Border flow effects in squeezed-film dampers having a gap separation comparable with the surface dimensions are studied with 2D and 3D FEM simulations and with analytic models derived from the linearized Reynolds equation for small squeeze-numbers. Surface elongations are extracted with 2D FEM simulations for 1D squeezed-film dampers for variable surface topologies for both linear and torsional modes of motion. To model 2D squeezed-film dampers, these elongations are used directly in the compact models, and the results are verified with 3D FEM simulations. FEM simulations show that a simple surface-elongation model gives excellent results, and extend the validity range of existing compact models. To improve the model, drag forces acting on the upper surface and the sidewalls are approximated with simple equations based on FEM simulations.
Journal: TechConnect Briefs
Volume: 2, Technical Proceedings of the 2004 NSTI Nanotechnology Conference and Trade Show, Volume 2
Published: March 7, 2004
Pages: 235 - 238
Industry sector: Sensors, MEMS, Electronics
Topic: MEMS & NEMS Devices, Modeling & Applications