Modelling springs for plastic hinge of column/beam

[aylsworth]

Hi.

Can someone help

#Axial Spring Parameters
limitCurve Axial $axialCurveTag $ColSecTag [expr $rhos*$fyt*$HCol*$BCol*$dt*(1/$s)] $ka $Pr 2 2 1 2 1 2 0 0
uniaxialMaterial LimitState $ColMatTagAxial $Py $Pdy $Pu $Pdu [expr -$Py] [expr -$Pdy] [expr -$Pu] [expr -$Pdu] 0 0 0 0 0 $axialCurveTag 1

#Shear Spring Parameters
limitCurve Shear $shearCurveTag $ColSecTag $rhos $fc $BCol $HCol $dt [expr $rhos*$fyt*$HCol*$BCol*$dt*(1/$s)] $kf $Vr 2 0 1 2 1 2 0.0
uniaxialMaterial LimitState $ColMatTagShear $Vcr $dcr $Vu $du [expr -$Vcr] [expr -$dcr] [expr -$Vu] [expr -$du] 0 0 $damage1 $damage2 $beta $shearCurveTag 2 0

#Rotational spring parameters (trilinear)
uniaxialMaterial Hysteretic $ColMatTagFlex $Mcr $Mdcr $My $Mdy $Mu $Mdu [expr -$Mcr] [expr -$Mdcr] [expr -$My] [expr -$Mdy] [expr -$Mu] [expr -$Mdu]$pinchX $pinchY 0 0 0;

section Aggregator $ColSecTag $ColMatTagAxial Vy $ColMatTagAxial P $ColMatTagFlex Mz



what is the correct element for this one?? Thanks!

[selimgunay]

You need to use a zerolength element and assign these materials to the element. Please remove the section Aggregator and let me know if you have any difficulties.

http://opensees.berkeley.edu/wiki/index ... th_Element

[aylsworth]

selimgunay wrote:
> You need to use a zerolength element and assign these materials to the
> element. Please remove the section Aggregator and let me know if you have
> any difficulties.
>
> http://opensees.berkeley.edu/wiki/index ... th_Element


Hi! Thank you for your reply. I used zerolength element to integrate the uniaxialmaterial, then used the section aggregator. However, my analysis is not converging. I am trying to simulate cyclic load test of a column from PEER Column Database - Saatcioglu and Ozcebe 1989, U4 (Rectangular). Can you help me with regard to this matter? Thank you so much!

Patrick

[selimgunay]

I don't think you need to use the section aggregator as there is no section used in the zerolength element. That may be the source of the problem.

[aylsworth]

selimgunay wrote:
> I don't think you need to use the section aggregator as there is no section
> used in the zerolength element. That may be the source of the problem.

Ah yes. Sorry I forgot to mention that my element is beamwithhinge then the axial spring is integrated to this element. Then shear and rotation is on zeroloength. Though I am not sure if the code below is correct.

#Axial Spring Parameters
limitCurve Axial $axialCurveTag $zeroLengthElement [expr $rhos*$fyt*$HCol*$BCol*$dt*(1/$s)] $ka $Pr 2 2 1 3 1 2 0 0
uniaxialMaterial LimitState $ColMatTagAxial $Py $Pdy $Pu $Pdu $Pu $Pdu [expr -$Py] [expr -$Pdy] [expr -$Pu] [expr -$Pdu] [expr -$Pu] [expr -$Pdu] 0 0 0 0 0 $axialCurveTag 1

#Shear Spring Parameters
limitCurve Shear $shearCurveTag $zeroLengthElement $rhos $fc $BCol $HCol $dt [expr $rhos*$fyt*$HCol*$BCol*$dt*(1/$s)] $kf $Vr 2 0 1 3 1 2 0.0
uniaxialMaterial LimitState $ColMatTagShear $Vcr $dcr $Vu $du $Vu $du [expr -$Vcr] [expr -$dcr] [expr -$Vu] [expr -$du] [expr -$Vu] [expr -$du] 0 0 $damage1 $damage2 $beta $shearCurveTag 2 0

#Rotation spring
limitCurve Axial $flexureCurveTag $zeroLengthElement [expr $rhos*$fyt*$HCol*$BCol*$dt*(1/$s)] $ka $Pr 1 0 1 3 6 5 0 0
uniaxialMaterial LimitState $ColMatTagFlex $Mcr $Mdcr $My $Mdy $Mu $Mdu [expr -$Mcr] [expr -$Mdcr] [expr -$My] [expr -$Mdy] [expr -$Mu] [expr -$Mdu] $pinchX $pinchY 0 0 0 $flexureCurveTag 1;

section Elastic $ColSecTag $Ec $ACol $IzCol;
section Aggregator $ColSecTag2 $ColMatTagAxial P

#Elements - node is 1-3 (zerolength) then 3-2 beamwithhinge (with axial spring)
element beamWithHinges $nonlinearbeamcolumn 3 2 $ColSecTag2 $Lpi $ColSecTag 0 $Ec $ACol $IzCol $ColTransfTag;
element zeroLength $zeroLengthElement 1 3 -mat $ColMatTagAxial $ColMatTagShear $ColMatTagFlex -dir 3 1 6;

[selimgunay]

Please use the axial material directly in the zerolength element in direction 2 and define your beam column element as elasticBeamColumn.

[aylsworth]

selimgunay wrote:
> Please use the axial material directly in the zerolength element in
> direction 2 and define your beam column element as elasticBeamColumn.


Thank you Sir! I was able to model the springs.

By the way, I have another question, is the shear spring incorporated in zerolength element compatible with beamwithhinge element with fiber section of concrete and steel? Does the shear spring in effect when I use the code below?
Thank you very much Sir for your help!

node 1 0 0;
node 2 0 0;
node 3 0 $LCol;

uniaxialMaterial LimitState $shearTag $Vcr $dcr $Vy $dy $Vu $du [expr -$Vcr] [expr -$dcr] [expr -$Vy] [expr -$dy] [expr -$Vu] [expr -$du] $pinchX $pinchY $damage1 $damage2 $beta $shearCurveTag 2 0
section fiberSec $ColSecTag{
...(concrete fibers and steel fibers defined here)
}

element beamWithHinges 1 2 3 $ColSecTag $Lpi $ColSecTag 0 $Ec $ACol $IzCol $ColTransfTag;
element zeroLength 2 1 2 -mat $shearTag -dir 2;

[selimgunay]

Yes the two lines are fine and the beamwith hinges and the shear spring will work. However, you need to constrain dofs 1 and 3, otherwise the element will be unstable in the axial direction and there will be a flexural hinge. The corrrect way to fix that would be:

element beamWithHinges 1 2 3 $ColSecTag $Lpi $ColSecTag 0 $Ec $ACol $IzCol $ColTransfTag;
element zeroLength 2 1 2 -mat $shearTag -dir 2;
equalDOF 1 2 1 3;

[aylsworth]

Thank you Sir!

[aylsworth]

For the rotation spring, is it possible to have a user-define limit curve for the uniaxialMaterial Hysteretic as when I try to run the code, it says to define limitcurve after $damage2 and DOF right after it.

uniaxialMaterial Hysteretic $matTag $s1p $e1p $s2p $e2p <$s3p $e3p> $s1n $e1n $s2n $e2n <$s3n $e3n> $pinchX $pinchY $damage1 $damage2 <$beta>

[selimgunay]

When you use the Hysteretic matreial with the syntax below, does it ask you to define a limitcurve?

uniaxialMaterial Hysteretic $matTag $s1p $e1p $s2p $e2p <$s3p $e3p> $s1n $e1n $s2n $e2n <$s3n $e3n> $pinchX $pinchY $damage1 $damage2 <$beta>

[aylsworth]

Yes SIr. The code I used is

uniaxialMaterial Hysteretic $ColMatTagFlex $Mcr $Mdcr $My $Mdy $Mu $Mdu [expr -$Mcr] [expr -$Mdcr] [expr -$My] [expr -$Mdy] [expr -$Mu] [expr -$Mdu] $pinchX $pinchY 0 0 0 4 6;

When I remove the 4 6 in the last part of the code, the programs terminates automatically when I run the whole code. Please check image link below for reference
https://drive.google.com/open?id=0BzIal ... XczWENHV1U

[selimgunay]

It should work with the following syntax

uniaxialMaterial Hysteretic $ColMatTagFlex $Mcr $Mdcr $My $Mdy $Mu $Mdu [expr -$Mcr] [expr -$Mdcr] [expr -$My] [expr -$Mdy] [expr -$Mu] [expr -$Mdu] $pinchX $pinchY 0.0 0.0 0.0

[aylsworth]

Thanks for the help Sir! I was able to run the model now though the result is somehow different from the cyclic data that I have.

[selimgunay]

You can always tune the parameters to match the experimental results better.