Empty Eigenvector Files

[batuturk]

Dear all,

I'm working on a 3-D bridge model. I want to get mode shapes after gravity loading analysis. But all my eigenvector output files are empty. The script I used is:

set lambda [eigen 10];
for {set i 1} {$i <= 10} {incr i} {
recorder Node -file eigenvector$i.out -node 109 -dof 1 3 "eigen $i";
}
analyze 1 0.1

I don't think there is a problem in my model since I've already verified it with SAP2000 model. My only problem is how to get eigenvectors after gravity analysis?

[Jeena]

Hi,

Check this example http://opensees.berkeley.edu/wiki/index ... hear_frame

It looks like you are defining the recorder eigen value command after performing the eigen analysis ... Define the " set lambda [eigen 10] " after the recorder definition loop ....

In the example they defined the recorder command in a for loop as,

for { set k 1 } { $k <= $numModes } { incr k } {
recorder Node -file [format "modes/mode%i.out" $k] -nodeRange 1 6 -dof 1 2 3 "eigen $k"
}

then performed eigen value analysis as,
set lambda [eigen $numModes];

and finally call a record command in the end as,

record

But I am not sure if your specific issue is because you are doing eigen value analysis after gravity analysis.

Thanks,
Jeena