Experimental Characterization of the static behaviour of microcatntilevers electrostatically actuated

TL;DR

This study experimentally validates mathematical models predicting the static behavior of microelectrostatic microbeams, highlighting the effects of geometrical nonlinearity and comparing different FEM approaches for accurate pull-in and displacement predictions.

Contribution

The paper provides experimental validation of coupled-field models for microcantilever static behavior, distinguishing linear and nonlinear regimes, and compares FEM solutions for improved accuracy.

Findings

Model accurately predicts pull-in voltage and displacement curves.

Nonlinear FEM solutions outperform linear models for large deflections.

Experimental results confirm the importance of considering geometrical nonlinearity.

Abstract

This paper concerns the experimental validation of some mathematical models previously developed by the authors, to predict the static behaviour of microelectrostatic actuators, basically free-clamped microbeams. This layout is currently used in RF-MEMS design operation or even in material testing at microscale. The analysis investigates preliminarily the static behaviour of a set of microcantilevers bending in-plane. This investigation is aimed to distinguish the geometrical linear behaviour, exhibited under small displacement assumption, from the geometrical nonlinearity, caused by large deflection. The applied electromechanical force, which nonlinearly depends on displacement, charge and voltage, is predicted by a coupled-field approach, based on numerical methods and herewith experimentally validated, by means of a Fogale Zoomsurf 3D. Model performance is evaluated on pull-in prediction and on the curve displacement vs. voltage. In fact, FEM nonlinear solution performed by a coupled-field approach, available on commercial codes, and by a FEM non-incremental approach are compared with linear solution, for different values of the design parameters.