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E distribution of nonlinear material under DC
Posted Oct 1, 2010, 12:45 a.m. EDT 4 Replies
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I want to know the E distribution of nonlinear material under DC.
Electric resistivity is a function of electric field in the material.
For example: Rou=3*E^12*exp(-0.215*E)
I established a simple rectangle model, with DC supply and nonlinear equation in the subdomain setting.
But error came out as below,
Messages: Undefined value found solvermodel
Stack trace:
at solvermodel.cpp, row 1837, (undefined value found in the equation residual vector, There are 417 degrees of freedom giving NaN/Inf in the vector for the variable V at coordinates: .......................)
At the first time, I thought maybe the boundary setting did some wrong. But to my model, no difficult setting in it.
So what should I do to solve this problem and get the answer?
Thanks a lot.
Janet
Electric resistivity is a function of electric field in the material.
For example: Rou=3*E^12*exp(-0.215*E)
I established a simple rectangle model, with DC supply and nonlinear equation in the subdomain setting.
But error came out as below,
Messages: Undefined value found solvermodel
Stack trace:
at solvermodel.cpp, row 1837, (undefined value found in the equation residual vector, There are 417 degrees of freedom giving NaN/Inf in the vector for the variable V at coordinates: .......................)
At the first time, I thought maybe the boundary setting did some wrong. But to my model, no difficult setting in it.
So what should I do to solve this problem and get the answer?
Thanks a lot.
Janet
4 Replies Last Post Oct 4, 2010, 5:10 a.m. EDT
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Posted:
1 decade ago
Janet,
did you make sure you used the right variable in your expression? Check variable names according to the application mode you use. The expression you showed in the posting will definitely not work.
Best regards
Edgar
did you make sure you used the right variable in your expression? Check variable names according to the application mode you use. The expression you showed in the posting will definitely not work.
Best regards
Edgar
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Posted:
1 decade ago
Hi, Janet,
I think maybe your definition of electric field E is not correct. If like, you can post your mph file here. We can try to solve this problem.
I think maybe your definition of electric field E is not correct. If like, you can post your mph file here. We can try to solve this problem.
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Posted:
1 decade ago
Thanks both of you.
Actually the electric field E I typed in model is `normE_embc`.
And I attched my model here. (A basic model)
Hope you can get me out of the problem.
Janet
Actually the electric field E I typed in model is `normE_embc`.
And I attched my model here. (A basic model)
Hope you can get me out of the problem.
Janet
Attachments:
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Posted:
1 decade ago
Janet,
I think you must check your expression. Your boundary settings generate a field of 710 kV/m. The exponential term in your expression exp(0.0152*710000) will result in a numerical error. This is a huge number. Also I assume, that your denominator should be E1*1e16 and not E1^16. 710000^16 is something like 1e93.
I presume you have an estimate what value the conductivity should be. Check if your expression gets you close to this estimate.
Your expression is numerically extremely unstable.
Best regards
Edgar
I think you must check your expression. Your boundary settings generate a field of 710 kV/m. The exponential term in your expression exp(0.0152*710000) will result in a numerical error. This is a huge number. Also I assume, that your denominator should be E1*1e16 and not E1^16. 710000^16 is something like 1e93.
I presume you have an estimate what value the conductivity should be. Check if your expression gets you close to this estimate.
Your expression is numerically extremely unstable.
Best regards
Edgar