FATIGUE FAILURE OF NUCLEAR PRESSURE-VESSEL STEELS - II - PREDICTION OF FATIGUE-CRACK PROPAGATION

An approximated analytical solution relating to the stress-strain-stat e (SSS) near the crack tip at cyclic mixed loading was obtained. Analy sis of conditions for damage accumulation in a material for gradient s tress and strain fields was performed. A fatigue crack propagation mod el was developed on the basis of the local stress-strain criterion of fatigue failure formulated in a preceding paper (Part 1) and the analy tical solution of the problem of the stress-strain-state near the crac k tip. It was shown as applied to nuclear pressure vessel steel 2Cr-Mo -Ni-V that the proposed model allows one to predict the fatigue crack growth rate at any loading asymmetry and arbitrary ratio of stress int ensity factors of I and II modes. Moreover, the model gives an adequat e prediction for the beginning of the spasmodic growth of a fatigue cr ack. (C) 1998 Elsevier Science Limited. All rights reserved.