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Re: Convergence Plot, what is it?
Hi Willem, the convergence plot when you are using the FFEPlus solver is actually of no use to typical users, it plots the convergence of some parameters that are internal to the solver.
Kind regards,
Prasad Bhonsule
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Re: Convergence Plot, what is it?
It may be worth your time to learn and understand what convergence means. It will help you understand the difference between good analysis and poor analysis. Maybe (just maybe) you can rise above the herd of poor analysts.
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Re: Convergence Plot, what is it?
Hi Roland, I do understand what convergence means in the context of both FEA and CFD. I used to train Simulation courses when I was working for a SolidWorks VAR. I understand when (and why) results diverge, as well as what methods can be used to help result converge.
However, the particular convergence plot that Willem is inquiring about (when using the FFEPlus solver) is actually of no use to users, and that's not coming from me, that's coming directly from the SolidWorks Knowledge Base. See the screenshot below:
Kind regards,
Prasad Bhonsule
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Re: Convergence Plot, what is it?
It's useful. Helpful, even. How is it not useful to be able to see that your analysis is converging? Beats the heck out of sitting for minutes or hours wondering if your ship will come in.
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Re: Convergence Plot, what is it?
p.s. Prasad--I have no doubts about your competence. That comment was directed at the OP.
Frankly, Sw Simulation makes it too easy to get well-packaged "results" that are usually poorly understood and just plain wrong. Most analyses seem to be thorough, complete answers to the wrong questions.
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Re: Convergence Plot, what is it?
While those 'pretty graphs' don't really mean anything to the FEA analyst they can give you some indication as to how the solve is going. If everything is heading downward toward the limit line then I let it run. If, as I have seen some times, it is oscillating up and down then usually the solve seems to fail and it is better (IMHO) to abort the run and find out what was done wrong on the input.
Do NOT confuse this with 'convergence' which is an indicator of whether you have reached a reasonable solution as Prasad has indicated above.
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Re: Convergence Plot, what is it?
Good point, James. Convergence has two different meanings in different scopes.
One is for a given solution to converge and yield a solution. The other is for strain values to "converge" toward a finite value as the mesh is refined and run repeatedly.
Both are important to know. The second, more so. I've seen more than a few failures due to would-be analysts failing to refine models to get converged results.
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Re: Convergence Plot, what is it?
I think it should be noted that, strictly speaking, a converged solution does not mean you have an accurate solution. Generally speaking, all accurate solutions are converged, but not all converged solutions are accurate.
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Re: Convergence Plot, what is it?
Absolutely, the "convergence graph" is merely some indication of the solver/computer progress and has nothing to do with a "converged" FEA solution.
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