Selected problems in micromechanics of fibrous composites
Micromechanical modelling procedures for prediction of overall thermomechanical behavior and local fields in unidirectional coated and uncoated fibrous composites are presented. General thermomechanical loading situations are considered. The formulation allots that the fiber could be at most cylindrically orthotropic, and the coating and matrix are transversely isotropic. Local fields of the composite are approximated through the exact solution of a single coated fiber in an infinite medium which the authors derive. Results are extended to laminated plates, consisting of two-phase unidirectional plies, subjected to in-plane loadings and uniform temperature changes. Effective thermal conductivities and local thermal intensities of such composites are also examined. The coated fiber may have an arbitrary orientation distribution. The micromechanical model employed is primarily based on the Mori-Tanaka approximation. Some new, simple formulae for the overall elastic moduli of multiphase transversely isotropic composites are derived. The inclusions considered are fibers with circular cross section and platelet-like reinforcements. Both unidirectional and completely random orientations are examined. Exact thermal expansion coefficients are found for three-phase fibrous media. Results are related to phase thermomechanical properties and overall elastic compliance only. The derivation is based on a novel decomposition procedure. Thermal effects can be uniquely expressed in terms of the solutions of mechanical loadings. Those are established for two-phase media and three-phase unidirectional fibrous composites as well as laminated plates consisting of two-phase fibrous plies. Finally, the existence of diagonal symmetry in estimates of overall elastic moduli of heterogeneous media is examined for several micromechanical models.
- Research Organization:
- Rensselaer Polytechnic Inst., Troy, NY (United States)
- OSTI ID:
- 5335838
- Country of Publication:
- United States
- Language:
- English
Similar Records
Analysis of properties of fiber composites with anisotropic constituents
Study of zero CTE (coefficients of thermal expansion) of graphite/epoxy composites
Related Subjects
360603* -- Materials-- Properties
CHEMICAL REACTIONS
COATINGS
COMPOSITE MATERIALS
DECOMPOSITION
ELASTICITY
EXPANSION
FIBERS
INCLUSIONS
ISOTROPY
LAYERS
MATERIALS
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
PARTICLES
PARTICULATES
PLATES
SYMMETRY
TEMPERATURE EFFECTS
TENSILE PROPERTIES
THERMAL EXPANSION
THERMODYNAMICS