The OpenSees Community

Hello,

The math does not render on the OpenSees wiki anymore.

Please fix so that it is readable.

-Alex

The return code from the analyze command can be used in the IDA to designate failed runs. Often it is done in this way:
set ok [analyze 1]
Then, at the end of the analysis, you can write the return code to a file:
set fid [open code.out w]
puts $fid $ok
close $fid

Try [eigen -fullGenLapack 1]. You only have 1 mass, so the generic eigen solver won't work.

Hello,

I would look at Santiago Zaruma's Thesis: Seismic stability of buckling-restrained braced frames, and Ozgur Atlayan's Dissertation: Hybrid Steel Frames for information on this.

From what I have seen and done, you are going to want to use beam-column elements for the frame (P-Delta for vertical elements), a phenomenological single-truss element for the BRB, and a gravity leaning column. Typically BRBFs are modeled with pinned beam-column connections, done with use of equalDOF constraints.

If you have no experience with OpenSees, try out the examples on the wiki. Some don't work anymore, but you should be able to get the gist of how to script with OpenSees.

Additionally, if you are just starting with OpenSees, I suggest you use my custom Notepad++ language - it has full support of the OpenSees & Tcl languages. https://github.com/ambaker1/OpenSeesNotepadPlusPlus

-Alex

Hello,

It is not clear what to do for beam recorders and what the different columns in output are. On the main wiki (https://opensees.berkeley.edu/wiki/inde ... mn_Element), it states to use the query "force". However, this gives the global force in my experience. Contrary to this, on the old website (https://opensees.berkeley.edu/OpenSees/ ... al/259.htm) it says to use "localForce" or "globalForce".
I was under the impression that "force" was "localForce", but that was in error.

I came to the conclusion that "localForce" is the correct query, and the columns are in the order Axial, Shear, and Moment, with two sets, one for the iNode and one for the jNode.

-Alex

It seems the math interpreter is broken on the OpenSees command manual wiki. I pulled up a cached version of the site on my browser, so I am quite confident it is not on my end.

-Alex

That makes sense.
Thank you!

I am struggling to understand the documentation for the Rayleigh command.

These are the inputs to the Rayleigh command:
$alphaM factor applied to elements or nodes mass matrix
$betaK factor applied to elements current stiffness matrix.
$betaKinit factor applied to elements initial stiffness matrix.
$betaKcomm factor applied to elements committed stiffness matrix.

I understand the first three, but what is the "committed stiffness matrix"?

-Alex

Hello all,

Editing Tcl files for OpenSees is not well supported by standard text editors, and the text editors that do support it are not robust (such as Cypress Editor).

So, I combined the functionality of Notepad++ with the OpenSees language support of Cypress Editor.
The code is located at https://github.com/ambaker1/OpenSeesNotepadPlusPlus/

In the repository, you will find a user-defined language file for OpenSees/Tcl, instructions on how to run OpenSees directly from Notepad++, instructions on how to create a "function definition" that generates a side-bar list of all defined variables, and an autocomplete file for the OpenSees language.

Directions for installation are in the Readme file on the repository.

If you have any questions, please email me at ambaker1@mtu.edu.

-Alex Baker
Michigan Technological University

Hi jjh,
Try adding this code at the end of your analysis:

puts "Press a key to continue"
gets stdin my_variable_name

It will prevent the screen from closing until a key is pressed.
-Alex Baker