Bending response of 3-D woven and braided preform composite materials
Three dimensional textile carbon-epoxy composites exhibit general anisotropy. Further, these materials may possess different modulus in uniaxial tension than that in compression. In an earlier material characterization effort, the tension, compression, and shear properties of these composites were determined. In this paper, theoretical modeling of flexure of the textile composites and experimental correlation are presented. Four point bending tests were conducted according to STM D709 standards to determine the load to mid-span deflection relationships for typical textile composites. The results of experimental analysis are compared with classical beam theory, theory of elasticity solutions considering material orthotropy and shear deflection, and finite element analysis considering material orthotropy and finite deformation/rotations. The derivation of a harmonic function, required for the theory of elasticity solution, is described in the paper. Homogeneous orthotropic elastic properties are assumed for the 3-D textile composites, which is a reasonable approximation for specimens considerably larger than the repeated geometric unit of the fiber preform. The so called ``flex modulus`` is determined from the experimental data.
- Univ. of Delaware, Newark, DE (United States)
- Lockheed Aeronautical Systems Company, Marietta, GA (United States)
- Publication Date:
- OSTI Identifier:
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ISBN 1-56676-220-0; TRN: IM9536%%327
- Resource Type:
- Resource Relation:
- Conference: 9. technical conference of the American Society for Composites, Newark, DE (United States), 20-22 Sep 1994; Other Information: PBD: 1994; Related Information: Is Part Of Proceedings of the American Society for Composites: Ninth technical conference; PB: 1319 p.
- Technomic Publishing Co., Inc., Lancaster, PA (United States)
- Country of Publication:
- United States
- 36 MATERIALS SCIENCE; COMPOSITE MATERIALS; FLEXURAL STRENGTH; CARBON FIBERS; EPOXIDES; TEXTILES; MATHEMATICAL MODELS; ELASTICITY; STRUCTURAL BEAMS; FINITE ELEMENT METHOD; STRESSES; STRAINS; EXPERIMENTAL DATA; CORRELATIONS