Prediction of settled cyclic behaviour of metals using first cycle data and combined hardening laws for reversed plasticity

Abstract

This paper presents a generalized concept of combined hardening which is examined by experimental and computational methods. A ‘kinematic displacement parameter’, β, relating the movement of the yield function surface to the Bauschinger effect, is defined in terms of its dependence on material properties and loading state. Experimental relations between β and the plastic strain, εp, are prsented for three metals. The monotonic stress-strain and β data are used in a finite element program to show that settled cyclic hysteresis loops are soon established. Settled cyclic stress-strain curves computed in this way are in good agreement with the experimental results for an aluminium alloy, a stainless steel that shows cyclic hardening, and a titanium alloy that shows little cyclic effect.