asdeasoft.net

Hi STKO, :
Im trying to get backbone curve from PDMY material by using customCommand in STKO as follows:
recorder Element –ele $eleNum -file $fName -dT $deltaT material $GaussNum backbone $p1 <$p2 …>
But I can not get the output file. Please have a look at my model in attachment.
Thank you for your help,
Buu

You had 2 mistakes:

• The "-" sign before the "ele" keyword is no a simple minus sign. It was a special character you pasted from somewhere and OpenSees did not recognized it. Please change it to a simple MINUS sign
• the material ID should be 1-based (from 1 to 4 in your case)

Here's the correct command format:
recorder Element -ele 723 -file bbc.out -dT 0.0089 material 1 backbone 54000

Yes, I copied it from Opensees wiki.
It worked now
Thank you for your reply

You're welcome

Dear STKO team,

Is it possible to extract backbone curves / tangent matrix with the .mpco recorder? I tried without success. It is indeed possible with the custom command and classic OpenSees recorder, but exploring the .hdf5 output files would be better for me.

Kind regards,

Sebastian

Have you tried adding this custom result string into the "custom element results" section of the MPCO Recorder?

Dear STKO Team,

I could record the tangent with the custom element results section, thank you. I could not record the backbone curve, maybe because it is not a tensor but rather two vectors relating shear strain and Gs. In any case the backbone curve is always the same for a given element, so I guess I can just record it with the OpenSees default recorder.

Kind regards,

Sebastian

In any case the backbone curve is always the same for a given element, so I guess I can just record it with the OpenSees default recorder.

Yes, it's like a material parameters so it should be the same for all elements with that material.