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An assessment of buffer strips for improving damage tolerance of composite laminatesGraphite/epoxy panels with buffer strips were tested in tension to measure their residual strength with crack-like damage. Panels were made with (45/0/-45/90)2S and (45/0/-45/0)2S layups. The buffer strips were parallel to the loading direction. They were made by replacing narrow strips of the 0 deg graphite plies with strips of either 0 deg S-Glass/epoxy or Kevlar-90/epoxy on either a one-for-one or a two-for-one basis. In a third case, 0 deg graphite/epoxy was used as the buffer material and thin, perforated Mylar strips were placed between the 0 deg plies and the cross-plies to weaken the interfaces and thus to isolate the 0 deg plies. Some panels were made with buffer strips of different width and spacings. The buffer strips arrested the cracks and increased the residual strengths significantly over those of plain laminates without buffer strips. A shear-lag type stress analysis correctly predicted the effects of layup, buffer material, buffer strip width and spacing, and the number of plies of buffer material
Document ID
Document Type
Reprint (Version printed in journal)
Poe, C. C., Jr.
(NASA Langley Research Center Hampton, VA, United States)
Kennedy, J. M.
(NASA Langley Research Center Hampton, Va., United States)
Date Acquired
August 11, 2013
Publication Date
January 1, 1980
Publication Information
Publication: Journal of Composite Materials Supplement
Volume: 14
Issue: 1, 19
Subject Category
Structural Mechanics
Accession Number
Distribution Limits

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