Springs are one of the important basic parts in mechanical products. There are many types of it, divided according to shape: coil spring, plate (piece) spring, disc spring, ring spring, plane (truncated cone) worm spring, etc.; According to the bearing characteristics, it is divided into: compression, tension, torsion spring, etc.

The stresses borne by springs mainly include: bending stress, torsional stress, tensile stress and composite stress.

The failure modes of the spring mainly include: breakage, deformation, loosening, and wear. where the Z principal analysis is fracture and deformation (loosening).

1. Brittle fracture: Most of the spring fractures belong to brittle fractures. Plastic fracture is possible only at high operating temperatures. In engineering, fatigue fracture, stress corrosion fracture and hydrogen embrittle fracture are called brittle fracture

2. Fatigue fracture: the spring breaks under the action of cyclic load.

3. Stress corrosion fracture: spring fracture phenomenon is caused by the joint action of tensile stress and corrosive medium.

4. Corrosion fatigue fracture: the spring breaks under the combined action of cyclic load and corrosive medium.

5. Hydrogen embrittlement, cadmium brittleness, black brittleness: brittle fracture caused by excessive impurity content in the spring material.

6. Abrasion: Wear is divided into: abrasive, fatigue and corrosion wear fracture.