Changing load pattern during static pushover analysis

[JAMINPARK]

Hello everyone

I made three types of codes for simple static pushover analysis as shown below.
My model is SDOF system with simple elastic material.

-Analysis 1-
pattern Plain 1 Linear {
load 2 10 0. 0.
};
integrator LoadControl 1.0
analysis Static
analyze 1
integrator LoadControl 1.5
analysis Static
analyze 1
integrator LoadControl 2.0
analysis Static
analyze 1

-Analysis 2-
pattern Plain 1 Linear {
load 2 10 0. 0.
};
integrator LoadControl 1.0
analysis Static
analyze 1
remove loadPattern 1
pattern Plain 1 Linear {
load 2 10 0. 0.
};
integrator LoadControl 1.5
analysis Static
analyze 1
remove loadPattern 1
pattern Plain 1 Linear {
load 2 10 0. 0.
};
integrator LoadControl 2.0
analysis Static
analyze 1

-Analysis 3-
pattern Plain 1 Linear {
load 2 10 0. 0.
};
integrator LoadControl 1.0
analysis Static
analyze 1
remove loadPattern 1
pattern Plain 2 Linear {
load 2 10 0. 0.
};
integrator LoadControl 1.5
analysis Static
analyze 1
remove loadPattern 2
pattern Plain 3 Linear {
load 2 10 0. 0.
};
integrator LoadControl 2.0
analysis Static
analyze 1

The results of Analysis 1 and Analysis 2 are different.
But the results of Analysis 2 and Analysis 3 are identical.

I don't understand why the difference has happened.
Only difference between Analysis 1 and Analysis 2 is removing load pattern and redefined it again.

I am gladly waiting for your help. Thank you!!

Jamin Park

[fmk]

you should be getting the same for all 3.

test the following:

proc buildTruss { } {
wipe
model basic -ndm 2 -ndf 2
uniaxialMaterial Elastic 1 300.0
uniaxialMaterial ElasticPP 2 2700.0 0.002
uniaxialMaterial Parallel 3 1 2 1
uniaxialMaterial Series 4 1 2 1
node 1 0.0 0.0
node 2 10.0 0.0
node 3 20.0 0.0
node 4 30.0 0.0
node 5 40.0 0.0
node 6 0.0 10.0
node 7 10.0 10.0
node 8 20.0 10.0
node 9 30.0 10.0
node 10 40.0 10.0
element truss 1 1 2 10.0 3
element truss 2 2 3 10.0 3
element truss 3 3 4 10.0 3
element truss 4 4 5 10.0 3
element truss 5 6 7 10.0 3
element truss 6 7 8 10.0 3
element truss 7 8 9 10.0 3
element truss 8 9 10 10.0 3
element truss 9 1 7 10.0 3
element truss 10 2 8 10.0 3
element truss 11 3 9 10.0 3
element truss 12 4 10 10.0 3
element truss 13 2 6 10.0 3
element truss 14 3 7 10.0 3
element truss 15 4 8 10.0 3
element truss 16 5 9 10.0 3
element truss 17 1 6 10.0 4
element truss 18 2 7 10.0 4
element truss 19 3 8 10.0 4
element truss 20 4 9 10.0 4
element truss 21 5 10 10.0 4
fix 1 1 1
fix 5 0 1
system SparseGeneral
constraints Plain
integrator LoadControl 1 1 1 1
test NormDispIncr 1.0e-8 10 0
algorithm Newton
numberer RCM
}

#-Analysis 1-
buildTruss
pattern Plain 1 Linear {
load 3 0 10.
};
integrator LoadControl 1.0
analysis Static
analyze 1
integrator LoadControl 1.5
analysis Static
analyze 1
integrator LoadControl 2.0
analysis Static
analyze 1

print node 3
#-Analysis 1-
buildTruss
pattern Plain 1 Linear {
load 3 0 10.
};
integrator LoadControl 1.0
analysis Static
analyze 1
integrator LoadControl 1.5
analysis Static
analyze 1
integrator LoadControl 2.0
analysis Static
analyze 1

print node 3
#-Analysis 3-
buildTruss
pattern Plain 1 Linear {
load 3 0 10
};
integrator LoadControl 1.0
analysis Static
analyze 1
remove loadPattern 1
pattern Plain 2 Linear {
load 3 0 10
};
integrator LoadControl 1.5
analysis Static
analyze 1
remove loadPattern 2
pattern Plain 3 Linear {
load 3 0 10
};
integrator LoadControl 2.0
analysis Static
analyze 1

print node 3

[JAMINPARK]

Thank fmk for your kind reply.

I am sorry that I uploaded wrong code.
My code is like below.
---------------------------------------------------------------------------------
proc buildModel { } {
wipe
model basic -ndm 2 -ndf 3
node 1 0 0;
node 2 0 5;
geomTransf Linear 1
element elasticBeamColumn 1 1 2 10.0 100.0 1.0 1
fix 1 1 1 1
system SparseGeneral
constraints Plain
integrator LoadControl 1 1 1 1
test NormDispIncr 1.0e-8 10 0
algorithm Newton
numberer RCM
}

#-Analysis 1-
buildModel
pattern Plain 1 Linear {
load 2 10. 0. 0.
};
integrator LoadControl 1.0
analysis Static
analyze 1
integrator LoadControl 1.5
analysis Static
analyze 1
integrator LoadControl 2.0
analysis Static
analyze 1
print node 2

#-Analysis 2-
buildModel
pattern Plain 1 Linear {
load 2 10. 0. 0.
};
integrator LoadControl 1.0
analysis Static
analyze 1
remove loadPattern 1
pattern Plain 1 Linear {
load 2 15. 0. 0.
};
integrator LoadControl 1.0
analysis Static
analyze 1
remove loadPattern 1
pattern Plain 1 Linear {
load 2 20. 0. 0.
};
integrator LoadControl 1.0
analysis Static
analyze 1
print node 2

#-Analysis 3-
buildModel
pattern Plain 1 Linear {
load 2 10. 0. 0.
};
integrator LoadControl 1.0
analysis Static
analyze 1
remove loadPattern 1
pattern Plain 2 Linear {
load 2 15. 0. 0.
};
integrator LoadControl 1.0
analysis Static
analyze 1
remove loadPattern 2
pattern Plain 3 Linear {
load 2 20. 0. 0.
};
integrator LoadControl 1.0
analysis Static
analyze 1
print node 2
---------------------------------------------------------------------------------

Using the proceeding code, you can find that the results of Analysis 1 and Analysis 2 are different each other.

Please check it again.

Thank you very much!!