PSI - Issue 14

K.C. Sahoo et al. / Procedia Structural Integrity 14 (2019) 60–67 K.C. Sahoo et.al./ S ructural Integrity Procedia 00 (20 8) 0 0 – 00

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Fig.8 Variation of time to onset of tertiary stage of creep deformation as a function of rupture life

Fig.9 Variation of damage tolerance factor with rupture life for 923K, 973K and 1023K of 304HCu SS

3.3 Creep life prediction based on FE-CDM:

Continuum damage mechanics has become a useful tool for the creep life prediction of materials operating under high temperature. Continuum Damage Mechanics (CDM) coupled with the finite element method has been widely used to predict the creep damage and the rupture behaviour of the steel. Since the contribution of primary creep deformation was small, it has been neglected in FE-analysis. Creep damage analysis through FE was done by using the damage law proposed by Kachanov[L. M. Kachanov., 1967, M.F. Ashby., 1984, B.F. Dyson.,1987] and creep rate equation (1). The predicted creep curve were found to be good agreement with experimental ones shown in Fig.10. The comparison between the experimental and predicted creep rupture life are shown in Fig.11. Long term life prediction from CDM approach could be good if change in dislocation density, phase change, formation of new precipitates and their coarsening would be considered [R. Oruganti.,2011, J. Christopher., 2013]