Effects of Method of Loading and Specimen Configuration on Compressive Strength of Graphite/Epoxy Composite Materials.
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER
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The focus of this investigation was to provide results that will support the selection of a reliable method of compressive testing coupon specimens of filament reinforced polymer matrix composite materials. Three test schemes were examined for testing graphiteepoxy composite material specimens to failure in compression, including an adaptation of the IITRI wedge grip compression fixture, a face-supported-compression fixture, and an end-loaded coupon fixture. The effects of specimen size, specimen support arrangement and method of load transfer on compressive behavior of GrEp were investigated. Compression tests with the modified IITRI and face-supported fixture were conducted on specimens of 12.5-, 25-, and 50-mm widths of 8-, 16-, and 24-ply thicknesses and of 0, OR - 45, and O or - 4590 fiber orientations. The end-loaded-coupon fixture was used to test 16-ply 0 OR - 4590 specimens. Compressive stress-strain, strength, and modulus data obtained with the three fixtures are presented with evaluations showing the effects of all test parameters, including fiber orientation. The IITRI fixture has the potential to provide good stressstrain data to failure for unidirectional and quasi-isotropic laminates. The face supported fixture was found to be the most desirable for testing OR - 45sub s laminates. MM
- Laminates and Composite Materials