Applying Cyclic Displacement History At A Control Node

[rehanwain]

Hi,

I am trying to apply cyclic displacement history on a node in a structure , using sp command but i am facing convergence problems . My unbalance just goes to a very big number after some iterations , can some one point out the possible error. Thanks .

#Lateral Displacement History Application
#Applying Displacement History
set dofValue 1 ;#Scaling factor is 1 for displacement history
set dofTag 1 ;# Horizontal Displacement history is applied
set dt 0.002;
set History "Series -dt $dt -filePath displacementhistory.txt"

pattern Plain 2 $History {
sp [expr $TotalNodeNo+10001] $dofTag $dofValue
}

updateMaterialStage -material 1 -stage 1

constraints Penalty 1.e18 1.e18
test NormDispIncr 1.e-4 200 1
numberer RCM
algorithm KrylovNewton
system SparseGEN
set gamma 0.5
set beta 0.25
integrator Newmark $gamma $beta
analysis Transient

analyze 495 0.002
wipe

[rehanwain]

The problem is not with number of iterations or tolerance . And i am working on a mode which has soil model (using 9 four node elements).

[fmk]

the unbalance is large due to the Penalty factors, i.e. 1e18 * (wanted displacement - actual displacement) can be a large number.