Why can the model only add 3mm displacement?

[xujin]

My model can only be loaded with a displacement of 3mm under the required direction load, otherwise it will not converge.
Can you help me find the reason?
This is a simple reinforced concrete column model with 3 nodes and 2 elements


wipe
model BasicBuilder -ndm 3 -ndf 6
set PI [expr 2.0*asin(1.0)]
#设置单位
set N 1.0
set m 1.0
set kg 1.0
set sec 1.0
set mm [expr $m*0.001]
set kN [expr $N*1000]
set Pa [expr $N/$m]
set kPa [expr $Pa*1000]
set MPa [expr $Pa*1e6]
set m2 [expr $m*$m]
set mm2 [expr $mm*$mm]
set mm4 [expr $mm*$mm*$mm*$mm]
set m3 [expr $m*$m*$m]
set m4 [expr $m*$m*$m*$m]
set p [expr $kg/$m3] ;# density
set a [expr $m/($sec*$sec)] ;#accelerated speed



set ps 0.018 ;#钢筋体积配箍率
set fyh [expr 241*$MPa] ;#箍筋的屈服强度
set fc [expr 42.4*$MPa] ;#混凝土抗压强度
set h [expr 0.426*$m] ;#箍筋肢距
set sh [expr 0.1*$m] ;#箍筋间距
set K0 [expr 1.0+$ps*$fyh/$fc] ;#箍筋对混凝土强度的提高系数
set fpc0 [expr $K0*$fc] ;#混凝土28天抗压强度
set epsc0 [expr 0.002*$K0] ;#约束混凝土极限抗压强度对应的应变值
set E0 [expr 2*$fpc0/$epsc0]
set fpcu0 [expr 0.2*$fpc0] ;#混凝土退化强度
set Z0 [expr 0.5/((3+0.29*$fc)/(145*$fc-1000)+0.75*$ps*sqrt($h/$sh)-0.002*$K0)] ;#应变软化斜率系数
#set epsU0 [expr （1.0-$fpcu0/($K0*$fc))+$epsc0]
set epsU0 [expr (-0.004-0.9*($ps*$fyh)/300)]
set ft0 [expr 0.01*$fpc0]
set Ets0 [expr $ft0/0.002]
set lambda0 0.1

#定义核心混凝土
#Concrete
#uniaxialMaterial Concrete02 $matTag $fpc $epsc0 $fpcu $epsU $lambda $ft $Ets
uniaxialMaterial Concrete02 1 [expr -$fpc0] [expr -$epsc0] [expr -$fpcu0] [expr -$epsU0] $lambda0 $ft0 $Ets0

set K1 1 ;#箍筋对混凝土强度的提高系数
set fpc1 [expr $K0*$fc] ;#混凝土28天抗压强度
set epsc1 [expr 0.002*$K1] ;#约束混凝土极限抗压强度对应的应变值
set E1 [expr 2*$fpc1/$epsc1]
set fpcu1 [expr 0.2*$fpc1] ;#混凝土退化强度
set Z1 [expr 0.5/((3+0.29*$fc)/(145*$fc-1000))] ;#应变软化斜率系数
set epsU1 -0.004
set ft1 [expr 0.01*$fpc1]
set Ets1 [expr $ft1/0.002]
set lambda1 0.1
#定义无约束混凝土
#Concrete
#uniaxialMaterial Concrete02 $matTag $fpc $epsc0 $fpcu $epsU $lambda $ft $Ets
uniaxialMaterial Concrete02 2 [expr -$fpc1] [expr -$epsc1] [expr -$fpcu1] [expr -$epsU1] $lambda1 $ft1 $Ets1



#定义钢筋+钢筋的直径和面
set Fy [expr 412*$MPa]
set E [expr 2.0e11*$Pa]
#uniaxialMaterial Steel02 $matTag $Fy $E $b $R0 $cR1 $cR2 <$a1 $a2 $a3 $a4 $sigInit>
uniaxialMaterial Steel02 3 $Fy $E 0.0006 18 0.925 0.15
set d [expr 0.018*$m]
set A [expr $d*$d/4*$PI]

puts "material finish"

set Lcolumn1 [expr 0.54*$m]
set Lcolumn2 [expr 3.24*$m]


node 1 0.0 0.0 0.0
node 2 0.0 0.0 $Lcolumn1
node 3 0.0 0.0 $Lcolumn2



fix 1 1 1 1 1 1 1
fix 3 0 0 0 0 0 0

#墩的截面
set b [expr 0.5*$m]
set h [expr 0.34*$m]
set A1 [expr $b*$h]
set cover 0.037
set y1 [expr $b/2.0-$cover]
set y2 [expr $b/2.0-$cover-1.42]
set z1 [expr $h/2.0-$cover]

section Fiber 1 {
patch rect 1 10 10 [expr $b/2.0-$cover] [expr $h/2.0-$cover] [expr $cover-$b/2.0] [expr $cover-$h/2.0]
patch rect 2 10 1 [expr $b/2.0] [expr $cover-$h/2.0] [expr -$b/2.0] [expr -$h/2.0]
patch rect 2 2 1 [expr $b/2.0] [expr $h/2.0-$cover] [expr $b/2.0-$cover] [expr $cover-$h/2.0]
patch rect 2 2 1 [expr $cover-$b/2.0] [expr $h/2.0-$cover] [expr -$b/2.0] [expr $cover-$h/2.0]
patch rect 2 10 1 [expr $b/2.0] [expr $h/2.0] [expr -$b/2.0] [expr $h/2.0-$cover]
layer straight 3 3 $A $y1 $z1 $y1 [expr -$z1]
layer straight 3 2 $A $y2 $z1 $y2 [expr -$z1]
layer straight 3 3 $A [expr -$y1] $z1 [expr -$y1] [expr -$z1]
layer straight 3 2 $A [expr -$y2] $z1 [expr -$y2] [expr -$z1]
}

section Fiber 2 {
patch rect 2 10 10 [expr $b/2.0] [expr $h/2.0] [expr -$b/2.0] [expr -$h/2.0]
layer straight 3 3 $A $y1 $z1 $y1 [expr -$z1]
layer straight 3 2 $A $y2 $z1 $y2 [expr -$z1]
layer straight 3 3 $A [expr -$y1] $z1 [expr -$y1] [expr -$z1]
layer straight 3 2 $A [expr -$y2] $z1 [expr -$y2] [expr -$z1]
}
puts "section finish"

geomTransf Linear 1 0 -1 0
#define elements
set nP 5
#element dispBeamColumn eleTag iNode jNode numIntgrPts secTag transfTag <-mass massDens> <-cMass> <-integration intType>
element nonlinearBeamColumn 1 1 2 $nP 2 1
element nonlinearBeamColumn 2 2 3 $nP 1 1
puts "element finish"

set N 0.1
set fcd 18.4e6
set P [expr $N*$fcd*$A1]
pattern Plain 1 Linear {
load 3 0.0 0.0 [expr -$P] 0.0 0.0 0.0
}
puts "Gravity finish"

constraints Plain
numberer RCM
system BandGeneral
test EnergyIncr 1.0e-6 200
algorithm Newton
integrator LoadControl 0.01
analysis Static
analyze 100

loadConst -time 0.0
pattern Plain 2 Linear {
load 3 1 1 0.0 0.0 0.0 0.0

}
integrator DisplacementControl 3 1 0.004
analyze 1

[selimgunay]

Your column seems to be more than 3 meters long, so 3 mm corresponds to 0.1% drift, which is too small. Does it start to yield at this point? If so, the noncovergence could be related to the steel02 post-yield transition parameters. You can try the default values and see what you get

[HUJIEFENG]

I have the same problem. Have you found the answer?

[lorencamarillo]

I think ensuring that material properties, especially those related to concrete and steel, are accurately determined is the most important thing.geometry dash lite

[norahcackle]

When it reaches this stage, does it begin to yield? If this is the case, the noncovergence could be connected to the characteristics of the steel02 post-yield transition mechanism. You are free to experiment with the default settings and see what results you obtain.

[PerryEmslie]

Double-check the material properties, especially those related to concrete and steel. Ensure that the material properties, such as Young's modulus, yield strength, and other parameters, are consistent with your expectations.

[sailboatporch]

I think this is based on the developer's settings. Providing the best information. Furthermore, each program needs to follow a certain coding algorithm to develop and improve.