Viscous damper brace

Ben-Peng · Post by **Ben-Peng** » Thu May 24, 2007 11:00 pm

Hi silvia,
I am doing a 2d portal with a viscous damper brace. and I defined a viscous material, but I am not sure how to define the brace(which section and element to use).

silvia · Post by **silvia** » Fri May 25, 2007 6:17 am

why not the truss with defined section, which would include the damper?

Ben-Peng · Post by **Ben-Peng** » Fri May 25, 2007 6:04 pm

Thanks, silvia!
I tried both of the truss commends.
1. element truss $eleTag $iNode $jNode $A $matTag
In this commend, $A affect the result of the analysis, I have no idea how to define it.
2. element truss $eleTag $iNode $jNode $secTag
With this commend, I used the Uniaxial section(section Uniaxial $secTag $matTag $string, which $string=P), but I found that the result was the same as that the structure has no damper brace.

silvia · Post by **silvia** » Fri May 25, 2007 7:47 pm

i don't know enough about it.
but i'd use the truss with a section, where i'd define the uniaxial material to be the section, aggregated with the damper...

Ben-Peng · Post by **Ben-Peng** » Fri May 25, 2007 11:28 pm

Thanks for your suggestion, silvia!
But I still have some trouble. I defined the damper with the viscous command, it is the relationship between the stress and the strain-rate(so is the force and the velocity). But with the section Aggregator command, the "$string" has the P, Mz, My, Vz, Vy, T to choose, but P is for the Axial force-deformation. I think that is why I found the analysis result was the same as the structure which has no damper brace. And how to do it correctly!

The script about the damper brace:
###########
uniaxialMaterial Viscous $IDVis $C $alpha ; # build viscous material

section Aggregator $VisSecTag $IDVis P -section $ColSecTag;

element truss 4 1 4 $VisSecTag ;