Predicting mode II delamination growth of composite materials to assist simplification of fatigue spectra by truncating non-damaging cycles validated with experiment

Abstract

A mode II delamination growth rate model was constructed using constant amplitude fatigue data from mode II displacement-controlled testing, for the purpose of failure prediction. Unidirectional precracked composite coupons were tested using a fully reversible three-point bending fixture. Using a series of constant amplitude delamination growth rate data, the growth of delamination propagation under variable amplitude block loading was predicted and compared with experimental results. The model was then utilised to assist simplification of the variable amplitude FALSTAFF fatigue spectra by identifying non-damaging cycles to truncate. A 77% reduction in fatigue spectra length was achieved and confirmed through experimental fatigue testing.