AUGMENTED LAGRANGIAN FINITE-ELEMENTS FOR PLATE CONTACT PROBLEMS

The present work investigates the unilateral frictionless contact betw een a plate and a rigid obstacle. Two sets of problems are studied: a plate constrained through unilateral edge supports and a plate seating in its undeformed configuration at a given distance from a rigid supp ort. The attention is concentrated on two augmented Lagrangian formula tions. The algorithmic implementation within a finite-element scheme i s presented and discussed. The importance of using appropriate plate e lements for the discretization of the structure is stressed. New gap e lements compatible with a robust plate element are derived. Computatio nal aspects are emphasized. A simple and effective numerical integrati on for the determination of the gap stiffnesses in partial contact wit h the support is proposed. Numerical results are carried out and Compa red with analytical solutions. The convergence to the solution of the perfectly constrained problem is numerically investigated. The inadequ acy of the penalty method and the satisfactory performance obtained fr om only one augmented Lagrangian procedure are emphasized.