stiffness in element recorder output

[moansari]

Hi
which stiffness does opensees mention in element recorder/section/stiffness output ?
it is axial stiffness? flexural stiffness?...
what i can calculate this stiffness?

[fmk]

the stiffness is not returned from any of the elements.

[mja441]

Hi
This is my question too. What exactly is the output of the element recorder/section/stiffness?
Moreover : What is the output of element recorder/section/deformation?
& finally: What is the output of element recorder/section/force?

I'm really stuck, so plz help me out on these issues.
Regards

[fbeckwit]

The section deformations are just that, the deformations that the section can experience. If you're using a fiber section, this is typically axial strain, curvature in the z-direction and curvature in the y-direction. If you've used a section aggregator to add more force-deformation relationships to your section (such as a torsion-strain relation), those deformations will show in the recorder as well.

The section forces are the forces associated with each of the deformations above. That is, axial force (Fx), moment about z (Mz) and moment about y (My).

I am unaware of a stiffness recorder for a section. I can't seem to find it on the wiki, nor have I ever used it. Outputting the stiffness would require outputting a matrix with all the stiffness influence coefficients.