Fatigue tests on fillet welded joints to assess the validity of Miner’s cumulative damage rule

Fatigue tests have been made on longitudinal non-load-carrying fillet welded joints using simple loading sequences in which each constant amplitude load cycle had secondary load cycles of one or two magnitudes appended to it. The tests have involved both as-welded and stress relieved specimens, and have been made under both tensile and alternating loading. In some instances, particularly under tensile loading, it was expected that stress interaction would occur so as to give values of Ʃ n / N > 1. However, Ʃ n / N was, in almost every case, less than 1.0 (i. e. Miner’s rule was unsafe). Based upon an empirical fit of an equation to one of the early sets of results, it proved possible to predict the remainder of the results with reasonable accuracy, and it has been shown that this approach can be formalized into a rule that would be relatively easy to apply in practice (equation (21)).