A LOW CYCLE FATIGUE LIFE PREDICTION FOR DISK GROOVE BOTTOMS

According to the theory of local strain fatigue,the fatigue experiments for the 30CrMnSiA disk have been completed on a multichannel radial loading fatigue rig (“Ferris”whell).A good number of the crack propagation curves of the groove bottoms in the disk have been obtained.The calculations show that the median LCF life to crack initiation is 8642 (cycles).In comparison with cyclic rotating tests,the test period on a multi channel radial loading fatigue test rig can be shortened greatly and the test data can be obtained easily.A smooth round bar specimen experiment method for predicting the LCF life of groove bottom in the disk is provided,which is better than the Morrow method.For the median LCF life,the ratio of the experimental life to the predited life is 1.2.