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Ultrasonic Assessment of Impact-Induced Damage and Microcracking in Polymer Matrix CompositesThe main objective of this NASA FAR project is to conduct ultrasonic assessment of impact-induced damage and microcracking in polymer matrix composites at various temperatures. It is believed that the proposed study of impact damage assessment on polymer matrix composites will benefit several NASA's missions and current interests, such as ballistic impact testing of composite fan containment and high strain rate deformation modeling of polymer matrix composites. Currently, impact-induced delamination and fracture in 6061-T6 aluminum/cast acrylic sandwich plates adhered by epoxy were generated in an instrumented drop-weight impact machine. Although only a small dent was produced on the aluminum side when a hemispherical penetrator tup was dropped onto it from a couple of inches, a large ring of delamination at the interface was observed. The delamination damage was often accompanied by severe shattering in the acrylic substratum. Damage patterns in the acrylic layer include radial and ring cracks and, together with delamination at the interface, may cause peeling-off of acrylic material from the sandwich plate. Theory of stress-wave propagation can be used to explain these damage patterns. The impact tests were conducted at various temperatures. The results also show clearly that temperature effect is very important in impact damage. For pure cast acrylic nil-ductile transition (NDT) occurs between 185-195 F Excessive impact energy was dissipated into fracture energy when tested at temperature below this range or through plastic deformation when tested at temperature above the NDT temperature. Results from this study will be used as baseline data for studying fiber-metal laminates, such as GLARE and ARALL for advanced aeronautical and astronautical applications.
Document ID
20010012150
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Liaw, Benjamin
(City Coll. of the City Univ. of New York NY United States)
Zeichner, Glenn
(City Coll. of the City Univ. of New York NY United States)
Liu, Yanxiong
(City Coll. of the City Univ. of New York NY United States)
Bowles, Kenneth J.
Date Acquired
August 20, 2013
Publication Date
August 1, 2000
Publication Information
Publication: HBCUs/OMUs Research Conference Agenda and Abstracts
Subject Category
Composite Materials
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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