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.

About conductive electrodes of piezoceramics layers

Please login with a confirmed email address before reporting spam

Hello everyone,

I am working on a piezoelectric energy harvester(substructure and a piezoceramic layer). I am applying a point force on the substructure and measuring the voltage from the surface of the piezoceramic to obtain voltage FRF (voltage/point force).

I want my model to account for the conductive electrodes bracketing the piezoceramic layer so that I can obtain uniform potential distribution throughout the surface of the piezoceramic. However, I couldnt find the appropriate boundary condition for this purpose.

I appreciate any help,
Bugra Bayik.

3 Replies Last Post Feb 27, 2013, 4:49 a.m. EST
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Feb 20, 2013, 2:51 a.m. EST
Hi

have you tried to use the terminal in "terminated" mode, or linked to a RC circuit ?,
Indeed I cannot find any perfect electric conductive layer (in the plane direction to mimic a conductor deposited on a boundary) in PZD
But I wonder if this BC (was there before) has not been replaced with the "floating potential" BC

--
Good luck
Ivar
Hi have you tried to use the terminal in "terminated" mode, or linked to a RC circuit ?, Indeed I cannot find any perfect electric conductive layer (in the plane direction to mimic a conductor deposited on a boundary) in PZD But I wonder if this BC (was there before) has not been replaced with the "floating potential" BC -- Good luck Ivar

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Feb 20, 2013, 7:44 a.m. EST
If what you want to know is the open circuit voltage of your harvester, I would suggest using a grounded boundary condition for one of the electrodes and a floating potential for the second.
If what you want to know is the open circuit voltage of your harvester, I would suggest using a grounded boundary condition for one of the electrodes and a floating potential for the second.

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Feb 27, 2013, 4:49 a.m. EST
Thanks a lot for the comments.

I tried floating potential and terminated boundary conditions. I am plotting electric potential amplitudes of arbitrary points on upper surface of the PZT. My FRF is between 0-200Hz and there are 6 modes in this range (they all can be observed in my measurement point). I attached the plots for:

case 1) Zero charge: It is resulting peaks at every natural frequency and arbitrary points on PZT have different amplitudes at each mode as expected.

case 2) Floating potential case: Arbitrary points on PZT have same amplitude so the uniform potential distribution is obtained. However, there is only one peak on the FRF. I lost the information for the other modes

case 3) Terminated case: In this BC i am getting an error as follows
Undefined value found.
- Detail: Undefined value found in the stiffness matrix.
.There are 1 equations giving NaN/Inf in the matrix rows for the variable mod1.pzd.V0_1
. at coordinates: (0,0,0), ...
and similarly for the degrees of freedom, NaN/Inf in the matrix columns.

I see that floating potential should be working. My question is why is it eleminating the peaks at other modes and resulting in only one peak?
Thanks a lot for the comments. I tried floating potential and terminated boundary conditions. I am plotting electric potential amplitudes of arbitrary points on upper surface of the PZT. My FRF is between 0-200Hz and there are 6 modes in this range (they all can be observed in my measurement point). I attached the plots for: case 1) Zero charge: It is resulting peaks at every natural frequency and arbitrary points on PZT have different amplitudes at each mode as expected. case 2) Floating potential case: Arbitrary points on PZT have same amplitude so the uniform potential distribution is obtained. However, there is only one peak on the FRF. I lost the information for the other modes case 3) Terminated case: In this BC i am getting an error as follows Undefined value found. - Detail: Undefined value found in the stiffness matrix. .There are 1 equations giving NaN/Inf in the matrix rows for the variable mod1.pzd.V0_1 . at coordinates: (0,0,0), ... and similarly for the degrees of freedom, NaN/Inf in the matrix columns. I see that floating potential should be working. My question is why is it eleminating the peaks at other modes and resulting in only one peak?

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.