BibTex format
@inproceedings{Nguyen:2017,
author = {Nguyen, SN and Gispert, CC and Greenhalgh, ES and Robinson, P and Allegri, G and Brown, KA},
title = {A new test method to characterize mixed mode II/III and I/II/III delamination},
year = {2017}
}
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TY - CPAPER
AB - © 2017 International Committee on Composite Materials. All rights reserved. Delamination is a critical damage mechanism in laminated composites, and currently represents the greatest limitation to achieving lightweight damage tolerant designs of primary aircraft structures. Current mode III delamination toughness tests often generate additional damage processes other than mode III delamination, such as intralaminar ply splits and crack migration to neighbouring ply interfaces, which invalidate the toughness measurements. In this study, a test rig capable of generating mode II/III and I/II/III delaminations over a range of mode mixities, up to a threshold proportion of mode III, and almost uniform mode III strain energy release rates, has been designed, developed, trialled and validated. Preliminary mixed-mode tests have been conducted on Hexcel IM7/8552 with 0°/0° and 0°/90° ply interfaces at the delamination plane. Fractography has been performed to elucidate and understand the failure mechanisms and characterize the fracture morphologies associated with mixed-mode II/III and I/II/III delamination. The fracture morphology of the IM7/8552 toughness coupons with a 0°/0° ply interface under pure mode II and mode II/III loading was exclusively delamination with little evidence of ply splitting or migration having had occurred. Directly ahead of the starter crack, the fracture morphology for both loading conditions presented a wedge of torn matrix, associated with the resin fillet. Beyond this fillet region, mode II/III loading presented slightly rotated cusps and a minor degree of fibre bridging. In summary, this paper presents a new mixed mode delamination test configuration, which still needs significant further development from the research community. In particular, the constraints applied to the specimen to achieve greater mode III components needs to be addressed. However, this new test method does offer a means to characterize delamin
AU - Nguyen,SN
AU - Gispert,CC
AU - Greenhalgh,ES
AU - Robinson,P
AU - Allegri,G
AU - Brown,KA
PY - 2017///
TI - A new test method to characterize mixed mode II/III and I/II/III delamination
ER -