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Mechanical properties of triaxially braided composites - Experimental and analytical resultsThis paper investigates the unnotched tensile properties of two-dimensional (2D) triaxial braid-reinforced composites both experimentally and analytically. The materials are graphite fibers in an epoxy matrix. Three different reinforcing fiber architectures were considered. There were considerable differences in the observed elastic constants from different size strain gage and extensometer readings. Larger strain gages gave more consistent results and correlated better with the extensometer readings. Experimental strains correlated reasonably well with analytical predictions in the longitudinal, 0 deg, fiber direction but not in the transverse direction. Tensile strength results were not always predictable even in reinforcing directions. Minor changes in braid geometry led to disproportionate strength variations. The unit cell structure of the triaxial braid was discussed with the assistance of computer analysis of the microgeometry. Photomicrographs of braid geometry were used to improve upon the computer graphics representations of unit cells. These unit cells were used to predict the elastic moduli with various degrees of sophistication. The simple and the complex analyses were generally in agreement, but none adequately matched the experimental results for all the braids.
Document ID
19930065238
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Masters, John E.
(Lockheed Engineering & Sciences Co., Inc.; NASA, Langley Research Center Hampton, VA, United States)
Foye, Raymond L.
(North Carolina Agricultural and Technical State Univ. Greensboro, United States)
Pastore, Christopher M.
(North Carolina State Univ. Raleigh, United States)
Gowayed, Yasser A.
(Auburn Univ. AL, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1993
Publication Information
Publication: Journal of Composites Technology & Research
Volume: 15
Issue: 2
ISSN: 0885-6804
Subject Category
Composite Materials
Accession Number
93A49235
Distribution Limits
Public
Copyright
Other

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