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heating an object, then cool and then reheat , step function

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Hello.
I wanted to study the behavior of the von Mises stress that will developed in a spheroidal object subjected to the following conditions.

time: 0 --> 3 mins ----- heating at constant temperature 45 C
time: 3 --> 4 mins ----- cooling at constant 15 C
time: 4 -->10 mins ----- reheating at 45 C

I am using version 4.0a for the coupled thermal diffusion and structural mechanics to study the temperature distribution and mechanical deformation. But I do not have an idea on how to put up the step function on the temperature settings on the conditions that I wanted to.

The step function in the under the Global Definitions seems do not have temperature settings.
Is there somebody out there who can give me some hints on how to properly do this.

I'll appreciate much for your help.
Thank you.

Jonathan


3 Replies Last Post 10.08.2012, 03:20 GMT-4
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Hello Jonathan Perez

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Posted: 1 decade ago 10.08.2012, 01:19 GMT-4
Hi Jonathon, have you found how to do that ? I need to do same thing here. Please help if you can ..
Hi Jonathon, have you found how to do that ? I need to do same thing here. Please help if you can ..

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Posted: 1 decade ago 10.08.2012, 01:35 GMT-4
Hello.
I have given it up. I was not able to find a solution to that. Instead, I created an equation using SOLVER function in EXCEL. From the equation that i was able to developed from the SOLVER function in EXCEL was imported/copied to COMSOL so it would create a similar condition.
Yet, i was not able to get the result that I expected.
But you can try that one. That method might work for you.
Regards,
Jonathan

Hello. I have given it up. I was not able to find a solution to that. Instead, I created an equation using SOLVER function in EXCEL. From the equation that i was able to developed from the SOLVER function in EXCEL was imported/copied to COMSOL so it would create a similar condition. Yet, i was not able to get the result that I expected. But you can try that one. That method might work for you. Regards, Jonathan

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 10.08.2012, 03:20 GMT-4
Hi

did you try to define a rectangular pulse (definition functions) and shape it to modulate your heat flux and the "h" for convecting cooling ?. It should be straightforward in COMSOL with a time stepping solver you can write any formula in all the fields (provided you do not make circular references though ...)

--
Good luck
Ivar
Hi did you try to define a rectangular pulse (definition functions) and shape it to modulate your heat flux and the "h" for convecting cooling ?. It should be straightforward in COMSOL with a time stepping solver you can write any formula in all the fields (provided you do not make circular references though ...) -- Good luck Ivar

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