Tribosystem

Last updated

A tribosystem is a tribological system that consists of at least two contacting bodies and any environmental factor that affects their interaction. [1] Tribologists study tribological systems in detail, and devise tribological test procedures.

Contents

Definition

According to ASTM G40-17, a tribosystem is "any system that contains one or more triboelements, including all mechanical, chemical, and environmental factors relevant to tribological behavior." [2] Here, triboelement refers to "one of two or more solid bodies that comprise a sliding, rolling, or abrasive contact, or a body subjected to impingement or cavitation." [2]

More simply speaking, a tribosystem is a tribological system that consists of at least two contacting bodies, including the environment in which the interaction takes place. [1] The complete description of a tribosystem includes all relevant factors that govern the tribological behavior of the system. Thus, depending on the aim of the tribological analysis, the tribosystem boundary is flexible and can be drawn more or less widely.

Describing Tribosystems

The description of tribosystems is based on a detailed assessment of relevant system inputs, outputs and losses, as well as an overall description of the system structure. [3] The following table gives an overview.

Complete Description of a Tribosystem [3]
InputsOutputsLossesSystem Structure
  • load
  • velocity
  • temperature
  • duration
  • disturbances
  • ...
  • friction
  • wear
  • vibrations
  • ...
  • triboelements (incl. properties)
  • system kinematics
  • interactions of triboelements

Relevance

The complete description of a tribosystem is the first step when devising a tribological test procedure. Since tribological tests are often carried out on simplified model systems using standardized tribometers, a complete description of the tribosystem allows for tribological testing across different scales.

For example, if the tribological analysis aims to investigate a specific gear contact in a complex gearbox, exact knowledge of tribological inputs allows tribologists to devise a simplified test setup involving two gears only. Conversely, if the analysis aims to develop a new lubricant formulation for gearbox applications, a rough description of the gearbox-tribosystem allows to reduce testing to relevant system inputs. Thus, detailed knowledge of the tribosystem can significantly reduce the development effort for machines and lubricants.

Related Research Articles

A lubricant is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. The property of reducing friction is known as lubricity.

Motor oil Lubricant used for lubrication of internal combustion engines

Motor oil, engine oil, or engine lubricant is any one of various substances that consist of base oils enhanced with various additives, particularly antiwear additives, detergents, dispersants, and, for multi-grade oils, viscosity index improvers. Motor oil is used for lubrication of internal combustion engines. The main function of motor oil is to reduce friction and wear on moving parts and to clean the engine from sludge and varnish (detergents). It also neutralizes acids that originate from fuel and from oxidation of the lubricant (detergents), improves sealing of piston rings, and cools the engine by carrying heat away from moving parts.

Lubrication The presence of a material to reduce friction between two surfaces.

Lubrication is the process or technique of using a lubricant to reduce friction and wear and tear in a contact between two surfaces. The study of lubrication is a discipline in the field of tribology.

Wear Damaging, gradual removal or deformation of material at solid surfaces

Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical or chemical. The study of wear and related processes is referred to as tribology.

Tribology is the science and engineering of interacting surfaces in relative motion. It includes the study and application of the principles of friction, lubrication and wear. Tribology is highly interdisciplinary, drawing on many academic fields, including physics, chemistry, materials science, mathematics, biology and engineering. People who work in the field of tribology are referred to as tribologists.

Rolling-element bearing

A rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing rolling elements between two bearing rings called races. The relative motion of the races causes the rolling elements to roll with very little rolling resistance and with little sliding.

The following outline is provided as an overview of and topical guide to human–computer interaction:

Gear oil

Gear oil is a lubricant made specifically for transmissions, transfer cases, and differentials in automobiles, trucks, and other machinery. It is of a high viscosity and usually contains organosulfur compounds. Some modern automatic transaxles do not use a heavy oil at all but lubricate with the lower viscosity hydraulic fluid, which is available at pressure within the automatic transmission. Gear oils account for about 20% of the lubricant market.

Troubleshooting is a form of problem solving, often applied to repair failed products or processes on a machine or a system. It is a logical, systematic search for the source of a problem in order to solve it, and make the product or process operational again. Troubleshooting is needed to identify the symptoms. Determining the most likely cause is a process of elimination—eliminating potential causes of a problem. Finally, troubleshooting requires confirmation that the solution restores the product or process to its working state.

The viscosity index (VI) is an arbitrary, unit-less measure of a fluid's change in viscosity relative to temperature change. It is mostly used to characterize the viscosity-temperature behavior of lubricating oils. The lower the VI, the more the viscosity is affected by changes in temperature. The higher the VI, the more stable the viscosity remains over temperature fluctuations. The VI was originally measured on a scale from 0 to 100; however, advancements in lubrication science have led to the development of oils with much higher VIs.

Grease is a solid or semisolid lubricant formed as a dispersion of thickening agents in a liquid lubricant. Grease generally consists of a soap emulsified with mineral or vegetable oil.

Oil analysis (OA) is the laboratory analysis of a lubricant's properties, suspended contaminants, and wear debris. OA is performed during routine predictive maintenance to provide meaningful and accurate information on lubricant and machine condition. By tracking oil analysis sample results over the life of a particular machine, trends can be established which can help eliminate costly repairs. The study of wear in machinery is called tribology. Tribologists often perform or interpret oil analysis data.

Condition monitoring is the process of monitoring a parameter of condition in machinery, in order to identify a significant change which is indicative of a developing fault. It is a major component of predictive maintenance. The use of condition monitoring allows maintenance to be scheduled, or other actions to be taken to prevent consequential damages and avoid its consequences. Condition monitoring has a unique benefit in that conditions that would shorten normal lifespan can be addressed before they develop into a major failure. Condition monitoring techniques are normally used on rotating equipment, auxiliary systems and other machinery, while periodic inspection using non-destructive testing (NDT) techniques and fit for service (FFS) evaluation are used for static plant equipment such as steam boilers, piping and heat exchangers.

Tribometer Instrument that measures tribological quantities

A tribometer is an instrument that measures tribological quantities, such as coefficient of friction, friction force, and wear volume, between two surfaces in contact. It was invented by the 18th century Dutch scientist Musschenbroek

A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and expressed in its functioning. Systems are the subjects of study of systems theory and other systems sciences.

Package testing

Package testing or packaging testing involves the measurement of a characteristic or property involved with packaging. This includes packaging materials, packaging components, primary packages, shipping containers, and unit loads, as well as the associated processes.

Space tribology is a discipline in the field of tribology which deals with tribological systems for spacecraft applications. Research in the field aims to design reliable tribological systems that can withstand the harsh environment of space.

Tribotronics is an area of research that combines machine elements and electronic components to create active tribological systems. This is achieved through continuous monitoring and adjustment of tribosystems, resulting in increased machine efficiency and lifetime.

Open System Tribology is a field of tribology that studies tribological systems that are exposed to and affected by the natural environment.

Extreme tribology refers to tribological situations under extreme operating conditions which can be related to high loads and/or temperatures, or severe environments. Also, they may be related to high transitory contact conditions, or to situations with near-impossible monitoring and maintenance opportunities. In general, extreme conditions can typically be categorized as involving abnormally high or excessive exposure to e.g. cold, heat, pressure, vacuum, voltage, corrosive chemicals, vibration, or dust. The extreme conditions should include any device or system requiring a lubricant operating under any of the following conditions:

References

  1. 1 2 Blau, P.J. Tribosystem analysis : a practical approach to the diagnosis of wear problems. Boca Raton. ISBN   9781498700511. OCLC   952212504.
  2. 1 2 ASTM International (2017). "ASTM G40-17: Standard Terminology Relating to Wear and Erosion". doi:10.1520/g0040-17.{{cite journal}}: Cite journal requires |journal= (help)
  3. 1 2 Horst., Czichos (2003). Tribologie-Handbuch : Reibung und Verschleiss ; mit 115 Tabellen. Habig, Karl-Heinz., Santner, Erich (2., überarb. und erw. Aufl ed.). Wiesbaden: Vieweg. ISBN   3528063548. OCLC   76560305.