Further considerations on anisotropic thermal efficiency of symmetric composites

The paper investigates the anisotropic thermal efficiency of symmetric composites made of two components, matrix and fiber reinforcement. The anisotropic degree of the composite is the ratio between the effective thermal conductivity in the direction parallel to the fiber reinforcement, and that in the perpendicular direction. The potential anisotropy of the materials is the ratio between the thermal conductivity of the fiber to that of the matrix. The anisotropic thermal efficiency is the ratio between the anisotropy degree of the composite, and the potential anisotropy of the two materials. The theoretical model solves the heat conduction equation under the two thermal assumptions of parallel isotherms and parallel heat fluxes, and without any empirical constant nor analogy with other phenomena, evaluating the anisotropic thermal efficiency of the symmetric composite. The variation of the anisotropic thermal efficiency is investigated versus the potential anisotropy of the materials and the ratio between fiber and matrix thicknesses. The anisotropic thermal efficiency has a maximum versus the ratio between fiber and matrix thicknesses, and decreases with the increase of the potential anisotropy, reaching a minimum, which is only dependent on the geometrical configuration of the symmetric composite.