the designer to increase the threshold speed of TEI and guard against foil-bearing failure.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141375849","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 : 2024-03-27DOI: 10.1177/13506501241240020
Ayush Jain, Shubham Soni, N. Vashishtha, Deepika Shekhawat
Wheel bearings play a crucial role in ensuring the smooth and reliable rotation of wheels in automotive applications. Grease is commonly used as a lubricant in wheel bearings. The physical properties of grease, such as viscosity, base oil type, and thickener composition, significantly influence the overall performance and longevity of wheel bearings. This study investigates the impact of grease's physical properties on wheel bearing friction torque and service life. To evaluate the effects of different grease formulations, a series of experiments were conducted using a four-ball tester, rheometer, and a custom-built test rig to measure bearing frictional torque and service life. Multiple greases with varying viscosity grades, base oil types (mineral oil, synthetic oil), and thickener compositions (lithium, diurea, and polyurea) were tested under controlled operating conditions. Friction torque measurements were obtained using a high-accuracy torque sensor, while service life was determined by monitoring the bearing life in actual endurance testing. The results indicated that grease physical properties directly affected wheel bearing friction torque and service life. Low to Medium-viscosity greases generally exhibited 35–40% lower friction torque due to enhanced lubrication film formation and reduced metal-to-metal contact however, excessively high viscosity resulted in 50–60% higher frictional torque and thereby increased energy consumption. Different base oil types showed varying friction reduction and service life level, with mineral oil in some cases showed lower frictional torque around 30–40% particularly at high temperature but with significant reduction in the service life. Furthermore, the thickener composition significantly influenced grease performance. Based on these findings, selecting the appropriate grease with optimal physical properties is crucial for minimizing friction torque and extending the service life of wheel bearings.
{"title":"Impact of grease physical properties on the friction torque and service life of wheel bearings","authors":"Ayush Jain, Shubham Soni, N. Vashishtha, Deepika Shekhawat","doi":"10.1177/13506501241240020","DOIUrl":"https://doi.org/10.1177/13506501241240020","url":null,"abstract":"Wheel bearings play a crucial role in ensuring the smooth and reliable rotation of wheels in automotive applications. Grease is commonly used as a lubricant in wheel bearings. The physical properties of grease, such as viscosity, base oil type, and thickener composition, significantly influence the overall performance and longevity of wheel bearings. This study investigates the impact of grease's physical properties on wheel bearing friction torque and service life. To evaluate the effects of different grease formulations, a series of experiments were conducted using a four-ball tester, rheometer, and a custom-built test rig to measure bearing frictional torque and service life. Multiple greases with varying viscosity grades, base oil types (mineral oil, synthetic oil), and thickener compositions (lithium, diurea, and polyurea) were tested under controlled operating conditions. Friction torque measurements were obtained using a high-accuracy torque sensor, while service life was determined by monitoring the bearing life in actual endurance testing. The results indicated that grease physical properties directly affected wheel bearing friction torque and service life. Low to Medium-viscosity greases generally exhibited 35–40% lower friction torque due to enhanced lubrication film formation and reduced metal-to-metal contact however, excessively high viscosity resulted in 50–60% higher frictional torque and thereby increased energy consumption. Different base oil types showed varying friction reduction and service life level, with mineral oil in some cases showed lower frictional torque around 30–40% particularly at high temperature but with significant reduction in the service life. Furthermore, the thickener composition significantly influenced grease performance. Based on these findings, selecting the appropriate grease with optimal physical properties is crucial for minimizing friction torque and extending the service life of wheel bearings.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140373774","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 : 2024-03-26DOI: 10.1177/13506501241240021
Taufiq Hidayat, Muhammad Imam Ammarullah, Rifky Ismail, M. Tauviqirrahman, Eko Saputra, M. D. P. Lamura, Chethan Kn, A. P. Bayuseno, Jamari
Based on several references, Asians carry out several daily activities that are different from Westerners, which require a greater range of motion. Because of that, a dual mobility (DM) implant was created that was adapted to the activities of Asian people. One of the factors that might shorten the life of a hip implant is wear. Simulations of wear that are based on computation can guide product design to reduce the amount of adhesive and abrasive wear. Even though advanced modeling approaches have been established, a great deal of wear is still not understood, especially regarding the metal-on-polyethylene articulations found on DM cups. It is critical to examine the wear on the DM cup's head-to-liner ratio to determine the proper head diameter and liner thickness for this DM cup. In this work, wear was analyzed using finite-element analysis and compared between three different femoral head diameters matched with different thicknesses of the polyethylene liner on DM cups. Wear was analyzed throughout the regular walking cycle at each head-to-liner ratio. The findings of this study can be used to develop a dual-mobility artificial hip joint for Asians with the slightest wear.
{"title":"Assessment of polyethylene wear in dual mobility implant for Asians on various head-to-liner ratios: A finite-element analysis","authors":"Taufiq Hidayat, Muhammad Imam Ammarullah, Rifky Ismail, M. Tauviqirrahman, Eko Saputra, M. D. P. Lamura, Chethan Kn, A. P. Bayuseno, Jamari","doi":"10.1177/13506501241240021","DOIUrl":"https://doi.org/10.1177/13506501241240021","url":null,"abstract":"Based on several references, Asians carry out several daily activities that are different from Westerners, which require a greater range of motion. Because of that, a dual mobility (DM) implant was created that was adapted to the activities of Asian people. One of the factors that might shorten the life of a hip implant is wear. Simulations of wear that are based on computation can guide product design to reduce the amount of adhesive and abrasive wear. Even though advanced modeling approaches have been established, a great deal of wear is still not understood, especially regarding the metal-on-polyethylene articulations found on DM cups. It is critical to examine the wear on the DM cup's head-to-liner ratio to determine the proper head diameter and liner thickness for this DM cup. In this work, wear was analyzed using finite-element analysis and compared between three different femoral head diameters matched with different thicknesses of the polyethylene liner on DM cups. Wear was analyzed throughout the regular walking cycle at each head-to-liner ratio. The findings of this study can be used to develop a dual-mobility artificial hip joint for Asians with the slightest wear.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140379995","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 : 2024-02-25DOI: 10.1177/13506501241233356
Sanjay Mohan, A. Anand, Ankush Raina, Parshant Kumar, M. I. Ul Haq, Marcel Graf, Subramanian Jayalakshmi, R. Arvind Singh
In this work, Fe-2Cu-0.8C-CaF2 self-lubricating composites with calcium fluoride solid lubricant (3 □ 12 wt.%) were examined for their friction and wear at 5 and 10 m/s, at 500 °C. Addition of CaF2 decreased density and hardness of composites. During sliding, materials gained weight due to oxidation. Compared to the base matrix (Fe-2Cu-0.8C), composites showed lower weight gain and lower coefficient of friction. Increase in porosity with CaF2 content increased oxidation resulting in higher weight gain and increased friction due to wear debris abrasion. Increase in speed reduced weight gain due to higher material loss. Adhesion was the dominant wear mechanism in base matrix; delamination and wear debris abrasion in composites. Temperature rise at sliding surfaces was theoretically estimated. Increase in speed increased temperature, which reduced friction due to softening and shearing of solid lubricant. Composite with 3 wt.% CaF2 showed least surface damage and 6 wt.% showed lowest coefficient of friction, i.e., lower by 16% and 10% at 5, 10 m/s than base matrix. Tribological response of the composites to a broad range of applied parameters, viz. speed, load and temperature taken from earlier works and present work is briefly summarized. The study suggests the dominant role of CaF2 content and the wear debris in altering the tribological response. Further, the stability of the developed composites at high temperature and high load conditions was also established. The study suggests that the developed composites could serve high-load and high-temperature applications for heavy machinery such as bearings, shafts and gears.
{"title":"High temperature tribological response of Fe-2Cu-0.8C-CaF2 self-lubricating composites at high speeds","authors":"Sanjay Mohan, A. Anand, Ankush Raina, Parshant Kumar, M. I. Ul Haq, Marcel Graf, Subramanian Jayalakshmi, R. Arvind Singh","doi":"10.1177/13506501241233356","DOIUrl":"https://doi.org/10.1177/13506501241233356","url":null,"abstract":"In this work, Fe-2Cu-0.8C-CaF2 self-lubricating composites with calcium fluoride solid lubricant (3 □ 12 wt.%) were examined for their friction and wear at 5 and 10 m/s, at 500 °C. Addition of CaF2 decreased density and hardness of composites. During sliding, materials gained weight due to oxidation. Compared to the base matrix (Fe-2Cu-0.8C), composites showed lower weight gain and lower coefficient of friction. Increase in porosity with CaF2 content increased oxidation resulting in higher weight gain and increased friction due to wear debris abrasion. Increase in speed reduced weight gain due to higher material loss. Adhesion was the dominant wear mechanism in base matrix; delamination and wear debris abrasion in composites. Temperature rise at sliding surfaces was theoretically estimated. Increase in speed increased temperature, which reduced friction due to softening and shearing of solid lubricant. Composite with 3 wt.% CaF2 showed least surface damage and 6 wt.% showed lowest coefficient of friction, i.e., lower by 16% and 10% at 5, 10 m/s than base matrix. Tribological response of the composites to a broad range of applied parameters, viz. speed, load and temperature taken from earlier works and present work is briefly summarized. The study suggests the dominant role of CaF2 content and the wear debris in altering the tribological response. Further, the stability of the developed composites at high temperature and high load conditions was also established. The study suggests that the developed composites could serve high-load and high-temperature applications for heavy machinery such as bearings, shafts and gears.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140433566","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 : 2024-02-25DOI: 10.1177/13506501241233353
Ziqi Chen, Ji Wang, Rui Li, Yujun Liu, Pengfa Yu
This research proposes a transient mixed elastohydrodynamic model considering turbulence and bush wear, as well as the concept of contact work, to study the transient tribo-dynamic characteristics of water-lubricated bearings. The effects of turbulence, wear depth, and wear deviation angle on transient tribo-dynamic characteristics of water-lubricated bearings are investigated. The findings show that turbulence significantly affects the dynamics of stable conditions and enhances the hydrodynamic effect, but little affects the frictional contact behavior. An appropriate wear depth favors improving the tribo-dynamic characteristics of the water-lubricated bearings, but it deteriorates as the wear depth continuously increases. Negative deviation angles are better for minimizing contact work and enhancing rotor stability. The lubrication and dynamic properties of water-lubricated bearings can be enhanced through a rational approach to wear morphology design. This research is important for the optimal design and diagnosis of water-lubricated bearings wear failures.
{"title":"Effects of turbulence and bush wear on the transient tribo-dynamic characteristics of water-lubricated bearings","authors":"Ziqi Chen, Ji Wang, Rui Li, Yujun Liu, Pengfa Yu","doi":"10.1177/13506501241233353","DOIUrl":"https://doi.org/10.1177/13506501241233353","url":null,"abstract":"This research proposes a transient mixed elastohydrodynamic model considering turbulence and bush wear, as well as the concept of contact work, to study the transient tribo-dynamic characteristics of water-lubricated bearings. The effects of turbulence, wear depth, and wear deviation angle on transient tribo-dynamic characteristics of water-lubricated bearings are investigated. The findings show that turbulence significantly affects the dynamics of stable conditions and enhances the hydrodynamic effect, but little affects the frictional contact behavior. An appropriate wear depth favors improving the tribo-dynamic characteristics of the water-lubricated bearings, but it deteriorates as the wear depth continuously increases. Negative deviation angles are better for minimizing contact work and enhancing rotor stability. The lubrication and dynamic properties of water-lubricated bearings can be enhanced through a rational approach to wear morphology design. This research is important for the optimal design and diagnosis of water-lubricated bearings wear failures.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140433834","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 : 2024-02-22DOI: 10.1177/13506501241232457
Georgios N Rossopoulos, Christos I. Papadopoulos
This paper presents two novel artificial intelligence-based approaches for evaluating the performance of heavily loaded marine journal bearings including shaft misalignment. Traditionally, the Sommerfeld number has been used as a key parameter to evaluate the performance similarity between different bearings. However, this method has limitations, particularly when dealing with complex elastic geometries, heavily loaded journal bearings and shaft misalignment. The first proposed approach leverages neural networks to analyze key bearing performance parameters and provide a more accurate and comprehensive assessment of bearing performance similarity, including additional parameters beyond the Sommerfeld number limitations. The second method utilizes artificial intelligence convolutional networks to assess the bearing similarity based on their simulated pressure profiles under isoviscous and isothermal hydrodynamic lubrication regime. The effectiveness of the proposed methods is demonstrated and compared to the traditional Sommerfeld number method, discussing various potential applications and extensions of this concept.
{"title":"AI techniques for evaluating misaligned journal bearing performance: An approach beyond the Sommerfeld number","authors":"Georgios N Rossopoulos, Christos I. Papadopoulos","doi":"10.1177/13506501241232457","DOIUrl":"https://doi.org/10.1177/13506501241232457","url":null,"abstract":"This paper presents two novel artificial intelligence-based approaches for evaluating the performance of heavily loaded marine journal bearings including shaft misalignment. Traditionally, the Sommerfeld number has been used as a key parameter to evaluate the performance similarity between different bearings. However, this method has limitations, particularly when dealing with complex elastic geometries, heavily loaded journal bearings and shaft misalignment. The first proposed approach leverages neural networks to analyze key bearing performance parameters and provide a more accurate and comprehensive assessment of bearing performance similarity, including additional parameters beyond the Sommerfeld number limitations. The second method utilizes artificial intelligence convolutional networks to assess the bearing similarity based on their simulated pressure profiles under isoviscous and isothermal hydrodynamic lubrication regime. The effectiveness of the proposed methods is demonstrated and compared to the traditional Sommerfeld number method, discussing various potential applications and extensions of this concept.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140438244","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 : 2024-02-21DOI: 10.1177/13506501241233628
H. Parikh, S. Chokshi, Vijay Chaudhary, Ankit D. Oza, Chander Prakash
Nowadays, there is a rising demand for bio-composite materials driven by the increasing need for sustainable alternatives and a desire to lessen dependence on conventional materials. These bio-composites resent eco-friendly solutions to address these challenges. In line with this, the present study focuses on the bio composite material which developed from polylactic acid (PLA) and wood dust (NF). Wood dust sourced from teak wood plants was employed as fillers. PLA served as the matrix material, supplemented with the plasticizer polyethylene glycol (PEG) to enhance PLA processing. The PLA/NF filament was produced through the extrusion process, and specimens were prepared using 3D printing techniques in accordance with ASTM standards. Various properties including mechanical, physical, thermal stability, and tribological properties were examined. Morphological structures were observed using scanning electron microscopy (SEM). The test results demonstrated improvements in enhanced mechanical robustness and tribological performance of the PLA composite. The tensile strength of the PLA/wood composite was enhanced by 11%. The hardness value of the PLA/wood composite increased by 27% with the addition of wood as filler material. However, the introduction of wood as filler material led to degradation in physical properties. The water absorption test revealed a thickness change of approximately 14% for the PLA wood composite, whereas for pure PLA, it was 9%. Thermal stability tests showed that the temperature resistance of PLA improved to 250 °C with the introduction of wood fillers. Biodegradability tests indicated that PLA wood composite has the potential to address environmental concerns associated with conventional materials.
{"title":"Development and characterization of eco-friendly extruded green composites using PLA/wood dust fillers","authors":"H. Parikh, S. Chokshi, Vijay Chaudhary, Ankit D. Oza, Chander Prakash","doi":"10.1177/13506501241233628","DOIUrl":"https://doi.org/10.1177/13506501241233628","url":null,"abstract":"Nowadays, there is a rising demand for bio-composite materials driven by the increasing need for sustainable alternatives and a desire to lessen dependence on conventional materials. These bio-composites resent eco-friendly solutions to address these challenges. In line with this, the present study focuses on the bio composite material which developed from polylactic acid (PLA) and wood dust (NF). Wood dust sourced from teak wood plants was employed as fillers. PLA served as the matrix material, supplemented with the plasticizer polyethylene glycol (PEG) to enhance PLA processing. The PLA/NF filament was produced through the extrusion process, and specimens were prepared using 3D printing techniques in accordance with ASTM standards. Various properties including mechanical, physical, thermal stability, and tribological properties were examined. Morphological structures were observed using scanning electron microscopy (SEM). The test results demonstrated improvements in enhanced mechanical robustness and tribological performance of the PLA composite. The tensile strength of the PLA/wood composite was enhanced by 11%. The hardness value of the PLA/wood composite increased by 27% with the addition of wood as filler material. However, the introduction of wood as filler material led to degradation in physical properties. The water absorption test revealed a thickness change of approximately 14% for the PLA wood composite, whereas for pure PLA, it was 9%. Thermal stability tests showed that the temperature resistance of PLA improved to 250 °C with the introduction of wood fillers. Biodegradability tests indicated that PLA wood composite has the potential to address environmental concerns associated with conventional materials.","PeriodicalId":20570,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139958048","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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