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Crystal axis of a piezoelectric crystal

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Hello everyone I have two questions

1. We are modelling a piezoelectric mems resonator, and we need the crystal C axis of the film to be in a particular (z) direction. How do we go about this? Is changing the strain electromechanical coupling matrix accordingly the solution? What other matrices/ parameters do we need to change?

2. We also need to find the fundamental/ eigen modes of the crystal. This needs both piezo and regular structural properties to be considered. In a similar problem in 3.5 we would be using piezo solid or strain physics (if I remember right) but how does one go about this in the new version? ( only the material properties relating to structural mechanics have a green check mark by them)

Thank you in advance.

1 Reply Last Post 2011年11月2日 GMT-4 15:49
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 2011年11月2日 GMT-4 15:49
Hi

I find it easiest to define a specific coordinate frame for each PZT direction, and then refer the material tensor w.r.t this coordinate frame. You can check the direction, by loading the initial conditions, and plotting the coordinate vectors RGB code. Pls note the different convention for the PZT material and the standard structural/solid material concerning the material stiffness tensors

--
Good luck
Ivar
Hi I find it easiest to define a specific coordinate frame for each PZT direction, and then refer the material tensor w.r.t this coordinate frame. You can check the direction, by loading the initial conditions, and plotting the coordinate vectors RGB code. Pls note the different convention for the PZT material and the standard structural/solid material concerning the material stiffness tensors -- Good luck Ivar

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