We formulated a thermo-chemo-mechanically coupled-theory which accounts for diffusion of hydrogen and large elastic-plastic deformations of metals. The theory accounts for the trapping of hydrogen at microstructural defects and places the notion of an equilibrium between trapped and diffusing hydrogen within a thermodynamically-consistent framework. The fully-coupled theory was implemented in a finite element program (using custom elements in Abaqus/Standard) and verified by comparing against simulation results available in the literature.
Through simulations of hydrogen diffusion at a blunt-crack, we studied how to appropriately model the physical problem of a metallic host exposed to gaseous hydrogen. Specifically, we demonstrated that the proper boundary condition for modeling such a system involves prescribing the chemical potential at the interface, rather than the concentration as was previously done in the literature.
Di Leo, C.V., and Anand, L. (2013). Hydrogen in metals: a coupled theory for species diffusion and large elastic-plastic deformations. International Journal of Plasticity, 43, 42-69. [html]
Di Leo, C.V., (2013). A coupled theory for diffusion of hydrogen and large elastic-plastic deformations of metals. M.S. Diss., Massachsetts Institute of Technology. [html]