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Topics - azing

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Wind Engineering (WE-UQ) / Load factor
« on: June 28, 2021, 09:45:03 PM »

When performing WE-UQ simulation of a 20-story frame with one sample and a dummy variable, I realized that the results don't match with pure OpenSees simulation results. This is because I was using a load factor to scale up the magnitude of the applied wind forces. I realized that if I specify the load factor as 1, but use a wind loading s enario that has been externally scaled before being used in WE-UQ as an input, then the results will match with OpenSees. It seems to me that the load factor input in the "existing" of the tool doesn't apply the factor properly. Is this a possibility or am I making a mistake somewhere else?

Thank you,

Wind Engineering (WE-UQ) / recorder options for base shear and PID
« on: June 09, 2021, 06:40:03 PM »

Is there a way to get the total base shear of the frame as one single EDP? I can record individual base shear values separately, but then I don't know if the maximum values happen at the same time. So I can't add them together. That is why I was wondering if there is a recorder command for frame's maximum base shear?

I can see that we can get maximum interstory drift as an EDP as well. But what is the recorder for that. Because whatever is done for PID, I might be able to use that for reactions as well.

Thank you,

Wind Engineering (WE-UQ) / pset doesn't work for certain parameters
« on: May 31, 2021, 04:28:50 PM »

I don't know why the pset command doesn't work for me for setting up certain parameters (My, theta_p, and theta_pc in the IMK material). They don't appear in the list of random variables in WE-UQ's user interface.


When I specify large number of samples in a forward propagation problem using LHS, my simulation fails. I have tried running this both on my laptop and on Designsafe:

- On the laptop, I get the error "Dakota has stopped working". If I choose the debug option, it says "an unhandled exception occurred in [11756] Dakota.exe".

- On Designsafe, the job status turn to "failed" and it says "APPS_USER_APP_FAILURE Failure indicated by Slurm status TIMEOUT with user application return code: 0:0".

* I have previously run this model for 32768 time steps with only one random variable and one sample using WE-UQ without any errors and got results comparable to deterministic OpenSees simulation results.
* I have also run the model as a test with only two time steps and 26 random variables and 30 samples successfully.

So I think the issue might not be because of the way the model and WE-UQ parameters are set up. It seems like it is due to the large number of samples. But I don't know why and how to resolve it.

Thank you,

Wind Engineering (WE-UQ) / numeric assignment for the pset command
« on: April 27, 2021, 07:26:27 PM »

When I use the pset command with an expression instead of a number like below:

pset mass_roof [expr 40.06/(2.*6.*12.)] 

the "mass_roof" random variable doesn't appear in the tool. I can replace the expression with a number for this specific case. But is it possible to be able to have expressions as inputs as well?

Wind Engineering (WE-UQ) / correlation between RVs in LHS method
« on: April 17, 2021, 03:45:35 AM »
In the current version, are the RVs uncorrelated? Does the shuffling approach in the current LHS sampling method configured in a way to prevent spurious correlations between RVs?

Wind Engineering (WE-UQ) / constraint handler
« on: April 12, 2021, 04:56:50 AM »

I'm just curious to know why isn't there a "constraint" section in the FEM section of WE-UQ?


Wind Engineering (WE-UQ) / existing event file format
« on: April 06, 2021, 05:10:56 PM »

What is an example of a valid existing wind event format?

Thank you,

Wind Engineering (WE-UQ) / recorders not generated
« on: March 30, 2021, 07:37:07 AM »

I am using OpenSees model of the 20-story SAC building in 2D as an input for WE-UQ. The model has a lot of elements and nodes, so I used the "user defined" option in the EDP section. If I use the "standard wind" option, Dakota will give me an error saying that "expected function values are not equal to the values found".

When using the user defined option, I modify the "recorder" and the "postprocess" files found on the website for the 9-story SAC building to just give me the results for the displacement at some node at roof level of the building. But no matter how I change the recorder and postprocess files, when I run the program, no disp.out files are generated for me in the work directories. Accordingly, I get zero and NAN values for the forward propagation analysis results. Could there be another reason for the zero and NAN results? I am using a stochastic wind event.

This is what I have in the recorder file:
recorder EnvelopeNode -file disp.out -node 1123  -dof 1  disp

This is what I have in the postprocess file:
set dispIn [open disp.out r]
while { [gets $dispIn data] >= 0 } {
     set maxDisp $data

# create file handler to write results to output & list into which we will put results
set resultFile [open results.out w]
set results []

foreach edp $listQoI {
    set splitEDP [split $edp "_"]   
    set response [lindex $splitEDP 0]
    set tag [lindex $splitEDP 1]
    set dof [lindex $splitEDP 2]
    if {$response == "Disp"} {
   set nodeDisp [lindex $maxDisp 0]
   lappend results $nodeDisp
    } else {
   lappend results 0.0

# send results to output file & close the file
puts $resultFile $results
close $resultFile

General Questions / Running on DesignSafe
« on: March 28, 2021, 04:11:18 AM »

When I try to run a WE-UQ simulation on DesignSafe, the status of the simulation doesn't go any further than "STAGING_INPUTS". I don't know what I'm doing wrong. I login, and then hit "run at DesignSafe". I'm just running a very small test model.

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