Development of a polycrystalline approach for the modelling of high cycle fatigue damage: Application to a HSLA steel

Abstract

For many metallic alloys, fatigue crack initiation is governed by the development of a localized plastic activity at the grain scale. Because of the irreversible nature of plasticity, a significant proportion of the total work is dissipated into heat during a cyclic loading. As a consequence, one may expect some correlation between heat dissipation and high cycle fatigue damage as both phenomena are closely related. The purpose of the present work is to study such correlation for a ferritic high strength low alloyed steel subjected to various cyclic loading conditions. For several uniaxial fatigue tests carried out under different load ratios and stress levels, an experimental dataset consisting of stress, strain and temperature measurements is used to estimate the evolution of the amount of dissipated energy. A clear correlation between dissipated energy and the number of cycles to failure is observed.