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

## Applying Cyclic Displacement History At A Control Node

**Moderators:** silvia, selimgunay, Moderators

### Re: Applying Cyclic Displacement History At A Control Node

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).

### Re: Applying Cyclic Displacement History At A Control Node

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