Mechanical engineering

Mechanical Engineering Definition

Mechanical engineering: based on relevant natural sciences and technical sciences, combined with technical experience in production practice, research and solve all theoretical and practical problems in the development, design, manufacture, installation, use, and repair of various machinery Subject. Machinery is one of the five elements (people, capital, energy, materials, and machinery) for production and services in modern society, and it participates in the production of energy and materials.

The development of machining technology

Before the industrial revolution, most of the machinery was wooden structures made by carpenters. Metal (mainly steel and iron) was only used to make instruments, clocks, locks, pumps, and small parts on wooden machinery. Metal processing mainly relies on the meticulous workmanship of the mechanic to achieve the required precision. With the widespread use of steam engines and the subsequent development of large-scale machineries such as mines, metallurgy, ships, and locomotives, more and more metal parts need to be formed and cut. The metal materials used have evolved from copper and iron to steel. the Lord.

Mechanical processing (including casting, forging, welding, heat treatment, and other technologies and equipment, as well as cutting processing technology and machine tools, cutting tools, measuring tools, etc.) has developed rapidly, thereby ensuring the supply of various mechanical equipment required for development and production. At the same time, with the increase in production batches and the development of precision processing technology, it has also promoted the formation of a large number of production methods (parts interchangeable production, professional division of labor and collaboration, assembly lines, assembly lines, etc.).

Development of Basic Theory of Mechanical Engineering

Before the 18th century, machinists relied solely on personal experience, intuition, and craftsmanship to make machinery, and had little to do with science. It wasn’t until the 18th to 19th centuries that the basic theories around mechanical engineering gradually formed.

Power machinery was first integrated with science, such as the theories of the inventors of the steam engine T. Savery and Watt applied physicists D. Papan and J. Black, physicists S. Carnot, WJM Rankin and Kelvin Based on the practice of steam engine, a new discipline-thermodynamics, etc. was established. At the beginning of the 19th century, the study of mechanical structure and movement in machinery was first listed as a course of the Higher Engineering School (Paris Polytechnic Institute).

Since the second half of the 19th century, design calculations have taken into account material fatigue. Subsequently, fracture mechanics, experimental stress analysis, finite element method, mathematical statistics, and electronic computers were successively used in design calculations.

Service areas of mechanical engineering

The service area of ​​mechanical engineering is very wide. All departments that use machinery, tools, and energy and material production do not require mechanical engineering services.

Modern mechanical engineering has 5 major service areas:

  1. Develop and provide energy conversion machinery, including various power machinery that converts thermal energy, chemical energy, atomic energy, electrical energy, fluid pressure energy, and natural mechanical energy into mechanical energy suitable for applications, and convert mechanical energy into other energy required Energy conversion machinery;
  2. Develop and provide machinery for the production of various products, including agricultural, forestry, animal husbandry, fishery machinery, and mining machinery, as well as various heavy industrial machinery and light industrial machinery, etc.;
  3. Develop and provide machinery for various services, such as material handling machinery, transportation machinery, medical machinery, office machinery, ventilation, heating, and air conditioning equipment, and environmental protection equipment such as dust removal, purification, and noise reduction;
  4. Develop and provide machinery for home and personal life, such as washing machines, refrigerators, clocks, cameras, sports equipment, and entertainment equipment, etc.;
  5. Develop and provide various mechanical weapons.

Subject content of mechanical engineering

The subject content of mechanical engineering can be divided into:

  1. Establish and develop engineering theoretical foundations that can be practically and directly applied to mechanical engineering. Such as engineering mechanics, fluid mechanics, engineering materials science, material mechanics, combustion, heat transfer, thermodynamics, tribology, mechanism, mechanical principles, mechanical parts, metal technology and non-metal technology, etc.;
  2. Research, design and develop new mechanical products, improve existing mechanical products and produce new-generation mechanical products to meet current and future needs;
  3. The production of mechanical products, such as the planning and realization of production facilities, the formulation of production plans and production scheduling, the preparation and implementation of manufacturing processes, design and manufacturing process equipment, determination of labor quotas and material quotas, processing, assembly, packaging and inspection, etc. ;
  4. Operation and management of machinery manufacturing enterprises, such as determining production methods, product sales, and production operation management;
  5. The application of mechanical products, such as selection, ordering, acceptance, installation, adjustment, operation, maintenance, and transformation of mechanical products and complete sets of mechanical equipment used in various industries;
  6. To study the environmental pollution and excessive consumption of natural resources caused by the manufacturing and use of mechanical products and the treatment measures.

Branches of Mechanical Engineering

Machinery can be divided into power machinery, crushing machinery, transportation machinery and material handling machinery according to their functions;

According to the service industry, it can be divided into agricultural machinery, chemical machinery, mining machinery, and textile machinery, etc.;
According to the working principle, it can be divided into thermal machinery, turbomachinery, bionic machinery, and fluid machinery.

The same working principle, the same function or machinery serving the same industry has the same problems and characteristics, so mechanical engineering has several different branch discipline systems. In addition, all machinery has to go through several stages of different nature of work in the process of research, development, design, manufacture, and operation.

These sub-disciplinary systems intersect and overlap each other, so that mechanical engineering may be divided into hundreds of sub-disciplines. For example, power machinery classified by function, thermal machinery, fluid machinery, turbine machinery, reciprocating machinery, steam power plant, nuclear power plant, internal combustion engine, gas turbine, and central power plant equipment and industrial power classified by industry Installations, railway locomotives, marine engineering, automotive engineering, etc. has complex intersecting and overlapping relationships.

Marine steam turbines are power machinery, thermal machinery, fluid machinery, and turbomachinery. They belong to ship power plants, steam power plants, and may also belong to nuclear power plants. The clockwork and heavy hammer devices used to drive the clock are also power machinery, but not thermal machinery, fluid machinery, turbine machinery, or reciprocating machinery. There are similar overlaps and crossover relationships between other branches. But the practical value is not great.

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