Mesh in Shear wall

[pgaire]

Hello everyone,
I modeled a shear wall with boundary elements in STKO and also tried to model the same using TCL script.
In STKO, I modeled the shear wall with the face element and assigned the boundary element to edges (bottom fig). Then the structure is divided into 4 uniform divisions (as global seed).
With the TCL script, the same model (Top fig) is developed with an intermediate node to incorporate the element meshing in STKO.
Running the analysis, I got the first period almost the same, however, the second period has a significant difference. Can anybody suggest the possible reason behind it? (Are these two modeling approaches equivalent to each other?)

Periods
First Second
i) STKO OpenSees 0.116367 0.0191965
ii) OpenSees with tcl 0.116767 0.0418712

Thank you.

[STKO Team]

It's not clear to me what you mean here:

With the TCL script, the same model (Top fig) is developed with an intermediate node to incorporate the element meshing in STKO.

What is the "intermediate node" ?

[pgaire]

Hello STKO Team,
Thank you for the reply.

By intermediate node, I meant I divided the boundary element into 4 parts.

[STKO Team]

Of course, there should be some difference between them.
could you share both models?

[pgaire]

Hello STKO team,

Yes, I found the difference. There was a difference in -GJ value while defining the fiber section. The difference was 1e13 and 1e15.
Now, I am getting the results closer.

Result:
Periods
First Second
STKO OpenSees: 0.118367 0.037438
OpenSees with TCL: 0.1183 0.03744
(I just wanted to confirm that these to modelling approach are equivalent to eachother)
Thank you.

[STKO Team]

If the 2 models are equal, yes. I mean, using STKO or using manually Tcl is just pre-processing. As far as they write the same thing, the result should be the same, because the solver is the same