Accession Number : ADA303089

Title :   Effects of Method of Loading and Specimen Configuration on Compressive Strength of Graphite/Epoxy Composite Materials.

Descriptive Note : Technical memo.,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER

Personal Author(s) : Clark, Ronald K. ; Lisagor, W. B.

PDF Url : ADA303089

Report Date : APR 1980

Pagination or Media Count : 45

Abstract : 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 graphite/epoxy 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 Gr/Ep 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 - 45/90 fiber orientations. The end-loaded-coupon fixture was used to test 16-ply 0/+ OR - 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 + OR - 45sub s laminates. (MM)

Descriptors :   *COMPRESSIVE STRENGTH, *GRAPHITE EPOXY COMPOSITES, STRESS STRAIN RELATIONS, LOAD DISTRIBUTION, BEAMS(STRUCTURAL), STIFFNESS, FIBER REINFORCED COMPOSITES, STRAIN(MECHANICS), PREPREGS, FAILURE(MECHANICS), COMPRESSIVE PROPERTIES, SANDWICH PANELS.

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE