Hello Opensees community ,
I'm trying to model a simple 2D Timoshenko cantilever with nodal X and Y Forces at the free end and PDelta transformation. I have 4 models with different mesh each: 2 points, 8 points, 20 points and 40 points. The problem is that I fail to get a convergence, each model gives me very different results. When I use linear geometric transformation the results are identical. Any thoughts?
Thank you,
Timoshenko beam issues
Moderators: silvia, selimgunay, Moderators
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TsarpalisD
- Posts: 8
- Joined: Tue Oct 18, 2016 9:06 am
- Location: National Technical University of Athens
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selimgunay
- Posts: 917
- Joined: Mon Sep 09, 2013 8:50 pm
- Location: University of California, Berkeley
Re: Timoshenko beam issues
When you say that you fail to get convergence, do you mean that the analysis is completed for different meshes but the analysis results are different?
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TsarpalisD
- Posts: 8
- Joined: Tue Oct 18, 2016 9:06 am
- Location: National Technical University of Athens
Re: Timoshenko beam issues
selimgunay wrote:
> When you say that you fail to get convergence, do you mean that the
> analysis is completed for different meshes but the analysis results are
> different?
Yes exactly. The cantilever is parallel to the Y axis, has length 9.28 meters and i apply the following forces at the free end: Fx = -200kN and Fy= 200 kN. The results are the following:
1) SAP2000 gives me 0.77 m horizontal displacement at the free end, which is the right answer
2) Opensees mesh 2 points gives -0.086 m
3) Opensees mesh 10 points gives 3.51 m
4) Opensees mesh 20 points gives me 1.03 m
5) Opensees mesh 120 points gives me 0.67 m
The results above are accounting PDelta transformation. In linear analysis all the results are identical.
, thank you
> When you say that you fail to get convergence, do you mean that the
> analysis is completed for different meshes but the analysis results are
> different?
Yes exactly. The cantilever is parallel to the Y axis, has length 9.28 meters and i apply the following forces at the free end: Fx = -200kN and Fy= 200 kN. The results are the following:
1) SAP2000 gives me 0.77 m horizontal displacement at the free end, which is the right answer
2) Opensees mesh 2 points gives -0.086 m
3) Opensees mesh 10 points gives 3.51 m
4) Opensees mesh 20 points gives me 1.03 m
5) Opensees mesh 120 points gives me 0.67 m
The results above are accounting PDelta transformation. In linear analysis all the results are identical.
, thank you