SINOPSIS

We developed a random walk model for solving the diffusion problem arising from composite materials of particulate inclusions with different shapes. Our two-phase material system contains circular or elliptical impermeable inclusions that are randomly embedded in a matrix material. A computational algorithm was developed for random walk simulation of molecules and to estimate the effective diffusion coefficient of the composites. The random walk model has been validated by solutions from finite element analysis and effective medium theories. Our computational results show that the density of random distribution and the volume fraction of inclusions have significant effects on effective diffusion coefficients. Moreover, the aspect ratio of inclusions can significantly reduce diffusion speed when the volume fraction of inclusions is greater than? 30%.