A model to predict fatigue crack initiation in plates with a pre-crack

摘要

A model is proposed on a macro scale to predict crack initiation caused by a constant amplitude fatigue load. It predicts the number of cycles (N_i) required to initiate the crack at the tip of a pre-crack, sharpened with a razor blade, by the relation N_i = α(KImax)β where KImax is the stress intensity factor corresponding to maximum stress of the fatigue load and α and β are the material constants to be determined by experiments. The validity of the model was checked on thin sheets of commercial aluminium, copper and mild steel.