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Analysis of interlaminar stresses in thick composite laminates with and without edge delaminationThe effect of laminate thickness on the interlaminar stresses in rectangular quasi-isotropic laminates under uniform axial strain was studied. Laminates from 8-ply to infinitely thick were analyzed. Thick laminates were synthesized by stacking (45/0/-45/90) ply groups, rather than grouping like plies. Laminates with and without delaminations were studied. In laminates without delaminations, the free-edge interlaminar normal stress distribution in the outer ply groups was insensitive to total laminate thickness. The interlaminar normal stress distribution for the interior ply groups was nearly the same as for an infinitely thick laminate. In contrast, the free-edge inter-laminar shear stress distribution was nearly the same for inner and outer ply groups and was insensitive to laminate thickness. In laminates with delaminations those delaminations near the top and bottom surfaces of a thick laminate have much larger total strain-energy-release rates (G sub t) and mode I-to-total (G sub t/G sub t) ratios than delaminations deep in the interior. Therefore, delaminations can be expected to grow more easily near the surfaces of a laminate than in the interior.
Document ID
19860035892
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Whitcomb, J. D.
(NASA Langley Research Center Hampton, VA, United States)
Raju, I. S.
(Analytical Services and Materials, Inc. Tabb, VA, United States)
Date Acquired
August 12, 2013
Publication Date
January 1, 1985
Subject Category
Composite Materials
Accession Number
86A20630
Funding Number(s)
CONTRACT_GRANT: NAS1-17090
Distribution Limits
Public
Copyright
Other

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