The Prediction of Creep-Rupture Times of Rotating Disks Using Biaxial Damage Relationships

Abstract

Lower-bound expressions for the rupture times corresponding to a maximum tension stress damage law are developed for the creep of disks rotating under conditions of plane stress and plane strain. Computed values of the lower-bound rupture times are shown to be in close agreement with the results of numerical solutions for maximum tension and biaxial tension stress damage laws. The lower-bound rupture time is shown to correspond with the result of a constant stress rupture test carried out under the conditions of the steady-state stress at a reference point in the structure. The steady-state reference stress, for two kinematically determinate structures and different rupture laws, is shown to closely predict values of the rupture time obtained from independent solutions.