Electromagnetic Propagation Radiative Transport in Fiberous Composites: Dependent Scattering Effects

摘要

Electromagnetic propagation and attenuation in a composite is significantly affected by its spectral and anisotropic characteristics in absorbing, emitting and scattering radiation. Due to their inherent inhomogeneity and directionality, reinforced composites can be very discriminating with respect to incoming radiation. The high volume fraction of fibers present in fiber-reinforced composites causes radiative dependent scattering and absorption effects to be important; that is, the scattering and absorption characteristics of one fiber may be affected by the presence of nearby fibers. Based on the configuration average of a random distribution of identical pair-correlated fibers embedded in a matrix, the dependent extinction efficiency for fibrous composites under normal incidence radiation is determined numerically. In addition, the dependent radiative transfer regime is established in terms of various combinations of fiber volume fraction, relative fiber size to incident wavelength and refractive index of fibers and matrix. It is found that the dependence of this dependent scattering regime on the refractive index of fibers and matrix is evident for small and medium size (a_v<2) fibers. For size parameter a_v>2, this dependence is insignificant and the limit of fiber volume fraction for independent scattering to apply is f less than 0.075±0.003.