Numerical approaches allowing for the local analysis of global models are listed, the Arlequin method being the topic of focus. By superposing mechanical states sharing energies, this method generates a partition of models framework that gives a consistent ``plasticity'' to the classical mechanical and numerical (mono-)modelling. It consists in a family of formulations of mechanical problems, each of them being derived by combining basic bricks whose choices are rigorously analysed. The effectiveness of this partition of models framework to allow concurrent multimodel and multiscale analysis is exemplified.