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A deformation-formulated micromechanics model of the effective Young's modulus and strength of laminated composites containing local ply curvatureA mathematical model based on the Euler-Bermoulli beam theory is proposed for predicting the effective Young's moduli of piecewise isotropic composite laminates with local ply curvatures in the main load-carrying layers. Strains in corrugated layers, in-phase layers, and out-of-phase layers are predicted for various geometries and material configurations by assuming matrix layers as elastic foundations of different spring constants. The effective Young's moduli measured from corrugated aluminum specimens and aluminum/epoxy specimens with in-phase and out-of-phase wavy patterns coincide very well with the model predictions. Moire fringe analysis of an in-phase specimen and an out-of-phase specimen are also presented, confirming the main assumption of the model related to the elastic constraint due to the matrix layers. The present model is also compared with the experimental results and other models, including the microbuckling models, published in the literature. The results of the present study show that even a very small-scale local ply curvature produces a noticeable effect on the mechanical constitutive behavior of a laminated composite.
Document ID
19900053097
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Lee, Jong-Won
(Texas A & M University College Station, United States)
Harris, Charles E.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1990
Subject Category
Composite Materials
Meeting Information
Meeting: Symposium on Composite Materials: Testing and Design
Location: Sparks, NV
Country: United States
Start Date: April 27, 1988
End Date: April 29, 1988
Sponsors: ASTM
Accession Number
90A40152
Funding Number(s)
CONTRACT_GRANT: NAG1-711
Distribution Limits
Public
Copyright
Other

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