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A new look at numerical analyses of free-edge stresses in composite laminatesThe edge stress problem for a + or - 45 deg graphite/epoxy laminate was examined. The reliability of the displacement formulated finite element method in analyzing the edge stress problem was investigated. Analyses of two well known elasticity problems, one involving a stress discontinuity and one a singularity, showed that the finite element analysis yields accurate stress distributions everywhere except in two elements closest to the stress discontinuity of singularity. Stress distributions for a + or - 45 deg laminate showed the same behavior near the singularity found in the well known problems with exact solutions. The displacement formulated finite element method appears to be a highly accurate technique for calculating interlaminar stress in composite laminates. The disagreement among the numerical methods was attributed to the unsymmetric stress tensor at the singularity.
Document ID
19810004862
Document Type
Technical Publication (TP)
Authors
Raju, I. S.
(NASA Langley Research Center Hampton, VA, United States)
Whitcomb, J. D.
(NASA Langley Research Center Hampton, VA, United States)
Goree, J. G.
(Clemson Univ.)
Date Acquired
September 4, 2013
Publication Date
December 1, 1980
Subject Category
Structural Mechanics
Report/Patent Number
L-13777
NASA-TP-1751
Funding Number(s)
PROJECT: RTOP 506-53-53-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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