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 fibre reinforcement. The anisotropic thermal efficiency is defined as the ratio between the anisotropy degree of the composite, and the potential anisotropy of the two materials. The anisotropic degree of the composite is the ratio between the effective thermal conductivity in the direction parallel to the fibre reinforcement, and that in the perpendicular direction. The potential anisotropy of the materials is the ratio between the thermal conductivities of the two materials of the composite. The theoretical model allows evaluating the anisotropic thermal efficiency of the symmetric composite under the two thermal assumptions of parallel isotherms and parallel heat fluxes. 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.