Modeling steel pipe as beam column

[Kefeng]

Hi all,

I am fairly new to OpenSEES so there are some things I am not sure how to do in OpenSEES.

I'd like to model the bending moment along a vertical steel pipe. To do that, I am modeling the pipes as force beam column elements.
I used a simple elastic section for the beam to setup the script, but now I'd like to use Steel01 uniaxial material to model the pipe. However, I don't know which section to use since force beam column elements don't have material tag as input.

My first guess would be to use an aggregator and use the same material tag for all quantities. Something like:

Code: Select all

ops.section("Aggregator", 1, mat_tag, "P", mat_tag, "Mz", mat_tag, "Vy")

The problem is that the pipe dimensions (diameter and wall thickness) are not accounted for.

Thanks for your help!

[mhscott]

Welcome to OpenSees! First, read this: https://portwooddigital.com/2019/09/14/ ... orks-name/

Next, you'll want to look at using fiber sections where you can define the section geometry with a circular patch.

https://openseespydoc.readthedocs.io/en ... patch.html

Or, you can use an elastic section and supply A and I based on your section geometry. With fiber sections, you can account for nonlinear material response, but the elastic section is good for debugging.

[Kefeng]

Thanks! Yes I used an elastic beam column to setup the model. Fiber sections with a circular patch seems to do the trick.