## Convergence Problem in large displacements in Corotational framework

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thomasJacob
Posts: 3
Joined: Fri Sep 08, 2017 7:18 am

### Convergence Problem in large displacements in Corotational framework

I've been trying to model a cantilever elastic beam which is loaded by a moment at its free end. The moment Mc will roll up the beam into a circle. Thus, large displacements are involved. The algorithm fails when the load factor is 0.52 with the convergence problem. I've tried various algorithms and test commands. here's the code:

wipe
model basic -ndm 2 -ndf 3

set A 4.0
set PI 3.1415927
set I 1.33333333
set L 10.0
set E 100.0
set Mc [expr 2*\$PI*(\$E*\$I/\$L)]

# Nodes
node 1 0.0 0.0
node 2 0.5882352941176471 0.0
node 3 1.1764705882352942 0.0
node 4 1.7647058823529411 0.0
node 5 2.3529411764705883 0.0
node 6 2.9411764705882355 0.0
node 7 3.5294117647058822 0.0
node 8 4.11764705882353 0.0
node 9 4.705882352941177 0.0
node 10 5.294117647058823 0.0
node 11 5.882352941176471 0.0
node 12 6.470588235294118 0.0
node 13 7.0588235294117645 0.0
node 14 7.647058823529412 0.0
node 15 8.23529411764706 0.0
node 16 8.823529411764707 0.0
node 17 9.411764705882353 0.0
node 18 10.0 0.0

# fix
fix 1 1 1 1

# geomTransf Corotational 1
geomTransf Corotational 1

# element
element elasticBeamColumn 1 1 2 \$A \$E \$I 1
element elasticBeamColumn 2 2 3 \$A \$E \$I 1
element elasticBeamColumn 3 3 4 \$A \$E \$I 1
element elasticBeamColumn 4 4 5 \$A \$E \$I 1
element elasticBeamColumn 5 5 6 \$A \$E \$I 1
element elasticBeamColumn 6 6 7 \$A \$E \$I 1
element elasticBeamColumn 7 7 8 \$A \$E \$I 1
element elasticBeamColumn 8 8 9 \$A \$E \$I 1
element elasticBeamColumn 9 9 10 \$A \$E \$I 1
element elasticBeamColumn 10 10 11 \$A \$E \$I 1
element elasticBeamColumn 11 11 12 \$A \$E \$I 1
element elasticBeamColumn 12 12 13 \$A \$E \$I 1
element elasticBeamColumn 13 13 14 \$A \$E \$I 1
element elasticBeamColumn 14 14 15 \$A \$E \$I 1
element elasticBeamColumn 15 15 16 \$A \$E \$I 1
element elasticBeamColumn 16 16 17 \$A \$E \$I 1
element elasticBeamColumn 17 17 18 \$A \$E \$I 1

timeSeries Linear 1
pattern Plain 1 1 {
}

# number of steps (increments)
set ninc 100

# Perform the Static incremental analysis
constraints Plain
numberer RCM
system BandGEN
test NormUnbalance 0.0001 100

algorithm Newton