Introduction of allowable stress data;

Allowable stress is the basic data in mechanical design and engineering structure design. In practical application, the allowable stress value is generally stipulated by the national engineering department on the principle of safety and economy according to the strength, load, environmental conditions, processing quality, calculation accuracy and the importance of parts or components.

The allowable stress is equal to the failure stress of the material (yield limit or strength limit for static strength design and fatigue limit for fatigue strength design) divided by the safety factor.

The concept of material mechanics;

Mechanics of materials is a subject that studies the strain, stress, strength, stiffness, stability and the limit of failure of various materials under various external forces.

Generally speaking, it is a compulsory course for college students majoring in mechanical engineering, civil engineering and related majors. Learning material mechanics generally requires students to take advanced mathematics and theoretical mechanics first. Material mechanics, theoretical mechanics and structural mechanics are also called the three major mechanics. The research object of material mechanics is mainly rod-shaped materials, such as rods, beams and shafts. Structural mechanics discusses truss structure, and elastic mechanics discusses plate and shell structure.

Mechanics of materials is a compulsory course for all engineering students, and it is also a necessary knowledge for designing industrial facilities. Learning material mechanics generally requires students to take advanced mathematics and theoretical mechanics first. Material mechanics, theoretical mechanics and structural mechanics are also called the three major mechanics. Most of the existing materials mechanics textbooks are mainly from Harbin Institute of Technology and Zhejiang University.