What is metal fatigue? What effect does metal fatigue have on the safety of mechanical equipment?

Metal fatigue refers to the destruction of metal materials under alternating stress.

Under the action of alternating stress, after a period of time, mechanical parts form microcracks in local high stress areas, and then microcracks gradually expand and fracture.

Fatigue damage is sudden in time, localized in position and sensitive to environment and defects, which is often difficult to be found in time and easy to cause accidents. Stress amplitude, average stress and cycle times are three main factors affecting metal fatigue.