randomVariablePositioner

[negin]

Hi,
Dear silvia
How can we define the cross section properties (fiber dimensions or area,…) in reliability analysis of for example a frame structure as random variables?
I mean which syntax of randomVariablePositioner command are needed?

Tank you very much

[koduru]

Hi,

the user's manual for reliability is available here,

http://www.civil.ubc.ca/faculty/THaukaa ... nsees.html

Hope this helps.

Smitha

[negin]

dear friend, Smitha
tanks for your help but I couldn’t find my answer there!. you know, in fact I want to define cross section properties of a member for example depth of a beam as random variable in reliability analysis, so I didn’t see such proper command.

negin

[koduru]

Hi Negin,

The syntax for the random variable positioner is dependent on the element and the section being defined. I suppose the manual doesn't have the full list.

Point the random variable positioner to where you have defined your cross-section properties. Sometimes they are defined in 1)element command, e.g, 'area' in elastic beam column, sometimes in the 2)section command, e.g, 'area' in elastic section.

This is the general syntax ( doesn't include, nodes , nodal load postioning),

randomVariablePositioner tag? -rvNum tag? -element tag? <-section tag?> <-material tag?> type?


Here is an example

randomVariablePositioner 1 -rvNum 1 -element 102 A

where 'A' is the area of element 102.

(or)

randomVariablePositioner 1 -rvNum 1 -element 102 -section 1 A
where 'A' is the area defined in section 1.


Try this depending on which element/section you are using. The dimensions can be defined as random variables in most cases.


Smitha

[negin]

Hi, Smitha

Thanks again for your time and reply. So, suppose we have a dispBeamColumn
element with rectangular (hxb) cross section defined using “patch quad” command, now how can we define h (depth of beam) as random variable?

For example
randomVariablePositioner 1 -rvNum 1 -element 102 -section 1 ???? what?

negin

[negin]

Hi, all

are there any similar web pages including full informetion or some examples about this topic?

thanks

[koduru]

Hi Negin,

For fiber cross section, only material parameters can be set as random variables . Currently, I dont think any other options are available for this type of section.

The other option may be programming in the source code.

Smitha

[negin]

Hi,

thank you Smitha, but I saw in a paper (from Haukaas T.) and he modeled this source of uncertainties!

dear Silvia, what do you think? please help me


thank you

[silvia]

sorry, but i don't use those feature of the program, you have to contact the original authors of those features -- Terje Haukhaus.

[koduru]

Hi Negin,

The official OpenSees does not have the implementations for the cross-section dimensions to be random variables. The general fiber section cannot be set with random dimensions.

The sections where dimensions can be set as random variables are

"section RCfiberSec tag? b? h? cover? Amain? Aside? coreTag? coverTag? steelTag? nfibers?

and

"section RCSection2d tag? coreTag? coverTag? steelTag? d? b? cover? Amain? Aside? nfcore? nfcover? nfs?"

You will have to get RCFiberSection2d.cpp,RCFiberSection2d.h, files (or)
RCSectionIntegration.cpp, RCSectionIntegration.h (from M. Scott) on this website.

http://www.civil.ubc.ca/faculty/THaukaa ... nsees.html

and then re-compile along with the additional changed files.

The syntax for random variable positioner would remain the same as before

randomVariablePositioner 1 -rvNum 1 -element 102 -section 1 type?

the available parameters for <type?> for "RCFiberSection2d" are
b ,h,cover,Amain, Aside

the available parameters for <type?> for "RCSectionIntegration" are
b , d, Amain, Aside, As, cover

Hope atleast this could help you

Smitha

[negin]

Hi,

Thank you for your time Smitha, you know I couldn’t get that files from UBC.
That is available only for authorized persons!?

Negin

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