Tertiary creep stage in a non linear kinematics and isotropic hardening elastovisco- plastic model

摘要

The aim of the present paper is to introduce tertiary creep stage phenomenon in an elasto-visco-plastic model taking intornaccount primary and secondary creep stages. The study is based on the "D.D.I. (Two Inelastic Strains)" model [2], in whichrnan elasto-plastic and a visco-plastic potentials are used to describe material behaviour under cyclic loading with dwell periodsrnat high temperature. Creep phenomenon are described with the visco-plastic part of the model, using a non linear kinematicrnhardening with a recovery time effect. Experimental data used to analyse the tertiary creep stage in weld metal are deducedrnfrom six creep tests at 600°C.rnA pseudo analytical procedure is proposed to identify tertiary creep parameters in the Two Inelastic Strains Model.rnSimulation at different stress levels shows that tertiary creep strain assessment is in good agreement with experimental results.