Combined mechanical and melting damage model for geomaterials

We present a new damage model combining mechanics and partial melting in accordance with the principles of non-equilibrium thermodynamics. On the mechanical side, elasto-viscoplactic damage is considered based on a self-consistent far from equilibrium thermodynamic framework; on the melt side, partial melting is calculated by using the thermodynamic MELTS Gibbs energy minimizer. In this framework, the partial melt appears as an additional damage parameter. The numerical implementations are accomplished by using Abaqus solver and the extendable User Material Subroutine. A simplified continental extension model is used to test the approach. This new model can be applied to geodynamic problems involving brittle and ductile faulting, partial melting, magma generation and the interaction between these activities.