Convergence error while pushover analysis

[gookki]

I'm going to modify the week_12 webinar model slightly and analyze it by combining the pushover of mode shape with self weight.
As advised here, I applied prescribed displacement, which caused problems that could not converge immediately even with very little lateral force. I need help with what the problem is. (but It is worked well in vertical load)

And in the current model, in order to increase the lateral force while maintaining the constant self weight, the constant definition is applied and the sp condition is linear definition is applied, so I wonder if this works as I thought.

(As an incidental question, I tried to put a specific value of sp into the code by referring to other utils.py files, but it didn't work. I want to try it, but I'd appreciate it if you could check the code

[LuisB]

Hey gookki, how are you? I was looking at your model and I found that you had applied both, gravity loads and lateral loads in the same analysis. I would recommend splitting those into two analyses. In addition, you should change the Constraints Handler to Penalty (remember that the value of the parameter can be around 8 orders of magnitude greater than the stiffest material in your model.
Note: The transformation method is not recommended to be used when multiple constraints have been applied (https://opensees.berkeley.edu/wiki/inde ... ion_Method).

Regarding your script, the property that you should use there is called real, so the code would be:
p.XObject.getAttribute(‘Ux value’).real = Uxvalue

[BuuNguyen]

Hello LuisB,

Penalty (remember that the value of the parameter can be around 8 orders of magnitude greater than the stiffest material in your model.

stiffest material means "K" value?
how can I define the stiffest material if
1/ I model soil domain only?
2/ I model soil + supper-structure?

Thank for your support.
Buu

[marafini.f]

Dear BuuNguyen,

You need to check which is the largest stiffness present in your model, it does not matter if you have only soil or soil+structure. You just need to go into your physical properties, check which materials you have used by comparing stiffness in the same units and choose the largest one to calculate the penalty parameter.

Do search for the word penalty in the whole forum, there should be a lot of threads in it and you could find more useful information.

Enjoy your modelling
Francesca