Modelisation de la deformation progessive des aciers inoxydables austenitiques sous differents chargements.

Abstract

This thesis is in addition to the research work that deals with the Ratcheting phenomenon and the elastoplastic behavior of 304L austenitic stainless steel at room temperature under the effect of cyclic loading. Two investigations have been performed in order to analyze the behavior of the material. ▪ The first relates to conventional strain-compression type tests with imposed strain providing information relating to the hardening / softening of the steel. Cyclic tests carried out in amplitudes of increasing strain with a proportional loading path. The intervention of the non-zero average stress plays a primordial role in the appearance of the ratcheting phenomena. Under the effect of the same conditions, imposed stress tests allow the characterization of this phenomenon leading to different cyclic behaviors and to the Let's examine some form of hysteresis loops. The results of the simulation show that Ratcheting is governed by the intensity of the mean stress. ▪ The second investigation was to analyze different cyclic contributions under the effect of multiaxial tension -compression / torsion under strain and stress loading imposed with a cross loading path. This investigation has three objectives: 1. A study of the phenomenon of over-hardening due to the effect of the second loading and to the 2D Ratcheting phenomenon forming the (Cross Hardening) on the evolution of hysteresis buckles of deformations and constraints. 2. A comparative study between 1D and 2D Ratcheting around the same non-zero average stress shows that the speed of the 2D Ratcheting is more accelerated than the 1D Ratcheting. 3. A study of the effect of primary and secondary loading at increasing amplitudes on 2D Ratcheting. The set of simulations is done with the calculation code Zebulon with the choice of Chaboche's