Elastic-plastic behavior of textured short-fiber composites

• Published in: Acta materialia Vol. 45; no. 8; pp. 3327 - 3340
• Main Authors: Dunn, M.L., Ledbetter, H.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-08-1997; Elsevier Science
• Subjects: Cross-disciplinary physics: materials science; rheology; Deformation, plasticity, and creep; Exact sciences and technology; Materials science; Physics; Treatment of materials and its effects on microstructure and properties; Constitutive equation; Short fiber; Fibre reinforced metal; Mechanical model; Fiber reinforced material; Theoretical study; Mechanical properties; Stress-strain relation; Modeling; Texture; Composite materials; Elastoplasticity; Property structure relationship; Microstructure
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/S1359-6454(96)00401-6

We propose a relatively simple micromechanics model to predict the elastic-plastic response of short-fiber composites with a preferred orientation of the reinforcement, i.e. a texture. Our theoretical efforts are directed toward a composite system with an elastic-plastic matrix containing elastic reinforcement, but the extension to allow elastic-plastic response of the reinforcement is straightforward. The theory is based on the combination of our recent model for textured elasticity of short-fiber composites and the often-used idea of a linear comparison composite to simulate the nonlinear behavior of the actual composite as proposed by Hill (
J. Mech. Phys. Solids, 1965,
13, 89) and Hutchinson (
Proc. R. Soc. London, 1970,
A319, 247). We compute the effective stress of the heterogeneously deforming matrix from the distortional energy of the matrix using the approach recently proposed by Qiu and Weng (
J. appl. Mech., 1992,
59, 261;
J. appl. Mech., 1995,
62, 1039). We give simple, easily used, results for orientation distributions of practical significance. We compare our predictions with measured stress-strain curves for an extruded SiC/6061-A1 short-fiber composite with a fiber orientation distribution that is axially symmetric about the extrusion axis. The predictions are in excellent agreement with measurements for the axial and transverse Young's moduli and the 0.2% yield stress. Good agreement is obtained between the predicted and measured flow stress over the entire range of deformation.