How to model spring or damper in OpenSees

[xwjshs]

Hi, everybody
how to model spring or damper in OS.
using what element and material to spring or damper.
thanks!

[vesna]

To model the damper you can use truss or corotational truss element (if you have large deformations) and assign viscous material. With this you can model the damper well if alpha is greater then 0.5. Soon, there will be more options on modeling the damper in OpenSees.

[xwjshs]

[quote="vesna"]To model the damper you can use truss or corotational truss element (if you have large deformations) and assign viscous material. With this you can model the damper well if alpha is greater then 0.5. Soon, there will be more options on modeling the damper in OpenSees.[/quote]

vesna, thank you very much. i will have a try.

however, is the damper with truss element 3D?

i need create 1D damper element in OS. please tell me how to do.

thank you.

[xwjshs]

vesna, thank you very much. i will have a try.

however, is the damper with truss element 3D?

i need create 1D damper element in OS. please tell me how to do.

thank you.[/quote]

[vesna]

First define viscous material:
uniaxialMaterial Viscous $matTag $C $alpha;

where $C is a damping coeff. and $alpha is power factor.

Then assign it to a truss (it will work in 1D):
element truss $eleTag $iNode $jNode $A $matTag

The explanation of arguments is given in the command manual:
http://opensees.berkeley.edu/wiki/index ... ss_Element

[xwjshs]

[quote="vesna"]First define viscous material:
uniaxialMaterial Viscous $matTag $C $alpha;

where $C is a damping coeff. and $alpha is power factor.

Then assign it to a truss (it will work in 1D):
element truss $eleTag $iNode $jNode $A $matTag

The explanation of arguments is given in the command manual:
http://opensees.berkeley.edu/wiki/index ... ss_Element[/quote]


thank you very much.

[xwjshs]

Hi, vesna

the truss element modeling damper is working, but can't output the force and deformation of the element.

in my script, using"recorder Element -file $dataDirDamper/DamperEleForce1.out -time -ele $Ele section 1 force;
recorder Element -file $dataDirDamper/DamperEleDeformation1.out -time -ele $Ele section 1 deformation;"

please tell me how to output the force and deformation of damper element.

thank you.

[vesna]

Try this:

recorder Element -file $dataDirDamper/DamperEleForce1.out -time -ele $Ele force;
recorder Element -file $dataDirDamper/DamperEleDeformation1.out -time -ele $Ele deformation;

[xwjshs]

[quote="vesna"]Try this:

recorder Element -file $dataDirDamper/DamperEleForce1.out -time -ele $Ele force;
recorder Element -file $dataDirDamper/DamperEleDeformation1.out -time -ele $Ele deformation;[/quote]

thank u.
using the script can output the force and deformation.
but outputting the deformation is 0 for element modeling damper. why?

[vesna]

The deformations of dampers should not be zero. I can take a look at your files if you send them to me at vesna AT berkeley DOT edu.

[xwjshs]

[quote="vesna"]The deformations of dampers should not be zero. I can take a look at your files if you send them to me at vesna AT berkeley DOT edu.[/quote]

i sorry and don't find your email.
this is script about damper elemnt.

#---------------
set dataDir5 DamperData;
set dataDirDamper $dataDir1/$dataDir5; # set up name of data directory -- remove
file mkdir $dataDirDamper; # create data directory

# Define uniaxial material of Damper
set IDmatTagDamper 601;
set DamperC 10000;
set DamperAlpha 0.6;

uniaxialMaterial Viscous $IDmatTagDamper $DamperC $DamperAlpha

# Define Damper Elements between pylon and beam----------------------------
# element truss $eleTag $iNode $jNode $A $matTag
set DamperEleStart 10000;
element truss 10001 50003 50004 1 $IDmatTagDamper;
element truss 10002 50005 50006 1 $IDmatTagDamper;

# Define All Damper RECORDERS -------------------------------------------------------------
recorder Element -file $dataDirDamper/DamperEleGlobalForce1.out -time -ele 10001 globalForce; # section forces, axial and moment, node j
recorder Element -file $dataDirDamper/DamperEleGlobalForce2.out -time -ele 10002 globalForce;

recorder Element -file $dataDirDamper/DamperEleForce1.out -time -ele 10001 force;
recorder Element -file $dataDirDamper/DamperEleForce2.out -time -ele 10002 force;
recorder Element -file $dataDirDamper/DamperEleDeformation1.out -time -ele 10001 deformation;
recorder Element -file $dataDirDamper/DamperEleDeformation2.out -time -ele 10002 deformation;

recorder Element -file $dataDirDamper/DamperEleLocalForce1.out -time -ele 10001 localForce;
recorder Element -file $dataDirDamper/DamperEleLocalForce2.out -time -ele 10002 localForce;

recorder Node -file $dataDirDamper/DamperNodeFree1.out -time -node 50003 50004 -dof 1 disp;
recorder Node -file $dataDirDamper/DamperNodeFree2.out -time -node 50005 50006 -dof 1 disp;

puts "Finish Damper Model";

this is a part of script in model. But if you need more imfornation i will send all scripts to your email.

thank u.

[vesna]

from what i see in your post, it all looks fine. would you send me your files on my e-mail:
vesna AT berkeley DOT edu

[xwjshs]

[quote="vesna"]from what i see in your post, it all looks fine. would you send me your files on my e-mail:
vesna AT berkeley DOT edu[/quote]

hi vesna

the model has sent to your E-mail

thank u.

[xwjshs]

hi vesna

the files with model have sent to your E-mail and please check your E-mail.

look forward to your reply. thank u.

[egeria]

Hi ,I want to model the viscous Damper,by using Zero Length element and .my viscous Damper is Linear (alpha = 1 and C= 1450) but after Running ,this warning appears :can you explain it ,what is this ?

WARNING ZeroLength::setDomain(): Element 46 has L= 500, which is greater than the tolerance

and am I correct by modeling the viscose damper ?(I am using the Open sees Navigator )