UCL Discovery

Abstract

The fatigue life behaviour of airframe components under spectrum loading differs markedly in the moderately high and low loading severity regimes. Statistical analysis of fatigue test and strength data leads to suitable safe S-N curves for each of these regions and the problem is how to construct a single S-N curve which blends these two curves together. A method of constructing such a curve is described here. This method has been incorporated into recent guidelines for compliance with design and airworthiness requirements.