Introduction to Tribology
|• Tribology is derived from the Greek word “Tribos”. Meaning of Tribos is Rubbing.|
• Tribology is a science that deals with friction, lubrication and wear in all contacting pairs.
• Tribological knowledge helps to improve service life, safety and reliability of interacting machine components; and yields substantial economic benefits.
Few Examples :
1) Example 1: Cam
2) Example 2 : Journal Bearings
3) Example 3: Gear
A pit on the surface of gear tooth is shown in Fig. 4. The pit generally occurs due to excessive contact stress. Understanding the effect of contact stress helps in developing an equation for estimation of perspective gear life.
Studies of fluid film bearings, rolling element bearings, seals, gears, cams, and brakes are some of the applications in which tribology is required.
Basic knowledge gained by Tribology course is very useful for industries related to power, steel, cement, oil etc. Practicing such knowledge in problems ranging from house hold appliances to large size ships earns great economic benefits. Therefore tribology course is often named as : “Industrial Tribology”, “Applied Tribology”.
Need of Tribology as subject :
• Friction, wear and lubrication have been taught in many science and engineering classes at a rudimentary level. It means empirically derived trends (friction force is proportional to loading force, static friction is greater than kinetic friction, viscous friction in a fluid is proportional to the normal contact force, etc.) are often used as the only predictive tools available. These approaches have the drawbacks of being predictive only over a limited range of parameters. Since the under-laying physical mechanisms are not well understood, often one does not even know which are the important parameters or over what range the observed trends are valid. This poor predictive power has led the field of tribology being perceived in many scientific quarters.
• Most tribological phenomena are inherently complicated and interconnected, making it necessary to understand the concepts of TRIBOLOGY in details.
• Integration of knowledge from multifaceted disciplines(solid mechanics, fluid mechanics, material science, chemistry etc) is essential and therefore a separate subject is required.
• Solid Mechanics: Focus is on expressions of contact stresses/deformations and surface temperatures due to rolling/sliding.
• Material Science: Focus is on atomic and micro scales mechanisms whereby solid surface degradation or alteration occurs during relative motion.
• Chemistry: Deals with reactivity between lubricants and solid surfaces.
• Thermodynamics: Heat and mass transfer in fluids and bounding solids.
See Also :