Abstract
A unified constitutive model which can predict cyclic plasticity, uniaxial and biaxial ratchetting, creep, and stress relaxation is required by designers of aeronautic equipment, nuclear reactors and so on. Detailed experimental observation of considering viscoplastic behavior of materials must be carried out to construct a unified constitutive model. In this paper, uniaxial and biaxial ratchetting tests and creep tests were carried out at room temperature and at 550°C using SUS 304 stainless steel. As a result, it is clarified that uniaxial ratchetting behavior is affected by the viscous deformation of the material, and that biaxial ratchetting behavior is affected by both the viscous deformation of the material and the deformation caused by nonproportional loading.
