Article
Engineering, Mechanical
Suhaib Ardah, Francisco J. Profito, Daniele Dini
Summary: This paper proposes an integrated finite-volume framework for solving thermal elasto-hydrodynamic lubrication problems and predicts the lubrication performance of non-conformal contacts. By considering fluid flow effects and thermal behavior, the framework is able to handle strong nonlinearity and improve convergence of the results.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Engineering, Mechanical
Haibin Wu, Constantine Khripin, Anand Jagota, Chung-Yuen Hui
Summary: It has been discovered that lubricated friction can be enhanced by the periodic variation of near-surface stiffness. In this study, we simulated the lubricated sliding of a rigid cylinder on a substrate with a periodic variation in mechanical stiffness. The results show that increasing the variation of near-surface stiffness can significantly increase the friction force. This research provides insight into the mechanism of friction enhancement and can guide the design of surfaces to control friction during lubricated sliding.
EXTREME MECHANICS LETTERS
(2022)
Article
Automation & Control Systems
Jiajia Zhao, Baobao Qi, Xianchun Song, Hongkui Jiang, Pengfei Dong
Summary: Ball screw is a key functional component commonly used in actuators of high-end machine tools, known for its high transmission efficiency, low environmental impact, and strong universality of working conditions. For high-precision ball screws, proper and constant preload is essential to maintain transmission accuracy and reliable dynamic characteristics. This paper proposes a calculation model of friction torque for ball screws based on the coupling of ball load distribution and thermal elastohydrodynamic lubrication, taking into account the contact elastic hysteresis friction and sliding friction. The study analyzes the influence of different friction terms on friction torque and establishes the coupling relationship among preload, rotational speed, and friction torque. The experimental results demonstrate the significance of the proposed method in improving internal preload and predicting precision degradation of ball screws.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2023)
Article
Engineering, Mechanical
Marko Polajnar, Benoit Thiebaut, Frederic Jarnias, Mitjan Kalin
Summary: The study investigates the effect of three different film-forming additives in PAO oil on EHD friction. Results show that these additives can either decrease or increase EHL friction, with surface energy being the most influential parameter. This suggests that the boundary films formed by additives play a crucial role in reducing EHL friction.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Haibin Wu, Chung -Yuen Hui, Anand Jagota
Summary: This paper investigates the problems in elasto-hydrodynamic lubrication when one of the contacting bodies is elastically soft. A numerical method is developed to solve both normal indentation and transient sliding lubrication problems, avoiding the difficulties of converging iterative methods.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
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
Materials Science, Multidisciplinary
Yoon-Seok Lee, Shunnosuke Yamagishi, Masataka Tsuro, Changwook Ji, Seungchan Cho, Yangdo Kim, Moonhee Choi
Summary: This study investigated the wear behavior and lubrication effect of AISI304 stainless steel under different lubrication conditions using a block-on-disk wear test. It was found that the oil lubrication demonstrated the best lubricating effect with unique chip-like debris. The observation of strain-induced martensitic (SIM) transformation after the wear test and the influence of lubrication regimes on wear behavior were significant findings from this study.
Article
Engineering, Mechanical
G. Boidi, P. G. Gruetzmacher, A. Kadiric, F. J. Profito, I. F. Machado, C. Gachot, D. Dini
Summary: This study demonstrated the potential of fast laser texturing techniques in improving the tribological performance of bearings and mechanical components. Dimples were found to reduce friction effectively compared to smooth surfaces, while grooves had less beneficial effects. Additionally, dimples promoted the formation of full film lubrication conditions at lower speeds.
Article
Chemistry, Physical
Samuel E. Solomon, Pierce Doubleday, Jared Landry, Vijay T. John, Noshir S. Pesika
Summary: Carbon microspheres can reduce friction and surface wear at low speeds and high loads. The size of the carbon microspheres and the lubrication gap determine the dominant lubrication mechanism in dilute colloidal lubricating systems.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Multidisciplinary Sciences
Yanzhong Wang, Kai Yang, Xiaomeng Chu, Wen Tang, Changyong Huang
Summary: An engineering calculation model is introduced to analyze point-contact elastohydrodynamic lubrication of spiral bevel gears, revealing the transient lubrication characteristics and film thickness variations during the meshing process.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Multidisciplinary
Akepati Bhaskar Reddy, Bulat Munavirov, Georgia A. Pilkington, Gabriel Calderon Salmeron, Mark W. Rutland, Sergei Glavatskih
Summary: The study revealed that higher dissociation of orthoborate ILs in biodegradable oil allows the formation of stable ionic boundary films, reducing friction and providing better wear protection; while phosphate and phosphinate ILs exhibit lower dissociation in biodegradable oil, resulting in increased friction and more severe wear.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2021)
Article
Nanoscience & Nanotechnology
Tom Reddyhoff, James P. Ewen, Pushkar Deshpande, Mark D. Frogley, Mark D. Welch, Wren Montgomery
Summary: Simple n-alcohols exhibit anomalous film-forming and friction behaviors under elastohydrodynamic lubrication (EHL) conditions. Liquid 1-dodecanol undergoes pressure-induced solidification in EHL contacts, forming different solid polymorphs with varying friction properties. A polymorph of 1-dodecanol at moderate temperature and pressure exhibits robust macroscale superlubricity, facilitated by the formation of lamellar, hydrogen-bonded structures promoting interlayer sliding.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Marvelucia Almeida, Flavia Bastos, Sara Vecchio
Summary: This article presents a mathematical and computational model to analyze sliding friction in lubricated contact between bearing surfaces using a realistic 3D model on a microscopic scale. The fluid-structure interaction model evaluates the effects of lubricant film thickness on friction in hydrodynamic and mixed lubrication regimes. Higher contact pressures were observed at the peaks of asperities, particularly during mixed lubrication where the fluid volume is smaller. The calculated friction coefficients, obtained through a homogenization procedure of shear and normal forces in hydrodynamic and mixed lubrication, were accurate and fell within the range specified in the Stribeck curve. The results demonstrate the capability of the computational model to examine the effects of lubrication on rough surface contact.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Mechanical
Jacopo Tacconi, Shahrokh Shahpar, Andrew King, Johannes Paulus Olufeagba, Raymarn Khan, Ian Sant, Martin Yates
Summary: Gear pumps are widely used in aero-engine fuel systems, and the design and analysis of hybrid journal bearings used in these pumps pose challenges. A numerical model has been developed to evaluate and design the pressure distribution of hybrid journal bearings for fuel pump applications. The tool has been validated and shows good accuracy and robustness.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Manufacturing
Tiewei Sun, Min Wang, Xiangsheng Gao, Yingjie Zhao
Summary: In this paper, a transmission efficiency model for double-nut ball screws considering kinematic analysis and lubrication status is proposed. The effectiveness and correctness of the model are verified through experimental testing.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART B-JOURNAL OF ENGINEERING MANUFACTURE
(2023)
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
Engineering, Mechanical
Pontus Johansson, Par Marklund, Marcus Bjorling, Yijun Shi
Summary: The tribological performance of carbon fiber reinforced PTFE composites sliding in a dry nitrogen environment is sensitive to changes in humidity and the counterface material, with the humidity effect reaching up to about 40% on the coefficient of friction and specific wear rate.
TRIBOLOGY INTERNATIONAL
(2021)
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
Jing Hua, Marcus Bjorling, Roland Larsson, Yijun Shi
Summary: Research shows that the properties of green lubricants can be influenced by the content of CO2 and water, resulting in changes in viscosity and friction. Therefore, by adjusting the CO2 and water content, the performance of the lubricant can be controlled.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Engineering, Chemical
Yinhu Xi, Marcus Bjorling, Andreas Almqvist
Summary: This work proposes a numerical model for three-dimensional rolling contact problems with one or two elastic layers, considering various creepages and employing the conjugate gradient method and the FFT technique for calculation efficiency. The numerical results are validated against existing results, showing significant modifications in traction and stick/slip results by adjusting layer parameters, which may be useful for improving rolling contact fatigue and mitigating wear problems in various mechanical systems.
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
Chemistry, Multidisciplinary
Jun Chen, Zhenyang Luo, Rong An, Par Marklund, Marcus Bjorling, Yijun Shi
Summary: This article discusses an intrinsic self-healing material, poly-silicone-urea, for the development of passive de-icing coatings to address the problems associated with traditional coatings. The material exhibits close to 99% self-healing efficiency and super low ice adhesion force, making it suitable for various practical applications and providing a new direction for future sustainable anti-icing and de-icing technologies.
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
Chemistry, Physical
V. Fadaei Naeini, M. Bjorling, J. A. Larsson, R. Larsson
Summary: This study investigates the viscosity of pure glycerol under high pressures and strain rates using molecular dynamics simulations. The results obtained by different methods are compared, and the evolution of glycerol viscosity with pressure and strain rate is ultimately achieved by combining experimental data with simulation results.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Nanoscience & Nanotechnology
Jun Chen, Par Marklund, Marcus Bjorling, Yijun Shi
Summary: Ice accumulation has a severe impact on social systems, and there is an urgent need for the development of durable anti-icing technologies. This research successfully formulated a hydrophobic coating based on graphene, which demonstrated excellent anti-icing properties in comprehensive field tests. The coating's micro-nano structure and semi-interpenetrating structure ensured its strength and hydrophobic behavior.
JOURNAL OF SCIENCE-ADVANCED MATERIALS AND DEVICES
(2023)
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
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
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
Multidisciplinary Sciences
Pontus Johansson, Kalle Kalliorinne, Par Marklund, Marcus Bjorling
Summary: Research in tribology often requires climate chambers for testing to replicate real environmental conditions. This study developed a humidity controlling system to accurately monitor and control humidity levels during testing, as humidity significantly affects the tribological performance of materials and lubricants. The climate controller was validated and offers a simple and cost-effective solution for humidity control in climate chambers.
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)