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#1 |
New Member
Bruno Ramoa
Join Date: Jul 2019
Posts: 18
Rep Power: 6 ![]() |
Hello to all,
I am trying to create a bouncing ball simulation with solids4foam. Something similar to this https://www.youtube.com/watch?v=WwZj8JXrLIo. I started to assemble this case from the impact bar tutorial but now I am having some trouble with the initialization of the case. I used the setFields to set the ball velocity to a very small value (1e-6) but it will not gain velocity due to the acceleration of gravity. Does anyone have experience with this? link for the case: https://drive.google.com/file/d/1Agw...ew?usp=sharing Additionally, is it possible to get the kinetic and internal energy from solids4Foam? Last edited by brunomramoa; March 18, 2020 at 18:54. |
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#2 | |
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,078
Rep Power: 33 ![]() ![]() |
Quote:
Code:
relaxationFactors { // Under-relaxatr ing the D equation by 0.99-0.9999 can improve convergence in // some cases, in particular when there are solidContact boundaries equations { //DD 0.9999; } // Under-relaxating the D field by 0.1-0.9 can improve convergence in some // cases fields { DD 0.7; } } Also for rigid motion, the solver struggles to define a reasonable normalisation factor for calculating the residuals so sometimes a time-step will go to the max correctors but if you look at the solution for different correctors it is not changing (or changing by a very small amount). Finally, I am not sure how important the solution tolerance is in these cases but it is something to be aware of. EDIT: Finally finally, you might need to use a finer plate mesh near the contact region as the contact quick-check algorithm can miss contact when the master and slave faces are very different in size; also a smaller time-step may help. Philip Last edited by bigphil; March 19, 2020 at 05:11. Reason: Added "finally finally" point |
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#3 | |
New Member
Bruno Ramoa
Join Date: Jul 2019
Posts: 18
Rep Power: 6 ![]() |
Quote:
What about the latter part? Is there any function to keep track of the kinetic and potential energy in the system? Best Regards! |
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#4 |
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,078
Rep Power: 33 ![]() ![]() |
I have just pushed a commit (55bd6bb2) to the development branch which adds a new functionObject called solidKineticEnergy and the tutorial tutorials/solids/linearElasticity/plateHole/bouncingPlateHole.
You can see from the code that it is relatively straight-forward to do. I aim to add some other energy function objects when I have time (but you might want to try it yourself). Philip |
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#5 |
Super Moderator
Philip Cardiff
Join Date: Mar 2009
Location: Dublin, Ireland
Posts: 1,078
Rep Power: 33 ![]() ![]() |
I pushed the solidPotentialEnergy function object to the development branch (20e0f235), to be merged with the master in due course.
This potential energy is defined a rho*g*h as opposed to internal strain energy (stress && strain), though I will aim to add that too when I have time. Philip |
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#6 |
New Member
Brian S. Featherstone
Join Date: Nov 2022
Posts: 2
Rep Power: 0 ![]() |
I'm moreover looking for a reply, because i am new here.
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#7 |
New Member
Brian S. Featherstone
Join Date: Nov 2022
Posts: 2
Rep Power: 0 ![]() |
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