*HEADING                                                                      
LATERAL BUCKLING: B31OS, *BEAM SECTION, SECTION=I   
*NODE
    1, 0.0000E+00, 0.0000E+00, 0.0, 0.0000E+00, 0.0000E+00,-1.0
    2, 6.0000E-01,-2.4222E-04, 0.0, 9.1382E-08, 4.5345E-04,-1.0
    3, 1.2000E+00,-4.8288E-04, 0.0, 1.7867E-07, 8.9808E-04,-1.0
    4, 1.8000E+00,-7.1826E-04, 0.0, 2.5496E-07, 1.3247E-03,-1.0
    5, 2.4000E+00,-9.4284E-04, 0.0, 3.1164E-07, 1.7237E-03,-1.0
    6, 3.0000E+00,-1.1500E-03, 0.0, 3.4040E-07, 2.0850E-03,-1.0
    7, 3.6000E+00,-1.3324E-03, 0.0, 3.3503E-07, 2.3984E-03,-1.0
    8, 4.2000E+00,-1.4830E-03, 0.0, 2.9322E-07, 2.6543E-03,-1.0
    9, 4.8000E+00,-1.5957E-03, 0.0, 2.1761E-07, 2.8439E-03,-1.0
   10, 5.4000E+00,-1.6654E-03, 0.0, 1.1591E-07, 2.9606E-03,-1.0
   11, 6.0000E+00,-1.6889E-03, 0.0, 0.0000E+00, 3.0000E-03,-1.0
   12, 6.6000E+00,-1.6654E-03, 0.0,-1.1591E-07, 2.9606E-03,-1.0
   13, 7.2000E+00,-1.5957E-03, 0.0,-2.1761E-07, 2.8439E-03,-1.0
   14, 7.8000E+00,-1.4830E-03, 0.0,-2.9322E-07, 2.6543E-03,-1.0
   15, 8.4000E+00,-1.3324E-03, 0.0,-3.3503E-07, 2.3984E-03,-1.0
   16, 9.0000E+00,-1.1500E-03, 0.0,-3.4040E-07, 2.0850E-03,-1.0
   17, 9.6000E+00,-9.4284E-04, 0.0,-3.1164E-07, 1.7237E-03,-1.0
   18, 1.0200E+01,-7.1826E-04, 0.0,-2.5496E-07, 1.3247E-03,-1.0
   19, 1.0800E+01,-4.8288E-04, 0.0,-1.7867E-07, 8.9808E-04,-1.0
   20, 1.1400E+01,-2.4222E-04, 0.0,-9.1382E-08, 4.5345E-04,-1.0
   21, 1.2000E+01, 0.0000E+00, 0.0, 0.0000E+00, 0.0000E+00,-1.0
*ELEMENT,TYPE=B31OS
 1,1,2
*ELGEN,ELSET=BEAM
 1,20,1,1
*BEAM SECTION,SECTION=I,ELSET=BEAM,MATERIAL=MAT
 0.345,0.69, 0.3,0.3, 0.027,0.027, 0.0145
 0.0,-1.0,0.0
*MATERIAL,NAME=MAT
*ELASTIC
 2.1E11,0.3125
*BOUNDARY
 1,1,4
 21,2,4
*STEP,NLGEOM,INC=50
*STATIC,RIKS
 .025, 1., 1.E-4, , ,11,3,-0.3
*DLOAD
BEAM, PZ, -100000.,
*MONITOR,NODE=11,DOF=3
*EL PRINT,FREQUENCY=20
*NODE PRINT,FREQUENCY=5
COORD, 
U, 
RF  , 
*NSET,NSET=NOUT,GENERATE
2,20
*NODE FILE,NSET=NOUT
U, 
*EL FILE,FREQUENCY=25
S,E
SF, 
*CONTROLS,PARAMETERS=FIELD

,0.0,
*OUTPUT,FIELD,OP=ADD
*NODE OUTPUT
WARP,RWM
*END STEP