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BC in assembly mode

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hello,

idk but i am getting an error in running the simulation. I am getting a warning saying: "MUMPS allocation factor increased to 1.44". What does it mean? is it due to the insufficient BC? I am working on joule heating interface. At the boundaries, which are in contact, I have set also the boundary conditions for the continuity of electric flux and heat flux. Where is the problem?

I would be grateful for any kind help.

Regards,

1 Reply Last Post 19.03.2013, 02:38 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 19.03.2013, 02:38 GMT-4
Hi

those are tricky and complex models contact resistance (heat and electric) are often pressure dependent and suffer from singularities if the part start to separate. One cannot easily say how to or give advices.

I remember I played with boundary conditions linked to positive pressure above a given value to define theur contact region, but one can also use the gap distance. Anyhow if there is separation with a fluid /air in beteween one have a topology change and this might reorder the elements ID's and give model incogherences. It's tricky but fully possible to do such advanced simualtions, it only takes some time and careful checks , and it gives very interesting results ;)

--
Good luck
Ivar
Hi those are tricky and complex models contact resistance (heat and electric) are often pressure dependent and suffer from singularities if the part start to separate. One cannot easily say how to or give advices. I remember I played with boundary conditions linked to positive pressure above a given value to define theur contact region, but one can also use the gap distance. Anyhow if there is separation with a fluid /air in beteween one have a topology change and this might reorder the elements ID's and give model incogherences. It's tricky but fully possible to do such advanced simualtions, it only takes some time and careful checks , and it gives very interesting results ;) -- Good luck Ivar

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