Doing Reversed Cyclic Analysis using DisplacementControl

[laskar]

Is it possible to analyze members tested under reversed cyclic loads using DisplacementControl command. DisplacementControl allows us to apply only one displacement increment. How can we apply a displacement history using DisplacementControl command?

Arghadeep Laskar.
University of Houston

[silvia]

look at the examples manual, there you will find the disp-controlled reversed cyclic loading.

[laskar]

Thanks for your reply Silvia. I am trying to analyze some coulmns tested under pseudo dynamic loads. For this I have to apply 6000 displacement increments to my column model during the analysis. Is it possible to associate these 6000 displacement increments from a .txt file to the DispacementControl command in the tcl/tk input file.

[silvia]

yes, use the sp command in the load pattern rather than load, and input it as a file
then do load control where you load increments are the same as your input increments

[laskar]

Thanks for your reply. However my displacement increments are not uniform. All 6000 increments are different. I have emailed you the txt file separately.

[silvia]

then input it as two inputs.
work through it to figure it out, please, do small tests on something simple.

[fmk]

if you actually want to use displacement control and not imposed displacements, then after you have defined your reference loads use something like this
(note this assumes one data point per line
and the last line in the file contains a number)

Code: Select all

set dataPoints [open a.dat]
set lines [split [read $dataPoints] \n]
foreach currentDisp $lines {
    set incrDisp [expr $currentDisp - $lastDisp]
    integrator DisplacementControl $controlNode $dof $incrDisp
    set ok [analyze 1]
    if {$ok != 0} {
       puts "FAILED - NEED TO WRITE SOME MORE CODE"
       break;
    }
    set lastDisp $currentDisp
}