RESONANT BEHAVIOUR OF BEAM-TYPE ELECTROSTATIC MICROACTUATORS

Abstract

MEMS, abbreviated for Micro-Electro-Mechanical Systems, are small integrated devices or systems that combine electrical and mechanical components. These system can sense, control and activate mechanical processes on the micro scale and function individually or in array to generate effects on the macro scale. These devices can be actuated in electromagnetic, electrostatic, electro-thermal and piezoelectric modes of actuations. These devices are prone to an undesirable behavior, called pull-in instability that limits their operational range, much less than entire range. AL We carry out the analysis of this pull-in instability in electrostatic mode of actuation and find the Critical parameters corresponding to this instability phenomenon, called pull-in parameters for 6. the parallel plate model and the continuous model of micro cantilever beam and fixed-fixed micro beam using an energy approach in static mode of actuation. Resonators are important application of MEMS devices. A particular frequency range is used for design of resonators. We present prismatic nonlinear model of electrostatically actuated micro beam accounting for the electrostatic forcing, restoring force and the mid plane stretching force and solve this model for frequency variations using the energy approach. It has been shown that mid plane stretching has a significant effect on frequency variation around the mid plane of the continuous system of the fixed-fixed beam. We also present the nonlinear model of shaped (non-prismatic) micro beams and solve them using the energy technique for frequency variations. A comparison between non-prismatic and prismatic micro beam's frequency variations have been carried out and it has been concluded that for a particular shaped beam (non-prismatic), there is 2.8335 % increment in maximum normalized natural frequency in comparison to the un-deformed beam's maximum normalized natural frequency