Getting Same Stresses at Gauss Points

[armkam]

Dear all,
Hi,

I did the following analysis for elastic material under the elements self weight.
The stresses at four nodes are the same.
Could you help me in this?


wipeAnalysis

model BasicBuilder -ndm 2 -ndf 2

node 1 0.0 0.0
node 2 1.0 0.0
node 3 0.0 1.0
node 4 1.0 1.0
node 5 0.0 2.0
node 6 1.0 2.0
node 7 0.0 3.0
node 8 1.0 3.0
node 9 0.0 4.0
node 10 1.0 4.0

fix 1 1 1
fix 2 1 1
fix 3 1 0
fix 4 1 0
fix 5 1 0
fix 6 1 0
fix 7 1 0
fix 8 1 0
fix 9 1 0
fix 10 1 0

set dt 5
set gamma 0.5

#---MATERIAL PROPERTIES
# soil mass density (Mg/m^3)
set rho [expr 18/9.81]
# soil elastic modulus
set Es 40000
# poisson's ratio of soil
set nu 0.3

nDMaterial ElasticIsotropic 10 $Es $nu
nDMaterial InitialStateAnalysisWrapper 1 10 2

set wgtX 0.0
set wgtY [expr -9.81*$rho]
element quad 1 1 2 4 3 1.0 "PlaneStrain" 1 0.0 0.0 $wgtX $wgtY
element quad 2 3 4 6 5 1.0 "PlaneStrain" 1 0.0 0.0 $wgtX $wgtY
element quad 3 5 6 8 7 1.0 "PlaneStrain" 1 0.0 0.0 $wgtX $wgtY
element quad 4 7 8 10 9 1.0 "PlaneStrain" 1 0.0 0.0 $wgtX $wgtY

recorder Node -file ESoilDispDir1.out -time -nodeRange 1 10 -dof 1 disp
recorder Node -file ESoilDispDir2.out -time -nodeRange 1 10 -dof 2 disp

recorder Node -file ESoilForceDir1.out -time -nodeRange 1 10 -dof 1 reaction
recorder Node -file ESoilForceDir2.out -time -nodeRange 1 10 -dof 2 reaction

recorder Element -file Estress1.out -time -dT $dt -eleRange 1 4 material 1 stress
recorder Element -file Estress2.out -time -dT $dt -eleRange 1 4 material 2 stress
recorder Element -file Estress3.out -time -dT $dt -eleRange 1 4 material 3 stress
recorder Element -file Estress4.out -time -dT $dt -eleRange 1 4 material 4 stress

recorder Element -file Estrain1.out -time -dT $dt -eleRange 1 4 material 1 strain
recorder Element -file Estrain2.out -time -dT $dt -eleRange 1 4 material 2 strain
recorder Element -file Estrain3.out -time -dT $dt -eleRange 1 4 material 3 strain
recorder Element -file Estrain4.out -time -dT $dt -eleRange 1 4 material 4 strain

constraints Transformation
test NormDispIncr 1.e-5 15 1
algorithm Newton
numberer RCM
system SparseGeneral
integrator LoadControl 1
analysis Static

InitialStateAnalysis on

analyze 4

InitialStateAnalysis off


setTime 0.0
wipeAnalysis



recorder Node -file SoilDispDir1.out -time -nodeRange 1 10 -dof 1 disp
recorder Node -file SoilDispDir2.out -time -nodeRange 1 10 -dof 2 disp

recorder Node -file SoilForceDir1.out -time -nodeRange 1 10 -dof 1 reaction
recorder Node -file SoilForceDir2.out -time -nodeRange 1 10 -dof 2 reaction

recorder Element -file stress1.out -time -dT $dt -eleRange 1 4 material 1 stress
recorder Element -file stress2.out -time -dT $dt -eleRange 1 4 material 2 stress
recorder Element -file stress3.out -time -dT $dt -eleRange 1 4 material 3 stress
recorder Element -file stress4.out -time -dT $dt -eleRange 1 4 material 4 stress

recorder Element -file strain1.out -time -dT $dt -eleRange 1 4 material 1 strain
recorder Element -file strain2.out -time -dT $dt -eleRange 1 4 material 2 strain
recorder Element -file strain3.out -time -dT $dt -eleRange 1 4 material 3 strain
recorder Element -file strain4.out -time -dT $dt -eleRange 1 4 material 4 strain

constraints Penalty 1.e16 1.e16
test NormDispIncr 1.e-5 35 1
algorithm KrylovNewton
numberer RCM
system ProfileSPD
integrator Newmark $gamma [expr pow($gamma+0.5, 2.)/4.]
analysis Transient
analyze 10 $dt