The effects of stress gradient and dimensional size on fatigue life were investigated.The relationship between the notched specimen and the smooth specimen was correlated by introducing the stress gradient effect factor

and a new model of predicting notched specimen based on the Walker modification for the mean stress effect was established.Three-dimensional elastic finite element (FE) analysis of a turbine disk was carried out to obtain the fatigue parameters for predicting its life.The result shows that this model can well reflect several effects on fatigue life

especially the effect of stress concentration on the fatigue life of specimen.If the mean stress

stress gradient and size effect are considered comprehensively

the prediction result of the disk is closer to the experiment result.This model gives a prediction falling within a scatter of two for both GH901 standard specimen and the disk.