Ramberg Osgood Material

[fbeckwit]

Hello,

I'm currently trying to implement the Ramberg-Osgood material into my model but am having issues with it. I noticed this material was in the source code but does not have any documentation on the wiki. Currently, it appears the material is implemented with the following command:

uniaxialMaterial RambergOsgoodSteel $matTag $Fy $E0 $resaAA $resaNN;

The terms $Fy and $E0 are self-explanatory while the $resaAA and $resaNN terms are less so. After looking into the source code, it appears the $resaNN term is the "r" coefficient as presented in most forms of the Ramberg-Osgood hysteretic rule. When using displacement-control integration in OpenSees, this model works only if the $resaNN term is set to an odd integer, otherwise it blows up. Does anyone else have any experience using this uniaxial material in OpenSees?

Thanks in advance.

[rezarahimi]

Hi fbeckwit

I am Reza Rahimi code developer of RambergOsgoodSteel uniaxial material. It behavior is added in new version of opensees (2.4.1).

if you email me I will send you its description.
email: mr.rezarahimi@gamil.com

some information are mention below:

uniaxialMaterial RambergOsgoodSteel $matTag $Fy $E $a $n
$matTag
integer tag identifying material
$Fy
yield strength
$E0
initial elastic tangent
$n
parameters to control the transition from elastic to plastic branches and controls the hardening of the material by increasing the n ,hardening ratio, will be decreased.
Commonly used values for $n are ~5 or greater. ($n must be odd number)
$a
“yield offset” and the Commonly used value for $a is 0.002

[fmk]

Reza,

Sorry I did not get back to you. If i have not already done so, I should provide you access to the wiki pages so that you can add any documentation you wish on the material

frank

[rezarahimi]

Dear Frank

I really appreciate your concern

so, I will wait for your email.

best regards

reza

[fmk]

you need to register on the wiki and i will give you access to it once i know your username

[rezarahimi]

Dear Frank,

I did not know that I should register on wiki
I registered as soon as I got your reply my username in wiki is "rezarahimi"

thank you for your time and support

reza

[fmk]

you should be able to edit now.

[rezarahimi]

Dear frank
when i wanted to type a formula in wiki i got this error
Failed to parse (Missing texvc executable; please see math/README to configure.)

when i searched this error I saw some pages by similar errors, like :
http://opensees.berkeley.edu/wiki/index ... ement_Test

what is the solution and your advise here?

best regards

[fmk]

sorry .. we switched to a new server that did not have the necessary software to create the images that were displayed. it is a depertmental server and i no longer have root access to install whatever i want. i can forward the request, but i am rather lo on their totem pole. in the meantime you might try seeing if you can create an image and upload that.

[rezarahimi]

thank you so mach for you help. I will create image of my formulas

[fmk]

do 1 first to see if it works.