Squeeze-film damping in solid-state accelerometers

Criteria are set forth that are aimed at altering the designer to the onset of nonlinear and compressible effects in accelerometers. A finite-element technique is presented that essentially solves Reynold's equation for small displacements and squeeze numbers by analogy with heat conduction in a solid with internal heat generation. Examples are presented that show film pressure profiles generated for complex geometries with nonuniform film thicknesses and squeeze velocities. A technique for mitigation of compressibility effects through film pressurization is suggested. Ideal damping results if both the squeeze number and the relative displacement are kept much less than 1.0. If these conditions are satisfied, one can then use finite-element techniques to estimate damping coefficients for other than simple geometries.>