*HEADING
 EIGENVALUE BUCKLING OF CYLINDER UNDER AXIAL LOAD (N=10,ALPHA=PI/20)  
*NODE
 10,  100.,0.,0.
 14,  98.768834,0.,15.6434465
 410, 100.,400.,0.
 414, 98.768834,400.,15.6434465
*NGEN,LINE=C,NSET=LOADB
 10,14,1, ,0.,0.,0.
*NGEN,LINE=C,NSET=BND3
 410,414,1, ,0.,400.,0.
*NGEN,NSET=BND1
 10,410,10
*NGEN,NSET=REST
 11,411,10
 12,412,10
 13,413,10
*NGEN,NSET=BND2
 14,414,10
*NSET,NSET=ALL
 BND1,BND2,BND3,REST
*NSET,NSET=LDB1
 10,14
*NSET,NSET=LDB2
 11,12,13
*****
*ELEMENT,TYPE=STRI3
 1, 10,20,11
 2, 20,21,11
*ELGEN,ELSET=EALL
 1, 4,1,2, 40,10,8
 2, 4,1,2, 40,10,8
*ELSET,ELSET=EPRINT
 1,2,3,4
*SHELL SECTION,ELSET=EALL,MATERIAL=MAT
 .25, 
*TRANSFORM,TYPE=C,NSET=ALL
 0.,0.,0., 0.,1.,0.
*MATERIAL,NAME=MAT
*ELASTIC
 30.E6,.3
*****
**
*AMPLITUDE, NAME=SHIFT, VALUE=RELATIVE
0.0, 15.0, 100.0, 15.0
**
*STEP
Pre-load to just below buckling load
*STATIC
*CLOAD,AMPLITUDE=SHIFT
 LDB1,3,1500.
 LDB2,3,3000.
*BOUNDARY
 BND1,YSYMM
 BND2,YSYMM
 BND3,ZSYMM
 LOADB,1,2
 LOADB,4
 LOADB,6
*EL PRINT,FREQUENCY=0
*NODE PRINT,FREQUENCY=0
*END STEP
**
*STEP
*BUCKLE
1, , 10,  40
*CLOAD
 LDB1,3,1500.
 LDB2,3,3000.
*BOUNDARY,LOAD CASE=2, OP=NEW
 BND1,YSYMM
 BND2,YASYMM
 BND3,ZASYMM
 LOADB,1,2
 LOADB,4
 LOADB,6
*NODE FILE
U, 
*END STEP