Mixed interpretation and extensions of the equivalent mass matrix approach for elastodynamics with contact

The present paper highlights the idea that the mass redistribution technique introduced by Khenous and co-workers (2006) [17,18] for elastodynamics with impact, can be reinterpreted as a mixed formulation in displacements and velocities in which a special compatibility condition is enforced. Such a formulation opens the route to various extensions and to variational integrators for impact problems, potentially with variational time adaption. Those ideas are exemplified in the design of such integrators and various mass redistribution schemes.