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Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

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elasticity matrix elements order

Posted 2012年5月16日 GMT-4 11:09 Version 4.3b 8 Replies

Silviu Zilberman
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Dear All,

I am trying to specify a new piezoelectric material. I have the all the required parameters, but I am uncertain about the order of the matrix elements. All matrices (e.g. elasticity matrix) are specified as a series of 21 numbers. I assume these are the upper triangular matrix elements of the corresponding 6x6 matrix. However, what is the elements order, is it row-wise or column wise?

Thanks, Silviu.
8 Replies Last Post 2014年4月7日 GMT-4 10:57
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 2012年5月16日 GMT-4 12:57
Hi

by hart I cannot tell, but it's een discussed a few times on the FORUM, try a search.

My way in such cases is to enter an increasing series 1,2,3,4 ... and then look how the tensor is populated

--
Good luck
Ivar
Hi by hart I cannot tell, but it's een discussed a few times on the FORUM, try a search. My way in such cases is to enter an increasing series 1,2,3,4 ... and then look how the tensor is populated -- Good luck Ivar
Silviu Zilberman
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Posted: 1 decade ago 2012年5月16日 GMT-4 14:12
Hi,

Thanks Ivar, that's a good idea. However, how can I see the tensor in matrix form?

Thanks,
Silviu.
Hi, Thanks Ivar, that's a good idea. However, how can I see the tensor in matrix form? Thanks, Silviu.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 2012年5月16日 GMT-4 15:18
Hi

Under the material stress charge tab you have the matrix displayer / entry tool (at least in 4.2a)
And you have the ordering (PZT = IEEE convention, not the same as the standard structural !!)

--
Good luck
Ivar
Hi Under the material stress charge tab you have the matrix displayer / entry tool (at least in 4.2a) And you have the ordering (PZT = IEEE convention, not the same as the standard structural !!) -- Good luck Ivar
Silviu Zilberman
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Posted: 1 decade ago 2012年5月16日 GMT-4 17:15
Thank you Ivar!

Silviu.
Thank you Ivar! Silviu.
Yang Ru-Yuan
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Posted: 1 decade ago 2012年12月20日 GMT-5 05:58
in isotropic material,the matrix is symmetric. there are 21 elements. the first 6 are xx, yy, zz, yz, xz, xy from the material property. the others are 14,24,34,44,15,25,35,45,55,16,26,36,46,56,66.
in isotropic material,the matrix is symmetric. there are 21 elements. the first 6 are xx, yy, zz, yz, xz, xy from the material property. the others are 14,24,34,44,15,25,35,45,55,16,26,36,46,56,66.
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago 2012年12月20日 GMT-5 10:59
Hi Yang,

The order you stated is not correct. Ivar provided the correct one above. The xx,yy,zz,yz,xz,xy is just the order of the stress tensor components in the stress vector. That order goes as follows: the three normal stress components XX, YY, then ZZ, followed by the 3 shear stress components YZ, XZ, and finally XY. When it comes to entering the 21 values in the 6x6 anisotropic elasticity matrix, they go by row (or column since it is symmetric) starting at the diagonal element. COMSOL also displays a 2D array for inputting the constants and avoiding confusion about the order.

Nagi Elabbasi
Veryst Engineering
Hi Yang, The order you stated is not correct. Ivar provided the correct one above. The xx,yy,zz,yz,xz,xy is just the order of the stress tensor components in the stress vector. That order goes as follows: the three normal stress components XX, YY, then ZZ, followed by the 3 shear stress components YZ, XZ, and finally XY. When it comes to entering the 21 values in the 6x6 anisotropic elasticity matrix, they go by row (or column since it is symmetric) starting at the diagonal element. COMSOL also displays a 2D array for inputting the constants and avoiding confusion about the order. Nagi Elabbasi Veryst Engineering
Abid Iqbal
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Posted: 1 decade ago 2014年3月23日 GMT-4 23:04
Hi
I am doing Piezo electric simulation. I want to see the effect of the varying temperature on the output piezoelectric open circuit voltage. I thought it will be better to start observing the resonance frequency with changing temperature. i used joule heating and thermal expansion. i increased the temperatur but the resonance frequency remains same. can anyone tell me why the frequency is not changing? or how can i make the elasticity coefficent temperature dependent?
Hi I am doing Piezo electric simulation. I want to see the effect of the varying temperature on the output piezoelectric open circuit voltage. I thought it will be better to start observing the resonance frequency with changing temperature. i used joule heating and thermal expansion. i increased the temperatur but the resonance frequency remains same. can anyone tell me why the frequency is not changing? or how can i make the elasticity coefficent temperature dependent?
Ngoc Nguyen
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Posted: 1 decade ago 2014年4月7日 GMT-4 10:57
I think the correct order is

11,12,22,13,23,33,14,24,34,44,15,25,35,45,55,16,26,36,46,56,66

Regards,
Ngoc
I think the correct order is 11,12,22,13,23,33,14,24,34,44,15,25,35,45,55,16,26,36,46,56,66 Regards, Ngoc

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