Three-dimensional simulation of moisture diffusion in polymer composite materials

This article presents a three-dimensional Galerkin finite element methodology (GFEM) for simulating Fickian diffusion with temperature-dependent diffusion coefficients, with particular application to moisture diffusion in composite materials. The coupled thermal and moisture diffusion problems are solved by using three-dimensional finite element method with orthotropic diffusion coefficients and an implicit time-stepping procedure. Both Frontal and Jacobi conjugate gradient (JCG) solution techniques are used. Numerical examples are presented to illustrate the methodology and include orthotropic diffusivities and multiple material regions. Moisture diffusion within a periodic unit cell of a typical composite material is also considered. The results show that the iterative JCG method is effective and computationally inexpensive to analyze diffusion three-dimensional diffusion problems with multiple materials.