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Experimental-Numerical Comparison of the Cantilever MEMS Frequency Shift in presence of a Residual Stress Gradient

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ABSTRACT

The dynamic characterization of a set of gold micro beams by electrostatic excitation in presence of residual stress gradient has been studied experimentally. A method to determine the micro-cantilever residual stress gradient by measuring the deflection and curvature and then identifying the residual stress model by means of frequency shift behaviour is presented. A comparison with different numerical FEM models and experimental results has been carried out, introducing in the model the residual stress of the structures, responsible for an initial upward curvature. Dynamic spectrum data are measured via optical interferometry and experimental frequency shift curves are obtained by increasing the dc voltage applied to the specimens. A good correspondence is pointed out between measures and numerical models so that the residual stress effect can be evaluated for different configurations.

No MeSH data available.


Experimental frequency spectrum of a microbeam with Vac=4.5V and three different values of DC voltage: 0V: fn=41640 Hz, Q= 43.4; 20V: fn=41230 Hz, Q=38.2; 40V: fn=40110, Q=35.9. Q factor was calculated with the half power method.
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f5-sensors-08-00767: Experimental frequency spectrum of a microbeam with Vac=4.5V and three different values of DC voltage: 0V: fn=41640 Hz, Q= 43.4; 20V: fn=41230 Hz, Q=38.2; 40V: fn=40110, Q=35.9. Q factor was calculated with the half power method.

Mentions: With the Fogale Zoomsurf 3D it is possible to obtain the frequency spectrum between 100 Hz and 2 MHz, applying the phase shifting interferometry technique [22], based on the measure of interference fringes phase, as shown in the spectrum graph (Figure 5). A square portion located on the tip of the cantilevers is selected as measurement spot. The increase of the dc voltage at constant ac voltage brings the system to appreciable increase of amplitude and reduction of the natural frequency. The effect can be visualized with a shift on the left of the resonance peak on the spectrum graph (Fig. 5). Frequency shift was measured until the reaching of pull-in, which appeared strongly dependent on the beam curvature.


Experimental-Numerical Comparison of the Cantilever MEMS Frequency Shift in presence of a Residual Stress Gradient
Experimental frequency spectrum of a microbeam with Vac=4.5V and three different values of DC voltage: 0V: fn=41640 Hz, Q= 43.4; 20V: fn=41230 Hz, Q=38.2; 40V: fn=40110, Q=35.9. Q factor was calculated with the half power method.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3927528&req=5

f5-sensors-08-00767: Experimental frequency spectrum of a microbeam with Vac=4.5V and three different values of DC voltage: 0V: fn=41640 Hz, Q= 43.4; 20V: fn=41230 Hz, Q=38.2; 40V: fn=40110, Q=35.9. Q factor was calculated with the half power method.
Mentions: With the Fogale Zoomsurf 3D it is possible to obtain the frequency spectrum between 100 Hz and 2 MHz, applying the phase shifting interferometry technique [22], based on the measure of interference fringes phase, as shown in the spectrum graph (Figure 5). A square portion located on the tip of the cantilevers is selected as measurement spot. The increase of the dc voltage at constant ac voltage brings the system to appreciable increase of amplitude and reduction of the natural frequency. The effect can be visualized with a shift on the left of the resonance peak on the spectrum graph (Fig. 5). Frequency shift was measured until the reaching of pull-in, which appeared strongly dependent on the beam curvature.

View Article: PubMed Central - PubMed

ABSTRACT

The dynamic characterization of a set of gold micro beams by electrostatic excitation in presence of residual stress gradient has been studied experimentally. A method to determine the micro-cantilever residual stress gradient by measuring the deflection and curvature and then identifying the residual stress model by means of frequency shift behaviour is presented. A comparison with different numerical FEM models and experimental results has been carried out, introducing in the model the residual stress of the structures, responsible for an initial upward curvature. Dynamic spectrum data are measured via optical interferometry and experimental frequency shift curves are obtained by increasing the dc voltage applied to the specimens. A good correspondence is pointed out between measures and numerical models so that the residual stress effect can be evaluated for different configurations.

No MeSH data available.