A MIXED FINITE-ELEMENT FOR SHELL-MODEL WITH FREE-EDGE BOUNDARY-CONDITIONS .3. NUMERICAL ASPECTS

The mixed formulation for shells, which is presented here, is based on Koiter's model for thin elastic shells, the Kirchhoff-Love's kinemati cal relations being ensured through the use of Lagrange multipliers. A fter a brief recall of the mixed variational formulation, we give an a ppropriate choice for finite elements approximation. Then, we develop some aspects, related to geometry approximation and numerical implemen tation. In particular, in order to overcome membrane locking, improvem ents are suggested and we check the good behaviour of this formulation on some classical examples of published papers.