
MicromechanicsUnidirectionalTransport PropertiesDiffusivity
The diffusion coefficient (permeability) of a lamina is calculated in terms of the diffusion coefficient of the matrix and the fiber content. The diffusion in the fiber is assumed to be negligible, which is true for fiberglass, carbon fibers, etc., but not for polymeric fibers such as Kevlar, Nylon, Vectran, etc. An update to the code is necessary for polymeric matrix.
Once the diffusion coefficient, or diffusivity, is known, the mass diffusion of a liquid or a gas through a composite lamina is calculated using Fourier's equation for diffusion, in terms of the diffusion coefficient of the lamina.
Fourier's equation applies equally to thermal and mass diffusion. Therefore, a heat transfer finite element code can be used to calculate the concentration in the same way that it can be used to calculate the temperature distribution. To access this resource please sign in or register (It's free!).
