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Dividing Thermal Stresses problem into 2 study steps?

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Would there be any downside in dividing a stationary thermal stresses problem into 2 study steps, where you first solve for only the heat transfer in step 1 and then solve only for solid mechanics in step 2 (obviously using the results from step 1)?


2 Replies Last Post 2020年3月24日 GMT-4 10:20
Jeff Hiller COMSOL Employee

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Posted: 5 years ago 2020年3月23日 GMT-4 15:40

Hello Andreas,

If the two physics are only one-way coupled, then I cannot think of any downside, and of course there in the upside that your peak memory usage will be lower when you split the problem (I assume that's why you're thinking of splitting the problem, did I guess that right?).

On the other hand, if the two physics are two-way coupled in any way (such as if the heat sources or any other aspect of the thermal problem are deformation dependent), then you can't split the problem.

In other words: If you could theoretically split the problem when solving the same equations with pen and paper, then you can do it in COMSOL too. Best,

Jeff

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Jeff Hiller
Hello Andreas, If the two physics are only one-way coupled, then I cannot think of any downside, and of course there in the upside that your peak memory usage will be lower when you split the problem (I assume that's why you're thinking of splitting the problem, did I guess that right?). On the other hand, if the two physics are two-way coupled in any way (such as if the heat sources or any other aspect of the thermal problem are deformation dependent), then you can't split the problem. In other words: If you could theoretically split the problem when solving the same equations with pen and paper, then you can do it in COMSOL too. Best, Jeff

Henrik Sönnerlind COMSOL Employee

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Posted: 5 years ago 2020年3月24日 GMT-4 10:20

Actually, you can expect a speed-up by at least a factor of 3 if you split it. Further advantages:

  • If one of the problems is nonlinear, you will not need to perform iterations for both
  • When the temperature problem is time dependent, you can usually still solve the stress problem as a sequence of stationary 'snapshots'
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Henrik Sönnerlind
COMSOL
Actually, you can expect a speed-up by at least a factor of 3 if you split it. Further advantages: * If one of the problems is nonlinear, you will not need to perform iterations for both * When the temperature problem is time dependent, you can usually still solve the stress problem as a sequence of stationary 'snapshots'

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