Absolute Acceleration of time history analysis

[Ulbong]

Hi Guys I'm trying to time history analysis for a single D.O.F column.
But I know that those results are "Relative" things. I want to get "Absolute" displacements and accelerations.
but I don't know what's wrong.
Here is my script below.


# Define RECORDERS -------------------------------------------------------------

recorder Node -file MODE/DFree.out -time -node 2 -dof 1 2 3 disp; # displacements of free nodes
recorder Node -file MODE/DBase.out -time -node 1 -dof 1 2 3 disp; # displacements of support nodes
recorder Node -file MODE/AFree.out -time -node 2 -dof 1 2 3 accel; # acceleration of free nodes
recorder Node -file MODE/ABase.out -time -node 1 -dof 1 accel; # acceleration of support nodes


# DYNAMIC ground-motion analysis -------------------------------------------------------------
# create load pattern
set G 9800
timeSeries Path 1 -dt 0.02 -filePath elcen.tcl -factor 1; # define acceleration vector from file (dt=0.005 is associated with the input file gm)
pattern UniformExcitation 1 1 -accel 1; # define where and how (pattern tag, dof) acceleration is applied

# set damping based on first eigen mode
set freq [expr [eigen -fullGenLapack 1]**0.5]
set dampRatio 0.05
rayleigh 0. 0. 0. [expr 2*$dampRatio/$freq]

wipeAnalysis; # clear previously-define analysis parameters
constraints Plain; # how it handles boundary conditions
numberer Plain; # renumber dof's to minimize band-width (optimization), if you want to
system BandGeneral; # how to store and solve the system of equations in the analysis
algorithm Linear # use Linear algorithm for linear analysis
integrator Newmark 0.5 0.25 ; # determine the next time step for an analysis
analysis Transient; # define type of analysis: time-dependent
analyze 1559 0.02; # apply 3995 0.01-sec time steps in analysis

puts "YES!"

---------------------------------------------------------------------end---------------------------------------------------------
Thank you for your help!

[selimgunay]

Below is an example of recording absolute accelerations

recorder Node -file nodesA.out -timeSeries 1 -time -node 1 2 3 4 -dof 1 accel

In uniform excitation analysis, this command generates output file nodesA.out that contains absolute accelerations for nodes 1, 2, 3, and 4

[Ulbong]

Thanks selimgunay
Should I make timesSeries before?
Cuz I got error " TimeSeries *getTimeSeries(int tag) - none found with tag: 1 "

[selimgunay]

Yes you need to create timeseries, which is actually the ground motion that you use