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Modelling a Cantilever beam with a piezoelectric patch, 2D
Posted Dec 7, 2011, 2:27 p.m. EST 1 Reply
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Hi all, I'm not able to modelling in the right way a cantilever beam with a piezoelectric bimorph patch...... I just tried to remodel the Tutorial: shear_bender.mph in the model library, but in 2D ..... it doesn't works..... Same can help me? ThankU
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1 Reply Last Post Dec 11, 2011, 5:51 a.m. EST
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Posted:
1 decade ago
Hi
I know there were a few formula bugs in the early 4.0a so you should reconstruct your model in a newer version. But I do also have a few general comments:
When you model such thin layer syou must ensure you have at least >2 elements across the layer, I mostly use a finer mesh, and I also mostly cut my layer into two to enhance the "neutral line" you have in the middle of the thickness of a uniform density/strength layer.
Your voltage is very low, normally one apply a 1-2 kV/mm so I would rather expect 2-4 kV on your electrode (if you have a layered PZT you must multiply the applied volts by the number of layers (often 10-50 per mm for most PZT)
Then you need to select the correct orientation, COMSOL uses the IEEE definition for the tensor orientation for PZT materials, which is different from the linear material tensor orientation, be aware ;) also in 2D "z" is out of the plane, you should reorient it along your 2D "y". I.e. use a "base vector coordinate and select 1 or 2 as the out of plane direction and then use that for the PZT
--
Good luck
Ivar
I know there were a few formula bugs in the early 4.0a so you should reconstruct your model in a newer version. But I do also have a few general comments:
When you model such thin layer syou must ensure you have at least >2 elements across the layer, I mostly use a finer mesh, and I also mostly cut my layer into two to enhance the "neutral line" you have in the middle of the thickness of a uniform density/strength layer.
Your voltage is very low, normally one apply a 1-2 kV/mm so I would rather expect 2-4 kV on your electrode (if you have a layered PZT you must multiply the applied volts by the number of layers (often 10-50 per mm for most PZT)
Then you need to select the correct orientation, COMSOL uses the IEEE definition for the tensor orientation for PZT materials, which is different from the linear material tensor orientation, be aware ;) also in 2D "z" is out of the plane, you should reorient it along your 2D "y". I.e. use a "base vector coordinate and select 1 or 2 as the out of plane direction and then use that for the PZT
--
Good luck
Ivar