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Record Details

Record 26 of 1962
Experimental Investigation of Textile Composite Materials Using Moire Interferometry
Offline Availability: Go to Request Form
Author and Affiliation:
Ifju, Peter G.(Florida Univ., Dept. of Aerospace Engineering, Mechanics and Engineering Science., Gainesville, FL United States)
Abstract: The viability as an efficient aircraft material of advanced textile composites is currently being addressed in the NASA Advanced Composites Technology (ACT) Program. One of the expected milestones of the program is to develop standard test methods for these complex material systems. Current test methods for laminated composites may not be optimum for textile composites, since the architecture of the textile induces nonuniform deformation characteristics on the scale of the smallest repeating unit of the architecture. The smallest repeating unit, also called the unit cell, is often larger than the strain gages used for testing of tape composites. As a result, extending laminated composite test practices to textiles can often lead to pronounced scatter in material property measurements. It has been speculated that the fiber architectures produce significant surface strain nonuniformities, however, the magnitudes were not well understood. Moire interferometry, characterized by full-field information, high displacement sensitivity, and high spatial resolution, is well suited to document the surface strain on textile composites. Studies at the NASA Langley Research Center on a variety of textile architectures including 2-D braids and 3-D weaves, has evidenced the merits of using moire interferometry to guide in test method development for textile composites. Moire was used to support tensile testing by validating instrumentation practices and documenting damage mechanisms. It was used to validate shear test methods by mapping the full-field deformation of shear specimens. Moire was used to validate open hole tension experiments to determine the strain concentration and compare then to numeric predictions. It was used for through-the-thickness tensile strength test method development, to verify capabilities for testing of both 2-D and 3-D material systems. For all of these examples, moire interferometry provided vision so that test methods could be developed with less speculation and more documentation.
Publication Date: Oct 01, 1995
Document ID:
19960021804
(Acquired Jun 11, 1996)
Accession Number: 96N25079
Subject Category: COMPOSITE MATERIALS
Document Type: Conference Paper
Publication Information: Mechanics of Textile Composites Conference; Part 1; 141-173; (NASA-CP-3311-Pt-1); (SEE 19960021796)
Financial Sponsor: NASA Langley Research Center; Hampton,VA United States
Organization Source: Florida Univ.; Dept. of Aerospace Engineering, Mechanics and Engineering Science.; Gainesville, FL United States
Description: 34p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: TEXTILES; MOIRE INTERFEROMETRY; COMPOSITE MATERIALS; COMPOSITE STRUCTURES; TENSILE STRENGTH; STRAIN MEASUREMENT; AIRCRAFT CONSTRUCTION MATERIALS; LAMINATES; DISPLACEMENT; SPATIAL RESOLUTION; SHEAR STRAIN; TWO DIMENSIONAL BODIES; THREE DIMENSIONAL COMPOSITES
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