Metal material fatigue phenomenon classification
The fatigue phenomenon of metal materials can be divided into the following types according to different conditions:
(1) High cycle fatigue: refers to the fatigue of the number of stress cycles of more than 100000 under conditions of low stress (the working stress is lower than the yield limit of the material, or even lower than the elastic limit). It is the most common type of fatigue damage. High cycle fatigue is generally referred to as fatigue.
(2) Low cycle fatigue: refers to fatigue with a stress cycle number of 10,000 to 100,000 or less under high stress (working stress close to the yield limit of the material) or high strain condition. Since the alternating plastic strain plays a major role in such fatigue failure, it is also called plastic fatigue or strain fatigue.
(3) Thermal fatigue: refers to the fatigue damage caused by the repeated action of thermal stress caused by temperature changes.
(4) Corrosion fatigue: refers to the fatigue damage of machine parts caused by the combined action of alternating load and corrosive medium (such as acid, alkali, seawater, reactive gas, etc.).
(5) Contact fatigue: This refers to the contact surface of the machine parts. Under repeated action of contact stress, pitting or surface crushing and peeling occurs, which causes failure of the machine parts.