Compression of Fatigue Spectra for Composite Materials

In this study a ground up approach was taken to develop a loading sequence simplification methodology for use with composite specimens undergoing mode II delamination. Models developed from fatigue data informed the application of two techniques: truncation and cycle merging. Experimental results showed good agreement with predictions for the truncated sequences which achieved length reductions of 77% and 74% for unidirectional and woven specimens respectively. By first performing truncation, cycle merging was successfully implemented achieving a 95% length reduction. The application of scaling allowed for damage to be re-introduced/removed, enabling the damage content to be matched with the original sequence.