Processing and Evaluation of 3D-Reinforced Needled Composite Laminate

Report No. ARL-TR-6107
Authors: Ryan P. Emerson, Jason Cain, Michael Simeoni, and Bradley Lawrence
Date/Pages: September 2012; 26 pages
Abstract: This report documents the fabrication and test of a woven glass/epoxy composite laminate that was reinforced in the through-thickness direction with aramid fibers using a needling process. The purpose of reinforcing laminated material in the through-thickness direction is to improve its delamination resistance/damage tolerance. The needled material was approximately 6.4-mm thick and was tested using American Standard Test Method ASTM standards to assess the improvements in impact response and any reductions in-plane strength, which is a typical tradeoff with 3D-reinforced stitched materials. Needled specimens exhibited 10–15% increase in effective stiffness (force-deflection response) under impact loading, and a 50% increase in compression-after-impact strength–a significant improvement in damage tolerance. Needled but non-impacted material exhibited a 9% increase in the in-plane compressive strength and a 17% increase in flexural strength, indicating at least that the needling process does not cause immediate tradeoffs in the in-plane strength of woven glass materials. Because the processing parameters were arbitrarily chosen, these experiments should be considered as proof-of-concept.
Distribution: Approved for public release
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Last Update / Reviewed: September 1, 2012