Cumulative fatigue damage studies of pinned-lug and clamped-lug structural elements in aluminium alloy

Abstract

In this paper the results of cumulative fatigue damage studies are given for pinned-lug and clamped-lug specimens in aluminium alloys. The growth of fatigue damage under constant amplitude loading and under variable amplitude loading is discussed and the effects of static pre-load on subsequent fatiguen performance are illustrated. Explanations of the observed patterns of behaviour are put forward based on consideration of the residual stresses which may be induced by plastic defamation at stress concentrations within the test specimens. It is concluded that, in the present state of knowledge, it is advisable to use variable amplitude loading for component evaluation. The importance of using specimens having engineering configurations when evaluating new materials is also stressed.