: NAFEMS BENCHMARK EXAMPLE 3DNLG-6
BUCKLING OF A FLAT PLATE WHEN SUBJECTED TO IN-PLANE SHEAR
*PREPRINT, MODEL=YES
*RESTART,WRITE,FREQ=999
**
*NODE, NSET=NALL
**
*ELEMENT, TYPE=SC8R, ELSET=ELALL
*ELGEN, ELSET=ELALL
**
*SHELL SECTION, ELSET=ELALL, MATERIAL=MAT
12.5,5
*MATERIAL, NAME=MAT
*ELASTIC, TYPE=ISO
6.4E+6, 0.3
**
*NSET,NSET=TOP
*NSET,NSET=BOT
*NSET,NSET=RIGHT
*NSET,NSET=LEFT
*NSET,NSET=CORNERS
*NSET,NSET=EDGE
CORNERS,TOP,BOT,RIGHT,LEFT
**
*NSET,NSET=NODECENTER
*NSET,NSET=EDGE,GENERATE
*ELSET, ELSET=ESIDE1, GENERATE
*ELSET, ELSET=ESIDE2, GENERATE
*ELSET, ELSET=ESIDE3, GENERATE
*ELSET, ELSET=ESIDE4, GENERATE
*SURFACE, NAME=EDGE1
 ESIDE1, S3
*SURFACE, NAME=EDGE2
 ESIDE2, S4
*SURFACE, NAME=EDGE3
 ESIDE3, S5
*SURFACE, NAME=EDGE4
 ESIDE4, S6
*STEP, INC=1000, NLGEOM
*STATIC,RIKS
         0.01,      1.,   1.E-5,      0.01, 1
*BOUNDARY, OP=NEW
 EDGE, 3,3, 0.
 NODECENTER, 1,2, 0.
*DSLOAD, FOLLOWER=NO, CONSTANT RESULTANT=YES
 EDGE1,TRVEC,16960.,-1., 0., 0.
 EDGE2,TRVEC,16960., 0., 1., 0.
 EDGE3,TRVEC,16960., 1., 0., 0.
 EDGE4,TRVEC,16960., 0.,-1., 0.
*OUTPUT,FIELD,FREQ=999
*NODE OUTPUT
 U,
*OUTPUT,HISTORY,FREQ=1
*NODE OUTPUT,NSET=NODECENTER
 U,
*NODE PRINT,FREQ=999,NSET=NODECENTER
 U3,
*NODE FILE, FREQ=1,NSET=NODECENTER
 U,
*EL PRINT,FREQ=0
*END STEP