【Daily Question No. 21】January 21, 2021
Thread Content
【Daily Question No. 21】January 21, 2021: The form of failure in which metal materials undergo significant plastic deformation before fracturing is called fatigue failure. True or False ( ) Please reply within two days.
Error analysis: Fatigue failure refers to the phenomenon of material destruction under alternating stresses that are far below the material’s strength limit or even its yield limit. Under cyclic stress and strain, the material gradually develops localized permanent cumulative damage at one or several locations; after a certain number of cycles, cracks may form or complete fracture may occur suddenly. Based on the amplitude and frequency of the cyclic load, fatigue can be classified into constant-amplitude fatigue, variable-amplitude fatigue, and random fatigue; depending on the number of cycles the material undergoes before failure (i.e., its lifespan) as well as the stress level of the fatigue load, fatigue can also be divided into high-cycle fatigue, low-cycle fatigue, and subcritical fatigue.