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Re: Need opinion to define constraints for a model
Joe Galliera
Oct 22, 2009 11:39 AM
No penetration except between the ring and the pipe.-
Re: Need opinion to define constraints for a model
Joe
Thanks for your reply. That's what I exactly did, but I got this error message "No equilibrium achieved" and I can only see the result up to the point that post touches the concrete. Do I have to take friction into account to balance the forces?
Regards,
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Re: Need opinion to define constraints for a model
Joe Galliera
Oct 22, 2009 9:15 PM
Not sure if friction would help, but you can turn on the soft spring option to give it just enough stability to solve and then possibly identify the problem. Make sure you turn the option off when solving with "fix."-
Re: Need opinion to define constraints for a model
I have already tried "soft spring option", the very same warning comes up (No equilibrium achieved). Do we have to add a force or constraint to stop axial displacement of the post? I guess, there will a normal reaction force between the disc and the ground.
I have also sent my model to our reseller to investigate this problem, I haven't heard anything form them so far.
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Re: Need opinion to define constraints for a model
I think that friction is needed in the no penetration contact set. Without it, I imagine that the post would slide out of the hole (assuming it is perfectly level) due to the location of the force applied.
--Bryson
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Re: Need opinion to define constraints for a model
It might help to remove the concrete temporarily, then restrain just the underside annulus of the 20mm thick ring. Run, and then, find the reaction forces at those locations. This might give a good idea of the reactions that the concreate would need to impart on the pipe to hold it there (you could resolve the net reaction force on the underside of the ring into force and equivalent moment vectors that the concrete would need to excert on the pole - since you've already identified the contact areas from concrete to the end of the pole). Just a thought to help isolate where and what value of reactions are required of the concrete). -
Re: Need opinion to define constraints for a model
Joe Galliera
Oct 24, 2009 11:13 PM
Try out the attached to see if that makes sense to you. In SWS 2009 SP4.1, implemented symmetry BC's, friction coeff of 0.5 on the contact between metal and concrete, and meshing controls.
This is a good example of where I made use of Draft quality elements to test out settings to make sure they work before committing it to a more lengthy yet more accurate High quality (2nd-order) element.
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Re: Need opinion to define constraints for a model
Hi Joe
Thanks for your model. I ran the study with "large displacement" flag on (program asked me to turn the option on). The same warning came up (Equilibrium satisfaction not achieved). I am wondering if you had the same warning too. I have SW2009 SP4.1 on 64bit Vista.
This simple model is giving me headache!
Regards,
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