How to simulate Isolator ( such as LRB)

[cctvcctv]

I'd like to simulate the responses of building with isolators ( elastomeric bearings), and anybody know how to define the element of bearing?

I know in the program Aladdin 2.0, fiber element can be used to simulate the isolator, and what in the Opensees?

Thanks!

[erol kalkan]

Did you try zero-length element?

[cctvcctv]

Thanks for your suggestion.

And I think the bearing( such as lead rubber bearing) should have length ( though it is small). But its mass can be neglected.

How to define this element without mass?

Another question is that is it possible to take account in the bi-directional effect of bearing, i.e. the model of bearing can consider the orthoganol hysteretic character of the bearings? such as in 3D Basis

Thanks!

[silvia]

I wonder if anyone is working on this model....

[jpadgett]

Did you ever figure out if there is a way to capture this bi-directional effect in Opensees? I just recently posted a similar question but have not discovered an appropriate way to model such isolation bearing response in 3d. Thanks.

[silvia]

sorry,
i haven't had a chance to look at this further.

[ngeorgal]

well i have tried to use

section Bidirectional $matTag $Es $Fy $Hiso $Hkin
element zeroLengthSection 100 1 2 10

and i have earthquakes at two directions . unfortunately the results using

recorder Element -file force100el.out -time -ele 100 force
recorder Element -file deformation100.out -time -ele 100 deformation

i do not get results in the Z direction but only in the X direction .


Silvia we have discussed by mail , but searching the forum i saw the questions of ccrvcctv and i posted my question here.

cctvcctv if you have made it to use the bidirectional section correctly to model the hysteretic isolator please send me your information at ngeorgal@gmail.com

[isolator]

When I build LRB bearing,I use "element elastomericBearing" this order,I want to ask you how to add bearing damping?Thanks!

[fmk]

if you must have damping there is a -doRayleigh option you can add. IT IS ONLY AN OPTION BECAUSE you would NOT TYPICALLY want to include it.

if it is for the vertical direction, you can apply it through the material.

[markant]

dear vesna,
i want to model a portal frame with high damping rubber bearing as a base isolator. but i do not want to model force-displacement as a bilinear model. in this case i do not want to model it using element elastomericbearing command. it should be real. e.g. curvilinear at the end of the hysteresis loop. can you suggest any model in opensees? any coomand?

mark

[vesna]

You can try to combine curvilinear (http://opensees.berkeley.edu/wiki/index ... r_Material) and bouc wen model.

[cdv]

Hello to everybody,
i am using the command BWBN to reproduce the hysteretic behavior of a bearing tested in my lab. I want also use the Simulink optimization tool available at: http://opensees.berkeley.edu/wiki/index ... Estimation.
But i got this error in the tool execution:

Error using slcontrol.Utilities/fevalCompiled (line 51)
**** Error ****

Error in ParameterEstimator.TransientExperiment/update (line 12)
[this.InputData, this.OutputData, this.InitialStates] = ...

Error in ParameterEstimator.TransientExperiment (line 30)
update(this);

Error in BW_pinch (line 39)
hExp = ParameterEstimator.TransientExperiment('BWBNpinch');

Is there someone that successfully used this tool?

Thank you in advance.