BEHAVIOR AND MODELING OF A 17-12-SPH STAINLESS-STEEL UNDER CYCLIC, UNI AND BIDIRECTIONAL, ANISOTHERMAL LOADINGS .2. MODELING

In the first part of this article (Bouchou & Delobelle, Int. J. Plast. [1996]), we show that the austenitic stainless steel 17-12 SPH posses ses a significant temperature history effect under anisothermal cyclic conditions. In particular this steel memorizes the maximal value of t he peak cyclic stress reached when the derivative of the maximal cycli c stress with respect to the temperature is positive. This property re mains true for bidirectional cyclic tests. From a microstructural poin t of view, this behavior is attributed to the short distance interacti ons between configurations of point defects and mobile dislocations (d ynamic strain aging phenomenon). In order to describe this history eff ect, a simple mathematical formulation is proposed in this article whi ch, after being integrated into a unified viscoplastic model developed elsewhere and taking into account a few modifications, leads to an ac ceptable phenomenological representation of the different experiments presented earlier.