MOMENTS AND SHEARS IN SHEAR WALL

[allano89]

Dear STKO team
Thank a lot you are so helpful and kind. Thanks a lot, your help is fundamental.I get the backstay effect and the results are so close to the ETABS.

Now I modeled the whole structure of my research but I get this problem, please your help.

[STKO Team]

The error message is saying that the model is singular.
But without the SCD model, I cannot tell you the reason for it. Can you share it?

[allano89]

Thanks a lot by your concern
I could to solve that problem. But I had another problem Please whats the meaning about this mistake? Because the model continued running.
And how to get the moment-curvature of the shear walls thans a lot for your answers.
Best regards.
PD I´ve attached the new mistake and the model (please. once you download it could you erase it?)

[STKO Team]

You're welcome!

But I had another problem Please whats the meaning about this mistake? Because the model continued running.

It's not a problem. It says that OpenSees had a convergence issue. Then the analysis loop written by STKO tries to reduce the time-step to allow convergence (it's because you chose Adaptive Time Step).

You can remove the attachment from your post

[allano89]

Thanks for your answer
I have the last quesion please. how to get the moment-curvature of the shear walls?
Best regards

[STKO Team]

At the moment you cannot do it because every element in opensees gives global forces as output, but not global deformations.
But I think it would be nice to add to opensees in the near future

[allano89]

The moment is different because, I think, you computed just by summing the Moment Reaction at each node, isn't it?
This is not enough. The total moment with respect to the center of the wall is:
SUM(MYi) + SUM(FZi * Di) (for each node "i").
I.e., you have to sum the moments and the couple given by the forces times the distance from the center of the wall.

This is not easy to do manually.
In the next STKO version (3.2.0) there will be a dedicated tool in the post-processor.

In the meantime, I prepared a "relatively" simple TCL script that allows you to do the "Section Cut" for integrating nodal forces and moments along a Linear Cut.
Note: For simplicity, it will work only in 3D models, only for 2-node beams and 4-node shells (like in your file).
Note: It works only if you use 1 partition (instead the integrated tool in version 3.2.0 will work for every element, and for any number of partitions)


Here's your modified file:
08-MODELO EMPOTRADO 2 PISOS.zip


You can create selections sets for all the Edges where you want to compute Section Cuts:
Sets.png


For each selection set, you can create "Regions", in order to have a TCL list of nodes for each Section Cut.
After all regions, there is a script for the Section Cuts.
In the first lines, you have the User-Parameters (i.e. settings that you can change). Have a look at the descriptions, but it should be pretty easy to understand.
SectionCutScript.png



Pay attention to the "cut_sides". it should be +1 if the elements are on the +X direction of the cut, or -1 otherwise:
Signs and elements.png



This script will generate 6 files (for the 6 components N, Vy, Vz, My, Mz, T) for each section cut in a folder called "CutFiles".
These files have the same format of the Monitor Plots, so that if you have a monitor, you will be able to see them in real-time:
IntegratedResults.png

Dear Stko team
Please how the script works? I should consider the face local axes or the edge local axes, because in the Y direction I get moments higuer than ETABS?

[STKO Team]

In the TCL script you have a list called "all_cut_directions"
Those local axes should match the ETABS ones... otherwise you will see results in another reference system