Effect of hydrogen concentration on brittle fracture

The problem of an isotropic linearly elastic solid subjected to external loading and hydrogen diffusion is analyzed. Governing equations for hydrogen transport under a,plane strain deformation are derived. It is interesting to note that the involvement of hydrogen concentration in constitutive equations would fulfill the condition of thermodynamic reciprocity. The order of singularity of the steady state hydrogen concentration at the crack tip is analyzed and compared with the equivalent uncoupled problem. A variational principle is established for the solution of governing differential equations with suitable boundary conditions. Finite element method can be constructed according to the variational principle. A problem of transient solution of hydrogen transport in the crack tip region is given for demonstrating the application of the finite element method.