section Uniaxial

[sisa]

hi!
I have a question about the section Uniaxial command...
Is it possible to create an element that have only a flexural response? I've tried to create it but it doesn't work and I thought that perhaps I have to assign also an axial response to the element...or is the nonlinearBeamColumn the problem?
my element is this (it's just a part of the code):

set Htrave 500.
set Btrave 300.
set My 174796000
set K 1.4566e13
set btrave 0.015
set SezTrave 2
set IDtrave 4

uniaxialMaterial Steel01 $IDtrave $My $K $btrave
section Uniaxial $SezTrave $IDtrave Mz
element nonlinearBeamColumn 3 2 4 $IDctrlSez $SezTrave 201

thank you

[andrett7]

Hi, to have just a flexural response you can write something like this:

set ColSecTagFlex 1
set ColSecTag 2
set MyCol 150;
set EI 1.e5
set b 0.01
uniaxialMaterial Steel01 $ColSecTagFlex $MyCol $EIColCrack $b
element nonlinearBeamColumn 1 1 2 $np $ColSecTagFlex $IDColTransf;

If you want to add also the effect of axial load you need to define another uniaxialMaterial and aggregate to the previous one:
uniaxialMaterial Elastic $ColMatTagAxial $EABeam;
section Aggregator $ColSecTag $ColMatTagAxial P $ColMatTagFlex Mz;
element nonlinearBeamColumn 1 1 2 $np $ColSecTagFlex $IDColTransf;

If you want to take into account automatically the interaction M-N you need to use fiber section


Andrea

[sisa]

thank you Andrea for your answer...but in this way I think there is an error because it doesen't recognize none section...it isn't?
really I don't understand the problem because I tried also to make a sample example with a cantilever and it doesn't work..the result are all zero!!!

#mensola caricata con una forza concentrata
wipe
model BasicBuilder -ndm 2 -ndf 3

node 1 0 0
node 2 0 5000

fix 1 1 1 1

#sezione trave
set My 174796000
set K 1.4566e13
set btrave 0.015
set SezTrave 2
set IDtrave 4

uniaxialMaterial Steel01 $IDtrave $My $K $btrave
section Uniaxial $SezTrave $IDtrave Mz
geomTransf Linear 201

element nonlinearBeamColumn 1 1 2 5 $SezTrave 201

pattern Plain 10 Linear {load 2 50000. 0. 0.}
system BandSPD
numberer RCM
constraints Plain
integrator LoadControl 1.0
algorithm Linear
analysis Static

analyze 1

puts "NodoAlto Disp=[nodeDisp 2 1]"
puts "Mbase M=[nodeReaction 1 3]"
print node 2
print node 1

[fmk]

the beam column elements need an axial component as well as a rotational component.