PDelta Effects for Models With Elements which doesn't include Geometric Transformation
Moderators: silvia, Moderators
PDelta Effects for Models With Elements which doesn't include Geometric Transformation
I have Modelled a Modular building in Opensees. This Includes Boxes( Modulesmade of shell elements) connected with two node link elements to form a building as shown below.
We also developed an experimental model of the same and noticed the results for the top displacement.
I could notice that there is a shift (shifting upward) of the baseline in the experimental results which i believe is due to the Pdelta effects while the experimental results, top displacement base line was on Y=0 line, i.e X axis. Also i can see that my Opensees Model has no way of getting Pdelta effects activated because Neither two node link element nor the shell elements used to model the boxes have coordinate transformation feature.
May i please get your idea on this? how can i let my Opensees model take in to account the Pdelta effects? is there any other way to account for that? Or is it not the Pdelta effects that's causing the shift of the base line?
I tried adding a leaner column, but it wasn't successful. i followed the exact procedure mentioned for that on Opensees website. But the eigenvalues were imaginary.
We also developed an experimental model of the same and noticed the results for the top displacement.
I could notice that there is a shift (shifting upward) of the baseline in the experimental results which i believe is due to the Pdelta effects while the experimental results, top displacement base line was on Y=0 line, i.e X axis. Also i can see that my Opensees Model has no way of getting Pdelta effects activated because Neither two node link element nor the shell elements used to model the boxes have coordinate transformation feature.
May i please get your idea on this? how can i let my Opensees model take in to account the Pdelta effects? is there any other way to account for that? Or is it not the Pdelta effects that's causing the shift of the base line?
I tried adding a leaner column, but it wasn't successful. i followed the exact procedure mentioned for that on Opensees website. But the eigenvalues were imaginary.

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 Joined: Mon Sep 09, 2013 8:50 pm
 Location: University of California, Berkeley
Re: PDelta Effects for Models With Elements which doesn't include Geometric Transformation
For this case, leaning column is the only option to consider pdelta effects. Imaginary eigenvalue can be because the leaning column itself is unstable as it has a hinge at the bottom and connected to only axial trusses. Did you assign masses to the leaning column ?
Re: PDelta Effects for Models With Elements which doesn't include Geometric Transformation
Hi Yes, i assigned masses to the leaning column. But still i keep getting imaginary Eigenvalues. IS the leaning column method valid for 3D models as well? mine is a 3d Model, but i assigned a leaning column to the first frame of the building only.
"Imaginary eigenvalue can be because the leaning column itself is unstable as it has a hinge at the bottom and connected to only axial trusses" if this is the case, what do you recommend to solve this issue?
"Imaginary eigenvalue can be because the leaning column itself is unstable as it has a hinge at the bottom and connected to only axial trusses" if this is the case, what do you recommend to solve this issue?
Re: PDelta Effects for Models With Elements which doesn't include Geometric Transformation
IS the leaning column method valid for 3D models as well? mine is a 3d Model, but i assigned a leaning column to the first frame of the building only.
https://www.doostihaa.com/1398/08/22/دا ... انگشت.html
https://www.doostihaa.com/1398/08/22/دا ... پوست.html
the leaning column itself is unstable as it has a hinge at the bottom and connected to only axial trusses" if this is the case, what do you recommend to solve this issue?
https://www.doostihaa.com/1398/08/22/دا ... انگشت.html
https://www.doostihaa.com/1398/08/22/دا ... پوست.html
the leaning column itself is unstable as it has a hinge at the bottom and connected to only axial trusses" if this is the case, what do you recommend to solve this issue?
Re: PDelta Effects for Models With Elements which doesn't include Geometric Transformation
S the leaning column method valid for 3D models as well? mine is a 3d Model, but i assigned a leaning column to the first frame of the building only.
https://www.doostihaa.com/1398/08/25/دا ... ونیم.html
https://www.doostihaa.com/1398/08/25/دا ... پدری.html
the leaning column itself is unstable as it has a hinge at the bottom and connected to only axial trusses" if this is the case.
https://www.doostihaa.com/1398/08/25/دا ... ونیم.html
https://www.doostihaa.com/1398/08/25/دا ... پدری.html
the leaning column itself is unstable as it has a hinge at the bottom and connected to only axial trusses" if this is the case.
Re: PDelta Effects for Models With Elements which doesn't include Geometric Transformation
mine is a 3d Model, but i assigned a leaning column to the first frame of the building only.
https://www.doostihaa.com/1398/09/01/دا ... رنگین.html
https://www.doostihaa.com/1398/09/01/دا ... مانکن.html
https://www.doostihaa.com/1398/09/01/دا ... کرگدن.html
https://www.doostihaa.com/1398/09/01/دا ... دیگری.html
https://www.doostihaa.com/1398/09/01/دا ... رنگین.html
https://www.doostihaa.com/1398/09/01/دا ... مانکن.html
https://www.doostihaa.com/1398/09/01/دا ... کرگدن.html
https://www.doostihaa.com/1398/09/01/دا ... دیگری.html
Re: PDelta Effects for Models With Elements which doesn't include Geometric Transformation
S the leaning column method valid for 3D models as well? mine is a 3d Model, but i assigned a leaning column to the first frame of the building only.
https://www.doostihaa.com/1398/09/04/دا ... مانکن.html
https://www.doostihaa.com/1398/09/04/دا ... ناست.html
https://www.doostihaa.com/1398/09/04/دا ... تعصب.html
https://www.doostihaa.com/1398/09/05/دا ... نیها.html
https://www.doostihaa.com/1398/09/07/دا ... کرگدن.html
https://www.doostihaa.com/1398/09/09/دا ... فید۳.html
https://www.doostihaa.com/1398/09/11/دا ... مانکن.html
https://www.doostihaa.com/1398/09/18/دا ... مانکن.html
https://www.doostihaa.com/1397/09/20/دا ... دقیقه.html
https://www.doostihaa.com/1398/09/14/دا ... لارج.html
https://www.doostihaa.com/1398/09/14/دا ... شیرین.html
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https://www.doostihaa.com/1398/09/21/دا ... کرگدن.htm
https://www.doostihaa.com/1398/09/28/دا ... کرگدن.htm
https://www.doostihaa.com/1398/09/04/دا ... مانکن.html
https://www.doostihaa.com/1398/09/04/دا ... ناست.html
https://www.doostihaa.com/1398/09/04/دا ... تعصب.html
https://www.doostihaa.com/1398/09/05/دا ... نیها.html
https://www.doostihaa.com/1398/09/07/دا ... کرگدن.html
https://www.doostihaa.com/1398/09/09/دا ... فید۳.html
https://www.doostihaa.com/1398/09/11/دا ... مانکن.html
https://www.doostihaa.com/1398/09/18/دا ... مانکن.html
https://www.doostihaa.com/1397/09/20/دا ... دقیقه.html
https://www.doostihaa.com/1398/09/14/دا ... لارج.html
https://www.doostihaa.com/1398/09/14/دا ... شیرین.html
https://www.doostihaa.com/1398/09/14/دا ... کرگدن.html
https://www.doostihaa.com/1398/09/14/دا ... الدل.html
https://www.doostihaa.com/1398/09/17/دا ... ملشد.html
https://www.doostihaa.com/1398/09/20/دا ... یالدل.htm
https://www.doostihaa.com/1398/09/27/دا ... یالدل.htm
https://www.doostihaa.com/1398/09/21/دا ... کرگدن.htm
https://www.doostihaa.com/1398/09/28/دا ... کرگدن.htm