Penalty approximation for non smooth constraints in vibroimpact
  We examine the penalty approximation of the free motion of a material point in an angular domain; we choose an over-damped penalty, and we prove that if the first impact point is not at the vertex, then, the limit of the approximation exists and is described by Moreau's rule for anelastic impacts.   The proofs rely on validated asymptotics and use some classical tools in the theory of dynamical systems. 
Laetitia Paoli, Michelle Schatzman