Summary : The fine optimization of composite structures needs to develop tools for modeling mechanical behavior increasingly sophisticated and taking into account the specificities of these materials-structure. A model of type layer-wise, kinematics by layer, is used here. It is based on the work of the team of multilayer structures at Navier Institute. This model includes 5n kinematic fields for a multilayer of n layers and is named "M4-5N". It approaches each layer with a plate Reissner and integrates the interfacial efforts generalized. The first version of the finite element code called MPFEAP (Multiparticle Finite Element Analysis Program) is enriched here by dynamic module that allows the calculation of modes and a problem of impact, and by taking into account non-linear or imperfect interfaces. The interface remains a frontier zone between two layers but with his own behavior that takes into account only the transverse shear and normal.