curvature in 3D model

Forum for OpenSees users to post questions, comments, etc. on the use of the OpenSees interpreter, OpenSees.exe

Moderators: silvia, selimgunay, Moderators

Post Reply
ehsanomranimemphis
Posts: 22
Joined: Thu Jun 08, 2017 2:31 pm
Location: Babol Noshirvani University of Technology

curvature in 3D model

Post by ehsanomranimemphis » Fri Aug 04, 2017 9:54 am

Hello All,
I have modeled a 2 spans bridge in 3D space. I used nonlinearbeamcolumn element for columns.
I'm wanna capture the curvature of column. I used the following commands:

recorder Element -file $dataDir/curvature.out -time -ele 1111 section 1 deformation;

When I open the output file I see 5 column. the first column shows time. But I don't know which of other 4 columns give curvature.
Is there anyone help me to find the column corresponding with curvature?

ehsanomranimemphis
Posts: 22
Joined: Thu Jun 08, 2017 2:31 pm
Location: Babol Noshirvani University of Technology

Re: curvature in 3D model

Post by ehsanomranimemphis » Sun Aug 06, 2017 6:11 am

Is there someone to be able to me?

selimgunay
Posts: 913
Joined: Mon Sep 09, 2013 8:50 pm
Location: University of California, Berkeley

Re: curvature in 3D model

Post by selimgunay » Mon Aug 07, 2017 10:12 pm

You can try to use <-xml $fileName> to see the headers.

If that does not work please use elastic materials and you can figure out the columns by comparing them with theoretical equations.

ehsanomranimemphis
Posts: 22
Joined: Thu Jun 08, 2017 2:31 pm
Location: Babol Noshirvani University of Technology

Re: curvature in 3D model

Post by ehsanomranimemphis » Tue Aug 08, 2017 7:14 am

Thank you Selimgunay. It worked.
I recorded using -xml $fileName. So I had the following headers:
xsi:noNamespaceSchemaLocation = "http://OpenSees.berkeley.edu/xml-schema ... enSees.xsd">
<ElementOutput eleType="ForceBeamColumn3d" eleTag="81" node1="82" node2="83">
<GaussPointOutput number="1" eta="-1">
<SectionOutput secType="SectionAggregator" secTag="1">
<ResponseType>eps</ResponseType>
<ResponseType>kappaZ</ResponseType>
<ResponseType>kappaY</ResponseType>
<ResponseType>theta</ResponseType>
</SectionOutput>
</GaussPointOutput>
</ElementOutput>
Now my problem is that, I don't know kappayY is curvature around golbal y or local one?

selimgunay
Posts: 913
Joined: Mon Sep 09, 2013 8:50 pm
Location: University of California, Berkeley

Re: curvature in 3D model

Post by selimgunay » Tue Aug 08, 2017 8:56 am

It is around the local y axis of the section

ehsanomranimemphis
Posts: 22
Joined: Thu Jun 08, 2017 2:31 pm
Location: Babol Noshirvani University of Technology

Re: curvature in 3D model

Post by ehsanomranimemphis » Tue Aug 08, 2017 2:31 pm

selimgunay wrote:
> It is around the local y axis of the section
Thank you so much.

ehsanomranimemphis
Posts: 22
Joined: Thu Jun 08, 2017 2:31 pm
Location: Babol Noshirvani University of Technology

Re: curvature in 3D model

Post by ehsanomranimemphis » Tue Aug 08, 2017 2:46 pm

Final question.
The base of columns in my model is fixed. So we expect the curvature in that region is equal zero. But when I recorded curvature in the element including support node (fixed base node) the value of max curvature is about 0.04 1/m while it should be zero. Actually the used element is nonlinearbeamcolumn with 5 np. When I record the curvature in section 1 it is about 0.04 but for section 5 it is about 0.00003 but I thought it should be zero. Is this result correct?
Thanks.

selimgunay
Posts: 913
Joined: Mon Sep 09, 2013 8:50 pm
Location: University of California, Berkeley

Re: curvature in 3D model

Post by selimgunay » Tue Aug 08, 2017 5:29 pm

At the fixed location, the rotation is zero, however the curvature is not zero. It looks like your column is a cantilever column, so at the top your curvature will be zero. Depending on the integration method that you are using the integration point might not be exactly at the top of the node.

Post Reply