Article
Materials Science, Multidisciplinary
Julio A. Cao-Romero-Gallegos, Leonardo Farfan-Cabrera, Jose Perez-Gonzalez, Benjamin M. Marin-Santibanez
Summary: This study analyzed the tribological and rheological behavior of mineral oil additivated with graphene nano-sheets as a lubricant, focusing on its potential application in automatic transmission systems. The addition of graphene nano-sheets made the lubricants non-Newtonian shear-thinning, increased viscosity at high shear rates, reduced wear rate for metallic interfaces, and enhanced the thermal stability and anti-shudder property of wet clutches.
Article
Engineering, Mechanical
Leonardo Israel Farfan-Cabrera, Ezequiel Alberto Gallardo-Hernandez, Manuel Vite-Torres, Jesus Gilberto Godinez-Salcedo
Summary: This study investigated the influence of ATF oxidation and sliding distance on the friction coefficients of a wet clutch. Results showed that ATF oxidation increased the friction coefficients of the wet clutch, while most cases saw a decrease in dμ/dυ values. Progressive sliding distance improved results when using fresh ATF, but decreased the slope when using aged ATF.
Article
Chemistry, Multidisciplinary
Liangjie Zheng, Biao Ma, Man Chen, Liang Yu, Qian Wang
Summary: This research investigates the influence of lubrication oil temperature on clutch disengaging dynamic characteristics through a comprehensive numerical model. It demonstrates that as the ATF temperature increases, the clutch disengaging duration shortens significantly and the uniformity of friction pairs varies. Additionally, the increase in ATF temperature accelerates the change of lubrication status between friction pairs and contributes to a decrease in contact torque and hydrodynamic torque.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Mechanical
Johannes Wirkner, Mirjam Baese, Astrid Lebel, Hermann Pflaum, Katharina Voelkel, Lukas Pointner-Gabriel, Charlotte Besser, Thomas Schneider, Karsten Stahl
Summary: The driving comfort and safety of the automotive powertrain are closely related to the performance and lifetime of the lubricant. This study investigates the performance loss of the lubricant caused by water contamination and iron particles, and evaluates their impact on user comfort.
Article
Engineering, Mechanical
Biao Ma, Qian Wang, Changsong Zheng, Liang Yu, Guoyu Wang, Liangjie Zheng
Summary: This study investigated the effect of ATF temperature on the dynamic friction-wear properties of the friction component in a wet multi-disc clutch during the running-in process. The results indicated that ATF temperature had a significant impact on the friction-wear performance in the clutch running-in process, highlighting the importance of selecting the optimal ATF temperature for improved performance.
INDUSTRIAL LUBRICATION AND TRIBOLOGY
(2022)
Article
Engineering, Mechanical
Daniel Strombergsson, Par Marklund, Kim Berglund
Summary: This study presents a dynamic simulation model to evaluate the vibrational response of rolling-element bearings with defects, optimizing the accelerometer positions. The results show an optimal position close to the primary loaded zone, with validation test rig experiments demonstrating reasonable qualitative agreement.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2021)
Article
Engineering, Chemical
Jonny Hansen, Marcus Bjorling, Roland Larsson
Summary: A new film parameter Lambda* was proposed in this study, taking into account the elasto-hydrodynamic lubrication effects induced by surface irregularities on the microscopic scale. The new model was validated through tribological tests and found to accurately predict the experimentally measured true mixed and full-film EHL regimes. The ability to accurately predict the mode of lubrication represents a major advance in designing tribological interfaces for optimal efficiency and durability.
Article
Chemistry, Multidisciplinary
Daniel Strombergsson, Par Marklund, Kim Berglund
Summary: This study explores the use of artificial neural networks to predict specific bearing failures in wind turbine gearbox failures by establishing a relationship between rotational speed and condition indicator values. By training with healthy data, the ANN is able to predict condition indicator values without the influence of failure, improving detection sensitivity for gearbox shaft bearing failures and previously undetected planet bearing failures.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Mechanical
Roland Larsson
Summary: The study of the lubrication mechanisms in the bouncing and impacting of a ball on an oily plate led to collaboration between myself and Professor Duncan Dowson. During a short visit to Leeds University as a PhD student, Duncan's guidance and connections with knowledgeable individuals in the field significantly contributed to my personal and scientific growth.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2021)
Article
Engineering, Mechanical
Maria Rodiouchkina, Jonna Lind, Leonardo Pelcastre, Kim Berglund, Asa Kassman Rudolphi, Jens Hardell
Summary: This study investigates the dry sliding behavior of fiber-reinforced thermosets and thermoplastics against stainless steel under typical hydropower conditions. Results show that the wear rates of both materials decrease significantly with time, with the thermoplastics exhibiting a decrease in coefficient of friction due to accelerated material transfer observed after 80 hours, while the fiber-reinforced thermoset shows its highest transfer amount after 20 hours. Surface analysis reveals severe abrasive wear of the counter surface caused by wear debris from steel and reinforcements in the material, accompanied by simultaneous increase in coefficient of friction for the thermoset. Crosssectional analysis indicates thinner transfer layers and higher wear of the steel in the middle of the wear tracks where sliding speed and load cycles are highest. These findings contribute to a more accurate interpretation of tribological performance of these materials, emphasizing the importance of counter surface material selection.
Article
Engineering, Mechanical
Maria Rodiouchkina, Henrik Lindsjo, Kim Berglund, Jens Hardell
Summary: The effect of stroke length on the tribological performance of polymer composites used for bearings in hydropower turbines was investigated. Results showed that increased stroke length led to higher wear rates, and different friction behaviors were observed for thermoset and thermoplastic materials. Surface analysis revealed more severe wear of the stainless-steel counter surface at longer stroke lengths.
Article
Engineering, Mechanical
Kalle Kalliorinne, Gustav Hinder, Joakim Sandberg, Roland Larsson, Hans-Christer Holmberg, Andreas Almqvist
Summary: In cross-country skiing races, slight reductions in aerodynamic drag and friction can determine the race outcome. The geometry of the ski greatly affects the friction between the skis and snow. By analyzing the normal force location corresponding to plantar pressure, the ski camber can be characterized while performing different tucking positions. It was found that leaning backwards in a tucking position reduces the risk of contact between kick wax and snow.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART P-JOURNAL OF SPORTS ENGINEERING AND TECHNOLOGY
(2023)
Article
Engineering, Mechanical
Kalle Kalliorinne, Joakim Sandberg, Gustav Hinder, Roland Larsson, Hans-Christer Holmberg, Andreas Almqvist
Summary: In cross-country skiing competitions, small changes in resistive forces can significantly affect the results, highlighting the importance of understanding and measuring frictional properties. Research has shown that combining Artificial Neural Networks and deterministic methods can effectively predict the ski-camber profile under loading conditions and its macro-scale contact characteristics with snow.
Article
Engineering, Mechanical
Kalle Kalliorinne, Bo N. J. Persson, Joakim Sandberg, Gustav Hinder, Roland Larsson, Hans-Christer Holmberg, Andreas Almqvist
Summary: In winter sports, the contact between equipment and snow or ice generates resistive force. The contact between skis and snow at different scales has been studied, showing that ski base textures with higher S-pk values have smaller real contact area and a rougher surface performs better at high speed by reducing viscous friction.
Article
Engineering, Electrical & Electronic
Marko Tosic, Roland Larsson, Karsten Stahl, Thomas Lohner
Summary: This study investigates the elastohydrodynamic lubrication (EHL) between nonconjugate meshing tooth flanks of a worm gear. The contact is characterized by a slender elliptical shape and high sliding. A validated numerical EHL model considering non-Newtonian, thermal, and transient effects is used to analyze the complete contact area of the worm gear. The study identifies and discusses the design factors that influence EHL film formation in worm gears.
Article
Engineering, Electrical & Electronic
Muhammad Ahmer, Fredrik Sandin, Par Marklund, Martin Gustafsson, Kim Berglund
Summary: The stochastic nature of grinding processes presents a challenge in predicting surface quality. This paper introduces a novel approach to predict the overall quality of individual parts and implement condition-based maintenance using sensors. The model trained with T-2 labels achieves over 94% accuracy in comparison to measured results, enabling reliable maintenance decision-making.
Article
Engineering, Mechanical
Jamal Choudhry, Roland Larsson, Andreas Almqvist
Summary: Wear is a complex phenomenon that is influenced by material and surface properties, operating conditions, and the surrounding environment. At the micro-scale, wear is the result of material removal due to plastic deformation and fracture. This study adopts a three-dimensional finite element model to simulate and investigate the main mechanisms of wear at the contacting asperities of a metal pair, taking into account thermal effects as well.
Article
Engineering, Mechanical
Maria Rodiouchkina, Kim Berglund, Fredrik Forsberg, Ilia Rodushkin, Jens Hardell
Summary: This study investigates the influence of stainless-steel counter surface roughness and lay on the tribological behavior of self-lubricating polymer composite bearings used in Kaplan turbines. The results show that overly smooth surfaces result in higher friction and wear of the counter surface, while rougher surfaces have a negative effect on the wear of the polymers.
Article
Engineering, Mechanical
Andre Rudnytskyj, Roland Larsson, Carsten Gachot
Summary: This study uses the finite element method and wear model to model the dry linear reciprocating block-on-flat wear experiment, and investigates the influence of block surface and alignment on the results. The changes in geometric shape and contact pressure are quantified using an extrapolation scheme.
Article
Engineering, Mechanical
Kim Berglund, Maria Rodiouchkina, Jens Hardell, Kalle Kalliorinne, Jens Johansson
Summary: The study aims to develop a novel reciprocating tribometer and test method that enables friction and wear tests under low-speed reciprocatory sliding with high contact pressures, and to evaluate the friction and wear performance of self-lubricating bearings for specific operating conditions found in Kaplan turbines.
Article
Engineering, Mechanical
Huiyi Yang, Yang Xu, Chao Xu
Summary: This study focuses on the impact of dry friction interfaces on the dynamics of jointed structures, particularly on the statistics of contact pressure distribution. Through experimental and simulation analysis, it is found that surface roughness and contact load have significant effects on contact area, contact stiffness, and mean contact pressure.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2024)
Article
Engineering, Mechanical
Guanglan Hu, Houfu Dai
Summary: The effect of metal coating on the machinability of cubic silicon carbide was investigated using molecular dynamics simulation. The results showed that the type of coating has a significant impact on cutting force, surface morphology, stress, and tool wear. Among the three metals studied, Cu coating had the greatest impact on improving cutting performance.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2024)
Article
Engineering, Mechanical
Yunfan Liu, Guozheng Ma, Lina Zhu, Cuihong Han, Zhen Li, Bin Zhang, Haichao Zhao, Haidou Wang, Shuying Chen
Summary: The service performance of coated self-lubricating spherical plain bearings can be improved by applying self-lubricating coatings, especially double-sided coatings. The presence of a large-area and complete mixed friction transfer film on the contact surfaces can cause a signal downstage before the signal mutation stage.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2024)
Article
Engineering, Mechanical
Yakup Artun, C. Oktay Azeloglu, Gokhan Taylan
Summary: This article investigates the tribological properties of polymer journal bearings, particularly focusing on radial journal bearings made from UHMWPE and POM materials with different surface qualities. The study examines the performance of these bearings under varying load and speed conditions, and analyzes the relationship between material and surface roughness in tribological performance.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2024)
