Modelling of rupture ductility of metallic materials for wide ranges of temperatures and loading conditions, part I: development of basic model

Abstract

ABSTRACT Ductility of metallic materials has practical importance in evaluating structural integrity against ductile fracture or creep rupture but it changes in a more complicated fashion than strength . In order to provide a means to predict the ductility under arbitrary conditions, a model applicable to wide ranges of temperatures and loading conditions was developed . This model consists of an equation describing the dependency on temperature and strain rate in a combined way and a power-law function of stress but emphasis is placed on the former which has two terms representing the behaviour at high and low temperatures. Based on the experimental data from various tests on four materials, effectiveness of the model was demonstrated. Relations between equivalent stress and equivalent strain rate defined in conjunction with the ductility model were also modelled by a similar equation with two terms, allowing the accurate prediction of the ductility in a purely analytical way.