The codes below get a strange result that I can’t understand. The model is a fiber-section RC column, and I am sure that the definition of it is correct.
#------------------------------------------------------------------
#establish model
…
…
#recorder
#------------------------------------------------------------------
recorder Node -file xx.out -time -node n -dof 1 disp;(where n is the node number I concern)
#------------------------------------------------------------------
constraints Plain;
numberer Plain;
system BandGeneral;
set Tol 1.e-8;
set maxNumIter 6;
set printFlag 0;
set TestType EnergyIncr ;
test $TestType $Tol $maxNumIter $printFlag;
set algorithmType Newton;
algorithm $algorithmType;
integrator LoadControl 1;
analysis Static
pattern Plain 100 Linear {
load 11 0 0.0 0.0;
}
set ok [analyze 3];
set a0 [nodeDisp 11 1]
puts $a0
remove loadPattern 100
pattern Plain 100 Linear {
load 11 100 0.0 0.0;
}
set ok [analyze 1];
set a1 [nodeDisp 11 1]
puts $a1
#----------------------------END--------------------------------------
At the beginning, I use a force pattern tagged 100 and the load value is 0.0. I [analyze 3].Certainly, the puts of $a0 is 0.0, and the recorder file have three zeros.
Then I remove the pattern 100,and add a new patter tagged 200 in which the load value is 100, and I [analyze 1].
If I know the load 100 is a very small value to my structure and the disp should be 0.01, my question is what will the puts of $a1 be?
As I understand the output of a1 should be 0.01;But the reality is OpenSEES output 0.04.
WHY?