displacements one story vs 2 stories

[mvlad]

Hello everyone!
I have one question for you.
I have made 2 models of the same industrial building (the same high, the same geometry,the same loads...and so on. perfectly identical)
One model is with just one story (columns are made in one piece).
The second model is exactly the same building with 2 stories (no element is inserted in the intermediate floor)
My question is why do I have differences in the building displacement?
Also why is the period of the structure different?

 

[Trenno]

I think it has something to do with the two storey model breaking the column into 2x sub-segments because the default option is to mesh frames/shells at intermediate stories.

Try dividing your one storey model columns into two segments and repeat the process.

How fine the mesh is on frame members will affect the natural frequency.

 

[Agent666]

I think trenno is onto it, I'm guessing some mass is being lumped at the intermediate storey (take a look at how the mass is distributed under 'mass source'. When you say period/displacement is different, is is minor differences or order of magnitude different (your pictures aren't that clear to read the numbers).

 

[PKonnerup]

Above is correct. Elements will be split at levels, and masses will be lumped in more points along the elements.