Micromechanically-based acoustic characterization of the fiber orientation distribution function of morphologically textured short-fiber composites: prediction of thermomechanical and physical properties

We apply our recently-developed acoustic approach to characterize the fiber orientation distribution function (ODF) of short fiber composites to predict relevant anisotropic thermomechanical properties of such composites. The acoustic approach consists of a tight coupling of acoustic velocity measurements and micromechanics modeling. It can not completely characterize the ODF, but delivers information regarding lower-order terms of the ODF when expanded in a series of generalized spherical harmonics. We apply the approach to two composite material systems (SiC/Al and glass/polyphenylene sulfide) with different overall symmetry (transversely istropic and orthotropic). For the two composites, we predict the overall anisotropic elastic moduli, thermal expansion coefficients, elastic–plastic constitutive behavior, and thermal conductivity. The predictions agree well with measurements in all cases; this demonstrates that the lower-order terms of the ODF expansion are sufficient to characterize a large number of other physical and mechanical properties of the composite, when coupled with the appropiate models. As a result, we conclude that the combination of acoustic velocity measurements and micromechanics modeling provides a powerful approach to characterize the fiber ODF, and its effect on overall composite properties.