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Convergence Speed on Tracking the Maximum Value Using Weak Contribution

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Hi COMSOL users and technicians,

I have a question on convergence speed in my simulation.

Following a post here, https://www.comsol.com/blogs/using-the-previous-solution-operator-in-transient-modeling/, I added a boundary weak contribution to track the maximum value of the damage function in solid mechanics module. The weak contribution reads, (mdmg-nojac(if(solid.damageGp>mdmg,solid.damageGp,mdmg))) * test(mdmg), where mdmg is the auxiliary varible maximum_damage.

Without this weak contribution, the model runs well and fast (within 15 min). Once I enable the weak contribution, the fully coupled slover would fail on convergence. The segragated solver does work, but with a very slow speed (around 6 hours).

My question is that, why this weak contribution would increase the computation burden so much? It seems to me that this weak contribution works as postprocessing, meaning, compare and assign a value. It should've been very quick in this way. Is there any trick that helps to speed up the calculation?

Any feedback would be highly appreciated.

Regards, Xiaokang


0 Replies Last Post 05.09.2019, 09:29 GMT-4
COMSOL Moderator

Hello Donovan Wang

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