O’zbekistоn respublikasi оliy va o’rta maxsus ta`lim vazirligi

The content of the discipline
The course "Tribology" includes:
- lecture hours
- practical exercises
- laboratory work.
The course will cover the following main sections:
- Introduction
- Nature and mechanisms of friction and wear
- Use of scientific knowledge in applied tribology
- Ecological and informational problems of tribology


1.2 Basic concepts
Tribology or tribonic is the science of friction, wear and lubrication, the interaction of contacting solids during their mutual movement. This term was proposed by the English scientist Peter Jost, who used it in his report to the chairman of the special commission to the British Ministry of Education and Science on March 9, 1966. In the next 42 years, tribology develops as an independent scientific discipline of fundamental and great practical importance. What are the grounds for such recognition?
Firstly, the application of tribological knowledge in the design and operation of machines gave great monetary savings already in the first years of the development of tribology. This is related to the following. Friction wear causes a huge investment in repairs and spare parts. Approximately one third of all metal-cutting machines and one in four workers are engaged in the repair of machines. The cost of running machines is constantly decreasing due to depreciation. Five times more production capacity is spent on the repair of tractors and the manufacture of spare parts for them than on the production of new tractors. There are areas of technology, the development of which depends directly on the level of solution of the problems of friction and wear. So, when drilling oil and gas wells with a depth of more than 5 км90% of the time is spent on tripping operations, due to the need to replace worn-out drilling tools.
Secondly, the growing importance of the global problems of mankind has become the basis for the general recognition of tribology in recent years. The great Russian scientist P.L. Kapitsa (an outstanding physicist, Nobel laureate, student of E. Rutherford) in the 50-60s expressed the opinion that the growth of the material culture of mankind and the increase in the population of the globe will cause irreversible changes in nature that are dangerous for people's existence. Elimination of the consequences of these changes is a series of problems called global, i.e. universal, covering the entire globe. These are raw materials, energy and environmental problems. The depletion of natural resources, the use of which determines the level of civilization and the well-being of mankind, is a major global problem. Until now, combustible materials remain the most important source of raw materials in the energy sector - coal, oil, gas, etc. If coal consumption remains at the current level, its reserves will last for about a thousand years. If, on the other hand, energy consumption continues to grow at the rate of the 20th century, coal reserves will be depleted in 100-150 years, even if the population remains the same. An even deeper crisis can be foreseen for other types of raw materials.
The energy problem is closely related to the raw material problem. Each of us feels the need to save energy at the household level.
The ecological problem is generated by the growth of the parameters of technological processes, which, at the modern level of civilization, have become commensurate with natural ones. This led to changes in the composition of water, air, soil, which violated the biological balance that existed in nature until now.
The importance of tribology as a means of mitigating global problems is very great. The efficiency of most machines is far from 50%, primarily due to friction losses (the “record holder” for this indicator is a steam locomotive with an efficiency of about 6%). Using the achievements of tribology, it is possible to save materials that are destroyed by wear. The connection of tribology with the environmental problem is explained by the following examples. A worn-out internal combustion engine increases the degree of atmospheric pollution by exhaust gases by 25-30% compared to a serviceable one. Depressurization of industrial installations containing moving seals is extremely dangerous for the environment. Of great social importance is the development of artificial human organs containing friction units - endoprostheses (i.e., implantable prostheses) of joints, heart valves, artificial kidneys, etc. The reduction of friction-generated noise and machine vibration contributes to the health of millions of working people.
And more about friction. Friction never manifests itself as, for example, the movement of electric charges or gravity. For fundamental physical reasons, this is an obsessive, almost inevitable companion of many phenomena around us, primarily the movement of bodies in the environment. Therefore, friction is secretly or obviously present everywhere, leaving an imprint on all types of human activity. Movement with the help of wheels, oars, on foot is possible due to friction. Ice and brake failure is a reduction in friction. Electrification of powders, fibers, films is generated by friction. The fact that friction is accompanied by the release of heat allowed people at the dawn of civilization to make fire. The heating of parts by friction with air has become a nightmare for the creators of high-speed aircraft and spacecraft. Any major practical success in tribology has always been accompanied by revolutionary changes in technology. Examples are the ancient invention of the wheel, the creation of special methods for processing friction surfaces, the use of the latest types of lubricants and bearings.
A number of concepts related to friction are standardized by GOST 27674-88, which includes about 100 terms. Below are deciphered those of them that will be mentioned before the presentation of the main course.
External friction or simply friction is the resistance to the relative movement of two bodies in contact, which occurs in the areas of their contact and acts in the plane of contact.
Internal friction is a phenomenon of resistance to the relative movement of parts of the same body.
Wear is the process of separation of material from the surface of a solid body during friction and (or) accumulation of its residual deformation, which manifests itself in a gradual change in size and (or) shape.
Wear is the result of the wear process.
A friction pair is a system of two elements, the contact surfaces of which move relative to each other. One of them is called the friction material, the other is called the counterbody.
Friction material - material used to work in friction conditions.
A counterbody is an element of a friction pair that works together with the friction material.
A friction surface is a surface that is involved in friction.
Lubricant is a material introduced onto a friction surface to reduce wear, surface damage and (or) friction force.
The friction force is the resistance force during the relative movement of one body over the surface of another under the action of an external force. It is directed tangentially to the common boundary between the bodies.
Tribology is an applied branch of tribology that covers the final stage of creating friction units. The principles of tribotechnics are reflected in the methods of calculation, design, manufacture, lubrication and operation of friction units.