displacementControl integrator

[simonkey]

When I use this integrator, am I supposed to be able to specify the final displacement value that the analysis reaches?

In other words, if I have the following:

set drift 0.001
set height 26.8333
set maxU [expr $height*$drift]
set dU [expr $maxU/100]

constraints Transformation
numberer RCM
system BandGeneral
test NormDispIncr 1.0e-12 30
algorithm Newton

integrator DisplacementControl $cntrlNode 1 $dU

analysis Static
set numSteps [expr int($maxU/$dU)]
analyze $numSteps

and maxU = numSteps*dU, is the final displacement value at the control node in dof 1 supposed to be exactly maxU?

If so, I'm getting output where the final displacement value is GREATER than maxU - any ideas?

[simonkey]

I want to also remark that I've tried

integrator DisplacementControl $cntrlNode 1 $dU 30 $minDu

with a very small maxU but I still get this situation where the displacements in the output are immediately larger than maxU. I stopped using the "30" in the command above because I thought the numIter was taken care of in the "test" command (maybe I'm wrong?)

[hnsmengyu]

maybe we have run into the same problem. can i have a look at you recorder command used to record the results

[simonkey]

set recTag1 [recorder Node -file $eigFolder/MasterNodeDisp_Long.out -time -node 39 -dof 1 2 disp]
set recTag2 [recorder Node -file $eigFolder/Reactions_Long.out -node 1 81 82 91 -dof 1 2 3 reaction]

[hnsmengyu]

i tried again with the displacement control method:integrator DisplacementControl $cntrlNode 1 $dU 30 $minDu . and find out that the final displacement is exactly the same with the maxU.
make sure the $cntrlNode is 39
by the way, what do you mean by seting the record command in the form of "set recTag1 [...]"

[simonkey]

I used the set recTag 1 so that I can pinpoint this recorder and remove it later on in the analysis such that output can be written WITHOUT me having to close the OpenSees DOS window.

I think my problem was from my load pattern. Thanks for your input.

~Neal Simon

[vesna]

Another way to get output files without exiting OpenSees is to have wipe command at the end of the tcl file.