/com, The CENTER option is used
/com,
/com, Expected load factor = -1.868
/com, predicted Fbuckling = -100-1.868*300 = -660.4
/com,
/com,********************************************************************
*stat,loadfactor2
finish
/delete,,rstp
/clear,nostart!********** CASE 3 **********
resume,model1,db
!********** Base analysis **********
/solu
antype,static
outres,all,all
nlgeom,on! Base analysis is nonlinear
rescontrol,define,all,1
nsubs,10,10,10
time,1
f,2,fx,-400.0! Buckling load prediction is dependent on
! this load level because base analysis is nonlinear
solve
finish
!********** Linear perturbation buckling analysis - first phase **********
/solu
antype,static,restart,1,5,perturb! Restart in the middle of loadstep
perturb,buckle,,,allkeep
solve,elform
!********** Linear perturbation buckling analysis - second phase **********
outres,all,all
f,2,fx,-500
bucopt,lanb,2,,,range! Expected load factor is greater than zero; no need to use CENTER
mxpand,2,,,yes
solve
finish
/post1
file,,rstp
set,1,1
*get,loadfactor3,active,0,set,freq
/com,********************************************************************
/com, Case 3: Nonlinear base analysis, Eigenvalue buckling analysis
/com, Buckling load is: Fbuckling = Frestart + Lamda *(Fperturbed)
/com, No CENTER Option is used and restarting from middle.
/com,
/com, Expected load factor = 0.9205
/com, predicted Fbuckling=-400*0.5-0.9205*500=-660.25
/com,
/com,********************************************************************
*stat,loadfactor3
finishExample 9.7: Linear Perturbation (Prestressed) Harmonic Analysis
/prep7! Build the model
et,1,188
sectype,1,beam,rect! Define beam section
secdata,0.2,0.4
mp,ex,1,2.0e11! Define material
mp,dens,1,7800
mp,nuxy,1,0.3Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential informationExample Inputs for Linear Perturbation Analysis