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Piezoelectric stator eigen frequency study
Posted 28 mars 2017, 08:31 UTC−4 Modeling Tools & Definitions, Parameters, Variables, & Functions, Structural Mechanics Version 5.0 2 Replies
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Hi,
I am modelling the resonance behavior of a piezoelectric stator which is a metallic structure bonded to a piezoelectric material. Under the Electrostatics physics module, I have a voltage terminal type boundary condition on the piezoelectric material top surface and a ground type BC on the opposite face.
The simulation run successfully and I get as result the set of resonance modes and there corresponding frequencies. However, I noticed that if I remove the terminal voltage BC, the frequencies of the resonance modes shift with non negligible values (500 Hz for a resonance frequency of 23 kHz).
From my point of view, the resonance frequencies depends only upon the structure dimensions and materials and have nothing to do with the presence or not of a terminal voltage.
If anyone can explain this phenomenon, I will be so thankful.
I am modelling the resonance behavior of a piezoelectric stator which is a metallic structure bonded to a piezoelectric material. Under the Electrostatics physics module, I have a voltage terminal type boundary condition on the piezoelectric material top surface and a ground type BC on the opposite face.
The simulation run successfully and I get as result the set of resonance modes and there corresponding frequencies. However, I noticed that if I remove the terminal voltage BC, the frequencies of the resonance modes shift with non negligible values (500 Hz for a resonance frequency of 23 kHz).
From my point of view, the resonance frequencies depends only upon the structure dimensions and materials and have nothing to do with the presence or not of a terminal voltage.
If anyone can explain this phenomenon, I will be so thankful.
2 Replies Last Post 28 mars 2017, 12:10 UTC−4
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Posted:
7 years ago
> From my point of view, the resonance frequencies depends only upon the structure dimensions and materials and have nothing to do with the presence or not of a terminal voltage.
This is a case where you need to readjust your intuition.
The stiffness of the piezo changes when you change the boundary conditions. There is a stiffness matrix with constant electric field and a stiffness matrix with constant electric displacement. They are not the same. And the piezo stiffness influences the eigenmode frequency.
D.W. Greve
DWGreve Consulting
This is a case where you need to readjust your intuition.
The stiffness of the piezo changes when you change the boundary conditions. There is a stiffness matrix with constant electric field and a stiffness matrix with constant electric displacement. They are not the same. And the piezo stiffness influences the eigenmode frequency.
D.W. Greve
DWGreve Consulting
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Posted:
7 years ago
It makes a lot of sense. It is like the case of a composite material, the stiffness of this latter depends upon the direction of the force acting on it.
Thank you very much for your answer.
I appreciate it.
Khaled
Thank you very much for your answer.
I appreciate it.
Khaled