Control of the pull-in instability of a capacitive micro-beam using SMA wires

This paper presents a study on the effects of the SMA wires on the static and dynamic pull-in instability of a capacitive microbeam. In the proposed model pre-strained SMA wires have been embedded into a double clamped microbeam which is actuated electrostatically. The governing equation of motion of the beam has been introduced and then Galerkin-based numerical methods have been used to solve it. The effects of the Number of SMA wires, their diameter, pre-strain and temperature on the produced recovery stress in SMA wires have been calculated. The results have shown that by changing each of these parameters, one can reach a desired magnitude of recovery stress as well as transmitted longitudinal force to the host beam, and consequently control the static and dynamic pull-in instability of the micro-structure.

Keywords:

SMA , MEMS , Electrostatic , Pull-in