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Nonlinear Static 3D with gravity loading: can't figure out how to output Velocity of Kinetic Energy.
What am I missing or forgetting?
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What I'm actually trying to accomplish is a drop test of a plastic part. I typically use explicit analyses for this but looked and evidently the plasticity is not included with explicit yet. So it will have to be implicit, dynamic, with a velocity if I can get it to work.
https://www.endevco.com/news/archivednews/2009/2009_02/tp321.pdf
At work I can use Ansys Explicit STR to test to see if what I'm wanting to do is valid.
Maybe I'm not smart enough to see why this wouldn't work but it will be fun anyway. If it works I'll let you know.
Also, is there a way to prevent Mecway from including any "Analysis" data from showing up in the CCX input file? This way I could run CCX examples with minimal modification. As it is now, or at least that I'm seeing, Mecway will always put in the Analysis data to the input file, therefore clashing with the CCX Analysis input data. Make sense?
*dynamic
0.001, 1., 0.000000001 , 0.002
also you must add a card to output result as well:
*NODE FILE,GLOBAL=YES
U,RF
*EL FILE
S,E
There is no way to prevent Mecway to include his data as far as I know. There are several cards that are not implemented (yet?), so in this case I preffer to run using the command line or Scite menu and just open the results file (.frd) in Mecway. What you can do is just leave the nodes and elements sections on the .inp file and add the boundary conditions on the Mecway's GUI. Be aware that Mecway will interpret resulsts files as if they were in N meters and in this case is N mm, so stress and displacements values are with the wrong unit.
According to the input file, material is Gummi (rubber), but is modeled as a very soft elastic material. I will try to run with an hyperelastic definition to see if we can see more deformation on the ball, because now I can't see any :-) just movement.
Another thing weird is that in the third impact it has more stress than in the first, I would say that the first would be the worst case. Could it be that due to the time increment we are not capturing exactly the moment when it makes contact (at least the first impact)?
For example, why in the ball example they add a initial velocity in horizontal direction and not in vertical as normally done? What about dumping?
Regards
Whenever I analyze drop tests, my part is modelled already touching the base (at the beginning of the analysis, or in other words at time=0), and then the initial velocity on the part is an easy calc based on drop height.
The only way I was able to make this work was if my contact was bonded, which of course is unacceptable for this type of problem.
But this type of problem really requires explicit, but evidently CCX cannot have plasticity in an explicit analysis just yet. This is why I was searching hi and lo for a free explicit solver that can handle plasticity. But no luck.
Sorry for the bad news.
Regards,
Scott
Luckily I get to use Explicit STR from Ansys at my workplace. I work for Husqvarna btw. If one can afford it, I definitely recommend it, it's extremely easy to use and very powerful.
Unfortunately, inherent with any explicit solution is potentially long run times, so running on many cores is critical. Ansys requires a separate licence purchase for being able to do this. They call it their 'HPC licence'. This can get pretty expensive though depending on how many cores you want to have access to.
If I had unlimited cash that's definitely what I'd use for a personal business. I've used it 100's of times and it's never let me down. But I don't have a personal business and I doubt I will anytime soon. I just like to play around with these free or low-cost tools to mainly see what they can do and what their limitations are.