M. Sofonea, N. Renon and M. Shillor,

A mathematical model for frictionless contact of a deformable body
with a rigid moving obstacle is analyzed. The Prandtl-Reuss
elastic-perfectly-plastic constitutive law is used to describe the
material's behavior and contact is modelled with a unilateral
condition imposed on the surface velocity. The problem is motivated
by the process of the plowing of the ground. A variational
formulation of the problem is derived in terms of the stresses and
the existence of the unique weak solution is proven. The proof is
based on arguments for differential inclusions obtained in Amassad
et al. (2001). Finally, a study of the continuous dependence of the
solution on the data is presented.