Fatigue life prediction and load cycle elimination during spectrum loading of composites

Modern aircraft contain a large number of composite structures which are loaded with different load spectra. The objective was to predict fatigue life for arbitrary load spectra from constant amplitude data and to study load elimination of load spectra. The basic assumption is that fatigue life is governed by delamination growth which is modeled with Parisʹ law. The model is used to predict the fatigue life of notched specimens loaded with a vertical fin spectrum and the predictions agree with experimental data. Load cycle elimination is also performed on two load spectra for two materials and the result suggests that 50% elimination can be used.