Issue with big model
Issue with big model
(OP)
I'm trying to simulate in A/View a kind of train consisting of several connected vehicles, with 8 tyres per vehicle. It seems to work fine when I apply no force or motion but the gravity. When the simulation starts it naturally bounds a bit on the floor and finally finds equilibrium. But when I try to set the movement I get miscellaneous errors or lockups. I have tried motions and forces to impose the motion I need, and I get different errors every time. These errors are a kind of random movement of some of the parts, that don't follow their logical movement or physical law...like if the joints exploded.
I don't know the reason of these errors but I guess I may have something to do with the complexity of the model itself (32 tyres, 37 gruebler count, 48 moving parts...) because when I reduce the model to 1 vehicle I can run it without these errors. The model is created in solidworks where the vehicles are built in a parametric way so that the vehicles are supposed to be identical.
Does anyone have an idea of what may be happening or have some heritage in models with a similar complexity?
Any idea or way forward is welcome, and if you are interested (or bored) I can email you the model
Thank you!
I don't know the reason of these errors but I guess I may have something to do with the complexity of the model itself (32 tyres, 37 gruebler count, 48 moving parts...) because when I reduce the model to 1 vehicle I can run it without these errors. The model is created in solidworks where the vehicles are built in a parametric way so that the vehicles are supposed to be identical.
Does anyone have an idea of what may be happening or have some heritage in models with a similar complexity?
Any idea or way forward is welcome, and if you are interested (or bored) I can email you the model
Thank you!





RE: Issue with big model
The typical problem with ADAMS is that you don't get enough of a run to actually see what the problem is. Try running just two or three vehicles and see if that gives you any clues.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Issue with big model
The tires are definitely making it tedious. If I remove the wheels there are no errors, whatever motion or constrains I add to the model, and it seems to move well... so it has to do with the tires for sure. Indeed, my feeling is that it has to do with getting them start rolling. But how can I optimize the tires? I'm using a pacejka 2002 tire (from an A/Car default .tir file) which I tunned in stiffness to perform like mine. I know that this tire works in other models, but actually these models have also had some similar errors randomly.
Kind regards
RE: Issue with big model
As such it isn't really a contact problem.
So, back to my suggestion, try two and then three vehicles.
If you can get anything sensible out of 3 vehicles then you are nearly home.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?