Basic knowledge of auto mechanics

1. Strength refers to the ability to resist permanent deformation and fracture. Commonly used criteria mainly include yield point and tensile strength.
2. Plasticity refers to the ability of a material to undergo irreversible permanent deformation. Commonly used criteria are elongation of area and reduction of area.
3. Hardness refers to the ability of a material to resist local deformation, especially plastic deformation, indentation or scratches. Hardness is a criterion for measuring the hardness of metal. Commonly used in production are Brinell hardness (HB, HBS) and Rockwell hardness (HR) test methods. The hardness value is obtained from the experiment, and can be obtained from the relevant book in actual application. Commonly used hardness is Brinell hardness. Brinell and Rockwell hardness values ​​are incomparable, because the test principles are different. The positive relationship between hardness and strength is related to plasticity.
4. Toughness refers to the ability of metal to absorb deformation energy before fracture. The commonly used criterion is mainly the impact resistance of metal materials, that is, the impact absorption energy.
5. Fatigue strength refers to the process in which parts have local permanent cumulative damage in one or several places under the action of cyclic stress, cracks or sudden complete fracture after a certain number of cycles.
6. Addition and subtraction balance force system axiom: When a certain force system acts on a rigid body, adding or subtracting a balance force system will not change the effect of the original force system on the rigid body.
7. Lattice refers to the spatial geometric framework of how atoms are arranged in a crystal. Crystal refers to the regular and periodic arrangement of metal atoms in three-dimensional space.
8. Common crystal structures include body-centered cubic lattice and face-centered cubic lattice.
9. Three-force equilibrium confluence theorem: If three non-parallel forces acting on a rigid body in the same plane make the rigid body in equilibrium, the center of action of these three forces will meet at one point.
10. Alloy refers to a substance that is composed of two or more metal elements and has metallic characteristics.
The most basic and independent substances that make up an alloy are called components. Usually refers to the elements that make up the alloy can also be a stable compound.
11. High-molecular materials are materials mainly composed of high-molecular compounds. High-molecular compounds include organic polymer compounds and inorganic polymer compounds.carThe main application in industry is synthetic organic high molecular polymers. Such materials mainly include plastics, rubber, synthetic fibers and adhesives.
12. Plastic is a general term for polymer synthetic materials that can be molded under certain temperature and pressure. Plastics are generally made by adding various additives on the basis of synthetic resins. Plastics are characterized by low density, high specific strength, good chemical stability, excellent electrical insulation, good friction reduction and wear resistance, good noise and vibration absorption, good forming processability, and low heat resistance.
13. Rubber is a polymer material composed of raw rubber and adding an appropriate amount of compounding agents. The characteristics are: high elasticity, strong vibration absorption ability, and certain corrosion resistance. Commonly used rubbers are styrene-butadiene (SBR), butadiene (BR), chloroprene (CR), nitrile (NBR), and polyacrylic acid (AR). Ceramics refers to a kind of inorganic non-metallic solid material made from various natural or synthetic compounds as basic raw materials, processed, shaped, dried, and sintered at high temperature. Its characteristics are: high hardness, high melting point and high temperature strength, high oxidation resistance, and better insulation properties. Commonly used industrial ceramics are: ordinary ceramics, alumina ceramics, silicon carbide ceramics, and silicon nitride ceramics.
14. Composite materials are multiphase solid materials artificially synthesized from two or more substances with different physical and chemical properties. It has the advantages of high specific strength and specific modulus, good fatigue resistance, strong vibration damping performance, good high temperature performance, and high fracture safety performance. A rigid body refers to an object that does not deform under the action of force.
15. The kinematic pair refers to a connection where two components are in direct contact and can produce a certain relative movement. The kinematic pair formed by two members through surface contact is called low pair, and the kinematic pair formed by contact in the form of points or lines is called high pair. The low pair is further divided into a moving pair and a rotating pair.
16. The planar linkage mechanism is composed of several rigid components connected to each other with low pairs, and they move in the same plane and parallel to each other. It can be divided into a hinged four-bar mechanism and a four-bar mechanism with a moving pair.
17. Other objects that restrict the movement of objects are called constraints. The force that the constraint acts on the constrained object is called the constraint reaction force.
The load-bearing capacity of a component refers to the ability of a component to meet the requirements of strength, grace and stability under external load.
The concentration of internal force is called stress, which indicates the strength of the force on a certain point on the section. When the stress reaches a certain level, the rod will be destroyed.
18. The relative moving entities that make up the machine are called components, and the non-detachable manufacturing units in the machine are called parts.
19. Hydraulic transmission refers to a transmission method that uses liquid as a working medium to achieve energy transmission.
20. Heat treatment refers to the process of heating, holding and cooling metal materials or workpieces in a solid state in a proper way to obtain the expected structure and performance. The purpose is to improve metal performance and process performance. Although there are many heat treatment methods, they all consist of three stages: heating, heat preservation and cooling.
The above concepts are willing to provide you with a convenient understandingcar repairRelated knowledge! Thanks!