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The influence of inclusion geometry on the elastic properties of discontinuous fiber composites
Author(s) -
Eduljee R. F.,
McCullough R. L.,
Gillespie J. W.
Publication year - 1994
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760340417
Subject(s) - materials science , ellipsoid , aspect ratio (aeronautics) , inclusion (mineral) , transverse isotropy , composite material , transverse plane , elastic modulus , isotropy , geometry , micromechanics , fiber , moduli , optics , mathematics , structural engineering , physics , thermodynamics , composite number , engineering , quantum mechanics , astronomy
Simplifying assumptions are used to reduce micromechanical treatments to compact expressions which directly reveal the role of the inclusion shape and aspect ratio in establishing the elastic behavior of heterogeneous materials. Attention is directed to the comparison of aligned ellipsoidal and cylindrical inclusions that exhibit transversely isotropic behavior characterized by five independent elastic constants. These comparisons show that the effective transverse in‐plane moduli ( E T * , k * and G TT * ) are essentially independent of inclusion shape for aspect ratio greater than ∼ 20; ellipsoidal inclusions provide higher longitudinal reinforcement than cylindrical inclusions of equivalent aspect ratio. Comparison of predictions with measured elastic moduli shows that both the cylindrical and ellipsoidal shape models for isolated inclusions overpredict longitudinal elastic constants for systems which exhibit evidence of inclusion agglomeration. The notion of an effective aspect ratio based on clusters of filaments responding as a coherent unit appears to provide a means for reconciling a wide range of experimental observations.