ABSTRACT
In this paper, the effect of creep-fatigue loading condition on crack
tip deformation and stress fields of Grade 91 steel at
600oC at crack initiation and growth is studied. By
using finite element debond analysis method, creep-fatigue crack growth
tests using C(T) specimens under various load ratios and hold times are
simulated, and the effect of creep-fatigue load ratio and hold time on
the plastic zone, creep zone, crack opening profile, equivalent stress,
crack-opening stress and triaxiality at crack initiation and growth is
presented. It is found that the crack tip deformation and stress fields
under tension-compression creep-fatigue loading are overall different
from those under tension-tension creep-fatigue and pure creep loading,
due to crack closure.
Keywords: creep fatigue, crack initiation, crack growth, crack
tip stress fields