Sportswear is widely used in various sports and serves multiple functions. A key feature is the ability to absorb sweat during physical activity, which can, however, cause discomfort due to stickiness. This study focuses specifically on the stickiness caused by sweat between sportswear and the skin by objectively evaluating stickiness using specific physical parameters and correlating them with sensory evaluation values. Moreover, there is little research on the adhesion force between sportswear and human skin. Therefore, this study aims to achieve the following objectives: (1) investigate the relationship between the adhesion force between human skin and fabrics and the sensation of stickiness; (2) examine the relationship between the adhesion force between artificial skin and fabric and that between human skin and fabric; and (3) clarify the impact of fabric wettability and geometry on the adhesion force under wet conditions. Experiments reveal that the sensory evaluation value and adhesion force against human skin corresponded. Additionally, a positive correlation was found between the adhesion force against human skin and an artificial skin sheet. These experimental results suggest that fabrics with a lower adhesion force can be achieved by decreasing the load area ratio at 30% Φ0.3 and increasing the contact angle and meniscus height.
{"title":"Influences of Wettability and Geometry on Adhesion Force between Sportswear Fabric and Human/Artificial Skin","authors":"Toshiaki Nishi, Atsushi Matsumura, Manami Koshida, Tatsufumi Matsumoto, Takeshi Yamaguchi","doi":"10.2474/trol.18.353","DOIUrl":"https://doi.org/10.2474/trol.18.353","url":null,"abstract":"Sportswear is widely used in various sports and serves multiple functions. A key feature is the ability to absorb sweat during physical activity, which can, however, cause discomfort due to stickiness. This study focuses specifically on the stickiness caused by sweat between sportswear and the skin by objectively evaluating stickiness using specific physical parameters and correlating them with sensory evaluation values. Moreover, there is little research on the adhesion force between sportswear and human skin. Therefore, this study aims to achieve the following objectives: (1) investigate the relationship between the adhesion force between human skin and fabrics and the sensation of stickiness; (2) examine the relationship between the adhesion force between artificial skin and fabric and that between human skin and fabric; and (3) clarify the impact of fabric wettability and geometry on the adhesion force under wet conditions. Experiments reveal that the sensory evaluation value and adhesion force against human skin corresponded. Additionally, a positive correlation was found between the adhesion force against human skin and an artificial skin sheet. These experimental results suggest that fabrics with a lower adhesion force can be achieved by decreasing the load area ratio at 30% Φ0.3 and increasing the contact angle and meniscus height.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"37 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135809047","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}
High-strength brass is commonly used to produce sliding parts; however, its wear resistance should be further improved to extend the service life and performance of machinery and equipment constructed using this material. In this study, friction stir processing (FSP), a technology based on friction stir welding, was used to improve the wear resistance of high-strength brass. Because the application of FSP requires subsequent finishing operations on the workpiece, milling and wire electrical discharge machining (WEDM) have been implemented and their effects on the surfaces modified by FSP were investigated. FSP refined the crystal grains, resulting in improved hardness from 240 to 300 HV. Sliding tests were conducted to evaluate the friction and wear properties under three conditions: without FSP, with FSP and milling, and with FSP and WEDM. After applying FSP and milling, the wear amount decreased by 15%, in other words, the wear resistance improved compared with that observed without FSP. With FSP and WEDM, the wear resistance did not improve.
{"title":"Improvement of Wear Resistance of High-Strength Brass by Friction Stir Processing","authors":"Masaya Hirukawa, Shouhei Kawada, Masaaki Miyatake, Shinya Sasaki","doi":"10.2474/trol.18.417","DOIUrl":"https://doi.org/10.2474/trol.18.417","url":null,"abstract":"High-strength brass is commonly used to produce sliding parts; however, its wear resistance should be further improved to extend the service life and performance of machinery and equipment constructed using this material. In this study, friction stir processing (FSP), a technology based on friction stir welding, was used to improve the wear resistance of high-strength brass. Because the application of FSP requires subsequent finishing operations on the workpiece, milling and wire electrical discharge machining (WEDM) have been implemented and their effects on the surfaces modified by FSP were investigated. FSP refined the crystal grains, resulting in improved hardness from 240 to 300 HV. Sliding tests were conducted to evaluate the friction and wear properties under three conditions: without FSP, with FSP and milling, and with FSP and WEDM. After applying FSP and milling, the wear amount decreased by 15%, in other words, the wear resistance improved compared with that observed without FSP. With FSP and WEDM, the wear resistance did not improve.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"236 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135809051","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}
In the future, sustainability and CO2 neutrality requirements will come from both customers and regulatory compliance. Each company should provide the greatest possible transparency regarding its sustainability efforts. In addition to the Footprint, the Handprint has to be considered, which can have a significant positive impact on sustainability during the product’s life span, including its development and production processes. In the case of dynamic seals, the reduction of friction, i.e., the optimization of the tribological system, makes a significant contribution to the Handprint. Based on this insight, a pressure rotary shaft seal has been developed with a specific sealing edge profile that reduces friction and wear, and thus increasing energy efficiency and service life.
{"title":"Carbon Footprint vs. Handprint of Dynamic Sealing Systems","authors":"Eberhard Bock, Ruth Bieringer","doi":"10.2474/trol.18.275","DOIUrl":"https://doi.org/10.2474/trol.18.275","url":null,"abstract":"In the future, sustainability and CO2 neutrality requirements will come from both customers and regulatory compliance. Each company should provide the greatest possible transparency regarding its sustainability efforts. In addition to the Footprint, the Handprint has to be considered, which can have a significant positive impact on sustainability during the product’s life span, including its development and production processes. In the case of dynamic seals, the reduction of friction, i.e., the optimization of the tribological system, makes a significant contribution to the Handprint. Based on this insight, a pressure rotary shaft seal has been developed with a specific sealing edge profile that reduces friction and wear, and thus increasing energy efficiency and service life.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"236 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135809052","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":"Dimensionless Numbers and Master Curves for Sliding Friction from the Kelvin-Voigt Viscoelasticity of Solids","authors":"Toshiki Watanabe, Shintaro Hatanaka, Ken Nakano","doi":"10.2474/trol.18.406","DOIUrl":"https://doi.org/10.2474/trol.18.406","url":null,"abstract":"","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"127 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135871794","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}
Samsul Mahmood, Emily Guo, Amanda Stirling, Kyle D. Schulze
Additive manufacturing is rapidly growing in popularity for manufacturing parts with tunable mechanical properties. Recent studies show that mechanical properties can be achieved by controlling the layer orientation and build structure. In this work the effect of print orientation on tribological properties of 3D printed PLA and ABS are investigated. PLA and ABS samples are printed using fused deposition modeling (FDM) with three different print orientations. Tribological results show that variation in build direction relative to the sliding direction causes anisotropy in wear properties. The best wear properties are achieved with the samples printed where the layers remain orthogonal to the sliding direction. The coefficient of friction remains mostly unaffected by print orientation. PLA samples demonstrate significantly better tribological properties compared to ABS. Varying the sliding speed between the interacting surfaces also affects the wear properties of both PLA and ABS. The results suggest that optimizing the build orientation can improve the wear performance of additively manufactured thermoplastics. This enables an additional paradigm when designing for functionally graded materials.
{"title":"Orientation Controls Tribological Performance of 3D-Printed PLA and ABS","authors":"Samsul Mahmood, Emily Guo, Amanda Stirling, Kyle D. Schulze","doi":"10.2474/trol.18.302","DOIUrl":"https://doi.org/10.2474/trol.18.302","url":null,"abstract":"Additive manufacturing is rapidly growing in popularity for manufacturing parts with tunable mechanical properties. Recent studies show that mechanical properties can be achieved by controlling the layer orientation and build structure. In this work the effect of print orientation on tribological properties of 3D printed PLA and ABS are investigated. PLA and ABS samples are printed using fused deposition modeling (FDM) with three different print orientations. Tribological results show that variation in build direction relative to the sliding direction causes anisotropy in wear properties. The best wear properties are achieved with the samples printed where the layers remain orthogonal to the sliding direction. The coefficient of friction remains mostly unaffected by print orientation. PLA samples demonstrate significantly better tribological properties compared to ABS. Varying the sliding speed between the interacting surfaces also affects the wear properties of both PLA and ABS. The results suggest that optimizing the build orientation can improve the wear performance of additively manufactured thermoplastics. This enables an additional paradigm when designing for functionally graded materials.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"37 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135809044","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}
Noor Ayuma Mat Tahir, Shahira Liza Kamis, Kanao Fukuda, Hiroki Akasaka
{"title":"Reducing Friction of Diamond-Like Carbon Film in Sliding through Fluorine Doping","authors":"Noor Ayuma Mat Tahir, Shahira Liza Kamis, Kanao Fukuda, Hiroki Akasaka","doi":"10.2474/trol.18.396","DOIUrl":"https://doi.org/10.2474/trol.18.396","url":null,"abstract":"","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"5 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135927909","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}
Connor Bovia, Griffin Gleeson, Lauren Buckley, Morgan Platz, Meagan B. Elinski
Nanoparticles are promising candidates as direct therapeutics and delivery systems for osteoarthritis treatments, primarily via intraarticular injection, but little is known about the impact on sliding behavior for a soft material surface like cartilage that would be encountered in a joint. Nanoparticle additives have primarily been studied in the context of hard material interfaces, such as metals or metal oxides, where different lubricating or anti-wear mechanisms depend sensitively on chemical composition, size, and concentration. To understand what nanoparticle parameters influence in situ (in a fluid environment) frictional behavior of soft materials, polyacrylamide (PAM) hydrogels were used as a model soft material platform. Friction tests were conducted in a rheometer with a tribology adapter, with PAM hydrogels molded in a petri dish and immersed in different nanoparticle containing fluid environments. A range of nanoparticle compositions were selected to compare broad categories: gold (metal) with a citrate capping ligand, nanodiamond (carbon), and zirconium dioxide (metal oxide). Comparing surface chemistry, concentration, and degree of aggregation, both nanoparticle surface chemistry and nanoparticle solution viscosity were found to modulate in situ hydrogel friction.
{"title":"Influence of Nanoparticle Chemical Composition on <i>In Situ</i> Hydrogel Friction","authors":"Connor Bovia, Griffin Gleeson, Lauren Buckley, Morgan Platz, Meagan B. Elinski","doi":"10.2474/trol.18.424","DOIUrl":"https://doi.org/10.2474/trol.18.424","url":null,"abstract":"Nanoparticles are promising candidates as direct therapeutics and delivery systems for osteoarthritis treatments, primarily via intraarticular injection, but little is known about the impact on sliding behavior for a soft material surface like cartilage that would be encountered in a joint. Nanoparticle additives have primarily been studied in the context of hard material interfaces, such as metals or metal oxides, where different lubricating or anti-wear mechanisms depend sensitively on chemical composition, size, and concentration. To understand what nanoparticle parameters influence in situ (in a fluid environment) frictional behavior of soft materials, polyacrylamide (PAM) hydrogels were used as a model soft material platform. Friction tests were conducted in a rheometer with a tribology adapter, with PAM hydrogels molded in a petri dish and immersed in different nanoparticle containing fluid environments. A range of nanoparticle compositions were selected to compare broad categories: gold (metal) with a citrate capping ligand, nanodiamond (carbon), and zirconium dioxide (metal oxide). Comparing surface chemistry, concentration, and degree of aggregation, both nanoparticle surface chemistry and nanoparticle solution viscosity were found to modulate in situ hydrogel friction.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"37 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135809046","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}
This study proposes a mathematical expression for the high-viscosity surface layer generated by the confinement of a lubricant film, which is evident in engine oil with a metallic detergent additive. The characteristics of a microtapered pad bearing lubricated by a confined high-viscosity film were clarified by solving a modified Reynolds equation for the confined high-viscosity lubricant film. The load capacity began to increase compared with that in the bulk viscosity case when the trailing gap decreased from twice the saturated high-viscosity layer thickness. The maximum value of the friction coefficient at the trailing gap near the layer thickness becomes remarkable compared with the case of the adsorbed high-viscosity layer model. Assuming that the increased effective viscosity caused by the confinement of the lubricant film is due to an adsorbed high-viscosity layer, the load capacity is significantly overestimated when the trailing gap is greater than the saturated high-viscosity layer thickness. Next, a mathematical expression of the synthetic viscosity of a lubricant with a polar additive having an adsorbed high-viscosity surface layer and a metallic detergent additive with a confined high-viscosity layer was proposed, and the characteristics of the microtapered pad bearings lubricated by the composite lubricant were investigated.
{"title":"Modified Reynolds Equation for Confined High Viscosity Film Lubrication and Lubrication Analysis of Micro-Tapered Pad Bearing","authors":"Kyosuke Ono","doi":"10.2474/trol.18.330","DOIUrl":"https://doi.org/10.2474/trol.18.330","url":null,"abstract":"This study proposes a mathematical expression for the high-viscosity surface layer generated by the confinement of a lubricant film, which is evident in engine oil with a metallic detergent additive. The characteristics of a microtapered pad bearing lubricated by a confined high-viscosity film were clarified by solving a modified Reynolds equation for the confined high-viscosity lubricant film. The load capacity began to increase compared with that in the bulk viscosity case when the trailing gap decreased from twice the saturated high-viscosity layer thickness. The maximum value of the friction coefficient at the trailing gap near the layer thickness becomes remarkable compared with the case of the adsorbed high-viscosity layer model. Assuming that the increased effective viscosity caused by the confinement of the lubricant film is due to an adsorbed high-viscosity layer, the load capacity is significantly overestimated when the trailing gap is greater than the saturated high-viscosity layer thickness. Next, a mathematical expression of the synthetic viscosity of a lubricant with a polar additive having an adsorbed high-viscosity surface layer and a metallic detergent additive with a confined high-viscosity layer was proposed, and the characteristics of the microtapered pad bearings lubricated by the composite lubricant were investigated.","PeriodicalId":23314,"journal":{"name":"Tribology Online","volume":"236 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135809049","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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