[hereford_jon]

We are using Ansys Mechanical to model a MEMS cantilever to determine its natural frequency. The cross section of the cantilever is approx 10 x 1.5 microns. There are some contacts in this assembly. The model runs well, but gives a warning about large contact stiffnesses and the specified contacts. As a sanity check we have run the model scaled x1000 (so the cantilever assembly is now in the millimeter range) and from scaling analysis we know that this is reasonable and that natural frequency will be 1/1000 of that of the original model for the same Young's Modulus and material density. At this size the warning message does not appear. I appreciate that at the original scale, features are particularly small with some dimensions less than 1 micron. To model MEMS devices for structural analysis, what is the best practice for geometry and contacts? If we have to work at the original size and so not use scaling laws (because of other considerations, for instance FSI and we need to correctly model fluid flow through an embedded channel in the cantilever in a coupled model) what would anyone advise for dealing with contacts at this small scale. From a geometry creation point of view, we appear to be almost at the limit of what SpaceClaim and SolidEdge can handle.