Fatigue damage accumulation around a notch using a digital image measurement system

A digital image measurement (DIM) system is used to study the plastic damage accumulation around a notch under conditions of low-cycle fatigue. This system incorporates a contrast correlation method to evaluation the level of plastic damage at each point of the studied area from two images acquired before and after the introduction of fatigue deformation. A compact tension specimen of 304 stainless steel with a notch radius of 1 mm is analyzed during the stages of fatigue crack initiation and growth. The results obtained using this measurement system are compared with those attained by means of a recrytallization technique.