/solu
antype,static,restart,,,perturb! Restart the linear base analysis
perturb,buckle,,,allkeep! This is a LP eigen-buckling analysis
solve,elform
!********** Linear perturbation buckling analysis - second phase **********
f,2,fx,-10.0
bucopt,lanb,2,,,range
mxpand,2,,,yes
solve
finish/post1
file,,rstp
set,1,1
*get,loadfactor,active,0,set,freq/com,*******************************************************************
/com, Case 1: Linear base analysis, Eigenvalue buckling analysis
/com, Buckling load is: Fbuckling = 0 + Lambda *(Fperturbed)
/com,
/com, Expected load factor = 66.0258
/com, predicted Fbuckling = 0-66.0258*10 = -660.258
/com,
/com,*******************************************************************
*stat,loadfactorfinish
/delete,,rstp
/clear,nostart!********** CASE 2 **********
resume,model1,db
!********** Base analysis **********
/solu
antype,static
outres,all,all
nlgeom,on! Base analysis is nonlinear
rescontrol,define,all,1
nsubs,2,10,2
time,1
f,2,fx,-100.0! 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,,,perturb! Restart at the end of loadstep
perturb,buckle,,,allkeep
solve,elform
!********** Linear perturbation buckling analysis - second phase **********
outres,all,all
f,2,fx,300
bucopt,lanb,2,,,center! Use CENTER option (default), we don't know if load factor
! is negative or positive
mxpand,2,,,yes
solve
finish
/post1
file,,rstp
set,1,2
*get,loadfactor2,active,0,set,freq
/com,********************************************************************
/com, Case 2: Nonlinear base analysis, Eigenvalue buckling analysis
/com, Buckling load is: Fbuckling = Frestart + Lambda *(Fperturbed),Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential informationLinear Perturbation Analysis