| Abstrakt: |
Total diffusion time and the total moisture absorption amount were proposed as the measurement standards of equivalent coefficients for composites moisture diffusion with impermeable fibers. Representative volume element (RVE) models and 2D transient finite element models of unidirectional fiber reinforced composites were established and the accuracy of the RVE model for calculating the equivalent diffusivity was verified. The influences of fiber volume fraction, fiber arrangement and interfaces on the equivalent moisture diffusivity were investigated using the RVE models. The results show that the equivalent moisture diffusivity decreases with the increase of fiber volume fraction. The equivalent moisture diffusivity of random fiber distribution is smaller than that of the periodic fibers distribution, and this difference can be neglected when the fiber volume fraction is relative small. The interfaces with higher diffusivity than matrix will apparently increase the composites diffusivity. |
