*HEADING
 RING BUCKLING ANALYSIS, CSS8, 4 X 10 MESH                 
*NODE
1,99.5,,
801,100.5
 21,70.35712473,70.35712473
821,71.06423151,71.06423151
*NGEN,NSET=SYM1
1,801,100
*NGEN,NSET=VARY1
21,821,100
*NGEN,NSET=INNER,LINE=C
1,21,1
*NGEN,NSET=OUTER,LINE=C
801,821,1
*NFILL,NSET=ALL1
INNER,OUTER,8,100
*NODE
1001,99.5,,1.0
1801,100.5,,1.0
1021,70.35712473,70.35712473  ,1.0
1821,71.06423151,71.06423151,1.0
*NGEN,NSET=SYM2
1001,1801,100
*NGEN,NSET=VARY2
1021,1821,100
*NGEN,LINE=C,NSET=INNER2
1001,1021,1,0,0.,0.,1.
*NGEN,NSET=OUTER2,LINE=C
1801,1821,1,0,0.,0.,1.
*NFILL,NSET=ALL2
INNER2,OUTER2,8,100
*NSET,NSET=SYM
SYM1,SYM2
*NSET,NSET=VARY
VARY1,VARY2
*NSET,NSET=ALL
ALL1,ALL2
*ELEMENT,TYPE=CSS8
 1, 1,3,1003,1001,201,203,1203,1201
*ELGEN,ELSET=EALL
1,4,200,1,10,2,100
*ELSET,GENERATE,ELSET=LOAD
4,2004,100
*MATERIAL ,NAME=A1
*ELASTIC
30.0E6,0.0
*SOLID SECTION,MATERIAL=A1,ELSET=EALL
1.0, 
*TRANSFORM, NSET=VARY
1,1,0,-1,1,0.
*BOUNDARY
ALL1,3
SYM,2
VARY,2
*STEP
*BUCKLE
1,
*DLOAD
LOAD,P2,1.0
*BOUNDARY,LOAD CASE=2, OP=NEW
ALL1,3
SYM,2
VARY,1
*NODE PRINT ,SUMMARY=NO
U,RF
*output,field
*node output
 u
*MODAL PRINT
*MODAL FILE
*OUTPUT,HISTORY,FREQUENCY=1
*MODAL OUTPUT
*END STEP