SYMPOSIA PAPER Published: 01 January 1981

Compression Testing of Graphite/Epoxy Composite Materials


The focus of this investigation was to provide results that will support the selection of a reliable method of compression testing coupon specimens of filament-reinforced polymer-matrix composite materials. Three schemes were examined for testing graphite/epoxy (Narmco T300/5208) composite material specimens to failure in compression, including an adaptation of the Illinois Institute of Technology Research Institute (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 graphite/epoxy 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], [±45], and [0/±45/90] fiber orientations. The end-loaded coupon fixture was used to test 16-ply [0/±45/90] 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 stress/strain data to failure for unidirectional and quasi-isotropic laminates. The face-supported fixture was found to be the most desirable for testing [±45], laminates.

Author Information

Clark, RK
NASA-Langley Research Center, Hampton, Va.
Lisagor, WB
NASA-Langley Research Center, Hampton, Va.
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Developed by Committee: D30
Pages: 34–53
DOI: 10.1520/STP29302S
ISBN-EB: 978-0-8031-4800-0
ISBN-13: 978-0-8031-0700-7