*HEADING
 RING BUCKLING ANALYSIS, C3D4, 4 X 10 MESH                 
*RESTART,WRITE
*NODE
1,99.5,,
801,100.5
 21,70.35712473,70.35712473
821,71.06423151,71.06423151
*NGEN,NSET=INNER,LINE=C
1,21,1
*NGEN,NSET=OUTER,LINE=C
801,821,1
*NFILL,NSET=ALL1
INNER,OUTER,8,100
*NODE
2001,99.5,,1.0
2801,100.5,,1.0
2021,70.35712473,70.35712473  ,1.0
2821,71.06423151,71.06423151,1.0
*NGEN,LINE=C,NSET=INNER2
2001,2021,1,0,0.,0.,1.
*NGEN,NSET=OUTER2,LINE=C
2801,2821,1,0,0.,0.,1.
*NFILL,NSET=ALL2
INNER2,OUTER2,8,100
*NFILL,NSET=ALL
ALL1,ALL2,2,1000
*NSET,NSET=SYM,GENERATE
1,801,100
1001,1801,100
2001,2801,100
*NSET,NSET=VARY
21,821,100
1021,1821,100
2021,2821,100
*ELEMENT,TYPE=C3D4
1, 1,2001,201,3
2, 201,2001,2201,2203
3,3,203,2203,201
4,3,2203,2003,2001
5,201,2001,2203,3
*ELGEN,ELSET=EALL
1,4,200,5,10,2,100
2,4,200,5,10,2,100
3,4,200,5,10,2,100
4,4,200,5,10,2,100
5,4,200,5,10,2,100
*ELSET,GENERATE,ELSET=LOAD1
17,2017,100
*ELSET,GENERATE,ELSET=LOAD2
18,2018,100
*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
LOAD1,P4,1.0
LOAD2,P3,1.0
*BOUNDARY,LOAD CASE=2, OP=NEW
ALL1,3
SYM,2
VARY,1
*NODE PRINT ,SUMMARY=NO
U,RF
*MODAL PRINT
*MODAL FILE
*OUTPUT,HISTORY,FREQUENCY=1
*MODAL OUTPUT
*END STEP