一个非线性分析实例（经典）

双层蜂窝纸板在位移载荷下的屈曲分析实例！！！
完整版命令流如下：
FINISH
/CLEAR,START
*afun,deg
*set,a,30
X=COS(A)
Y=SIN(A)
L=8.7E-3
H=8.7E-3
Z=30E-3
/PREP7
et,1,shell181
r,1,4.9e-4
r,2,4.4e-4
r,3,2.2e-4
et,1,shell181
r,1,4.9e-4
r,2,4.4e-4
r,3,2.2e-4
mp,ex,1,7.6e8
mp,prxy,1,0.3
tb,biso,1
tbdata,1,4.25e6
tbdata,2,200e6
mp,ex,2,3.6e8
mp,prxy,2,0.3
tb,biso,2
tbdata,1,3.0e6
tbdata,2,100e6
mp,ex,3,3.6e8
mp,prxy,3,0.3
tb,biso,3
tbdata,1,3.0e6
tbdata,2,100e6
k,1,0,0,0
K,2,L*X,L*Y,0
K,3,L*X,H+L*Y,0
k,4,0,l+2*l*y
k,5,0,2*l+2*l*y
L,1,2
L,2,3
l,3,4
l,4,5
lgen,2,1,4,1,,2*l+2*l*y,,,0,0
nummrg,kp
*get,nmax1,line,,num,max
cm,ldanyuan,line
*get,nmax,kp,,num,max
k,nmax+1,0,0,z
l,1,nmax+1
adrag,ldanyuan,,,,,,nmax1+1
arsym,x,1,8,1,,0,0
agen,4,1,16,1,2*l*x,,,,0,0
nummrg,kp
rectng,-l*x,7*l*x,0,4*l+4*l*y
wpoffs,,,z
rectng,-l*x,7*l*x,0,4*l+4*l*y
wpoffs,,,-z
arsym,z,all
aovlap,all
asel,s,loc,z,z,z
asel,a,loc,z,0,0
asel,a,loc,z,-z,-z
mat,1
real,1
esize,0.002
amesh,all
asel,a,loc,y,0,l*y
*do,i,1,3
asel,a,loc,y,i*h+i*l*y,i*h+(i+1)*l*y
*enddo
asel,inve
mat,2
real,2
esize,0.002
amesh,all
asel,s,loc,z,z,z
asel,a,loc,z,0,0
asel,a,loc,z,-z,-z
asel,a,loc,x,-l*x,-l*x
*do,i,1,8
asel,a,loc,x,(i-1)*l*x,(i-1)*l*x
*enddo
asel,inve
mat,3
real,3
esize,0.002
amesh,all
finish
/sol
antype,0
nlgeom,on
nropt,full,,
cnvtol,u,,0.05,,,
autots,1
neqit,70
nsubst,2000,3000,
nsel,s,loc,z,0.03
d,all,,0,,,,all,,,,,
allsel
nsel,s,loc,z,-0.03
cp,1,uz,all
allsel
nsel,s,loc,z,0.03
cp,2,uz,all
allsel
nsel,s,loc,z,-0.03
d,all,,0.005,,,,uz,,,,,
allsel
kbc,0
outres,erase
outres,all,all
eqslv,spar
lnsrch,auto
time,10
/status,solu
solve
save
finish
变形图如下：

应力等值分布如下：