*HEADING
  - INCOMPRESSIBLE HYPERELASTICITY (REDUCED POLYNOMIAL), PLANAR TENSION
*NODE,NSET=ALL
*ELEMENT,TYPE=CPS4R,ELSET=ONE
*NSET,NSET=SIDE1
*NSET,NSET=SIDE2
*NSET,NSET=SIDE3
*NSET,NSET=SIDE4
*SOLID SECTION,ELSET=ONE,MATERIAL=REDUCED
*MATERIAL,NAME=REDUCED
*HYPERELASTIC,REDUCED POLYNOMIAL, N=1
100.,
*STEP,NLGEOM,INC=20
PLANAR TENSION
*STATIC,DIRECT
1.,20.
*BOUNDARY,OP=NEW
SIDE1,2
SIDE3,2
SIDE4,1
SIDE2,1,1,5.
*EL PRINT,F=10
S,
E,
*NODE PRINT,F=10
U,RF
*EL FILE,F=10
S,E
*NODE FILE,F=10
U,RF
*END STEP