Thesis defence B. Sajadi: MEMS

11 December 2017 15:00 - Location: Aula, TU Delft - By: webredactie

On the Mechanics and Stability of Micro-Plates in Electrically Loaded MEMS Devices. Promotor: A. van Keulen (3mE). 

In the last decades, Micro-Electro-Mechanical Systems (MEMS) have drawn immense attention due to their potential use in a wide variety of modern applications. The performance of these devices hinges on the deflection and movement of their micro-mechanical components and clearly, improvement and innovation of MEMS require an in-depth understanding of the nonlinear mechanics of these components. This thesis provides an investigation on nonlinear mechanics of micro-plates in electrostatic MEMS devices. In particular, the nonlinear mechanics and stability of a clamped circular micro-plate in interaction with an electrostatic field are studied and the effects of different loading conditions on the stability of such a system are addressed.  The results of this study suggest that  in presence of a differential pressure  the steady state motion of an electrically actuated micro plate can be bi-stable or even multi-stable. A differential  pressure can cause additional limit points and an unstable solution branch in the _static or dynamic_ steady state solutions of the system. One of the newly observed critical points in static loading is shown to be highly sensitive to the applied differential pressure suggesting the possibility of employing this limit point for sensing applications. In addition, this thesis provides a study on analysing it nano-plates within the framework of  continuum mechanics. In this regard, the nonlinear vibrations of an electrically actuated graphene resonator is modelled and a methodology is proposed for characterization of its mechanical properties. The proposed techniques for modelling the mechanics of micro-plates in MEMS devices, are simple and computationally efficient. They can provide in-depth insight into MEMS behaviour and can be useful for designing MEMS with plate-like micromechanical components.

More information?

For access to theses by the PhD students you can have a look in TU Delft Repository, the digital storage of publications of TU Delft. Theses will be available within a few weeks after the actual thesis defence.