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Hi Dr. Terzic,

Sorry for my late answer. I ran the code that you modified, but the element force output (element 26 in the code, which is the spring) is all zero (except the first column, which is the load applied).

P.S.: I was able to find the eigenvalues by utilizing an equivalent EPP material. I guess the eigenvalue problem is caused by the gap in HGM. (It is not possible to define the gap equal to zero in HGM).

# HyperbolicGapMaterial Pushover
# units kg - m - N

wipe; # clear opensees model
model basic -ndm 2 -ndf 3; # 2 dimensions, 3 dof per node

# Nodal Coordinates
# node $nodeTag (ndm $coords) <-mass (ndf $MassValues)>

#Left Deck

node 1 0 11.6

# Nodes For Zerolength Element Definition

node 27 0 11.6

# Mass

mass 1 4000.6 0 0

# Transformation
# The OpenSees Geometric Transformation Command defines how the element coordinates correlate to the global model coordinates.
# In a 2D problem, element orientation does not need to be considered, and can be the same for all elements.
# The linear transformation will be used in this demonstration:
#geomTransf Linear $transfTag <-jntOffset $dXi $dYi $dXj $dYj>

geomTransf Linear 1

#Elements

# Abutment

set Kmax 24000000; # The initial tangent stiffness [N/m/m]
set Kur 24000000; # Unloading/reloading stiffness[N/m/m]
set Rf 0.8; # Failure ratio [dimensionless]
set Fult -550000; # Ultimate (maximum) passive resistance [N/m]
set gap -0.0254; # Initial gap [m]

uniaxialMaterial HyperbolicGapMaterial 1 $Kmax $Kur $Rf $Fult $gap

element zeroLength 26 1 27 -mat 1 -dir 1 -doRayleigh 1

# Bondary Conditions
# fix $nodeTag (ndf $ConstrValues)
# DX DY RZ

fix 1 0 1 1
fix 27 1 1 1

eigen -fullGenLapack 1

# HyperbolicGapMaterial Pushover
# units kg - m - N

wipe; # clear opensees model
model basic -ndm 2 -ndf 3; # 2 dimensions, 3 dof per node

# Nodal Coordinates
# node $nodeTag (ndm $coords) <-mass (ndf $MassValues)>

#Left Deck

node 1 0 11.6

# Nodes For Zerolength Element Definition

node 27 0 11.6

# Transformation
# The OpenSees Geometric Transformation Command defines how the element coordinates correlate to the global model coordinates.
# In a 2D problem, element orientation does not need to be considered, and can be the same for all elements.
# The linear transformation will be used in this demonstration:
#geomTransf Linear $transfTag <-jntOffset $dXi $dYi $dXj $dYj>

geomTransf Linear 1

#Elements

# Abutment

set Kmax 24000000; # The initial tangent stiffness [N/m/m]
set Kur 24000000; # Unloading/reloading stiffness[N/m/m]
set Rf 0.8; # Failure ratio [dimensionless]
set Fult -550000; # Ultimate (maximum) passive resistance [N/m]
set gap -0.0254; # Initial gap [m]

uniaxialMaterial HyperbolicGapMaterial 1 $Kmax $Kur $Rf $Fult $gap

element zeroLength 26 1 27 -mat 1 -dir 1 -doRayleigh 1

# Bondary Conditions
# fix $nodeTag (ndf $ConstrValues)
# DX DY RZ

fix 1 0 1 1
fix 27 1 1 1

# Define RECORDERS ------------------

recorder Element -file Output/HGMForce26.out -time -ele 26 force;
recorder Element -file Output/HGMDef26.out -time -ele 26 deformation;
recorder Node -file Output/HGMDisp1.out -time -node 1 -dof 1 disp;

# Pushover

pattern Plain 2 Linear {
load 1 1000 0.0 0.0
}

# displacement parameters
set IDctrlNode 1; # node where disp is read for disp control
set IDctrlDOF 1; # degree of freedom read for disp control (1 = x displacement)
set Dmax 0.15; # maximum displacement of pushover: drift
set Dincr [expr 0.005]; # displacement increment

# analysis commands
constraints Plain; # how it handles boundary conditions
numberer RCM; # renumber dof's to minimize band-width (optimization)
system BandGeneral; # how to store and solve the system of equations in the analysis (large model: try UmfPack)
test NormUnbalance 1.0e-6 400; # tolerance, max iterations
algorithm Newton; # use Newton's solution algorithm: updates tangent stiffness at every iteration
integrator DisplacementControl $IDctrlNode $IDctrlDOF $Dincr; # use displacement-controlled analysis
analysis Static; # define type of analysis: static for pushover
set Nsteps [expr int($Dmax/$Dincr)];# number of pushover analysis steps
set ok [analyze $Nsteps]; # this will return zero if no convergence problems were encountered
puts "Pushover complete"; # display this message in the command window

wipe all;

Dr. Vesna,

Thank you for your reply.

I ran a pushover analysis on the Hyperbolic material independently. It turned out with the following error:

WARNING bandgenlinlapacksolver::solve() -LAPACK routine returned 1
DisplacementControl::newStep<void> - failed in solver
StaticAnalysis::analyze() - the Integrator A failed at iteration: 0 with domain at load factor 0.1
analyze failed, returned: -2 error flag

Then I went ahead and ran an eigenvalue analysis to check the model with some mass applied on node 1 with the following command: "eigen -fullGenLapack 1". There were no error messages and the eigenvalue turned out 0.

I seems like the stiffness cannot be initiated somehow. What would you suggest on this issue?

Also, if you also agree that there is some kind of bug with the use of this material in version 2.4.0, is there anyway that I can obtain some earlier version for immediate use of this material until the bug is fixed?

Thank you very much.

Could this be an issue of the units in recorder?

Because the ultimate passive resistance force [Fult] unit in the input of hyperbolicgapmaterial is in terms of [force/m] which means [per meter of abutment width] as indicated in the following page:
http://opensees.berkeley.edu/wiki/index ... p_Material

Is it possible that the recorded force output unit for this material is in terms of [force per meter of abutment width]?

Dr. Terzic, I appreciate your quick response. I was able to record the force, after I posted my problem here. But this time the forces are smaller than they should be, where the displacements are correct.
For instance, I recorded a peak force about 500 kN, but it should be about 7500 kN.
So, I went ahead and checked my units, but I couldn't find any problem. Also given I found the correct eigenvalues and displacements, there shouldn't be a problem in units.
I recorded the forces utilizing -xlm to see if I'm recording the correct force component and they are correct too. There are force recordings in axial force columns of the output, and all others are zero as they should be.
I didn't understand what I'm doing wrong or what the problem might be.

Hi Dr. Terzic,

I am having a problem with getting the hysteresis of a Hyperbolic element. I have defined the material and recorders like this:

-------------------------------------------------------------------------------------------
node 1 0 10.7
node 21 87.2 10.7

node 27 0 10.7
node 28 87.2 10.7

set Kmax 24000000; # The initial tangent stiffness [N/m/m]
set Kur 24000000; # Unloading/reloading stiffness[N/m/m]
set Rf 0.8; # Failure ratio [dimensionless]
set Fult -550000; # Ultimate (maximum) passive resistance [N/m]
set gap -0.0254; # Initial gap [m]

uniaxialMaterial HyperbolicGapMaterial 1 $Kmax $Kur $Rf $Fult $gap

element zeroLength 26 27 1 -mat 1 -dir 1
element zeroLength 27 21 28 -mat 1 -dir 1

# Bondary Conditions

fix 1 0 1 0
fix 21 0 1 0
fix 27 1 1 1
fix 28 1 1 1

#recorders

recorder Element -file Output/LeftAbutmForceHGM1.out -time -ele 27 force;
recorder Element -file Output/LeftAbutmDefHGM1.out -time -ele 27 deformation;

---------------------------------------------------------------------------

I conducted time history analysis. However, Force output is all zero.

So, i couldn't achieve the hysteresis curve. I suppose I don't have any mistake in defining the material and element, because I solved the eigenvalues and they are correct.
Which recorders should I use to obtain hysteresis curve? Thank you.

Thank you for the reply. I solved my problem by using equalDOF at the nodes where I want same displacement and defining the load with "load" command.

Hi all,

I have a backwall-embankment system (3D) where soil is surrounded by a steel box. The backwall behavior mode is shear. I want to perform a pushover analysis. The maximum horizontal displacement (X) is 0.15m. Since the behavior mode is shear I need to apply the displacement to all wall nodes in X direction. This means I need to control all wall nodes. So I used sp command to define the load. However, the recorded displacements at the nodes where I applied the displacements are not matching. What may cause this problem?

Thanks in advance!

Hi,

I recently started to use OpenSees soil materials. I'm trying to model a very simple SSI problem between a wall and soil. I followed the steps explained in "Excavation Supported by Cantilevered Sheet Pile Wall". As a result I was able to complete gravity analysis with "InitialStateWrapper" successfully. Then I tried to conduct gravity analysis. I keep getting the following error message:

"ProfileSPDLinDirectSolver::solve() - aii < 0 (i,aii):(0,0)
WARNING NewtonRaphson::solveCurrentStep() -theLinearSysOfEqn failed in solve ()
DirectIntegrationAnalysis::analyze() -the Algorithm failed at time 1
Opensees > anaylze failed, returned: -3 error flag"

I searched the forum. Apparently this means there is an error in the model, most probably due to material definition or boundary conditions. I checked everything several times, however I couldn't find the source of this error. I would appreciate if someone could help me on this issue. The following is the simplified input file:

wipe

#-----------------------------------------------------------------------------------------
# 1. CREATE SOIL NODES AND FIXITIES
#-----------------------------------------------------------------------------------------
model BasicBuilder -ndm 2 -ndf 2
source DisplayModel2D.tcl; # procedure for displaying a 2D perspective of model
source DisplayPlane.tcl; # procedure for displaying a plane in the model

# define soil nodes

node 72 -0.530769231 0
node 73 -0.530769231 0.426
node 79 -0.1 0
node 80 -0.1 0.426

puts "Finished creating all -ndf 3 soil nodes..."

# define fixities for soil nodes

fix 72 1 1
fix 73 1 0
fix 79 0 1

puts "Finished creating all -ndf 2 boundary conditions..."

#-----------------------------------------------------------------------------------------
# 2. DESIGNATE LIST OF SOIL NODES FOR RECORDERS
#-----------------------------------------------------------------------------------------

set sNodeInfo [open SoilNodesInfo.dat w]
puts $sNodeInfo " 72 -0.530769231 0"
puts $sNodeInfo " 73 -0.530769231 0.426"
puts $sNodeInfo " 79 -0.1 0"
puts $sNodeInfo " 80 -0.1 0.426"
close $sNodeInfo

#-----------------------------------------------------------------------------------------
# 3. CREATE LAGRANGE MULTIPLIER NODES FOR BEAM CONTACT ELEMENTS
#-----------------------------------------------------------------------------------------

for {set k 1} {$k <= 2} {incr k 1} {
node [expr 1000+$k] 0.00 0.00
}
puts "Finished creating all -ndf 2 nodes..."


#-----------------------------------------------------------------------------------------
# 4. CREATE SOIL MATERIALS
#-----------------------------------------------------------------------------------------

# define pressure depended material for soil (!!!!!)
#nDMaterial PressureDependMultiYield $tag $nd $rho $refShearModul $refBulkModul $frictionAng $peakShearStra $refPress $pressDependCoe $PTAng $contrac $dilat1 $dilat2
#$liquefac1 $liquefac2 $liquefac3 <$noYieldSurf=20 <$r1 $Gs1 …> $e=0.6 $cs1=0.9 $cs2=0.02 $cs3=0.7 $pa=101>
nDMaterial PressureDependMultiYield02 5 2 2.24 42735.4 128206.2 40 0.1 \
100.0 0.5 26 0.013 0.0 0.3 \
0.0 30 5.0 3.0 1.0 \
0.0 0.532 0.9 0.02 0.7 101.0

# element thickness
set thick1 2.74
# body force in x-direction
set xWgt1 0.00
# body force in y-direction
set yWgt1 [expr -9.81*2.1]

puts "Finished creating all soil materials..."

#-----------------------------------------------------------------------------------------
# 5. CREATE SOIL ELEMENTS
#-----------------------------------------------------------------------------------------

element quad 1 72 79 80 73 $thick1 PlaneStrain 5 0.0 0.0 $xWgt1 $yWgt1


puts "Finished creating all soil elements..."

# create list of permanent elements with connectivities for post-processing
set eleFile [open SolidElementInfo.dat w]
puts $eleFile "1 72 79 80 73"
close $eleFile

puts "Finished creating equalDOF for base..."


#-----------------------------------------------------------------------------------------
# 6. CREATE BEAM NODES AND FIXITIES
#-----------------------------------------------------------------------------------------
model BasicBuilder -ndm 2 -ndf 3

# define beam nodes
node 82 0.0 -0.213
node 83 0.0 0.213
node 85 0.0 0.639

puts "Finished creating all -ndf 3 beam nodes..."

# create list of beam nodes and locations for post-processing
set bNodeInfo [open NodesInfo3.dat w]

puts $bNodeInfo "82 0.0 -0.213"
puts $bNodeInfo "83 0.0 0.213"
puts $bNodeInfo "85 0.0 0.639"
close $bNodeInfo

# fix the top node of the wall in the vertial direction
fix 85 0 1 0

puts "Finished creating all -ndf 3 boundary conditions..."

#-----------------------------------------------------------------------------------------
# 7. CREATE BEAM MATERIALS
#-----------------------------------------------------------------------------------------

# beam properties
set thick 0.2
set area 0.2
set I 9.75e-4
set beamE 30000
set numIntPts 3
set transTag 1
set secTag 1

# geometric transformation
geomTransf Linear $transTag

# beam section
section Elastic $secTag $beamE $area $I

puts "Finished creating all beam materials..."

#-----------------------------------------------------------------------------------------
# 8. CREATE BEAM ELEMENTS
#-----------------------------------------------------------------------------------------

element dispBeamColumn 66 83 82 $numIntPts $secTag $transTag
element dispBeamColumn 67 85 83 $numIntPts $secTag $transTag
puts "Finished creating all beam elements..."

# create list of beam elements with connectivities for post-processing
set beamInfo [open beamElementInfo.dat w]
puts $beamInfo " 66 83 82"
puts $beamInfo " 67 85 83"
close $beamInfo

#-----------------------------------------------------------------------------------------
# 9. CREATE CONTACT MATERIAL FOR BEAM CONTACT ELEMENTS
#-----------------------------------------------------------------------------------------

# two-dimensional contact material
nDMaterial ContactMaterial2D 3 0.2 1000.0 0.0 0.0

puts "Finished creating all contact materials..."

#-----------------------------------------------------------------------------------------
# 10. CREATE BEAM CONTACT ELEMENTS
#-----------------------------------------------------------------------------------------

# set gap and force tolerances for beam contact elements
set gapTol 1.0e-4
set forceTol 1.0e-4

# define beam contact elements
element BeamContact2D 1001 83 82 79 1001 3 $thick $gapTol $forceTol
element BeamContact2D 1002 85 83 80 1002 3 $thick $gapTol $forceTol

# display the model with the node numbers
DisplayModel2D NodeNumbers

#-----------------------------------------------------------------------------------------
# 10. GRAVITY ANALYSIS
#-----------------------------------------------------------------------------------------

# Newmark parameters
set gamma 0.5
set beta 0.25
updateMaterialStage -material 5 -stage 0
constraints Transformation
test NormDispIncr 1e-5 30 1
algorithm Newton
numberer RCM
system ProfileSPD
integrator Newmark $gamma $beta
analysis Transient

analyze 10 500

puts "Finished with elastic gravity analysis..."