about the prestressing tendon

[liushqi]

Hello,
i got a problem when i simulate post-tensioned precast segmental column, what i use for prestressing tendon is truss element ,and the material is ElasticPP, but the analysis failed ,when i change the material into other material (concrete01), it works , how can i correct the model ?
thank you anyone helps!
here is my model:

# Precast Segmental Bridge Columns
# Liu_Shaoqian,April 2013
# |(segment)
# |
# ---(joint)
# |(segment)
# |
# ---(joint)
# |(segment)
# |
# ---(joint)
# |(segment)
# |
# ---(joint)
#
# SET UP
# -----------------------
wipe
model BasicBuilder -ndm 2 -ndf 3
set dataDir Data
file mkdir $dataDir
source LibUnits.tcl

# --------------NODES----------------
set LCol [expr 425*$mm]
set LJoint [expr 25*$mm]
set LBot [expr 300*$mm]
# ------------------------
node 1 0.0 0.0
node 2 0.0 $LBot
node 3 0.0 [expr $LBot+$LJoint]
node 4 0.0 [expr $LBot+$LJoint+$LCol]
node 5 0.0 [expr $LBot+2*$LJoint+$LCol]
node 6 0.0 [expr $LBot+2*$LJoint+2*$LCol]
node 7 0.0 [expr $LBot+3*$LJoint+2*$LCol]
node 8 0.0 [expr $LBot+3*$LJoint+3*$LCol]
node 9 0.0 [expr $LBot+4*$LJoint+3*$LCol]
node 10 0.0 [expr $LBot+4*$LJoint+4*$LCol]
node 12 0.0 [expr 2*$LBot+4*$LJoint+4*$LCol]
node 11 0.0 [expr $LBot+4*$LJoint+4*$LCol]
# -----------------------
# Boundary Condition
fix 1 1 1 1
fix 2 1 1 1
equalDOF 10 11 1 2 3
# ----------------------

# ----------------------MATERIAL-------------------
# Material Tag
set IDconU 1; # Material Tag of Unconfined concrete
set IDconC 2; # Material Tag of confined concrete
set IDreinf 3; # Material Tag of reinforcement
set IDpres 4; # Material Tag of prestress steel
set IDconJ 5; # Material Tag of joint concrete
# Nominal concrete compressive strength
set fcU [expr -35.00*$MPa]
# Concrete strength(Core)
set fc [expr -42.84*$MPa]
set Ec [expr 31.50*$GPa]

# Unconfined concrete
set fc1U $fcU
set eps1U -0.002
set fc2U [expr 0.20*$fc1U]
set eps2U -0.006
set lambda 0.1
set ftU [expr -0.07*$fc1U]
set EtsU [expr $ftU/0.002]

# Confined concrete
set fc1c $fc
set eps1c -0.003
set fc2c [expr 0.2*$fc1c]
set eps2c -0.014
set ftc [expr -0.07*$fc1c]
set Etsc [expr $ftc/0.002]

# Reinforcing steel
set fy [expr 335.00*$MPa]
set Er [expr 200.00*$GPa]
set b 0.01
set R0 18
set cR1 0.925
set cR2 0.15

# Prestress steel
set Ep [expr 195.00*$GPa]
set epsyP 0.008
set epsyN -0.002
set eps0 0.0023
uniaxialMaterial Concrete02 $IDconU $fc1U $eps1U $fc2U $eps2U $lambda $ftU $EtsU
uniaxialMaterial Concrete02 $IDconC $fc1c $eps1c $fc2c $eps2c $lambda $ftc $Etsc
uniaxialMaterial Steel02 $IDreinf $fy $Er $b $R0 $cR1 $cR2
uniaxialMaterial ElasticPP $IDpres $Ep $epsyP $epsyN $eps0
uniaxialMaterial Concrete01 $IDconJ $fc1c $eps1c $fc2c $eps2c
# ----------------------

# ----------------------SECTION----------------------
set SecTagC 1
set SecTagJ 2
# ---------------------
set SecWidth [expr 450*$mm]; # width of the section
set SecDepth [expr 450*$mm]; # depth of the section
set HolWidth [expr 230*$mm]; # width of the hole
set HolDepth [expr 230*$mm]; # depth of the hole
set Cover [expr 20*$mm]; # concrete cover
set DiaBar [expr 8*$mm]; # longitudianl bar diameter
set AreaBar [expr $PI*pow($DiaBar,2)/4]; # area of the longitudianl bar
set DiaStirrup [expr 8*$mm]; #diameter of stirrups
set Shift [expr 33*$mm]; #distance from the beginning of the web to the first reinf. bar

set numFiber1 7; #number of reinforceng bars in layer type 1
set numFiber2 3; #number of reinforceng bars in layer type 2

#number of subdivision for one patch
set numSubdivIJ1 10
set numSubdivJK1 1
set numSubdivIJ2 6
set numSubdivJK2 1
set numSubdivIJ3 1
set numSubdivJK3 8
set numSubdivIJ4 1
set numSubdivJK4 6
set numSubdivIJ5 10
set numSubdivJK5 2
set numSubdivIJ6 2
set numSubdivJK6 8

#coordinates that define different patches of confined and unconfined concrete and layers of reinforcement
set y1 [expr $SecDepth/2.0]
set z1 [expr $SecWidth/2.0]
set z2 [expr $z1-$Cover-$DiaStirrup-$DiaBar/2.0]
set y2 [expr $HolDepth/2.0]
set z4 [expr $HolWidth/2.0]
set z3 [expr $z4+$Cover+$DiaStirrup+$DiaBar/2.0]
set y3 [expr $y1-$Cover-$DiaStirrup-$DiaBar/2.0]
set y4 [expr $y2+$Cover+$DiaStirrup+$DiaBar/2.0]

#coordiantes for steel layers
set z4s [expr $z4-$Shift]

section Fiber $SecTagC {
#cover
# nfIJ nfJK yI zI yJ zJ yK zK yL zL
patch quad $IDconU $numSubdivIJ1 $numSubdivJK1 -$y1 $z2 $y1 $z2 $y1 $z1 -$y1 $z1
patch quad $IDconU $numSubdivIJ1 $numSubdivJK1 -$y1 -$z1 $y1 -$z1 $y1 -$z2 -$y1 -$z2
patch quad $IDconU $numSubdivIJ2 $numSubdivJK2 -$y2 $z4 $y2 $z4 $y2 $z3 -$y2 $z3
patch quad $IDconU $numSubdivIJ2 $numSubdivJK2 -$y2 -$z3 $y2 -$z3 $y2 -$z4 -$y2 -$z4
patch quad $IDconU $numSubdivIJ3 $numSubdivJK3 $y3 -$z2 $y1 -$z2 $y1 $z2 $y3 $z2
patch quad $IDconU $numSubdivIJ3 $numSubdivJK3 -$y1 -$z2 -$y3 -$z2 -$y3 $z2 -$y1 $z2
patch quad $IDconU $numSubdivIJ4 $numSubdivJK4 $y2 -$z3 $y4 -$z3 $y4 $z3 $y2 $z3
patch quad $IDconU $numSubdivIJ4 $numSubdivJK4 -$y4 -$z3 -$y2 -$z3 -$y2 $z3 -$y4 $z3
#confined core
patch quad $IDconC $numSubdivIJ5 $numSubdivJK5 -$y3 $z3 $y3 $z3 $y3 $z2 -$y3 $z2
patch quad $IDconC $numSubdivIJ5 $numSubdivJK5 -$y3 -$z2 $y3 -$z2 $y3 -$z3 -$y3 -$z3
patch quad $IDconC $numSubdivIJ6 $numSubdivJK6 $y4 -$z3 $y3 -$z3 $y3 $z3 $y4 $z3
patch quad $IDconC $numSubdivIJ6 $numSubdivJK6 -$y3 -$z3 -$y4 -$z3 -$y4 $z3 -$y3 $z3
#reinforcement
# $yStart $zStart $yEnd $zEnd
layer straight $IDreinf $numFiber1 $AreaBar -$y3 $z2 $y3 $z2
layer straight $IDreinf $numFiber1 $AreaBar -$y3 -$z2 $y3 -$z2
layer straight $IDreinf $numFiber1 $AreaBar -$y3 $z3 $y3 $z3
layer straight $IDreinf $numFiber1 $AreaBar -$y3 -$z3 $y3 -$z3
layer straight $IDreinf $numFiber2 $AreaBar $y3 -$z4s $y3 $z4s
layer straight $IDreinf $numFiber2 $AreaBar -$y3 -$z4s -$y3 $z4s
layer straight $IDreinf $numFiber2 $AreaBar $y4 -$z4s $y4 $z4s
layer straight $IDreinf $numFiber2 $AreaBar -$y4 -$z4s -$y4 $z4s
}
section Fiber $SecTagJ {
patch quad $IDconJ $numSubdivIJ5 $numSubdivJK5 $y2 -$z1 $y1 -$z1 $y1 $z1 $y2 $z1
patch quad $IDconJ $numSubdivIJ5 $numSubdivJK5 -$y1 -$z1 -$y2 -$z1 -$y2 $z1 -$y1 $z1
patch quad $IDconJ $numSubdivIJ6 $numSubdivJK6 -$y2 $z4 $y2 $z4 $y2 $z1 -$y2 $z1
patch quad $IDconJ $numSubdivIJ6 $numSubdivJK6 -$y2 -$z1 $y2 -$z1 $y2 -$z4 -$y2 -$z4
}
# --------------------------ELEMENT--------------------------
set APres [expr 840*$mm2]
set np1 4
set np2 2
geomTransf PDelta 1
set eleType nonlinearBeamColumn
# -------------------
element $eleType 1 2 3 $np2 $SecTagJ 1
element $eleType 2 3 4 $np1 $SecTagC 1
element $eleType 3 4 5 $np2 $SecTagJ 1
element $eleType 4 5 6 $np1 $SecTagC 1
element $eleType 5 6 7 $np2 $SecTagJ 1
element $eleType 6 7 8 $np1 $SecTagC 1
element $eleType 7 8 9 $np2 $SecTagJ 1
element $eleType 8 9 10 $np1 $SecTagC 1
element truss 9 1 11 $APres $IDpres
# Displacement of free nodes
recorder Node -file Data/DFree.out -time -node 10 11 -dof 1 2 3 disp
# Displacement of support nodes
recorder Node -file Data/DBase.out -time -node 1 2 -dof 1 2 3 disp
# reaction of support nodes
recorder Node -file Data/RBase.out -time -node 1 2 -dof 1 2 3 reaction
# element forces
recorder Element -file Data/FCol.out -time -ele 8 force
# ---------------------------------------

# ---------------------------LOAD-----------------------
set Weight [expr 280*$kN]
pattern Plain 1 Linear {
load 10 0.0 -$Weight 0.0
}
puts "analysis"
constraints Transformation
numberer RCM
system BandGeneral
test NormDispIncr 1.0e-12 6
algorithm Newton
integrator LoadControl 0.1
analysis Static
analyze 10
puts "Model Builded"

[vesna]

It is about the system that you use to solve the system of equations. Try system BandSPD when using ElasticPP material.