Absolute Acceleration under Multi-Directional Inputs

[suusie]

Hello,

I am wondering if the script below to generate absolute acceleration under multiple-directional inputs (horizontal & vertical motions) is o.k. or not:
(I want to get absolute acceleration at node 1 in the horizontal & vertical directions, in 2-Dimensional space)

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

wipe all;
model BasicBuilder -ndm 2 -ndf 3;

timeSeries Path 3 -dt $dtX -filePath $GMFileX -factor $GMFactX;
timeSeries Path 4 -dt $dtZ -filePath $GMFileZ -factor $GMFactZ;

recorder Node -file nodeAccelX.out -timeSeries 3 -time -node 1 -dof 1 accel; # To get absolute acceleration at node 1 in horizontal direction
recorder Node -file nodeAccelZ.out -timeSeries 4 -time -node 1 -dof 2 accel; # To get absolute acceleration at node 1 in vertical direction

set compX "Series -dt $dtX -filePath $GMFileX -factor [expr $GMFactX * $g]"
set compZ "Series -dt $dtZ -filePath $GMFileZ -factor [expr $GMFactZ * $g]"

pattern UniformExcitation 1 1 -accel $compX
pattern UniformExcitation 2 2 -accel $compZ

analyze $nData $DtAnalysis

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

I hope to hear from you soon


./

[skamalzare]

You can always check your recording at boundaries with your input motion. If they were the same, you are recording the absolute values (You might see some noise, but they should generally match).

UniformExcitation command returns relative values in recorders, but you're adding your time-series (3 & 4) to the relative values. Therefore, you should get the absolute values.

SK

[suusie]

Thanks for your reply, skamalzare!

So overall the above script of mine seems to work fine to get absolute acceleration!!

Yea, I will double check this by looking at the boundaries with my motion as you wrote