Fragility Analysis

A place to ask questions on how to use OpenSees to perform Finite Element Reliability Analysis

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xan
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Location: Indian Institute of Technology Delhi

Fragility Analysis

Post by xan » Wed Sep 25, 2013 4:35 am

How could I use the FragilityAnalysis.cpp file in OpenSees API to generate fragility curves?

Are there any examples portraying the use of API and how to use APIs?

mhscott
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Re: Fragility Analysis

Post by mhscott » Wed Sep 25, 2013 8:26 am

You will probably have to create fragility curves manually using loops and FORM analysis in your Tcl script instead of using FragilityAnalysis.cpp. If you post your script or describe more specifics, I can point you to the OpenSees/Tcl commands you'll need to do the fragility analysis.

xan
Posts: 4
Joined: Tue Aug 13, 2013 10:40 am
Location: Indian Institute of Technology Delhi

Re: Fragility Analysis

Post by xan » Wed Sep 25, 2013 9:39 am

Thanks for the quick response.

I'm quite new to OpenSees currently. I'm still learning and have just tried out simple programs to generate frames.

My project concentrates on generating fragility curves for building frames with passive dampers for seismic analysis. Hence, I was wondering if I will have to code my own fragility function or is there something already in OpenSees that I could make use of. This is all I can tell you currently. But, within a fortnight, I would definitely, come up with a script and post it as you've suggested.

If I'll have to make my own fragility function, using loops etc. as you suggested, what is the use of FragilityApnalysis C++ file in APIs?

mhscott
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Re: Fragility Analysis

Post by mhscott » Wed Sep 25, 2013 9:46 am

To make a long story short, some analysis modules for reliability are deprecated, and FragilityAnalysis.cpp is one of them.

xan
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Joined: Tue Aug 13, 2013 10:40 am
Location: Indian Institute of Technology Delhi

Re: Fragility Analysis

Post by xan » Wed Oct 02, 2013 7:27 am

Hi Professor Scott,

As I told you earlier, I've tried out some basic examples from OpenSees Documentation.

As I've to generate fragility curves using passive vibration control devices, I will have to define my material and the parameters.
uniaxialMaterial $someMaterial $matID $Cd $a ($Cd=Damping Co-efficient , $a = Damping exponent)

The steel frame would be coded as I saw in examples, by :
1. Defining Geometry
2. Defining Nodes.
3. Defining the single point constraints
4. Setting up mass
5. Setting up column and beam properties.

After, this when my frame is ready along with the damper, (I'll also have to connect the damper between two nodes), my setup will be complete.
After this, I'm completely unaware on how to generate the fragility curves. You'd told me about the Fragility module being deprecated, I'll have to use FORM analysis. Could you please help me a bit? I'm new and not able to find proper documentation/examples on using the FORM analysis.

Thanks.

mhscott
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Re: Fragility Analysis

Post by mhscott » Thu Oct 03, 2013 8:54 am

There are actually a few ways to go with fragility analysis that do not require FORM analysis. One is you can create loops that do nonlinear dynamic analyses over varying levels of an intensity measure (Sa, PGA, etc.) while recording your demand parameter or measure of damage for each run. Then, you will fit distributions to the responses. But first, check out some papers on fragility analysis, come up with the loops, intensity measure, and demand parameter you need, then I could offer more directed help.

xan
Posts: 4
Joined: Tue Aug 13, 2013 10:40 am
Location: Indian Institute of Technology Delhi

Re: Fragility Analysis

Post by xan » Thu Oct 24, 2013 9:07 am

Respected Sir,

I've mailed you my code samples and other relevant details.

Thankyou.

samk
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Re: Fragility Analysis

Post by samk » Tue Sep 15, 2015 3:38 am

Thank you mhscott sir, This helps me out in my queries. Reliability analysis is one of my weak zone as always. :cry:

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