I - Plate models for thin structures -- I.0 - A short description of the chapter -- I.1 - The three dimensionnal elastic-model -- I.2 - The Kirchhoff-Love assumption -- I.3 - The Kirchhof f-Love plate model -- I.4 - The Naghdi model revisited using mixed variational formulation -- I.5 - About the rest of the book -- References of Chapter I -- II - Variational formulations for bending plates -- II.0 - A brief summary of the chapter -- II. 1 - Why a mixed formulation for plates -- II.2 - The primal variational formulation for Kirchhoff-Love model -- II.3 - The Reissner-Mindlin-Naghdi model for plates -- II.4 - Natural duality techniques for the bending plate model -- II.5 - A comparison between the mixed method and the one of section II.2.4 -- References of Chapter II -- III - Finite element approximations for several plate models -- III.0 - A summary of the chapter -- III. 1 - Basic results in finite element approximation -- III.2 - C1 elements -- III.3 - Primal finite element methods for bending plates -- III.4 - The penalty-duality finite element method for the bending plate model -- III.5 - Numerical approximation of the mixed formulation for a bending plate -- References of Chapter III -- IV - Numerical tests for the mixed finite element schemes -- IV.0 - A brief description of the chapter -- IV. 1 - Precision tests for the mixed formulation -- IV.2 Vectorial and parallel algorithms for mixed elements -- IV.3 - Concluding remarks -- References of Chapter IV -- V - A Numerical model for delamination of composite plates -- V.O - A brief description of the chapter -- V. 1 - What is delamination of thin multilayered plates -- V.2 - The three-dimensional multilayered composite plate model with delamination -- V.3 - A plate model for large delamination -- V.4 - The three-dimensional energy release rate -- V.5 - The mechanical example and the numerical method -- V.6 - Concluding remarks -- References of Chapter V.