Analysis of residual stress field in strain-hardened hollow circular discs subjected to autofrettage by radial temperature difference

Abstract

Autofrettage is a material forming procedure commonly practised to induce beneficial compressive residual stresses in the proximity of the inner wall of a thick-walled cylinder or hollow disc that are subjected to high pressure in service. This work presents theoretical predictions of residual stresses induced in a hollow circular disc subjected to autofrettage by a radial temperature difference across its wall thickness, called thermal autofrettage. A plane stress condition is assumed for the analysis. The plastic flow of the material in the disc under radial temperature difference is modelled using von Mises yield criterion incorporating Ludwik’s material strain hardening law. The solutions for the thermo-elasto-plastic stresses upon loading the disc by a plastically deforming radial temperature difference and the thermal residual stresses after cooling the disc to room temperature are obtained. The process is numerically exemplified for a typical disc. The beneficial effect of autofrettage-induced residual stresses on the in-service pressure carrying capacity of the disc is investigated. The results obtained in this work are corroborated with the solutions of a corresponding analytical model based on Tresca yield criterion.