International audienceCoupled problems arise because certain aspects of some systems have previously been modelled separately, assuming (implicitly) an uncoupled behaviour. More often then not, computational approaches and mature software have been developed for each of these aspects in isolation. If one has to consider now the coupled problem, it would be advantageous if this previous work could be put to good use. This, in particular, concerns the developed software. In this presentation we will analyse the requirements for this to be achieved, and outline some of the possible solutions. Several tasks have to be accomplished: Non-matching spatial grids and geometric representations have to be joined, fulfilling certain consistency requirements. Similarly non-matching time-stepping schemes have tobe combined. After outlining a possible mathematical formulation for the coupling, the joining of the software will be considered. We view the original software which is modelling some aspect as a software-engineering component, and we describe a component-based approach to achieve a consistently coupled and (if so desired) distributed computational simulation