In microsystem technology, the numerical simulation of coupled problems is one of the principal challenges. There are three main reasons for the fact that, here, the coupling of different physical effects (structural dynamics, fluid dynamics, heat transfer, or electromagnetics, e.g.) is more frequently encountered than in the macro world: First, aspects of scaling often lead to a dominance of surface effects on volume dependent effects. Second, especially in sensors a lot of different physical phenomena are used for signal conversion, and, finally, in some microsystems different physical effects have an influence on each other.

We present a classification of the most important couplings in the microsystem world, and we give a survey on existing solution techniques with emphasis on methods based on the so-called partitioned solution. Here, there is no joint model, neither continuous nor discrete, but the coupled problem is solved by an outer iteration realizing the coupling and by arbitrary inner solution processes for each single problem. The coupling is done via changed boundary conditions, geometries, or parameters after each step of iteration. This approach seems to be advantageous, since its modularity allows the use of existing and efficient codes for each sub-problem. Therefore, only the outer iteration has to be organized with some kind of interface for the coupling. Furthermore, this technique seems to be perfectly suited for parallelization, especially for the use of (heterogeneous) workstation clusters.

Finally, some first numerical results concerning the simulation of a micro-miniaturized two-valve membrane pump are presented.