Set force to zero

[Strep]

Dear all,
Is there any way I can set time and forces to zero after a static reverse analysis?
I model a four storey one bay frame. First I aply a static reverse analysis up to yielding and then I want to keep the current state of stiffnes and perform a dynamic nonlinear analysis. The problem is that i can set the time to zero with the command LoadConst -time 0.0 but with this command i also keep the residual forces from the cyclic analysis.

[vesna]

Try this:

remove loadPattern $patternTag

[Strep]

thank you for your reply,

I have used the remove loadPattern command but the initial force remains nonzero...
I have also used the wipeAnalysis command with the same results...

[vesna]

Here is what you need to do after you perform static reverse analysis and remove load pattern.

Assuming the tag of the your reverse load pattern is 100 here is the script that may help you get rid of forces:

setTime 0.0
puts "EleForces befor remove [eleResponse 1 forces]"
puts "Displacement befor remove [nodeDisp $IDctrlNode 1]"
remove loadPattern 100

wipeAnalysis

set lambda [eigen 1]
rayleigh 0. 0. 0. [expr 2*0.2/sqrt($lambda)];

test EnergyIncr 1.0e-12 10 0
algorithm Newton
numberer RCM
constraints Plain
integrator Newmark 0.5 0.25
system BandGeneral
analysis Transient

analyze 1500 0.5
puts "EleForces after free vibration [eleResponse 1 forces]"
puts "Displacement after free vibration [nodeDisp $IDctrlNode 1]"

setTime 0.0

You will need to replace arguments of eleResponse and nodeDisp to match arguments of your model.
This script performs free vibrations with a very high damping ratio (20%) to get rid of residual forces.