  A method for simulation of elastoplastic solids in multibody systems with
nonsmooth and multidomain dynamics is developed. The solid is discretised into
pseudo-particles using the meshfree moving least squares method. The particles
carry strain and stress tensor variables that are mapped to deformation
constraints and constraint forces. The discretised solid model thus fit a
unified framework for nonsmooth multidomain dynamics for realtime simulations
including strong coupling of rigid multibodies with complex kinematic
constraints such as articulation joints, unilateral contacts with dry friction,
drivelines and hydraulics. The nonsmooth formulation allow for impulses, due to
impacts for instance, to propagate instantly between the rigid multibody and
the solid. Plasticity is introduced through an associative perfectly plastic
modified Drucker-Prager model. The elastic and plastic dynamics is verified for
simple test systems and the capability of simulating tracked terrain vehicles
driving on a deformable terrain is demonstrated.
