Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
82,882
result(s) for
"Lubrication"
Sort by:
A Review of Mixed Lubrication Modelling and Simulation
Majority of the rolling contacts applied in complex interacting machine elements for example bearings and gears perform under Mixed Lubricating (ML) conditions, where the lubricant film can’t fully separate the asperities of the two contacting surfaces. Highly loaded, interacting asperity surrounded with lubricant film, leads to the development of surface originated defects such as scuffing, micropitting, and wear in the ML region. This region exists amid Elastohydrodynamic Lubrication and Boundary Lubrication which needs consolidated knowledge of fluid film and direct contact of asperities, this makes the problem more difficult to solve numerically. Numerous authors have used the Reynolds equation or its modified versions to solve the lubrication problem numerically. However, still, some uncertainty is there to model mixed lubrication operating conditions, with traditional Reynold’s equation, because the assumptions commonly made in Elastohydrodynamic lubrication are not valid within the context of mixed lubrication regime. In this paper previously, used models for mixed lubrication have been examined, and various development in related fields are discussed. Therefore, this review will provide an integrated, synthesized overview of the topic and in turn will lead to benefits for wide-ranging academic, industrial and research communities.
Journal Article
Sustainable lubrication
\"This book overviews recent advances in the development of lubricants and their usage in different tribological systems, starting from nanoscale contacts up to macroscale assemblies with specific focus on sustainable green lubrication choices including base fluids. Further, it covers advances and optimization of new type of lubrication systems according to their usage in various tribological systems as gears, bearings, micro-electromechanical systems, and production equipment. Furthermore, the few examples and case studies about utilization of synthetic lubricants in bearings, gears, dental and so forth has been included. Features: explores information on the present and future of sustainable lubricants due to its accelerated demands in industries, provides conceptual overview of lubricant application in manufacturing and automobile industries, discusses lubricants used in the micro-electromechanical systems (MEMS), nano-electromechanical systems (NEMS), tribo-systems under extreme conditions and for biomedical applications, and reviews information about various types of additives and their role in lubricants, and their cost effectiveness. This text also includes case studies related to journal-bearing/gear drive systems. Finally, this shortform book is geared towards students and researchers in mechanical engineering, automobile engineering, chemical engineering and chemistry, manufacturing, mechanical, materials and metallurgy\"-- Provided by publisher.
Book
Minimum quantity lubrication machining nickel base alloy: a comprehensive review
Nickel-based alloys have great application value in aerospace, biomedical industry, chemical industry, and other fields. However, nickel-based alloys are known to be difficult to process, which will generate a lot of heat and friction during processing, which limits the application range of nickel-based alloys. Therefore, a large amount of cutting fluid needs to be used during processing, and the cutting fluid will cause harm to human health and the environment. In order to solve these problems, scholars proposed to use the minimum quantity lubrication (MQL) to replace the conventional flood cooling lubrication technique. Recently, many papers have proposed to use MQL for lubrication /cooling in the processing of nickel-based alloys. However, few studies have approached this topic comprehensively. To bridge this gap, this study conducts a comprehensive literature review of the progress made in the processing of nickel-based alloys using various MQL methods. It should be noted that these studies are divided into four categories: vegetable oil-based MQL, cryogenic cooling-based MQL, solid lubricant-based MQL, and electrostatic atomization-based MQL. It is crucial to compare the advantages of these cooling and lubricating technologies in machining nickel-based alloys, analyze their experimental results, and assess their impact on machining quality and tool wear. This review reveals that compared to traditional MQL, vegetable oil-based MQL is more energy-saving and environmentally friendly, resulting in approximately 30% improvement in surface quality and a 50% reduction in tool wear. The addition of solid lubricants to vegetable oil further enhances its lubrication performance. Cryogenic cooling-based MQL enables the attainment of finer grains and smaller sawtooth chips. Electrostatic atomization MQL, by altering the atomization process of traditional MQL, produces more uniform droplets, leading to a 42.4% reduction in tool wear and a 47% improvement in machined surface quality. The purpose of this paper is to help researchers identify existing gaps and to enable MQL to improve the processing quality and application range of nickel-based alloys. Finally, the present technical challenges and future research directions are put forward.
Journal Article
All aboard! : Elijah McCoy's steam engine
Simple text and illustrations explore the life of inventor, Elijah McCoy. Includes explanation of the saying, \"The real McCoy.\"
Book
Unlocking the secrets behind liquid superlubricity: A state-of-the-art review on phenomena and mechanisms
Superlubricity, the state of ultralow friction between two sliding surfaces, has become a frontier subject in tribology. Here, a state-of-the-art review of the phenomena and mechanisms of liquid superlubricity are presented based on our ten-year research, to unlock the secrets behind liquid superlubricity, a major approach to achieve superlubricity. An overview of the discovery of liquid superlubricity materials is presented from five different categories, including water and acid-based solutions, hydrated materials, ionic liquids (ILs), two-dimensional (2D) materials as lubricant additives, and oil-based lubricants, to show the hydrodynamic and hydration contributions to liquid superlubricity. The review also discusses four methods to further expand superlubricity by solving the challenge of lubricants that have a high load-carrying capacity with a low shear resistance, including enhancing the hydration contribution by strengthening the hydration strength of lubricants, designing friction surfaces with higher negative surface charge densities, simultaneously combining hydration and hydrodynamic contribution, and using 2D materials (e.g., graphene and black phosphorus) to separate the contact of asperities. Furthermore, uniform mechanisms of liquid superlubricity have been summarized for different liquid lubricants at the boundary, mixed, and hydrodynamic lubrication regimes. To the best of our knowledge, almost all the immense progresses of the exciting topic, superlubricity, since the first theoretical prediction in the early 1990s, focus on uniform superlubricity mechanisms. This review aims to guide the research direction of liquid superlubricity in the future and to further expand liquid superlubricity, whether in a theoretical research or engineering applications, ultimately enabling a sustainable state of ultra-low friction and ultra-low wear as well as transformative improvements in the efficiency of mechanical systems and human bodies.
Journal Article
Molecular dynamics simulation of the Stribeck curve: Boundary lubrication, mixed lubrication, and hydrodynamic lubrication on the atomistic level
Lubricated contact processes are studied using classical molecular dynamics simulations for determining the entire range of the Stribeck curve. Therefore, the lateral movement of two solid bodies at different gap height are studied. In each simulation, a rigid asperity is moved at constant height above a flat iron surface in a lubricating fluid. Both methane and decane are considered as lubricants. The three main lubrication regimes of the Stribeck curve and their transition regions are covered by the study: Boundary lubrication (significant elastic and plastic deformation of the substrate), mixed lubrication (adsorbed fluid layer dominates the process), and hydrodynamic lubrication (shear flow is set up between the surface and the asperity). We find the formation of a tribofilm in which lubricant molecules are immersed into the metal surface—not only in the case of scratching, but also for boundary lubrication and mixed lubrication. The formation of a tribofilm is found to have important consequences for the contact process. Moreover, the two fluids are found to show distinctly different behavior in the three lubrication regimes: For hydrodynamic lubrication (large gap height), decane yields a better tribological performance; for boundary lubrication (small gap height), decane shows a larger friction coefficient than methane, which is due to the different mechanisms observed for the formation of the tribofilm; the mixed lubrication regime can be considered as a transition regime between the two other regimes. Moreover, it is found that the nature of the tribofilm depends on the lubricant: While methane particles substitute substrate atoms sustaining mostly the crystalline structure, the decane molecules distort the substrate surface and an amorphous tribofilm is formed.
Journal Article
Review of Tribological Failure Analysis and Lubrication Technology Research of Wind Power Bearings
Wind power, being a recyclable and renewable resource, makes for a sizable portion of the new energy generation sector. Nonetheless, the wind energy industry is experiencing early failure of important components of wind turbines, with the majority of these issues also involving wind power bearings. Bearing dependability is directly tied to the transmission efficiency and work performance of wind turbines as one of its major components. The majority of wind turbine failures are due to bearings, and the vast majority of bearing failures are due to lubrication. The topic of improving the accuracy and life of wind power bearing motion is becoming increasingly essential as the wind power industry develops rapidly. This study examines the various constructions and types of wind turbines, as well as their bearings. We also examined the most typical causes of friction and lubrication failure. Furthermore, contemporary research on wind turbine bearings has been compiled, which mostly comprises the study and development of lubrication technology and other areas. Finally, a conclusion and outlook on current challenges, as well as future research directions, are offered.
Journal Article
On the Elastohydrodynamic Film-Forming Properties of Metalworking Fluids and Oil-in-Water Emulsions
Oil-in-water (O/W) emulsions are water-based lubricants and used as fire-resistant hydraulic fluids and metalworking fluids (MWFs) in industry. The (elasto-)hydrodynamic film-forming properties of O/W emulsions have been studied extensively in literature. Typical elastohydrodynamic lubrication (EHL) behaviors are revealed at low rolling speeds followed by a starved EHL regime at elevated speeds. These emulsions are self-prepared and mostly stable only for a limited time ranging from hours to several days. By contrast, the film-forming behavior of water-miscible commercial MWFs (long-term stable O/W emulsions) has rarely been reported. This restricts the understanding of the lubrication status of many tribological interfaces in manufacturing processes, e.g., the chip-tool contact in cutting. In this work, the (elasto-)hydrodynamic film-forming property of two commercial MWFs is investigated by measuring the film thickness on two ball-on-disc test rigs using different optical interferometry techniques. For comparison, two self-prepared simple O/W emulsions with known formulation have also been investigated. Experimental results from the two test rigs agree well and show that the two self-prepared emulsions have typical EHL behaviors as reported in literature. However, for the two commercial MWFs, there is almost no (elasto-)hydrodynamic film-forming ability over the whole range of speeds used in this study. This could be explained by the cleaning and re-emulsification effects of the MWFs. The lubrication mechanism of the two MWFs is mainly boundary lubrication rather than hydrodynamic lubrication.
Graphical Abstract
Journal Article
Review of the evolution and prevention of friction, wear, and noise for water-lubricated bearings used in ships
With the development of green tribology in the shipping industry, the application of water lubrication gradually replaces oil lubrication in stern bearings and thrust bearings. In terms of large-scale and high-speed ships, water-lubricated bearings with high performance are more strictly required. However, due to the lubricating medium, water-lubricated bearings have many problems such as friction, wear, vibration, noise, etc. This review focuses on the performance of marine water-lubricated bearings and their failure prevention mechanism. Furthermore, the research of marine water-lubricated bearings is reviewed by discussing its lubrication principle, test technology, friction and wear mechanism, and friction noise generation mechanism. The performance enhancement methods have been overviewed from structure optimization and material modification. Finally, the potential problems and the perspective of water-lubricated bearings are given in detail.
Journal Article