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3d piezocomposite (xy direction only deformation and zero electric field)

Posted 22.05.2014, 09:02 GMT-4 MEMS & Nanotechnology, Piezoelectric Devices, Structural Mechanics Version 4.3b 4 Replies

Andreas Emmanouil Tzatzanis
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I have a 3d piezocomposite cube.
How can i move it in the xy direction only.
The other strains have to be zero(S11, S22...etc)
How can the volume average electric fields(Ex, Ey, Ez) be predifined as zero.

Thanks in advance
4 Replies Last Post 26.05.2014, 06:43 GMT-4
Pieter Westerik
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Posted: 1 decade ago 26.05.2014, 04:41 GMT-4
Movement can be restricted by adding a 'prescribed displacement' node to your physics and setting all displacements except those that you want to permit to 0.
How are your electric fields formed? I quess by setting certain boundary conditions? I think you will have to make them depend on the vollume integral of the electric fields in your domain.
Movement can be restricted by adding a 'prescribed displacement' node to your physics and setting all displacements except those that you want to permit to 0. How are your electric fields formed? I quess by setting certain boundary conditions? I think you will have to make them depend on the vollume integral of the electric fields in your domain.
Andreas Emmanouil Tzatzanis
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Posted: 1 decade ago 26.05.2014, 05:58 GMT-4

Movement can be restricted by adding a 'prescribed displacement' node to your physics and setting all displacements except those that you want to permit to 0.
How are your electric fields formed? I quess by setting certain boundary conditions? I think you will have to make them depend on the vollume integral of the electric fields in your domain.

Thanks for your answer.

I don't want the displacement to be zero. I want the average volume deformation(average volume strain)
to be zero.
I actually found the solution. The cube has to be sheared for example in x direction
And you have to put periodic condition(continuity) to x+ x- , y+ y-, z+ z-.

As for the electric field i just grounded the hole material and it seems to be almost zero.(Electric periodic conditions are used too).
The simulation goes like this. I apply a prescribed displacement as a load. The piezoelectric material
creates an electric field. But i don't want that. I am not sure what i did i correct.
How this volume integral dependance work?


Can you imagine how a cube could have a non zero volume average strain in the direction x
and zero in the direction xy and xz.

thanks in advance


[QUOTE] Movement can be restricted by adding a 'prescribed displacement' node to your physics and setting all displacements except those that you want to permit to 0. How are your electric fields formed? I quess by setting certain boundary conditions? I think you will have to make them depend on the vollume integral of the electric fields in your domain. [/QUOTE] Thanks for your answer. I don't want the displacement to be zero. I want the average volume deformation(average volume strain) to be zero. I actually found the solution. The cube has to be sheared for example in x direction And you have to put periodic condition(continuity) to x+ x- , y+ y-, z+ z-. As for the electric field i just grounded the hole material and it seems to be almost zero.(Electric periodic conditions are used too). The simulation goes like this. I apply a prescribed displacement as a load. The piezoelectric material creates an electric field. But i don't want that. I am not sure what i did i correct. How this volume integral dependance work? Can you imagine how a cube could have a non zero volume average strain in the direction x and zero in the direction xy and xz. thanks in advance
Pieter Westerik
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Posted: 1 decade ago 26.05.2014, 06:38 GMT-4
I do not understand. The whole idea of piezoelectric material is that there is a direct relation between electric field and strain. If you do not want this you should not use piezoelectric material.

What are the physical reasons in the device that you are trying to model for putting these restrictions on strains and electric fields?
I do not understand. The whole idea of piezoelectric material is that there is a direct relation between electric field and strain. If you do not want this you should not use piezoelectric material. What are the physical reasons in the device that you are trying to model for putting these restrictions on strains and electric fields?
Andreas Emmanouil Tzatzanis
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Posted: 1 decade ago 26.05.2014, 06:43 GMT-4
I am using an homogenization theory. You can look to this paper www.uni-magdeburg.de/ifme/l-numerik/quellen/PAC0121-BergerH.pdf on page 4

Basically this is an easy way to calculate average properties of the piezocomposite material.

Thanks in advance
I am using an homogenization theory. You can look to this paper http://www.uni-magdeburg.de/ifme/l-numerik/quellen/PAC0121-BergerH.pdf on page 4 Basically this is an easy way to calculate average properties of the piezocomposite material. Thanks in advance

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