Un metodo di accoppiamento tra modelli continui ed atomistici con discussione e applicazioni specifiche

This thesis describes a detailed study of a bridging domain method for coupling continuum models with molecular models. The method based on a multiscale approach that belongs to the category defined as "concurrent", allows in particular to simulate the propagation of a wave in the entire domain and to analyze the resulting displacements. The applications presented consider a number of atoms of the order of thousands in the analysed domain instead of hundreds as it is commonly done in published examples. The influence of the choice of in shape functions in the continuum discretization is investigated in detail as well as that of the lengths of the overlapping domain. The thesis includes a review of the principal methods used for coupling continuum models with molecular models. The aim of this thesis is to give a contribution to simulations which allow to understand how characteristics of materials, at an atomistic scale, can influence the behaviour of structures. This is important in several fields like civil and mechanical engineering, chemical sciences, electronic applications and physics.