Is this command right to get the EigenValue and Frequencies?

[cctvcctv]

# Calculate the Frequencies and Mode shapes
set f [open mode.out a+]
#statement line
puts $f " Period Frequency"
puts $f " T/sec Hz"
set lambda [eigen 10]
for {set i 0} {$i<10} {incr i 1} {
set lambdaa [lindex $lambda $i]
set omega [expr pow($lambdaa,0.5)]
set Tperiod [expr 2*3.14/$omega]
set Freq [expr 1/$Tperiod]
# period (sec.) and frequency
puts $f "$Tperiod\t $Freq"
}
close $f



Thanks a lot!

I use it , but get unreasonable results!

[silvia]

please post the file, there may be things wrong with the masses and stiffnesses.