post-buckling analysis of steel struts

If you have a script you think might be useful to others post it
here. Hopefully we will be able to get the most useful of these incorporated in the manuals.

Moderators: silvia, selimgunay, Moderators

Post Reply
pejman_opensees
Posts: 123
Joined: Tue Oct 31, 2006 10:40 am
Location: k.n.toosi University

post-buckling analysis of steel struts

Post by pejman_opensees »

this is a standardized code which peforms cyclic loading test on a steel
tubular strut. model definition is according to tests done by popov et al in EERC 81/04.
pinned-pinned tubular steel struts with a snap through( inital deformation) is modeled and several hysteritic loading loop is applied and the result completely matches with the experimental hysteritic loops depicted by popov et al (in page 58 EERC 81/04).
(units are kips-in)

Code: Select all

wipe
model basic -ndm 2 -ndf 3
node 1 0 0
node 2 152.81 0.61123
node 3 305.6184 0
fix 1 1 1 0
fix 3 0 1 0
fix 2 0 0 0
geomTransf Corotational 1   
uniaxialMaterial Steel02 1 40 29800 0.003 20 0.925 0.15 0.0005 0.01 0.0005 0.01
section Fiber 1 {
patch circ 1 20 2 0 0 7.75 8.25 0 360
}

element nonlinearBeamColumn 1 1 2 4 1 1
element nonlinearBeamColumn 2 2 3 4 1 1

recorder Node -file Node2.out -time -node 3 -dof 1  disp
recorder plot node2.out test 0 0 400 400 -columns 2 1
and loading is as follows:

Code: Select all

pattern Plain 1 Linear { load 3 1.0 0.0 0.0}
test EnergyIncr 1.0e-8 30 0
algorithm Newton
system UmfPack
numberer RCM
constraints Plain
analysis Static
set peak [ list 0.25 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5 5.5 6]
for {set i 1} {$i<=13} {incr i} {
	set dU [expr -1.0*pow((-1.0),$i)*[lindex $peak [expr $i-1]]/100.0]
	integrator DisplacementControl 3 1 $dU 1 $dU $dU
	analyze 100
}
hope it will help!

[/code]
Pejman
luoyunbiao
Posts: 16
Joined: Sun Apr 08, 2007 10:00 pm
Location: Kyoto Unviersity
Contact:

Re: post-buckling analysis of steel struts

Post by luoyunbiao »

thank you!It is very useful.
Disaster Prevention Research Institute
http://www.steel.dpri.kyoto-u.ac.jp/
Kyoto University, Kyoto, Japan
luoyunbiao@hotmail.com
Post Reply