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Problem of the Electrical-Mechanical-Electrical Process of Piezoelement

Posted 27 nov. 2019, 10:02 UTC−5 Piezoelectric Devices Version 5.4 3 Replies

Siyuan Li
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Hi!

I have a model with 2 piezoelemts sticked together. On the left side I input a 1V 10kHz sin signal and on the right side I can only get about 0.1V. I have also made a experiment with 2 piezoelements (EPZ-20ms64w), but the output was about 960mV. Besides the deformation of Piezo looks quite strange. Did I set something wrong or just I missed other modules?

The 2 piezo elements were attached to a copper plate and the polarization direction was set to the X axis (global coordinate).

I also uploaded my mph file in the attachment. The first one uses Piezoelectric Devices, the second one uses Acoustic-Piezoelectric Interaction.

Can anyone help me with this? This is important for my master thesis! Thank you!

3 Replies Last Post 21 janv. 2020, 09:26 UTC−5
COMSOL Moderator

Hello Siyuan Li

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Hamid Basaeri
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Posted: 5 years ago 6 janv. 2020, 16:48 UTC−5

Hi Siyuan,

One reason that you are not getting the output voltage you expect can be due to the fact that you are not operating at the resonance frequency of your piezo elements. 10kHz may be far off the resonance frequency of your transducers. So, when you apply 1V of voltage to your transmitter it does not result in its maximum stress and deflection. In fact, I looked at your second model and I changed 10kHz to 1Hz and I got much higher voltages than 0.1V on the right piezo element. You can also use Frequency Domain study instead of a Time Dependent.

Hamid

Hi Siyuan, One reason that you are not getting the output voltage you expect can be due to the fact that you are not operating at the resonance frequency of your piezo elements. 10kHz may be far off the resonance frequency of your transducers. So, when you apply 1V of voltage to your transmitter it does not result in its maximum stress and deflection. In fact, I looked at your second model and I changed 10kHz to 1Hz and I got much higher voltages than 0.1V on the right piezo element. You can also use Frequency Domain study instead of a Time Dependent. Hamid
Siyuan Li
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Posted: 5 years ago 15 janv. 2020, 10:56 UTC−5

Hi Siyuan,

One reason that you are not getting the output voltage you expect can be due to the fact that you are not operating at the resonance frequency of your piezo elements. 10kHz may be far off the resonance frequency of your transducers. So, when you apply 1V of voltage to your transmitter it does not result in its maximum stress and deflection. In fact, I looked at your second model and I changed 10kHz to 1Hz and I got much higher voltages than 0.1V on the right piezo element. You can also use Frequency Domain study instead of a Time Dependent.

Hamid

Hi Hamid,

Thank you for your reply, I've tried the simulation in frequency domain. Indeed the resonance frequency is about 110kHz and before that the Amplitude of output is about 0.2V. It accords with the simulation in time domain. But when I change the frequency to 110kHz, the output is not a sin wave anymore. It's more like a triangular form. Do you know why it shows like that? Thank you very much.

Siyuan

>Hi Siyuan, > >One reason that you are not getting the output voltage you expect can be due to the fact that you are not operating at the resonance frequency of your piezo elements. 10kHz may be far off the resonance frequency of your transducers. So, when you apply 1V of voltage to your transmitter it does not result in its maximum stress and deflection. In fact, I looked at your second model and I changed 10kHz to 1Hz and I got much higher voltages than 0.1V on the right piezo element. You can also use Frequency Domain study instead of a Time Dependent. > >Hamid Hi Hamid, Thank you for your reply, I've tried the simulation in frequency domain. Indeed the resonance frequency is about 110kHz and before that the Amplitude of output is about 0.2V. It accords with the simulation in time domain. But when I change the frequency to 110kHz, the output is not a sin wave anymore. It's more like a triangular form. Do you know why it shows like that? Thank you very much. Siyuan
Hamid Basaeri
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Posted: 5 years ago 21 janv. 2020, 09:26 UTC−5
Updated: 5 years ago 21 janv. 2020, 09:38 UTC−5

Hi Siyuan,

I guess when you increased the frequency from 10kHz to 110kHz, you may need more points in time to solve for. The way you define it now in your model does not do that. It just assumes the same number of points in one period. If you don't have enough points in one period of your sine wave, you may end up seeing the wave as a triangular signal rather than a sine one.

Good luck, Hamid

Hi Siyuan, I guess when you increased the frequency from 10kHz to 110kHz, you may need more points in time to solve for. The way you define it now in your model does not do that. It just assumes the same number of points in one period. If you don't have enough points in one period of your sine wave, you may end up seeing the wave as a triangular signal rather than a sine one. Good luck, Hamid

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