Axial force- elongation of brace

[mbopen]

Hi
Please help me about my question

I model an X braced frame with 3 story. for brace element I use nonlinear beam column element and divided it to two element for applying imperfection (for modeling Buckling)
Now how can I draw Axial force- elongation of each brace in stories of frame. can I use these recorders or not?

recorder Element -file deformBrace1.out -ele $braceelement1 section $bracesection1 deformation
recorder Element -file forceBrace1.out -ele $braceelement1 section $bracesection1 force

if these are not corrected please help me about corrected recorders.

[selimgunay]

I think you should be able to use these recorders. Please let me know if you experience any problems.

[mbopen]

thanks for nice reply, as I said, I use nonlinear beam column element for braces and divided it to two element for applying imperfection in my 3 story braced frame. when I use this records for each of 2 element of one brace and draw Axial force- elongation of each brace under the seismic record, I expect to have a behavior similar to figure (a) in following link :
http://ascelibrary.org/cms/attachment/6 ... 5225/2.gif

But my hysteresis doesn't have negative part in compressive zone.

[selimgunay]

I haven't noticed the section in your post, you cannot use the section recorder, please try the below recorders

recorder Element -file Elmt_AxFrc.out -time -ele 1 axialForce
recorder Element -file Elmt_AxDef.out -time -ele 1 deformations

[mbopen]

thanks for nice reply. But when I use those recorders as you said. I have 2 output files with only time column and I think opensees doesn't know them?

[selimgunay]

Then please use

recorder Element -file ele1local.out -time -ele 1 localForce; and

recorder Node -file nodes.out -time -node 1 2 3 4 -dof 1 2 disp;

You need to compute the deformation of the brace from the nodal displacements