The OpenSees Community

Thank you very much Dr. for your quick and complete answer! and I still have that idea to collect these useful information! or at least put a button here to report a post as a useful answer!
thank you for your help.

Hello,

I want to record the rotation of a beam at it's ends. I'm confused which recorder is right to use? and I would appreciate if anyone give some additional explanation about these recorders.
When I use a recorde like this:
recorder Element -file Beam-rotation68.out -time -ele 68 -section 1 plasticDeformation(or basicDeformation)
it gives me nothing, and I find that I have to not mention the section. why? and each one of three columns represent what?
When I use "deformation" like below:
recorder Element -file Beam-rotation68.out -time -ele 68 -section 1 deformation
I can specify the section I want to see its deformation, and it gives just two columns. which column in which recorder gives the rotation of beam end?
My model is 2D!

Thank you very much.

Hi,
I have asked this question before, and it may be useful for you too. here is the link to the post:
http://opensees.berkeley.edu/community/ ... =2&t=60763
But I have a question from you! why do you want to model concentrated hinge?? one of the main advantages of OpenSees is modeling distributed plasticity! you can use a nonlinearBeamColumn with fiber sections which considers P-M interaction.

Hello,

can anyone explain a bit more about Corotational transformation? my main problem is about this sentence written in command manual: "Currently the transformation does not deal with element loads and will ignore any that are applied to the element". what exactly will happen according to this notice?
I would greatly appreciate if you can give me more information about this.

Dear OpenSees experts!
When I want to add a uniform load this error appears:
expected integer but got "-type"
.
.
.
# define GRAVITY -------------------------------------------------------------
pattern Plain 1 Linear {
eleLoad -ele 3 -type -beamUniform -500
}
expected integer but got "-type"
If I write everything in a file and use "source" command to run the analysis, no error appear:-??
I even check one of opensees examples with 2.4.0 and 2.4.3 versions!

Thank you.

Dear fmk,
Could we use uniform beam loads to impose weight for vertical elements, like columns? or brace elements?
Thanks.

Hi,

Here is Dr. Mckenna's suggestion in analysis failure! :

fmk: start by changing the elements to be elastic beam columns. if that fails your nodes, elements or boundary conditions are messed up.
if it works change the section to be elastic for the nonlinear beam columns. if that fails check your beam definitions.
if that works change the materials to be elastic. if it fails your section is wrong.
if that works your materials are incorrectly defined. look at the parameters or consider switching material types.

Good Luck!

its really sad not to get any response...conclusion: never post anything on off days!

Hello

I am modeling a dual system steel structure (moment frame with concentric bracing) for progressive collapse analyses. I developed my model with these specifications:
- It is a 2D model
- 10 story
- 3 bays
- material : Uniaxial material steel01 + MinMax material
- fiber sections
- Beam With Hinges element
- first bay is braced which I will remove a column there in first floor.

I have some problems as follows:
-how can I define a rigid diaphragm while I cant use equalDOF or truss element? because I'm using Beam With Hinges elements and I'm removing a column, so when I add a truss element it effects the vertical displacement of near removed column!
-I read somewhere that Opensees did not consider buckling in concentric braces. is this true? If yes, what should I do in that case?
-I have problem in defining Rayleigh damping. because I cant do eigen analyses when I remove a column (it fails in convergence). And I think assigning Rayleigh damping in progressive collapse should be different than other ground motion situations. Is anyone have any information in this case? ( I know this is not an Opensees question but if anyone have any suggestions I will appreciate!)

Thank you very much.

Hello
I need some examples about following concepts:
1-Rayleigh Damping : how can we use Rayleigh damping in different situations. For example in progressive collapse analysis
2-considering PMM interaction in elements

And it will very useful if you add more explanations to the manual or add some tips about how someone could use a command for a specific purpose!

Thank you very much.

# boxSec.tcl: tcl procedure for creating a Box steel fiber section
# written: Hamed Shoarian Sattari ### hshoar@yahoo.com
# date: 10/2013
#---
#--- input parameters
# secID = section ID number
# matID = material ID number
# h = box height (z direction)
# w = box width (y direction)
# t = thickness
# nfh = number of fibers along box height
# nfw = number of fibers along box width
# nft = number of fibers along thickness
proc boxSec { secID matID h w t nfh nfw nft} {
set a [expr $w/2]
set b [expr $h/2]
set c [expr ($w/2)-$t]
set d [expr ($h/2)-$t]
#---
section Fiber $secID {
#--- patch rect $matTag $numSubdivY $numSubdivZ $yI $zI $yJ $zJ
patch rect $matID $nft $nfh -$a -$b -$c $b
patch rect $matID $nft $nfh $c -$b $a $b
patch rect $matID $nfw $nft -$c -$b $c -$d
patch rect $matID $nfw $nft -$c $d $c $b
}
}

Thank you very much dear Prof. Scott
for the new beamWithHinges is it right to use steel01 in fiber sections of both hinges and interior section of element?
is steel 01 has cyclic degradation?
I'm not sure using steel01 is the right material for progressive collapse, because I think I need to model the strength loss for load redistribution. am I right?
Or maybe I can use steel01 with MinMax material.

The reason I've decided to use elasticBeamColumn with zerloength elemnts as hinges was that I can record the rotation of zerolength element and compare it with allowable values in GSA. How can I get the rotation of plastic hinges formed in a beamWithHinges?
And I'm still have those questions about using fiber sections. actually the reason of my confusion is pm interaction!

Dear Prof. Scot
maybe I'm asking repetitive questions, but, its because I'm really confused:-??
I defined the column with elasticBeamColumn and zerlongth elemnts to demonstrate plastic behavior. A steel column with square hollow section which has two zerolength element at ends as concentrated plastic hinge.
If I have to use fiber section for zerolength elements, which material I should use to achieve this goal, while I have to satisfy the guidelines about hinge properties which defines a force-deformation or moment-rotation curve?
another issue is that how is the force-deformation and moment-rotation curve related to interaction curve?
and the last question is that using elasticBeamColumn in this case is right or not?
Always appreciate your helps!

Thank you Dear Prof. Scott
As you mentioned here and in my previous post, the yieldSurface sections are not documented. I took a look at source code but I couldn't use it.
Can you please explain me how can I use fiber o yieldsurface sections?
I appreciate your quick and informative replies.