Can anyone please tell me how to replace these hinges with plastic hinges in OpenSees

[RajArora]

This is the example of a 1 storey single bay frame subjected to lateral point loading at joint 3. At every node in this frame, I have assigned hinges now I have to convert this code into SWAY MECHANISM for the frame by changing all hinges with plastic hinges. So what are the steps required for that to change hinges into plastic hinges with zero-length (concentrated plasticity)
Take suitable values if needed
model BasicBuilder -ndm 2 -ndf 3
# Units: kip, in
# Define the model builder
model BasicBuilder -ndm 2 -ndf 3
# Set some variables
set L1 236
set L2 157
set A 167
set E 20000
set I 2325.69
# Define total 8 nodes nodes with hinge
node 1 0.0 0.0
node 2 0.0 0.0
node 3 0.0 $L2
node 4 0.0 $L2
node 5 $L1 $L2
node 6 $L1 $L2
node 7 $L1 0.0
node 8 $L1 0.0

# Define single point constraints
fix 1 1 1 1
fix 7 1 1 1
# ndR ndC dofs
equalDOF 1 2 1 3
equalDOF 3 4 1 3
equalDOF 5 6 1 3
equalDOF 7 8 1 3
# Define force-deformation relationship for spring
uniaxialMaterial ElasticPP 2 1050 0.02
uniaxialMaterial Elastic 3 -50
uniaxialMaterial Parallel 1 2 3
# id ndI ndJ mat dir
element zeroLength 1 1 2 -mat 1 -dir 2
element zeroLength 2 3 4 -mat 1 -dir 2
element zeroLength 3 5 6 -mat 1 -dir 2
element zeroLength 4 7 8 -mat 1 -dir 2
# Geometric transformation
geomTransf Linear 1
# id ndI ndJ A E I transf
element elasticBeamColumn 10 1 3 $A $E $I 1
element elasticBeamColumn 11 3 5 $A $E $I 1
element elasticBeamColumn 12 5 7 $A $E $I 1
pattern Plain 1 Linear {
load 3 90.0 0.0 0.0
}
recorder Node -file ZeroLength1.out -time -node 3 -dof 2 disp
integrator LoadControl 1 1 1 1
test EnergyIncr 1.0e-6 10 1
algorithm Linear
numberer Plain
constraints Transformation 1.0
system SparseGeneral -piv
analysis Static
analyse 1


Reply asap

[selimgunay]

You need to develop a uniaxialmaterial with an inelastic relationship and assign it to your zerolength element in the rotational degree of freedom.

[AKSHAYNAIK]

Well did it work @Raj?