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Material properties in axialsymmetric form for 2D axialsymmetric simulations

Posted 22.01.2013, 04:40 GMT-5 Materials, Structural Mechanics Version 4.2a 3 Replies

Michael Schneider
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I have the following problem:

I'd like to perform a 2 dimensional axialsymmetric simulation of a piezoelectric thin film on a silicon bulk and a round metal electrode on top. Since the coordinate system of the problem is already axialsymmetric, I'd like to enter the material properties (the material tensors) in the same fashion, meaning I'd like to define the material properties in r and in z direction. When I add a material from the library, however, all the material tensors are in xyz configuration.

Is there a easy way to achieve this? Or does COMSOL calculate the appropriate material parameters from the cartesian configuration? And if yes, how does it this calculation?

Thanks, already appreciating the help :)

Greetings
Michael
3 Replies Last Post 22.01.2013, 07:42 GMT-5
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 22.01.2013, 04:49 GMT-5
Hi

material properties are normally defined in Cartesian, and COMSOL looks after any mapping, but your material must bi isotropic along at least X-Y if Z is the axial direction otherwise you do not respect the axi-symmetry

If you want to enter the parameters in cylindrical coordinates you must write out the equations yourself

--
Good luck
Ivar
Hi material properties are normally defined in Cartesian, and COMSOL looks after any mapping, but your material must bi isotropic along at least X-Y if Z is the axial direction otherwise you do not respect the axi-symmetry If you want to enter the parameters in cylindrical coordinates you must write out the equations yourself -- Good luck Ivar
Michael Schneider
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Posted: 1 decade ago 22.01.2013, 07:01 GMT-5

material properties are normally defined in Cartesian, and COMSOL looks after any mapping, but your material must bi isotropic along at least X-Y if Z is the axial direction otherwise you do not respect the axi-symmetry


How does COMSOL then translate material properties like the coupling matrix into the rz coordinate frame? Specifically, I'm modelling AlN with a coupling matrix of
d31=d32 (so it is axialsymmetric)
d33
d15=d24
everything else = 0

Would that translate into dzz=d33 and dzr=d31? Or am I missing something here?

Thanks again :)
Michael
[QUOTE] material properties are normally defined in Cartesian, and COMSOL looks after any mapping, but your material must bi isotropic along at least X-Y if Z is the axial direction otherwise you do not respect the axi-symmetry [/QUOTE] How does COMSOL then translate material properties like the coupling matrix into the rz coordinate frame? Specifically, I'm modelling AlN with a coupling matrix of d31=d32 (so it is axialsymmetric) d33 d15=d24 everything else = 0 Would that translate into dzz=d33 and dzr=d31? Or am I missing something here? Thanks again :) Michael
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 22.01.2013, 07:42 GMT-5
Hi

you need to define the coordinate system under the PZT node tab,
by default material 33 is Z (and one of the other is "r") pls check, I'm saying this from back in my mind not from the doc files

--
Good luck
Ivar
Hi you need to define the coordinate system under the PZT node tab, by default material 33 is Z (and one of the other is "r") pls check, I'm saying this from back in my mind not from the doc files -- Good luck Ivar

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