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AC/DC mangetic and electric fields error?

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Hello,
I am using comsol 4.0a to analysis Speaker parts (3D, modeling Pro Engineering).

But when I try to solve this problem, comsol solver show me the error in below.

What does this error mean ?
(I want to COMSOL 'Loudspeaker Driver' example using this 3D Speaker parts)

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Attempt to evaluate negative power of zero.
- Function: ^
Failed to evaluate temporary symbolic derivative variable.
- Variable: mod1.mf.murzz@VDN$mod1.curlAz
- Defined as: (dmod1.mat2.def.MUR_dx1((sqrt((((mod1.mf.By^2)+(mod1.mf.Bx^2))+(mod1.mf.Bz^2)))/unit_T_cf))*(((2*mod1.mf.Bz)*(((((mod1.mf.By^2)+(mod1.mf.Bx^2))+(mod1.mf.Bz^2))^-0.5)*0.5))*(1/unit_T_cf)))
Failed to evaluate temporary symbolic derivative variable.
- Variable: mod1.mf.murinvzz@VDN$mod1.curlAz
- Defined as: (((dmod1.mat2.def.MUR_dx1((sqrt((((mod1.mf.By^2)+(mod1.mf.Bx^2))+(mod1.mf.Bz^2)))/unit_T_cf))*(((2*mod1.mf.Bz)*(((((mod1.mf.By^2)+(mod1.mf.Bx^2))+(mod1.mf.Bz^2))^-0.5)*0.5))*(1/unit_T_cf))))*((-1)/(mod1.mf.murzz^2)))
Failed to evaluate temporary symbolic derivative variable.
- Variable: mod1.mf.Hz@VDN$mod1.curlAz
- Defined as: (((((((dmod1.mat2.def.MUR_dx1((sqrt((((mod1.mf.By^2)+(mod1.mf.Bx^2))+(mod1.mf.Bz^2)))/unit_T_cf))*(((2*mod1.mf.Bz)*(((((mod1.mf.By^2)+(mod1.mf.Bx^2))+(mod1.mf.Bz^2))^-0.5)*0.5))*(1/unit_T_cf))))*((-1)/(mod1.mf.murzz^2))))*mod1.mf.Bz)+mod1.mf.murinvzz)*(1/mu0_const))
Failed to evaluate expression.
- Expression: d(d((-mod1.mf.Hx*test(mod1.curlAx)-mod1.mf.Hy*test(mod1.curlAy)-mod1.mf.Hz*test(mod1.curlAz)+mod1.mf.Jx*test(mod1.Ax)+mod1.mf.Jy*test(mod1.Ay)+mod1.mf.Jz*test(mod1.Az))*(dvol),{test@3}),mod1.curlAz)

8 Replies Last Post 2011年9月20日 GMT-4 06:05

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Posted: 1 decade ago 2011年9月5日 GMT-4 07:46
Hi!

I have got the same error, if I want to use a BH-curve for a material.
In such a case you have to define a second "Ampere's Law" for this part and switch there the "Magnetic field" from "Relative permeability" to "HB curve".
I hope, the names are still correct, because I am in 4.2.

Ralf
Hi! I have got the same error, if I want to use a BH-curve for a material. In such a case you have to define a second "Ampere's Law" for this part and switch there the "Magnetic field" from "Relative permeability" to "HB curve". I hope, the names are still correct, because I am in 4.2. Ralf

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Posted: 1 decade ago 2011年9月8日 GMT-4 22:55
Hello!

I switch there the "Magnetic field" from "Relative permeability" to "HB curve".
But I don't know 'Magnetic field norm' in air (material property).

What is the Magnetic field norm ?
Hello! I switch there the "Magnetic field" from "Relative permeability" to "HB curve". But I don't know 'Magnetic field norm' in air (material property). What is the Magnetic field norm ?

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Posted: 1 decade ago 2011年9月9日 GMT-4 02:11
Hi!

You should only change the setting for your iron materials; air parts should remain at "relative permeability", which is 1 for air.

Ralf
Hi! You should only change the setting for your iron materials; air parts should remain at "relative permeability", which is 1 for air. Ralf

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Posted: 1 decade ago 2011年9月14日 GMT-4 09:01
Hi!

Sorry,, My problem is like this. (Attach file)

I change the setting for second "Ampere's Law" from "Magnetic Field" in "Remanent flux density" to "HB curve".
Then material property in air need to "Magnetic Field norm"

Second "Ampere's Law" domains 9, but domains 9 is Air domain.
(I follow the COMSOL example 2D - Symmetric "Loudspeaker Driver")

Please let me know how to solve it.
Hi! Sorry,, My problem is like this. (Attach file) I change the setting for second "Ampere's Law" from "Magnetic Field" in "Remanent flux density" to "HB curve". Then material property in air need to "Magnetic Field norm" Second "Ampere's Law" domains 9, but domains 9 is Air domain. (I follow the COMSOL example 2D - Symmetric "Loudspeaker Driver") Please let me know how to solve it.


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Posted: 1 decade ago 2011年9月15日 GMT-4 05:12
Hi!

In the example this domain is defined with "remanent flux density" with 0.4T; try this one, if you want to have a permanent magnet. In your case I think, it should be a value for B in y-direction.

Ralf
Hi! In the example this domain is defined with "remanent flux density" with 0.4T; try this one, if you want to have a permanent magnet. In your case I think, it should be a value for B in y-direction. Ralf

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Posted: 1 decade ago 2011年9月18日 GMT-4 22:02
Hi!

Thank you for your help.
But still the problem is not solving//......

Could you please test my sample file?..


You can download sample file by this URL. (file size 83mb, 1, 2, 3 is same file.)
1. goo.gl/uwqth
2. bigmail.mail.daum.net/Mail-bin/bigfile_down?uid=J_pMfp9SI-FOSQ.13MIpGJGcoY51YyaU
3. bigmail.mail.daum.net/Mail-bin/bigfile_down?uid=59IQZfuUp.7TActklXhaZgG1QDHvZW9j
Hi! Thank you for your help. But still the problem is not solving//...... Could you please test my sample file?.. You can download sample file by this URL. (file size 83mb, 1, 2, 3 is same file.) 1. http://goo.gl/uwqth 2. http://bigmail.mail.daum.net/Mail-bin/bigfile_down?uid=J_pMfp9SI-FOSQ.13MIpGJGcoY51YyaU 3. http://bigmail.mail.daum.net/Mail-bin/bigfile_down?uid=59IQZfuUp.7TActklXhaZgG1QDHvZW9j

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Posted: 1 decade ago 2011年9月20日 GMT-4 05:30
Hi!

If you clear mesh and clear solution, you can attach the file here...

Ralf
Hi! If you clear mesh and clear solution, you can attach the file here... Ralf

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Posted: 1 decade ago 2011年9月20日 GMT-4 06:05
Hi!

Thank you for your advise.
My sample file save clear mesh and clear solution and attach file in this form.

Could you please check my attached file?
Hi! Thank you for your advise. My sample file save clear mesh and clear solution and attach file in this form. Could you please check my attached file?

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