View the mode shape of an eigen analysis

[bayram_aygun]

# Procedure to calculate the periods and eigen vectors of a bridge
#
# BGN, Mar 2004, Mostly taken from OSP.
#
proc ModalAnalysis { nModes name } {

#Wipe the analysis
wipeAnalysis

#Perform Eigen Value analysis
set eigenvalues [eigen $nModes]

#Set up recorders for eigen vectors
set jjj 0
for {set jjj 0} {$jjj < $nModes} {incr jjj 1} {
recorder Node -file tempFile[expr {$jjj}].tmp -node all -dof 1 2 3 "eigen [expr $jjj + 1]"
}


#Run a one step gravity load with no loading.
test EnergyIncr 1e-6 20 0
algorithm Newton
system SparseGeneral
integrator LoadControl 1 1 .0000001 1
numberer Plain
constraints Transformation
analysis Static
analyze 1

#Wipe the analysis
wipeAnalysis

#Remove the recorders
remove recorders

#Create .eig file
set _fID [open $name/$name.eig w]

#Open the temp files
for {set jjj 0} {$jjj < $nModes} {incr jjj 1} {
set _fIDt [open tempFile[expr {$jjj}].tmp]
set tempPeriod [expr 2*3.1416/sqrt([lindex $eigenvalues $jjj])]
set tempValues [read -nonewline $_fIDt]
puts $tempPeriod;# $tempValues
puts $_fID "$tempPeriod $tempValues"
close $_fIDt
file delete tempFile[expr {$jjj}].tmp
}

#Close the .eig File
close $_fID
}

I hope it's clear now how to create an ".eig" file now. Take care,

[kishor]

Hello Bayram Aygun!

I tried to view mode shapes through OSP for several times but I am not getting it. Can u send an example file that works on OSP to view mode shapes?

to



thanks

[bayram_aygun]

I was using OSP to visualize my bridge-foundation-soil model but I don't feel comfortable with the mode shapes I'm getting with OSP, so I turned to the viewing codes Silvia posted here.

I'm using the latest version (v2.0.0) and I'm able to run the procedures without getting an error, BUT when the figures start appearing my computer crashes down I see "NOT RESPONDING" signs on the figures. Every time I try to visualize the mode shapes OpenSees shuts down. Maybe some of the commands in the procedures are not compatible with the latest version, I don't know.

I'd really appreciate if you could help me out on this,

Thanks,

[silvia]

you may not have enough memory....

[bayram_aygun]

The computer I'm using is a 32bit, dual core computer with Windows XP. I doubt that memory is going to be a problem (1.95GB of RAM).

What else can be the problem?

[silvia]

some element types may not be compatible with the mode view.

[WhiteNoise]

[quote="silvia"]yes, but only with the latest version of OS.
[put these procs into a file and then source it.]


Hello,
I did run my model as well as the code mentioned here by Silvia Mazzoni.
I got thee windows: deformed shape, node number and the third one seems to be for the modes. However, they appear in the monitor for a very short time (maybe a couple of dt) and I can't visualize them properly. It is possible to frozen the images or save them in a file?? maybe I'm doing something wrong...

[ebe79442114]

you must add "after 1000000" command after view mode to enable pause program.

i get mode shape for SSI system:



i run it under linux.

[silvia]

nice!
what kinds of elements are you using??

[ebe79442114]

four node quad element for soil with two degree of freedom for each node and elastic beam column for base plate and structure.

[mgs]

Hi everyone,

I am wondering to know if it is possible to change the color of either nodes or deformed shape for viewing the mode shapes?