An automated means of generating realistic, flight-by-flight helicopter airframe fatigue spectra based on the design usage spectrum and measured flight loads data is presented, together with a new spectrum truncation method called the Indexed Rainflow Filter (IRF). Although a planned experimental verification of the IRF method is yet to be completed, theoretical calculations indicate that it is capable of producing order-of-magnitude reductions in the number of turning points without significantly affecting the essential fatigue characteristics of the spectrum. The ability to produce such spectra will facilitate the development of more modern and cost-effective analytical and test-based helicopter airframe fatigue management programs.
展开▼
