qrdopt,yes! Allow reuse of QRDAMP Lanczos modes later
cmrot,contact2,0.0,0.0,1.9! Apply rotational velocity along rotZ
solve,elform! 1st phase of perturbation
! Free blocks to see rigid body modes, if any.
! This is an example of modifying loads or B.C. in the 2nd
! phase of linear perturbation.
vsel,s,,,1,2,,1
ddele,all,all
allsel
modopt,qrdamp,20,50,,on! Try QRDAMP eigensolver
!modopt,unsym,20,50! Alternatively use UNSYM eigensolver j
15-0.31718E-02 1183.7 j 1
solve! 2nd phase of perturbation
finish
/post1
file,modal,rstp
*get,FREQ_IMAG1,mode,1,freq,imag
*get,FREQ_IMAG2,mode,5,freq,imag
*get,FREQ_IMAG3,mode,10,freq,imag
*get,FREQ_IMAG4,mode,15,freq,imag
*get,FREQ_IMAG5,mode,20,freq,imag
*stat,FREQ_IMAG1
*stat,FREQ_IMAG2
*stat,FREQ_IMAG3
*stat,FREQ_IMAG4
*stat,FREQ_IMAG5
finishExample 9.6: Using Linear Perturbation to Predict a Buckling Load
!********** CASE 1 **********
!********** Base analysis ***********
/prep7! Build the model
et,1,188sectype,1,beam,rect! Define beam section
secdata,0.2,0.4
mp,ex,1,1.0e8! Define material
mp,dens,1,1000
mp,nuxy,1,0.3
local,11,0,0,0,0,45,0,0! Create model and mesh it
csys,11
k,1,0,0,0
k,2,10,0,0
l,1,2
lesize,1,,,10
lmesh,1
allsel,alld,1,all,0! Fix end of beam
allsel,all
nrotate,all
finishsave,model1,db! Save model as model1.db for use in cases 2 and 3
/solu
antype,static
outres,all,all
f,2,fx,-1000.0! Buckling load prediction is independent of
! this load level because base analysis is linear
rescontrol,linear,all,1! Needed to generate restart file
solve
finish
!********** Linear perturbation buckling analysis - first phase **********Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential informationExample Inputs for Linear Perturbation Analysis