Axial shear waves in fiber-reinforced composites with multiple interfacial layers between fiber core and matrix

Abstract

Effects of interfacial material properties on the overall dispersion and attenuation of axial shear waves in a multiphase fiber-matrix composite are investigated. The fiber-matrix composite consists of identical fibers that are embedded in a matrix. Multiphase interfacial regions are assumed to exist between the fiber core and the matrix, and their material properties (shear modulus μ and density ρ) are assumed to have linear or exponential variation between fiber core and matrix. Only the case of axial shear waves is studied; thus, the effective axial shear modulus ( M), axial shear wave phase speed ( B), and axial shear wave specific damping capacity ( Ψ) are obtained. The analyses indicate, among others, that the effective mechanical properties of the multiphase composite depend on (in addition to the fiber volume, c, and dynamic parameters I n ) the variations of material properties in the interfacial region. Numerical computations show the following: 1. The effective axial shear wave phase speed ( B) of the composite with multi-interfacial region does not vary with driving frequencies when the frequency range is under 30 Khz. Specifically, for frequency range under 30 Khz, the multiphase composite is indispersive. 2. For the same composite, a higher frequency range will beget higher attenuation. 3. Under the same frequency, certain composites will have higher attenuation; composites with thicker interfacial region, composites with less smooth variation of the interfacial region, and composites with exponential variation (compared with those of linear variation) of the interfacial region.