sinusoidal cyclic load

[kyonten]

Hi all,

I'm trying to apply cyclic load (constant amplitude) via a Trig Series in a transient analysis. The analysis runs but it appears that the cyclic load is not applied because the the displacements, stresses and strains are same as at the end of the previous analysis.

The cyclic step is as follows:

# create a LoadPattern with a Sine time series
# define amplitude of cyclic force
set Fy -50. ;# magnitude
# Apply sinusoidal vertical load
set SineSeries "Trig 0. 1000. 1."
pattern Plain 2 $SineSeries {
load 5 0.0 $Fy 0.0
load 6 0.0 $Fy 0.0
}

Does this approach not work for transient analysis? The goal for me is to get the accumulated strains (double amplitude) under constant stress. Also the material I'm using is able to model cyclic mobility.

Thanks.

[fmk]

it does work, there is something wrong with the other part of your script. i suggest you start with the following simple example until you find your problem.

[code]
model basic -ndm 2 -ndf 2

node 1 0.0 0.0
node 2 0.0 10.0 -mass 0.0 1.0
uniaxialMaterial Elastic 1 300.0
element truss 1 1 2 10.0 1
fix 1 1 1
fix 2 1 0

set Fy -50. ;# magnitude
set SineSeries "Trig 0. 1000. 1."
pattern Plain 2 $SineSeries {
load 2 0.0 $Fy
}

recorder Node -time -file node.out -node 2 -dof 2 disp
recorder plot node.out "test" 0 130 500 100 -columns 1 2

system BandGen
constraints Plain
test NormDispIncr 1.0e-12 10 0
algorithm Newton
numberer RCM
integrator Newmark 0.5 0.25
analysis Transient
for {set i 1} {$i < 1000} {incr i 1} {
analyze 1 0.01
}

[/code]

[kyonten]

Thanks, Frank. I got it to work.