Shear interaction?

[toggi007]

I´m having trouble aggregating shear to my model: There is no error, but there is no increase in displacement during pushover analysis. The results are the same with or without aggregated shear and no matter how large or small the shearstiffness is defined, my model is in 2D?
I have a fibersection with sectiontag 1 and I aggregate shear to the section by creating a new section with tag 2 (Section aggregator) combining existing section and uniaxialmaterial representing the shearstiffness accordingly:

set G [expr 26800/(2.0*(1+0.2))] #Shear modulus
set GA [expr 305*552*$G] #Shear stiffness
uniaxialMaterial Elastic 6 $GA # Material to represent shearstiffness
section Aggregator 2 6 Vy -section 1 # Aggregate shear to existing fibersection

set ColTransfTag 1;
geomTransf Corotational $ColTransfTag;

for {set k 1} {$k <= $Nrele} {incr k 1} {
element dispBeamColumn $k $k [expr $k+1] $numIntgrPts 2 $ColTransfTag;
}
recorder Node -file Data/A1_vesna/A1_Nonlinear.out -time -node $node -dof 2 disp;

[toggi007]

really no comments, anyone?

[toggi007]

Also when using section recorder with deformation I get gammY = 0 and Vy = 0. Still I´m only interested in the displacements due to shear!
Someone plz help?

[silvia]

where is your section recorder command?

[toggi007]

Shear deformations in the elastic range are usually small and neglected, however in the inealstic range of responce shear deformations can be large. So here are some questions...
1)as I am using uniaxial elastic material to represent shear, the shear responce will be in the elastic range even though I´m doing inelastic elements?
2) So I´m thinking doing this will give me just the same as my handcalculations?
3) Then there is fiberint and dispbeamInt option that seems to be only adapted for shearwalls because you cannot define one strip with concrete and the next with both concrete and steel, need to be the same over an element of constant thickness, so i´m thinking it cannot be used on my beams because the reinforcement is not evenly distributed over the beam height?

regarding your question:
Here is the section recorder
recorder Element -xml Data/A1_vesna/secDefo.out -time -ele [expr $Nrele/2] section $numIntgrPts forceAndDeformation

[toggi007]

Hi again, one more question, but please read the post above first.
4) When using nonlinearbeamColumn element I get the additional displacements due to shear that I wanted, though I wanted to get them with the dispbeamcolumn element (post above)
and yes they are almost the same as my handcalculations. So how can I consider inelastic shear deformation?

also still the element recorder above doesn´t work

Thank you for your previous replies, you´r the best

[toggi007]

Hi, would appreciate some comments, anyone?

[vesna]

To consider inelastic shear deformation define material that represents shear as nonlinear.

Try this recorder:
eval "recorder Element -xml Data/A1_vesna/secDefo.out -time -ele [expr $Nrele/2] section $numIntgrPts forceAndDeformation"

[toggi007]

Hi, is it true that when adding shear-strain to section with M-curvature you can only do so with forcebasedbeamcolumn element because........ is based on forcebased elements? I´m assuming that this is what section aggregator does?

[vesna]

section aggregator assigns shear force-deformation to already defined section. It does not account for interaction with other sectional forces.

[toggi007]

Yes I know, what I´m really asking is why section aggregator cannot be used with displacement based element? (Or why it can only be used with force based element?)

[vesna]

it can be assigned to both, force-based and deformation-based elements.

[lovelywind]

i faced the same problem that aggregating shear to model before! i havent solve yet! thanks you guys help!

[toggi007]

Are you sure Vesna, xml files show zeros where the shear strains should be. But this happens only when I use the displacement based element.
Note that the only modification I make is to change between elements (disp & force based)

[fmk]

only the force beam column will include the effect of shear in the calculation. i suggest you look at the source code if you are interested further.