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problem with conditional material properties

Posted May 8, 2012, 8:50 a.m. EDT Low-Frequency Electromagnetics, Heat Transfer & Phase Change Version 4.2a 3 Replies

Mohammad Arif Saber
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Hi,

I am trying to give a conditional electrical conductivity as a material property. It will be something like when the voltage becomes 0 then the conductivity should be 1 other than that it will change with the voltage. I am using a rectangular pulse as a pulsed voltage. So after the pulse the conductivity should be 1. I am using v4.2a. will be very glad if someone replies.

I used this but this is not converging,

if(v>0,(2.205*(10e-3*0.05)/(v*1*pi*0.65)),1)


Thanks ,
Arif
3 Replies Last Post May 9, 2012, 4:13 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago May 8, 2012, 10:00 a.m. EDT
Hi

I believe you can try like that, but the solver might well have trouble with such Dirac steps, you can as well, I assume, use a smoothened step() or rect() function from COMSOL, then you will have a smoother transition

--
Good luck
Ivar
Hi I believe you can try like that, but the solver might well have trouble with such Dirac steps, you can as well, I assume, use a smoothened step() or rect() function from COMSOL, then you will have a smoother transition -- Good luck Ivar
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago May 8, 2012, 10:01 a.m. EDT
Try using a continuous function and “v>eps” instead of “v>0”, where eps is a small number.
Try using a continuous function and “v>eps” instead of “v>0”, where eps is a small number.
Mohammad Arif Saber
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Posted: 1 decade ago May 9, 2012, 4:13 a.m. EDT
Thanks a lot Ivar and Nagi, Will try to do so .
Thanks a lot Ivar and Nagi, Will try to do so .

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