The thin ice covering the polar oceans is a complex geomaterial that is constantly breaking and moving under the action of the wind and ocean currents and that experiences transitions between a brittle solid and a granular fluid state. We have developed a simple continuum mechanical framework in the view of representing accurately its dynamical behavior in regional and global sea ice or coupled climate models. It combines the concepts of elastic memory, progressive damage and viscous-like relaxation of stresses. Here, we present this framework and its ongoing numerical development based on Finite Element, Discontinuous Galerkin methods.