A method of a floating frame of reference that performs splitting of a deformable solid into rigid and deforming parts is presented within the context of discrete element method. The decomposition is made in such a way that the deforming part of the velocity field does not contribute to the motion of the center of mass and to the rotational motion. The corresponding numerical method that computes both rigid and deforming motions is presented and extended to simulation of multi-body dynamics allowing non-smooth contact interactions, such as impacts and friction. Numerical experiments, where the method is compared with a more traditionally used Total Lagrangian method, justify its preference as a more efficient tool for the simulation of assemblies of stiff and massive objects.
