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타이틀	Characterizing Delamination Migration in Carbon/Epoxy Tape Laminates
저자	Ratcliffe, James G.;; Czabaj, Michael W.;; Obrien, Thomas K.
Keyword	CANTILEVER BEAMS;; DELAMINATING;; EPOXY MATRIX COMPOSITES;; FINITE ELEMENT METHOD;; FRACTOGRAPHY;; KINKING;; LAMINATES;; LOAD TESTS;; MECHANICAL PROPERTIES;; PLASTIC TAPES;; PLY ORIENTATION;; POLYTETRAFLUOROETHYLENE;; SCANNING ELECTRON MICROSCOPY;; SIMULATION
URL	http://hdl.handle.net/2060/20120016321
보고서번호	NF1676L-15085
발행년도	2012
출처	NTRS (NASA Technical Report Server)
ABSTRACT	A new test method is presented for the purpose of investigating migration of a delamination between neighboring ply interfaces in fiber-reinforced, polymer matrix tape laminates. The test is a single cantilever beam configuration consisting of a cross-ply laminate with a polytetrafluoroethylene (PTFE) insert implanted at the mid-plane and spanning part way along the length of the specimen. The insert is located between a 0-degree ply (specimen length direction) and a stack of four 90-degree plies (specimen width direction). The specimen is clamped at both ends onto a rigid baseplate and is loaded on its upper surface via a piano hinge. Tests were conducted with the load-application point located on the intact portion of the specimen in order to initiate delamination growth onset followed by migration of the delamination to a neighboring 90/0 ply interface by kinking through the 90- degree ply stack. Varying this position was found to affect the distance relative to the load-application point at which migration initiated. In each specimen, migration initiated by a gradual transition of the delamination at the 0/90 interface into the 90- degree ply stack. In contrast, transition of the kinked crack into the 90/0 interface was sudden. Fractography of the specimens indicated that delamination prior to migration was generally mixed mode-I/II. Inspection of the kink surface revealed mode-I fracture. In general, use of this test allows for the observation of the growth of a delamination followed by migration of the delamination to another ply interface, and should thus provide a means for validating analyses aimed at simulating migration.