Problem with Fiber sections in analysis

[dudchenkoav]

Hello!

I have a problem with analysis of fiber beam elements. When I perform a simple beam bending test and add a fiber section in the section tree I get an error error when I run the solver (figure below). This takes place even without the fiber section assignment (This means that the fiber section is only in the section tree and it is not assigned to any element. In that case a simple section is assigned to the beam elements and worked well before fiber section was added). What can be the reason of that? How can I fix it?

Best Regards,
Aleksandr

[STKO Team]

It is a crash in OpenSEES. Unfortunately there is no error message. Can you please post your *.SCD here so that we can have a look?

[dudchenkoav]

Dear STKO team,

the main problem is that the last version of *.scd file was generated for the model that worked. Anyway, old *.SCD file and other files generated for OpenSees are attached and can be downloaded using the following link:
https://dropmefiles.com/Zw8aW
I used this file share as forum did not allow me uplodaing that files.

[STKO Team]

Dear User,

I could run your model without any problem. The file seems correct and well built. I think the problem is elsewhere.
Are you using the OpenSEES version distributed with STKO?
Or are you using your own version?
Can you try to run OpenSees.exe manually?

• go in the directory where you have your *TCL files generated by STKO
• open a command line (cmd)
• type the following command
  "C:\Program Files\STKO\opensees\opensees_303.bat" main.tcl
  (for standard command line)
  or
  & "C:\Program Files\STKO\opensees\opensees_303.bat" main.tcl
  (for windows power shell)

Let me know.

[dudchenkoav]

Dear STKO team,
I use standard version of OpenSeesSP solver which was downloaded from its official website:
https://opensees.berkeley.edu/OpenSees/ ... wnload.php
I have tested various variants of solver running including its execution from Windows command line. In all the cases I got the same error and execution stop right after the solver start. I followed accurately all the instructions (https://asdeasoft.net/?stko-trial) and for other files without fiber sections the solver worked well.

Best Regards,
Aleksandr

[STKO Team]

Dear User,

We couldn't replicate your issue because we were using our own version of OpenSEES. Instead you are using the latest compiled version from the official website which is 3.1.0.

So we downloaded it and in fact we could reproduce your problem. Looking into the source code we noticed that there was a bug in the new source code that leads to the crash. Note that this bug has been fixed 14 days ago (as you can see here: https://github.com/OpenSees/OpenSees/co ... 4f964fa60f), however it has not been recompiled since then.

I think they will update the executable file in the next days.
For the moment you can avoid the crash by specifing the optional parameter -GJ.

In fact the bug was that in the new version, they did not do any check to tell if the optional parameter was specified or not. So they try to get the value, and if you do not specify it, you have a crash.

Let us know if it solves your problem

[dudchenkoav]

Dear STKO Team,

unfortunately, using additional option in command line has not resolved the problem. So, I will wait till the compilation on the new version of OpenSees solver.

[STKO Team]

Dear User, the -GJ Option is not something that you should pass to the command line.
It is the optional linear torsional behavior of the cross section(G (shear modulus) * J (torsional constant)).

Please, edit the fiber cross section and do this:

GJ.png (24.54 KiB) Viewed 7144 times

[STKO Team]

Moreover I noticed that you are running opensees manually from the command line. It is fine, but it will be easier for you if you run it from STKO.

You can add new opensees version in the analysis step Kits. If you don't know how to do this, please repy to this post and I will explain.

[dudchenkoav]

Dear STKO team,

thanks a lot. Now it works. Actually, I used command line only to test. Usually, I run solver from STKO GUI.