EXPERIMENTAL-OBSERVATION ON VISCOPLASTIC BEHAVIOR OF SUS-304 - (CREEPAND RATCHETTING BEHAVIOR)

A unified constitutive model which can predict cyclic plasticity, unia xial and biaxial ratchetting, creep, and stress relaxation is required by designers of aeronautic equipment, nuclear reactors and so on. Det ailed experimental observation of considering viscoplastic behavior of materials must be carried out to construct a unified constitutive mod el. In this paper, uniaxial and biaxial ratchetting tests and creep te sts were carried out at room temperature and at 550 degrees C using SU S 304 stainless steel. As a result, it is clarified that uniaxial ratc hetting behavior is affected by the viscous deformation of the materia l, and that biaxial ratchetting behavior is affected by both the visco us deformation of the material and the deformation caused by nonpropor tional loading.