*HEADING
LATERAL BUCKLING: B31OS, *BEAM SECTION, SECTION=ARBITRARY
*NODE
*ELEMENT,TYPE=B31OS
*ELGEN,ELSET=BEAM
*BEAM SECTION,SECTION=ARBITRARY,ELSET=BEAM,MATERIAL=MAT
 5, -0.15,-0.3315, 0.15, -0.3315, 0.027
     0.0, -0.3315, 0.0
     0.0, 0.3315,0.0145
     0.15,0.3315,0.0
     -0.15,0.3315,0.027
 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  ,
*NODE FILE
U,
*EL FILE,FREQUENCY=25
S,E
SF,
*END STEP