Analysis of the fatigue strength under two load levels of a stainless steel based on energy dissipation

Abstract

In this paper the fatigue behaviour of a stainless steel AISI 304L is analysed. In the first part of the
work the results obtained under constant amplitude fatigue are presented and synthesised in terms of both
stress amplitude and energy released to the surroundings as heat by a unit volume of material per cycle, Q. Then
some specimens have been fatigued in variable amplitude, two different load level tests: the first level was set
higher while the second was lower than the constant amplitude fatigue limit. The Q values, evaluated during the
second part of the fatigue test, have been compared with those calculated under constant amplitude fatigue at
the same load level. The comparison allowed us to notice that the Q parameter is sensitive to the fatigue damage
accumulated by the material during the first part of the fatigue test.