An Investigation on Thermal Stress Ratcheting under Multiaxial Stresses

Abstract

In this paper, the discussions are focussed on yield function to be applied to the general method for estimating the deformation due to multiaxial thermal stress ratcheting, which the authors had already proposed before. The yield function employed is the one which enables us to consider the effects of anisotropy and cyclic hardening of material and the Bauschinger's effect as well as the influence of temperature; the anisotropy of material and the cyclic hardening are considered to be caused by the variations of the shape and the magnitude of yield surface, respectively, while the translational change of yield surface contributes to the Bauschinger's effect.
Deformations of hollow cylindrical specimens of low carbon steel subjected to cyclic axial thermal stress with steady stresses of combined tension and torsion were detected in order to examine the propriety of the analytical procedure.
The effect of torsional stress on the ratcheting strain is discussed analytically, and the predicted ratcheting limit diagram of the material is also included.