Bistability of curved microbeams actuated by fringing electrostatic fields

Slava Krylov, Bojan R. Ilic, Stella Lulinsky

Research output: Contribution to journalArticlepeer-review

Abstract

In this work we investigate the feasibility of two-directional switching of an initially curved or pre-buckled electrostatically actuated microbeams using a single electrode fabricated from the same structural layer. The distributed electrostatic force, which is engendered by the asymmetry of the fringing fields in the deformed state, acts in the direction opposite to the deflection of the beam and can be effectively viewed as a reaction of a nonlinear elastic foundation with stiffness parameterized by the voltage. The reduced order model was built using the Galerkin decomposition with linear undamped modes of a straight beam as base functions and verified using the results of the numerical solution of the differential equation. The electrostatic force was approximated by means of fitting the results of three-dimensional numerical solution of the electrostatic problem. Static stability analysis reveals that the presence of the restoring electrostatic force may result in the suppression of the snap-through instability as well as in the appearance of additional stable configurations associated with higher buckling modes of the beam that are not observed in "mechanically" loaded structures. We show that two-directional switching of a pre-buckled beam between two stable configurations cannot be achieved using quasistatic loading. Furthermore, we show that switching is both associated with the dynamic snap-through mechanism and possible within certain interval of actuation voltages. Using a single-degree-of-freedom (lumped) model, estimation voltage boundaries are obtained. Theoretical results illustrate the feasibility of the suggested operational principle as an efficient mechanism in the arena of non-volatile mechanical memory devices.

Original languageEnglish
Pages (from-to)403-426
Number of pages24
JournalNonlinear Dynamics
Volume66
Issue number3
DOIs
StatePublished - Nov 2011

Keywords

  • Curved microbeam
  • Electrostatic actuation
  • MEMS/NEMS
  • Snap-through buckling

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