Hi, I'm trying to undestand how BeamContact2D element works. I created a simple problem with only one solid element, one beam element and one contact element. I think my problem is the definition of the Lagrange multiplier node from the BeamContact2D element.
From the elmement wiki: ...The Lagrange multiplier node (2 DOF) is required to enforce the contact condition. Each contact element should have a unique Lagrange multiplier node. The Lagrange multiplier node should not be fixed, otherwise the contact condition will not work.
I don't undestand which node should I choose! I'm trying to do something similar to the "Excavation of cohesionless soil supported by a cantilevered sheet pile wall" example
Here is the error I get:
ContactMaterial2D nDmaterial - Written: K.Petek, P.Mackenzie-Helnwein, P.Arduino, U.Washington
BeamContact2D element - Written: C.McGann, P.Arduino, P.Mackenzie-Helnwein, U.Washington
Vector::operator/(double fact) - divide-by-zero error coming
WARNING SuperLU::solve(void)- Error 4 returned in factorization dgstrf()
WARNING NewtonRaphson::solveCurrentStep() -the LinearSysOfEqn failed in solve()
StaticAnalysis::analyze() - the Algorithm failed at iteration: 0 with domain at load factor 1
OpenSees > analyze failed, returned: -3 error flag
And this is the problem I'm talking about:
##################################################################################
# define dimensions
model BasicBuilder -ndm 2 -ndf 2
# define soil nodes
# nodeTag xcoord ycoord
node 1 0.00000 0.00000
node 2 1.00000 0.00000
node 3 0.00000 1.00000
node 4 1.00000 1.00000
# define fixities for soil nodes
# nodeTag xfix yfix
fix 1 1 1
fix 2 1 1
# define soil material
# matTag E nu sw
nDMaterial ElasticIsotropic 1 60000000 0.4 2753
# define soil elements
# eleTag nodes thick mat press mass qx qy
element quad 1 2 4 3 1 1 PlaneStrain 1 0 0 1000 1000
# define dimensions
model BasicBuilder -ndm 2 -ndf 3
# define beam nodes
# nodeTag xcoord ycoord zcoord
node 5 0.00000 0.00000 0.00000
node 6 0.00000 1.00000 0.00000
# define fixities for beam nodes
# nodeTag xfix yfix zfix
fix 5 1 1 0
# beam section
# tag E nu Iz
section Elastic 2 200000000 0.5 9.75e-4
geomTransf Linear 1
#beam element
# tag nodes ipoints sectag transtag
element dispBeamColumn 2 5 6 3 2 1
# two-dimensional contact material
# tag mu G c t
nDMaterial ContactMaterial2D 3 0.1 1000 0 0
# define beam contact elements
# tag BN1 BN2 SN1 LMN1 matTag width gTol fTol
element BeamContact2D 201 5 6 1 3 3 1 1e-10 1e-10
# set contact elements to be frictionless
setParameter -value 0 -ele 201 friction
# define analysis parameters for gravity phase
constraints Transformation
test NormDispIncr 1e-5 60 1
algorithm Newton
numberer RCM
system SparseGeneral
integrator LoadControl 1
analysis Static
#recorder
recorder Node -file Node_xdisplacements.out -time -nodeRange 1 4 -dof 1 disp
recorder Node -file Node_ydisplacements.out -time -nodeRange 1 4 -dof 2 disp
analyze 1
##################################################################################
BeamContact2D definition
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