A COMPARATIVE-STUDY OF ANISOTROPIC CREEP THEORIES

Quantitative comparisons are drawn between the predictions of three ki nds of multiaxial anisotropic creep constitutive equations (the author 's model, the Murakami-Ohno model and the Mroz-Trampczynski-Hayhurst m odel) with special consideration of repeated stress changes. Numerical simulations of these anisotropic creep models are performed regarding the creep behavior observed for type 304 stainless steel at 650 degre es C under repeated multiaxial nonproportional loading conditions. Fro m these results, it is shown that these creep models can reproduce fai rly well the observed anisotropic creep behavior and that the predicti ve capabilities are almost comparable with each other. The similaritie s and differences between them are also discussed within the context o f the structure of the theories and the procedure to determine the mat erial constants involved.