Overview
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.
Publications
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]