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

Abstract : The aim of this work was to characterise materials S2/8552 and IM7/8552 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 10(exp 8) cycles at 20 Hz. For both materials, a consistent decrease in the values of G were observed between 1 and 10(exp 8) cycles. The static fracture toughness was higher for S2/8552 than for IM7/8552 for Mode I, Mode II and mixed mode loading. A more cost effective method of generating high cycle fatigue data has been developed.