*HEADING
 SQUARE PLATE - ELASTIC BUCKLING  ( LOAD INCR ) - STRI3  4 X 4   
*NODE,NSET=N101
101,  ,  ,1.E-4
*NODE,NSET=N105
105,1.
*NODE
501,0.,1.
505,1.,1.
*NGEN,NSET=YSYM
101,105
*NGEN,NSET=XSYM
101,501,100
*NGEN,NSET=YEDG
501,505
*NGEN,NSET=XEDG
105,505,100
*NFILL
XSYM,XEDG,4,1
*ELEMENT,TYPE=STRI3,ELSET=ONE
1,101,102,202
17,101,202,201
*ELGEN,ELSET=EALL
1,4,1,1,4,100,4
17,4,1,1,4,100,4
*SHELL SECTION,MATERIAL=A1,ELSET=EALL
0.01,3
*MATERIAL,NAME=A1
*ELASTIC
1.E8,0.3
*BOUNDARY
YSYM,YSYMM
XSYM,XSYMM
YEDG,3
YEDG,5
XEDG,3
XEDG,4
XEDG,6
*STEP,NLGEOM,INC=20
*STATIC
 .1,1. , , .1
*CLOAD
105,1,-12.5
205,1,-25.
305,1,-25.
405,1,-25.
505,1,-12.5
*PRINT,RESIDUAL=NO
*EL PRINT,ELSET=ONE ,SUMMARY=NO,POSITION=CENTROID
S, 
*EL FILE,ELSET=ONE ,POSITION=CENTROID
S, 
*NODE PRINT,SUMMARY=NO
U,CF1
*NODE FILE,NSET=N101
U, 
*NODE FILE,NSET=N105
CF, 
*END STEP