DCB, 4ENF and MMB Delamination Characterisation of S2/8552 and IM7/8552

The aim of this work was to characterise materials S28552 and IM78552 using methods developed in a previous project contract N68171-96-C. Delamination onset was measured using servo-hydraulic and multi-station test equipment designed to test DCB, MMB, and 4ENF specimens The electromechanical multi-station equipment was used to generate delamination onset date to 10exp 8 cycles at 20 Hz. For both materials, a consistent decrease in the values of G were observed between 1 and 10exp 8 cycles. The static fracture toughness was higher for S28552 than for IM78552 for Mode I, Mode II and mixed mode loading. A more cost effective method of generating high cycle fatigue data has been developed.