Dear STKO Team
Sorry for asking too many questions
I want to make rigiLink beam on modeling.
To connect two nodes with rigid link beam, do I create "node to node link" in the interaction, and then generate rigidLink in the mp of the contraint? Do I need anything else?
After modeling like this, I opened the mpco file, and the rigidlink beam part looked a little strange, so I post a question.
rigidLink Beam
Re: rigidLink Beam
Dear user,
don't you worry, we are here to help.
You created rigid link in the right way, but deformed shape is a little bit strange.
If you share your model with us, we will check it.
Thank you
don't you worry, we are here to help.
You created rigid link in the right way, but deformed shape is a little bit strange.
If you share your model with us, we will check it.
Thank you
Re: rigidLink Beam
Dear user,
We had a look at your file and we did some changes to improve the convergence of the pushover analysis and now we managed to push it further up to a displacement of 0.6 units.
However the main reason for nonconvergence is that you are using many materials that can suddenly fail and their strength can drop down to 0. This is very challenging for convergence. For example both concrete models you are using in the columns have a 0 residual stress! same for many MinMax materials...
With those models, the best choice is to either reduce the time step to very tiny values, or to provide some residual strength.
Here is a list of changes that we made in the attached file.
We had a look at your file and we did some changes to improve the convergence of the pushover analysis and now we managed to push it further up to a displacement of 0.6 units.
However the main reason for nonconvergence is that you are using many materials that can suddenly fail and their strength can drop down to 0. This is very challenging for convergence. For example both concrete models you are using in the columns have a 0 residual stress! same for many MinMax materials...
With those models, the best choice is to either reduce the time step to very tiny values, or to provide some residual strength.
Here is a list of changes that we made in the attached file.
 Fiber cross section must have the GJ option. In version 3.2.0 it is mandatory... Since you already provided a Torsion in the aggregator, I simply put the section GJ to 1.0e10.
 Some of your ElasticPPGap have the damage option, but not the eta option (default eta = 0). If you use the damage option, then the eta option is mandatory. So I checked them and left them to 0. (I know, this is a wrong documentation in OpenSees)
 In the analyses, I changed the test from Energy to DispIncr. Why? Since you are using Penalty, the Unbalance will never go to 0. But if you use Energy, keep in mind that the Energy comes from the inner product of the incremental displacement and the unbalance. So I suggest to always use DispIncr when using Penalty for constraints
 I changed the defaul algorithm to KrylovNewton, setting the maxDim to 200, so that the tangent is computed only once per step (maxDim, means how many iteration between two next updates of the tangent matrix...), this is much more stable for this kind of problems.
 Finally I used many more time steps... typical when you have these sudden load drops!
 Attachments

 FPS_fold_push.zip
 (235.89 KiB) Downloaded 43 times
Re: rigidLink Beam
Dear STKO Team
Thank you for your kind and detailed reply!
Considering all the suggestions, I'll try modeling again
Thank you very much!
Thank you for your kind and detailed reply!
Considering all the suggestions, I'll try modeling again
Thank you very much!