CUED Publications database

Fabrication and testing of a high resolution extensometer based on resonant MEMS strain sensors

Ferri, M and Belsito, L and Mancarella, F and Masini, L and Roncaglia, A and Yan, J and Seshia, AA and Zalesky, J and Soga, K (2011) Fabrication and testing of a high resolution extensometer based on resonant MEMS strain sensors. In: UNSPECIFIED pp. 1056-1059..

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Abstract

A novel type of linear extensometer with exceptionally high resolution of 4 nm based on MEMS resonant strain sensors bonded on steel and operating in a vacuum package is presented. The tool is implemented by means of a steel thin bar that can be pre-stressed in tension within two fixing anchors. The extension of the bar is detected by using two vacuum-packaged resonant MEMS double- ended tuning fork (DETF) sensors bonded on the bar with epoxy glue, one of which is utilized for temperature compensation. Both sensors are driven by a closed loop self-oscillating transresistance amplifier feedback scheme implemented on a PCB (Printed Circuit Board). On the same board, a microcontroller-based frequency measurement circuit is also implemented, which is able to count the square wave fronts of the MEMS oscillator output with a resolution of 20 nsec. The system provides a frequency noise of 0.2 Hz corresponding to an extension resolution of 4 nm for the extensometer. Nearly perfect temperature compensation of the frequency output is achieved in the temperature range 20-35 C using the reference sensor. © 2011 IEEE.

Item Type: Conference or Workshop Item (UNSPECIFIED)
Uncontrolled Keywords: Extensometer MEMS resonator strain sensor vacuum packaging
Subjects: UNSPECIFIED
Divisions: Div C > Applied Mechanics
Div D > Geotechnical and Environmental
Depositing User: Cron Job
Date Deposited: 07 Mar 2014 12:04
Last Modified: 27 Nov 2014 19:19
DOI: 10.1109/TRANSDUCERS.2011.5969171