Reg! Model compatibility issue while reading the stress and deformation profile

[Rajkanu]

Dear STKO team,
I am trying to model an arch. My model units are in mm, and I have applied an acceleration of 0.74 g as a body force according to the required loading condition. After running the analysis, I obtained the stress and displacement/deformation results attached with this email. But I am facing a few difficulties in interpreting the results:

Could you please check whether the stress distribution (stress profile) and displacement profile appears reasonable, and correct?
When I increase the deformation scale factor in the post-processing view, the model appears distorted and it seems to be a compatibility issue. Could you please explain:
What is this called?
Whether it indicates a problem with the model or is simply a visualization effect?
Is the overall model setup correct based on the applied body force and boundary conditions?
Are there any modeling or meshing issues that could affect the accuracy of the results?

I have attached the model files and result screenshots.
Thank you

[STKO Team]

Your model seems correct.

First error: Pay attention to the horizontal force. Since you are modeling in mm, g = 9810, not 9.81.

Second optimization:
The distortion you see is because you increased the deformation scale of non-structured tetrahedra a lot. In order to improve the quality of the results (and not only the visualization), try to create extra cut lines to have all 6-sided volumes that can be meshed with structured hexahedra.

stru_mesh.png (211.72 KiB) Viewed 1438 times

[Rajkanu]

Thank you for your reply.

Regarding the extra cut lines, I would prefer not to add them because I want to keep the masonry brick pattern as a half-brick and full-brick arrangement model.

I also changed the value of g from 9.81 to 9810, after making this change, I am getting the error:

"ERROR: the analysis did not converge."

Could you please suggest how I can fix it and when this happens?

Thank you.

[STKO Team]

It makes sense. now you're increasing the applied force. try to use the adaptive time stepping to overcome the convergence issue

[Rajkanu]

Thank you for your response. I tried using the adaptive time step, but I am getting this warning

Screenshot 2026-06-25 182951.png (124.66 KiB) Viewed 1265 times

. The analysis is also taking a very long time to run and is using a lot of memory. After it finishes, I get these below screenshots and it is not running the analysis.

I also tried changing the numInc and the algorithms, but that makes the analysis take even longer.

Could you please help me understand how to fix this?

[STKO Team]

can you share your model?

[Rajkanu]

Yes.
PFA

[STKO Team]

Try this one but you should run it with openseesmp

Querycmodel.zip

(1.57 MiB) Downloaded 13 times