1993 年 59 巻 566 号 p. 2440-2447
An alternative form of the auxiliary hardening rule is developed to describe the anisotropic creep behavior under multiaxial nonproportional repeated stress changes. The auxiliary hardening rule controls the combined isotropic and kinematic hardening with a memory surface in which isotropic hardening is suppressed and kinematic promoted. Differences from the previous studies are found in the alternative definitions of the memory surface and its evolution equations. A method for the enhancement of the creep recovery is also proposed within the present constitutive framework. The applicability and insufficiency of the creep model are elucidated by comparison with the typical experimental results on multiaxial nonproportional repeated creep. The simulated results of the isotropic and kinematic hardening models, which are derived as special cases of the present model, are included.