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Tension Strength, Failure Prediction and Damage Mechanisms in 2D Triaxial Braided Composites with NotchThe unnotched and notched (open hole) tensile strength and failure mechanisms of two-dimensional (2D) triaxial braided composites were examined. The effect of notch size and notch position were investigated. Damage initiation and propagation in notched and unnotched coupons were also examined. Theory developed to predict the normal stress distribution near an open hole and failure for tape laminated composites was evaluated for its applicability to 2D triaxial braided textile composite materials. Four different fiber architectures were considered; braid angle, yarn and braider size, percentage of longitudinal yarns and braider angle varied. Tape laminates equivalent to textile composites were also constructed for comparison. Unnotched tape equivalents were stronger than braided textiles but exhibited greater notch sensitivity. Notched textiles and tape equivalents have roughly the same strength at large notch sizes. Two common damage mechanisms were found: braider yarn cracking and near notch longitudinal yarn splitting. Cracking was found to initiate in braider yarns in unnotched and notched coupons, and propagate in the direction of the braider yarns until failure. Damage initiation stress decreased with increasing braid angle. No significant differences in prediction of near notch strain between textile and tape equivalents could be detected for small braid angle, but the correlations were weak for textiles with large braid angle. Notch strength could not be predicted using existing anisotropic theory for braided textiles due to their insensitivity to notch.
Document ID
19960021803
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Norman, Timothy L.
(West Virginia Univ. Morgantown, VA United States)
Anglin, Colin
(West Virginia Univ. Morgantown, VA United States)
Date Acquired
August 17, 2013
Publication Date
October 1, 1995
Publication Information
Publication: Mechanics of Textile Composites Conference
Volume: Part 1
Subject Category
Composite Materials
Accession Number
96N25078
Funding Number(s)
CONTRACT_GRANT: NAG1-1381
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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