How is low-cycle fatigue identified in materials testing?

In the context of materials testing, low-cycle fatigue is identified based on the number of stress cycles a material can withstand before failure. Specifically, a material is considered to suffer from low-cycle fatigue if it fails in 10,000 cycles or fewer.1

Fatigue testing generally involves the repeated application of stresses that vary in a regular cycle between maximum and minimum values, often using machines that employ a rotating eccentric weight to produce the load. During these tests, investigators may measure the number of cycles required to initiate a crack as well as the total number of cycles until complete rupture occurs. Because fatigue is a statistical phenomenon, researchers typically test numerous specimens to establish reliable data regarding a material's behavior.12