Menu

Discussion Forum

New Discussion
Filtrer

Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

piezoelectric resonator thickness shear mode

Posted 23 juil. 2014, 18:35 UTC−4 MEMS & Nanotechnology, Piezoelectric Devices, MEMS & Piezoelectric Devices Version 4.3b 2 Replies

Farrukh Mateen
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

I have a simple question about the thickness shear mode example tutorial provided with the MEMS model library in 4.3b. The resonator consists of a cylindrical piezoelectric material (Quartz) sandwiched between a positive terminal (top surface of the cylinder) and ground (bottom surface of the cylinder). If in the model the frequency domain analysis is run between 5.09MHZ and 5.13MHZ you get a good shear resonance, with terminal voltage of 10V. I have tried this and also if I increase the voltage to say 50 V I get the same resonance mode shape but higher amplitude which makes sense. ALso if I turn the terminal voltage to 0v there is no resonance at all. This is all perfectly intuitave.

But if I run an eigenfrequency analysis and ask for the first 50 eigenfrequencies then it doesnt matter whether the terminal voltage is set to 0v or 100v or 10v etc it will always give me the entire eignefrequencies along with the modes there amplitudes. SO my question is that shouldnt at 0v the eigenfrequencies should also be zero as in if the resonantor is still resonating at all those frequencies then whats the use of having the terminal voltage in the first place ???

Or is it that the software is reporting eigenfrequencies as the resonators own frequencies with which it will resonate when no external force or damping is applied.

2 Replies Last Post 30 juil. 2014, 10:29 UTC−4
Pieter Westerik
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 28 juil. 2014, 07:57 UTC−4
In eigenfrequency analysis, just the mode shape and the corresponding eigenfrequency is calculated. In a physical situation the amplitude will be proportional to the exciting voltage, but as long as no non-linear effects occur, the mode shape and corresponding resonance frequency will not change.
In eigenfrequency analysis, just the mode shape and the corresponding eigenfrequency is calculated. In a physical situation the amplitude will be proportional to the exciting voltage, but as long as no non-linear effects occur, the mode shape and corresponding resonance frequency will not change.
Farrukh Mateen
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 30 juil. 2014, 10:29 UTC−4
Thanks a lot this makes the situation pretty clear.
Thanks a lot this makes the situation pretty clear.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content