Accession Number : ADA305031

Title :   The Effect of Impact Damage and Circular Holes On the Compressive Strength of A Graphite-Epoxy Laminate,

Descriptive Note : Technical memo.,

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

Personal Author(s) : Starnes, James H., Jr. ; Rhodes, Marvin D. ; Williams, Jerry G.

PDF Url : ADA305031

Report Date : OCT 1978

Pagination or Media Count : 37

Abstract : An experimental investigation was conducted to determine the effect of low-velocity impact damage and circular holes on the compressive strength of a 48-ply orthotropic graphite-epoxy laminate. Specimens were impacted by 1.27-cm-diameter aluminum spheres with speeds ranging from 52 to 101 m/s. Some specimens were impacted without any applied compressive load and then loaded to failure to determine their residual strength. Other specimens were loaded to a prescribed axial compressive strain and impacted while at that applied load. Loaded specimens that did not fail catastrophically on impact were subsequently loaded to failure to determine their residual strength. Low-velocity impact damage was found to degrade seriously the laminate static compressive strength. Low-strain compression-compression cyclic loading was found to degrade further the compressive strength of impact-damaged specimens. Specimens with circular holes having diameters up to a third of the specimen width were loaded to failure in compression. It was found that circular holes can also degrade the static compressive strength of the laminate. The effects of circular holes and impact damage on the compressive strength of the laminate are compared. (MM)

Descriptors :   *TERMINAL BALLISTICS, *EPOXY LAMINATES, *COMPRESSIVE STRENGTH, *GRAPHITE EPOXY COMPOSITES, LAMINATES, PROJECTILES, IMPACT TESTS, DAMAGE ASSESSMENT, TEST EQUIPMENT, STRAIN(MECHANICS), STRENGTH(MECHANICS), IMPACT STRENGTH, HOLES(OPENINGS), AEROSPACE CRAFT, PREPREGS, FAILURE(MECHANICS), CIRCLES.

Subject Categories : Laminates and Composite Materials
      Ballistics

Distribution Statement : APPROVED FOR PUBLIC RELEASE