beam column joint modelling

[farukpolat3535]

Hello stko team;
In my study, first we compared the eigenvalue results for the model with rigid joints and model with flexible joints (with moment-rotations).
The units are in N and mm. In the flexible model we defined joint moment-rotations and joint elements with a length of 250 mm (half of the beam and column dimensions).

For the rigid joint model T1= 0.66 sec, on the other hand for a flexible joint model it is 2.64 sec.
As you mentioned in the video we considered the penalty value due to flexural stiffness (6 e13) and it is taken as 1e18.
But the period is 2.64 sec, so which penalty value do you suggest that we can consider? I have already sent the model with email.

Best Regards.

[marafini.f]

Dear Faruk,
Sorry if it took so long, I am looking at your model.
I have a question, the nodal masses you input, for example on the first level, they are 9.61233 what?, like in what units?
Francesca

[farukpolat3535]

Dear Francesca
Nodal masses are in kg unit. I found it by dividing the floor weight by 9810 (N/mm2).

[marafini.f]

Dear Faruk,
if you divided the floor weight by 9810, then your masses are not in kg, but in N/(mm/s^2).
I would like you to check your calculations though, because from a quick look, the order of magnitude of the wall load on the floors is of 10 N/mm, is the same order of magnitude of the nodal mass on the first floor, so there is something wrong there.

To clarify the conversions you have to operate:

REFERENCE
N = 1;
mm = 1;
s = 1;

MULTIPLIERS
m = 1000.0;

CALCULATIONS
p = <N/mm> (load you want to turn into mass)
g = 9810 <mm/s^2>
m = p/g (mass to apply) <N/(mm/s^2)>

Also, if you can check out the assignments in terms of conditions and properties you made of your models, if you selected all the right elements, as the wall 20/285 elastic load is applied on a column too, so please check all the others.
Let me know if you obtain better results.

Enjoy your modeling.
Francesca

[farukpolat3535]

Dear Francesca;
Thank you for mistake about assigning 20/285 wall load to a column. I changed it. In our model masses are in (N*s^2/mm).
Updated Floor weight is 3116000 (N) 3116000/9810 = and floor mass is 317,6 (N*s2/mm).

Nodal masses are 317,6/22 = 14,4 (N*s2/mm).
In the updated model when we use penalty factor (K) for joint material (K) = 1e+19

*First Mode Period = 0,67 sec. and it is close to rigid model.

But when we use penalty factor K= 1e+18

*First Mode Period = 2,08 sec.

We will consider K as 1e+19.

Best Regards.

[marafini.f]

Dear faruk,
I am glad I could help.
As for the penalty value, it is possible that with a lower value your constraints are handled differently, yielding a more flexible response. It is normal you must use different values for different structures.

Good luck with your PhD and enjoy your modeling.
Francesca