EFFECT OF CREEP-FATIGUE LOADING CONDITION ON CRACK TIP FIELDS OF GRADE
91 STEEL AT CRACK INITIATION AND GROWTH
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.