ASTM D8503 is a brand new tribometrical scuffing tests where adhesive failure (scuffing, scoring) is initiated by temperature step increases and not by load step increases as per FZG, 4-ball, Timken, SRV, etc.. This test method determines the upper temperature limit for operating a lubricant and can also be used to determine the upper temperature limit of non-EP lubricating oils to protect against scuffing with increasing temperature. It illuminates also the retention of frictional properties over increasing temperature. It illuminates to formulators the formation and stability of protecting tribofilms with increasing temperature. Combining the temperature step increases with the electrical contact resistance gives new insights in the “Life” of tribofilms.
{"title":"Bestimmung der oberen Temperatur- grenze von Schmierstoffen gegen adhäsives Versagen","authors":"Mathias Woydt, Zhiliang Jin, Ailian Lei, Xiaogang Li, Binbin Wei","doi":"10.24053/tus-2023-0022","DOIUrl":"https://doi.org/10.24053/tus-2023-0022","url":null,"abstract":"ASTM D8503 is a brand new tribometrical scuffing tests where adhesive failure (scuffing, scoring) is initiated by temperature step increases and not by load step increases as per FZG, 4-ball, Timken, SRV, etc.. This test method determines the upper temperature limit for operating a lubricant and can also be used to determine the upper temperature limit of non-EP lubricating oils to protect against scuffing with increasing temperature. It illuminates also the retention of frictional properties over increasing temperature. It illuminates to formulators the formation and stability of protecting tribofilms with increasing temperature. Combining the temperature step increases with the electrical contact resistance gives new insights in the “Life” of tribofilms.","PeriodicalId":53690,"journal":{"name":"Tribologie und Schmierungstechnik","volume":"9058 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135814651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christian Wilbs, Matthias Adler, Daniel Fröhlich, Alisa Bellon, Nicole Schuster, Jasmin Menzel, Emely Bopp
This paper introduces the new µ-mechanical characterization method and its application for the post-test radial shaft seal (RSS) analysis of dynamic lubricant-elastomer compatibility tests. Therefore, the measurement procedure and accuracy will be discussed as well as the features which can be drawn from the measured force-displacement curve. Furthermore, it will be shown, how these features allow a precise evaluation of the seal material condition regarding hard deposits, hardening and softening. This will be summarized by showing the correlation of the visual-haptic elastomer assessment and the results of the newly developed characterization method which will increase the informative value of dynamic lubricant-elastomer tests.
{"title":"μ-Mechanical characterization of tribologically stressed elastomer surfaces with respect to radial shaft sealing systems","authors":"Christian Wilbs, Matthias Adler, Daniel Fröhlich, Alisa Bellon, Nicole Schuster, Jasmin Menzel, Emely Bopp","doi":"10.24053/tus-2023-0020","DOIUrl":"https://doi.org/10.24053/tus-2023-0020","url":null,"abstract":"This paper introduces the new µ-mechanical characterization method and its application for the post-test radial shaft seal (RSS) analysis of dynamic lubricant-elastomer compatibility tests. Therefore, the measurement procedure and accuracy will be discussed as well as the features which can be drawn from the measured force-displacement curve. Furthermore, it will be shown, how these features allow a precise evaluation of the seal material condition regarding hard deposits, hardening and softening. This will be summarized by showing the correlation of the visual-haptic elastomer assessment and the results of the newly developed characterization method which will increase the informative value of dynamic lubricant-elastomer tests.","PeriodicalId":53690,"journal":{"name":"Tribologie und Schmierungstechnik","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135814653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ein tribologischer, dankender Blick über den Teich","authors":"Manfred Jungk","doi":"10.24053/tus-2023-0016","DOIUrl":"https://doi.org/10.24053/tus-2023-0016","url":null,"abstract":"","PeriodicalId":53690,"journal":{"name":"Tribologie und Schmierungstechnik","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135815137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Katrin Alt, Felix Bernhardt, Klaus Ganz, Alexander Hüttinger, Markus Wöppermann
A new measurement device is introduced for analysing worn radial shaft seals (RSSs). This device enables unified and reproducible analysis and allows an automated nanoindentation for reliably detecting material changes at the seal edge.
{"title":"Measurement device and automation solution for analysing tribologically damaged radial shaft seals","authors":"Katrin Alt, Felix Bernhardt, Klaus Ganz, Alexander Hüttinger, Markus Wöppermann","doi":"10.24053/tus-2023-0019","DOIUrl":"https://doi.org/10.24053/tus-2023-0019","url":null,"abstract":"A new measurement device is introduced for analysing worn radial shaft seals (RSSs). This device enables unified and reproducible analysis and allows an automated nanoindentation for reliably detecting material changes at the seal edge.","PeriodicalId":53690,"journal":{"name":"Tribologie und Schmierungstechnik","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135814485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The elemental analysis in grease samples is common practice in their analysis. However, there is no international standard available describing procedures. Thus, numerous often-similar approaches are used in commercial laboratories. In contrast to lubricating oils, grease analyses are influenced by the matrix, originating from different thickeners. We have compared the results from the most common methods, XRF, RDE-OES and ICP-OES. The latter method using modern microwave assisted sample preparation. The analysis using ICP-OES after microwave-assisted digestion leads to low LODs compared to the other methods used in this study.
{"title":"Die Analyse von Abrieb- und Additiv elementen in Schmierfetten: XRF, RDE-OES oder ICP-OES?","authors":"Christoph J. Rohbogner, Thomas Fischer","doi":"10.24053/tus-2023-0018","DOIUrl":"https://doi.org/10.24053/tus-2023-0018","url":null,"abstract":"The elemental analysis in grease samples is common practice in their analysis. However, there is no international standard available describing procedures. Thus, numerous often-similar approaches are used in commercial laboratories. In contrast to lubricating oils, grease analyses are influenced by the matrix, originating from different thickeners. We have compared the results from the most common methods, XRF, RDE-OES and ICP-OES. The latter method using modern microwave assisted sample preparation. The analysis using ICP-OES after microwave-assisted digestion leads to low LODs compared to the other methods used in this study.","PeriodicalId":53690,"journal":{"name":"Tribologie und Schmierungstechnik","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135814488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Patrick Wingertszahn, Sebastian Schmitt, Stefan Thielen, Manuel Oehler, Balázs Magyar, Oliver Koch, Hans Hasse, Simon Stephan
Lubricants play a central role in many technical applications, e.g. in bearings and gears as well as in machining processes. In such applications, lubricants are exposed to extreme conditions in the contact area. In lubrication gaps, the pressure can reach values up to 5 GPa. The thermophysical properties of lubricants, and in particular the viscosity, at such extreme conditions have an important influence on the friction and wear behavior of a tribosystem. Accordingly, reliable lubricant property models are a prerequisite for accurate tribological simulations, e.g. elastohydrodynamic lubrication (EHL) simulations. Presently, the vast majority of experimental thermophysical property data are only available up to 1 GPa. Thus, reliable and robust models with strong extrapolation capabilities to higher pressure are required. In this work, viscosity measurements of squalane in a temperature range be tween 20 °C and 100 °C and pressures up to 1 GPa were carried out. Based on that data, a physical model for the viscosity was developed. The model is built by combining a molecular-based equation of state with the so-called entropy scaling approach. Finally, we demonstrate how this fluid property model can be favorably integrated in an EHL simulation by an application programming interface (API). The novel hybrid modeling approach is promising for future applications.
{"title":"Measurement, Modelling, and Appli cation of Lubricant Properties at Extreme Pressures","authors":"Patrick Wingertszahn, Sebastian Schmitt, Stefan Thielen, Manuel Oehler, Balázs Magyar, Oliver Koch, Hans Hasse, Simon Stephan","doi":"10.24053/tus-2023-0017","DOIUrl":"https://doi.org/10.24053/tus-2023-0017","url":null,"abstract":"Lubricants play a central role in many technical applications, e.g. in bearings and gears as well as in machining processes. In such applications, lubricants are exposed to extreme conditions in the contact area. In lubrication gaps, the pressure can reach values up to 5 GPa. The thermophysical properties of lubricants, and in particular the viscosity, at such extreme conditions have an important influence on the friction and wear behavior of a tribosystem. Accordingly, reliable lubricant property models are a prerequisite for accurate tribological simulations, e.g. elastohydrodynamic lubrication (EHL) simulations. Presently, the vast majority of experimental thermophysical property data are only available up to 1 GPa. Thus, reliable and robust models with strong extrapolation capabilities to higher pressure are required. In this work, viscosity measurements of squalane in a temperature range be tween 20 °C and 100 °C and pressures up to 1 GPa were carried out. Based on that data, a physical model for the viscosity was developed. The model is built by combining a molecular-based equation of state with the so-called entropy scaling approach. Finally, we demonstrate how this fluid property model can be favorably integrated in an EHL simulation by an application programming interface (API). The novel hybrid modeling approach is promising for future applications.","PeriodicalId":53690,"journal":{"name":"Tribologie und Schmierungstechnik","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135814649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The lubrication film pressure of certain tribological contacts of hydraulic axial piston machines is generated partly by hydrodynamics and partly by a load-dependent hydrostatic relief. Matching these pressure components is a challenge in the design of tribological contacts with variable relative velocity and variable load. In particular, the operating and wear behavior of the slipper-swashplate-contact in axial piston machines has currently not been fully investigated under these conditions. Thus, in this work, a simulative and experimental investigation of the slipper-swashplate-contact is presented, to identify major factors influencing wear during operating point changes.
{"title":"Experimental and Simulative Investigation of a Partially Hydrostatic Relieved Contact in Variable Speed Axial Piston Machines","authors":"Felix Schlegel, Amos Merkel, Katharina Schmitz","doi":"10.24053/tus-2023-0023","DOIUrl":"https://doi.org/10.24053/tus-2023-0023","url":null,"abstract":"The lubrication film pressure of certain tribological contacts of hydraulic axial piston machines is generated partly by hydrodynamics and partly by a load-dependent hydrostatic relief. Matching these pressure components is a challenge in the design of tribological contacts with variable relative velocity and variable load. In particular, the operating and wear behavior of the slipper-swashplate-contact in axial piston machines has currently not been fully investigated under these conditions. Thus, in this work, a simulative and experimental investigation of the slipper-swashplate-contact is presented, to identify major factors influencing wear during operating point changes.","PeriodicalId":53690,"journal":{"name":"Tribologie und Schmierungstechnik","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135814484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Moritz Lengmüller, Enzo Maier, Thomas Lohner, Karsten Stahl
Fiber-reinforced materials feature transversely isotropic elasticity. Although its influence on pressures, shapes, and sizes has been studied extensively for dry contacts, the transferability to lubricated contacts is fragmented. This numerical study investigates how the content and orientation of short fibers in fiber-reinforced polymers (FRP) affect elastohydrodynamic lubrication (EHL) of point contacts. Material properties are modeled with Tandon-Weng homogenization. For EHL modeling, a fully coupled approach based on finite element discretization is used. Results on hydrodynamic pressure and film thickness as well as material stress distribution are analyzed. It is shown that the combination of fiber content and orientation defines the effective contact stiffness that determines the contact shape, size, and film thickness. The following extended abstract is an excerpt from the publication “Effect of Transversely Isotropic Elasticity on Elastohydrodynamic Lubrication of Point Contacts” (https://doi.org/10.3390/polym14173507) that is based on the awarded thesis “Numerical Study on Anisotropic TEHL Contacts with Short Fiber Reinforced Polymers”)
{"title":"Numerical Study on Anisotropic EHL Contacts with Short Fiber Reinforced Polymers","authors":"Moritz Lengmüller, Enzo Maier, Thomas Lohner, Karsten Stahl","doi":"10.24053/tus-2023-0024","DOIUrl":"https://doi.org/10.24053/tus-2023-0024","url":null,"abstract":"Fiber-reinforced materials feature transversely isotropic elasticity. Although its influence on pressures, shapes, and sizes has been studied extensively for dry contacts, the transferability to lubricated contacts is fragmented. This numerical study investigates how the content and orientation of short fibers in fiber-reinforced polymers (FRP) affect elastohydrodynamic lubrication (EHL) of point contacts. Material properties are modeled with Tandon-Weng homogenization. For EHL modeling, a fully coupled approach based on finite element discretization is used. Results on hydrodynamic pressure and film thickness as well as material stress distribution are analyzed. It is shown that the combination of fiber content and orientation defines the effective contact stiffness that determines the contact shape, size, and film thickness. The following extended abstract is an excerpt from the publication “Effect of Transversely Isotropic Elasticity on Elastohydrodynamic Lubrication of Point Contacts” (https://doi.org/10.3390/polym14173507) that is based on the awarded thesis “Numerical Study on Anisotropic TEHL Contacts with Short Fiber Reinforced Polymers”)","PeriodicalId":53690,"journal":{"name":"Tribologie und Schmierungstechnik","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135814487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The determination of the fatigue life of rolling bearings is recommended to be conducted using the standard calculation models defined in ISO 281. These models yield reliable results for rotating applications. The standard models are continuously refined to align with advancements in bearing production processes and material improvements. However, when dealing with rolling bearings exposed to complex load conditions including oscillatory movements, as seen in rotor blade bearings in wind turbines, a validated calculation model has yet to be established. In the domain of structural mechanics, fatigue life evaluation for steel components is based on S-N curves. Variable operational loads are treated as load collective, and the load cycle to failure N under given operational conditions is determined through the application of the linear damage rule. This paper introduces a novel model that integrates the linear damage rule with established conventional bearing theories. Within one internal stress cycle, all rolling contacts are regarded as an internal load collective. To evaluate the internal load collective, the stress state at each rolling contact is assessed based on the S-N curve determined in alternating torsional loads. The core rationale behind the selection of an S-N curve lies in the stress criterion τo based on Lundberg-Palmgren theory, which is incorporated in the new model. This paper includes a comprehensive step-by-step procedure for applying the new model, utilizing the cylindrical roller bearing NU 1006 as a reference. The results of this study indicate a favorable agreement between the fatigue life obtained using the new model and those determined according to ISO 281. Furthermore, a new approach is introduced to analytically account for residual stress - es when measured values are available. In this study, by applying this new approach, the results were observed to be in close agreement with the test results. Based on this investigation, it can be confirmed that the new model has the potential to provide reliable results without necessitating the bearing life exponent as well as the correction factors often required in conventional calculation models.
{"title":"Fatigue life prediction of rolling bearings based on damage accumulation considering residual stresses","authors":"Jae-il Hwang, Gerhard Poll","doi":"10.24053/tus-2023-0021","DOIUrl":"https://doi.org/10.24053/tus-2023-0021","url":null,"abstract":"The determination of the fatigue life of rolling bearings is recommended to be conducted using the standard calculation models defined in ISO 281. These models yield reliable results for rotating applications. The standard models are continuously refined to align with advancements in bearing production processes and material improvements. However, when dealing with rolling bearings exposed to complex load conditions including oscillatory movements, as seen in rotor blade bearings in wind turbines, a validated calculation model has yet to be established. In the domain of structural mechanics, fatigue life evaluation for steel components is based on S-N curves. Variable operational loads are treated as load collective, and the load cycle to failure N under given operational conditions is determined through the application of the linear damage rule. This paper introduces a novel model that integrates the linear damage rule with established conventional bearing theories. Within one internal stress cycle, all rolling contacts are regarded as an internal load collective. To evaluate the internal load collective, the stress state at each rolling contact is assessed based on the S-N curve determined in alternating torsional loads. The core rationale behind the selection of an S-N curve lies in the stress criterion τo based on Lundberg-Palmgren theory, which is incorporated in the new model. This paper includes a comprehensive step-by-step procedure for applying the new model, utilizing the cylindrical roller bearing NU 1006 as a reference. The results of this study indicate a favorable agreement between the fatigue life obtained using the new model and those determined according to ISO 281. Furthermore, a new approach is introduced to analytically account for residual stress - es when measured values are available. In this study, by applying this new approach, the results were observed to be in close agreement with the test results. Based on this investigation, it can be confirmed that the new model has the potential to provide reliable results without necessitating the bearing life exponent as well as the correction factors often required in conventional calculation models.","PeriodicalId":53690,"journal":{"name":"Tribologie und Schmierungstechnik","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135814486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mass finishing is able to achieve tribological surface optimization through improved surface topography and a modified surface zone structure. The running-in behavior includes both topographical aspects and aspects of the formation of a third body. By means of surface finishing to different levels of roughness, the topographical run-in can be shortened and the formation of the third body can be influenced. Favorable running-in behavior is made possible by conditioning effects, for example in the structure, by a finishing process with a suitable input of frictional energy.
{"title":"Reibungsoptimierung durch Gleit- schleifen: Das Einlauf- und Reibverhalten über Topographie einstellen","authors":"Florian Reinle, Dominic Linsler","doi":"10.24053/tus-2023-0015","DOIUrl":"https://doi.org/10.24053/tus-2023-0015","url":null,"abstract":"Mass finishing is able to achieve tribological surface optimization through improved surface topography and a modified surface zone structure. The running-in behavior includes both topographical aspects and aspects of the formation of a third body. By means of surface finishing to different levels of roughness, the topographical run-in can be shortened and the formation of the third body can be influenced. Favorable running-in behavior is made possible by conditioning effects, for example in the structure, by a finishing process with a suitable input of frictional energy.","PeriodicalId":53690,"journal":{"name":"Tribologie und Schmierungstechnik","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47620527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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