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Rosen-type piezo transformmer simulation

Posted Nov 23, 2011, 10:38 a.m. EST MEMS & Nanotechnology, MEMS & Piezoelectric Devices Version 4.2 5 Replies

Sneha Lele
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Hello,

I'm trying to simulate a rectangular Rosen-type piezo transformer using the MEMS module.

Since the input and output parts are differently polarized, does it have to be treated as two different entities or just the coordinate axis settings have to be different for both?
Also can the transformer body be assumed free with just terminal and ground applied to the input upper and lower surfaces and output surface with floating potential? Do the I/O terminals have to be assigned metallic properties (for eg. Aluminium)?

I am quite new to COMSOL and would really appreciate some guidelines.

Thank you.
Sneha
5 Replies Last Post Apr 1, 2012, 5:37 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago Nov 24, 2011, 3:54 a.m. EST
Hi

You need to add a specific material property per PZT orientation, and within that node you can use a pre-define the coordinate frame the most appropriate

You can apply the voltage to the boundaries as constants without modelling the conductor layer (to start with, depends on their influence, mas, stiffness ...

--
Good luck
Ivar
Hi You need to add a specific material property per PZT orientation, and within that node you can use a pre-define the coordinate frame the most appropriate You can apply the voltage to the boundaries as constants without modelling the conductor layer (to start with, depends on their influence, mas, stiffness ... -- Good luck Ivar
Sneha Lele
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Posted: 1 decade ago Mar 6, 2012, 11:29 a.m. EST
Hello,

Thanks for your inputs.

I have now built a transformer with differently polarized, freely oriented resonators. I haven't used a pre-defined piezo material but used values from a research paper. I have not used a conducting layer for now.

I think my model works fine in terms of admittance at resonance and anti-resonance, mechanical displacement and electric potential for a frequency sweep (not sure though if I'm missing out on something).

But for Eigenfrequency analysis I keep getting a series of warnings 'The relative residual is greater than the relative tolerance.' What is this related to?
Also the 1st four eigenfrequencies I get are complex numbers. What is the implication of these numbers? How do I translate them into actual frequency in Hertz?

I'm attaching the model. Can you please throw some light on it? Also can you please suggest if there is anything that I may have done wrong in the design?

Your inputs will really help a lot!
Thanks.

Sneha




Hello, Thanks for your inputs. I have now built a transformer with differently polarized, freely oriented resonators. I haven't used a pre-defined piezo material but used values from a research paper. I have not used a conducting layer for now. I think my model works fine in terms of admittance at resonance and anti-resonance, mechanical displacement and electric potential for a frequency sweep (not sure though if I'm missing out on something). But for Eigenfrequency analysis I keep getting a series of warnings 'The relative residual is greater than the relative tolerance.' What is this related to? Also the 1st four eigenfrequencies I get are complex numbers. What is the implication of these numbers? How do I translate them into actual frequency in Hertz? I'm attaching the model. Can you please throw some light on it? Also can you please suggest if there is anything that I may have done wrong in the design? Your inputs will really help a lot! Thanks. Sneha

Attachments:

Sneha Lele
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Posted: 1 decade ago Mar 19, 2012, 11:55 a.m. EDT
Can anyone please help me with my questions below?

I am stuck in the analysis... any input would really prove helpful.

Sneha
Can anyone please help me with my questions below? I am stuck in the analysis... any input would really prove helpful. Sneha
Borodinas Sergejus
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Posted: 1 decade ago Mar 30, 2012, 11:35 p.m. EDT
Hello Shena,
Please open attached file, it's you modified file.
Regards
Hello Shena, Please open attached file, it's you modified file. Regards

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Sneha Lele
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Posted: 1 decade ago Apr 1, 2012, 5:37 p.m. EDT
Hello Borodinas,

Thanks for your reply.
What modification have you made in the file? Also I'm using COMSOL 4.2 (not 4.2a), sorry for the confusion.

I'm attaching a modified file, here I have applied a 'spring foundation' to my structure instead of free structure. My susceptance, potential and displacement graphs seem to agree with each other.
But I don't understand the eigenfrequency calculation. I get values very close to each other and I can't see a clear distinction between these frequencies with respect to deformation or electric potential.

Any inputs would really help me understand the transformer behaviour clearly. Is there anything significant I'm missing out?
Thank you.

Sneha
Hello Borodinas, Thanks for your reply. What modification have you made in the file? Also I'm using COMSOL 4.2 (not 4.2a), sorry for the confusion. I'm attaching a modified file, here I have applied a 'spring foundation' to my structure instead of free structure. My susceptance, potential and displacement graphs seem to agree with each other. But I don't understand the eigenfrequency calculation. I get values very close to each other and I can't see a clear distinction between these frequencies with respect to deformation or electric potential. Any inputs would really help me understand the transformer behaviour clearly. Is there anything significant I'm missing out? Thank you. Sneha

Attachments:

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