Nonsteady Effective Thermal Conductivity of Dense Fibrous Composites with Graded Interface

摘要

The multiple scattering of thermal waves by dense fibers with a functionally graded interface in composites isnconsidered, and the analytical solution of the nonsteady effective thermal conductivity of composites is presented.nThe Fourier heat conduction lawis applied to analyze the propagation of thermalwaves in the fibrous composite.Thenscattering and refraction of thermal waves by cylindrical fiberswith a nonhomogeneous interface layer in thematrixnare expressed by using the wave function expansion method. The theory of quasi-crystalline approximation and thenconditional probability density function are employed to treat the multiple scattering of thermal waves from thendense fibers.Through analysis, it is found that the nonsteady effective thermal conductivity under higher frequenciesnis quite different from the steady thermal conductivity. In different regions of wave frequency, the effects of thenfunctional form of gradation and the properties and thickness of the functionally graded layers on the nonsteadyneffective thermal conductivity show great differences.