Constitutive Equation of Cyclic Creep under Increasing Stress Condition

Abstract

A constitutive equation of cycle creep is introduced after an experimental investigation of the effect of increasing maximum stress on the strain accumulation behaviors under various increasing true-stress controlled and load controlled conditions. A strain hardening type constitutive equation can describe the strain accumulation quantitatively under a gradually increasing maximum stress condition. The calculated results of the cyclic creep behaviors in load controlled tests agree fairly well with the experimental observations. A method of determination of material constants in the constitutive equation by the load controlled tests is proposed.