• Euler-Bernoulli beam;
  • normal compliance;
  • Signorini's condition;
  • weak solution;
  • control variational method;
  • optimal state;
  • finite difference method;
  • numerical simulations.


We consider a mathematical model which describes the equilibrium of an elastic beam in contact with two obstacles. The contact is modeled with a normal compliance type condition in such a way that the penetration is allowed but is limited. We state the variational formulation of the problem and prove an existence and uniqueness result for the weak solution. Then, we provide an alternative approach to the model, based on the control variational method. Necessary and sufficient optimality conditions are derived, together with an approximation property. We also adapt our results to some versions of the model which describe the contact with a single obstacle. For this type of problems we present two methods of numerical approach, based on the iterative control variational method and the Newton method, respectively, and provide numerical simulations for the two algorithms.