THE BAUSCHINGER AND HARDENING EFFECT ON RESIDUAL STRESSES IN THICK-WALLED CYLINDERS OF SUS 304

Abstract

A thick-walled cylinder of strain hardening material with closed ends, which is assumed to obey Von-Mises yield criterion is considered. An elastoplastic and residual stress analysis of thick-walled cylinders is performed with the incremental theory of plasticity. Critical pressures of direct and reverse yielding are investigated using the Von-Mises yield criterion as well as the Bauschinger effect factor (BEF). The material selected is SUS 304 stainless steel. The material's loading and unloading properties including the (BEF) are obtained experimentally and represented mathematically as a continuous function of effective plastic strain. The material model and the BEF have been incorporated in an analytical-numerical model so as to predict the cylinders plastic and residual stresses as well as the critical pressures of direct and reverse yielding. The analytical-numerical model for the prediction of critical inner pressure, plastic stress distributions and the subsequent residual stresses of thick-walled cylinders is validated by using experimental results. Residual stresses with and without the BEF are obtained and the corresponding results are compared. In the case study of a specific cylinder (Radii ratio of β=2), it has been concluded that residual stresses subsequent to a 45% overstrained condition are at the onset of reverse yielding when the BEF is considered.