The bridge model does not converge

[Gao hw]

Dear STKO team,
Hello! When I use STKO to establish a full-bridge model according to opensees source code to study its seismic response, the model does not converge, showing "Large trial strain". May I ask why such a situation occurs and how can I modify it to solve this problem?
I have uploaded the source code and model to the attachment, looking forward to your reply
Best wishes!

[STKO Team]

Sorry, but there are many differences (mistakes) between the model in STKO and the source code.
I found some of them, but there may be others (we cannot check all of them):

• One node at the base is not fixed
• Some interaction do not have the 2NodeLInk element property assigned
• All interaction do not have a local axes that match the local axes given in the source code
• In all elastic section you did not check the Optional attribute to activate the alphaY and alphaZ (i.e. if you don't check it, the beam will be euler, not timoshenko)

Please review the model carefully and make sure they are the same.

[Gao hw]

Thank you for your reply, which helps me a lot! I will carefully check the model error, thank you for your patient guidance.

[STKO Team]

You're welcome

[Gao hw]

About your third questionIn ,the bridge model, the local coordinates of the twoNodeLink element are consistent with the global coordinate direction. The three directions of the local coordinates of the twoNodelink element in the source code correspond to three uniaxial materials. Therefore, I want to make the local coordinates of the twoNodeLink element in the bridge model consistent with the direction in the source code, but using the 'Reverse' command can only convert the local coordinates of "line geometry". How to convert the local coordinate direction of the twoNodeLink element?

[ValentinaSB]

Ho Gao hw,

You can create local Axes in the Work Tree and assign them to your twoNodeLink.

Screenshot 2023-05-22 092601.jpg (28.88 KiB) Viewed 2316 times

Let us know if it is what you needed.

Best,
Valentina

[Gao hw]

Thank you for your reply, which is exactly what I need. The problem has been solved, thank you again

[ValentinaSB]

You are welcome!