Stress assisted diffusion in elastic and viscoelastic materials

Abstract

The governing field equations and boundary conditions for stress assisted diffusion are derived from basic principles of continuum mechanics and irreversible thermodynamics. Attention is confined to elastic and viscoelastic material response, with emphasis on isotropy and the case of small strains. It is shown that both the diffusion process and the saturation levels are stress dependent. In viscoelstic materials the time-dependence of the moisture boundary condition causes the saturation level to drift with time. In addition, the diffusion process becomes non-linear in stress, in spite of the linearity of the mechanical behavior.