*HEADING
 Single element model to test fit of hyperelastic test data
*NODE,NSET=ALL
1,
2,1.
3,1.,1.,
4,0.,1.,
5,0.,0.,1.
6,1.,0.,1.
7,1.,1.,1.
8,0.,1.,1.
*NSET,NSET=FACE1
1,2,3,4
*NSET,NSET=FACE2
5,6,7,8
*NSET,NSET=FACE3
1,2,5,6
*NSET,NSET=FACE4
2, 
*NSET,NSET=FACE42
3,6,7
*NSET,NSET=FACE5
3,4,7,8
*NSET,NSET=FACE6
4,1,8,5
*EQUATION
**
** Since the S11 output is Cauchy or true stress, we need to
** determine the nominal stress for post-processing.
** Nodes 3,6,7 are tied to node 2 in dof 1 so that:
** Nominal stress (dof 1) = RF1 (@ node 2) / Original area
** (w/c is 1 x 1 = 1)
2, 
FACE42,1,1, 2,1,-1
*ELEMENT,TYPE=C3D8RH,ELSET=ONE
1,1,2,3,4,5,6,7,8
*SOLID SECTION,ELSET=ONE,MATERIAL=TREL
*MATERIAL,NAME=TREL
**
** To use the OGDEN model, simply replace the POLYNOMIAL
** parameter with the OGDEN parameter.
** To change the strain energy function order, change the N
** parameter.
**
*HYPERELASTIC,N=1,POLYNOMIAL,TEST DATA INPUT
*UNIAXIAL TEST DATA
 0.054E6,  0.038
 0.152E6,  0.1338
 0.254E6,  0.221
 0.362E6,  0.345
 0.459E6,  0.46
 0.583E6,  0.6242
 0.656E6,  0.851
 0.73E6,  1.4268
*BIAXIAL TEST DATA
 0.089E6,  0.0200
 0.255E6,  0.1400
 0.503E6,  0.4200
 0.958E6,  1.4900
 1.703E6,  2.7500
 2.413E6,  3.4500
*PLANAR TEST DATA
 0.055E6,  0.0690
 0.324E6,  0.2828
 0.758E6,  1.3862
 1.269E6,  3.0345
 1.779E6,  4.0621
**
** In every step the step time and magnitude of displacement are
** equal so that history plots of RF at node 2 actually
** correspond to nominal strain vs nominal stress.
**
*STEP,NLGEOM,INC=50000
Step 1: Uniaxial Tension
*STATIC,DIRECT
.02, 1.8
*BOUNDARY,OP=NEW
FACE1,3
FACE3,2
FACE6,1
FACE4,1,1, 1.8
*ENERGY PRINT
*EL PRINT,FREQUENCY=500
S, 
E, 
*NODE PRINT,FREQUENCY=500
U,RF
*OUTPUT,FIELD, OP=ADD,FREQUENCY=1
*NODE OUTPUT
U
*OUTPUT,HISTORY,OP=ADD,FREQUENCY=1
*NODE OUTPUT, NSET=ALL
U,RF1,RF2
*END STEP
**
**
*STEP,NLGEOM,INC=20
Step 2: Unload
*STATIC,DIRECT
.1, 1.8
*BOUNDARY,OP=MOD
FACE4,1
*OUTPUT,FIELD, OP=NEW,FREQUENCY=0
*OUTPUT,HISTORY,OP=NEW,FREQUENCY=0
*END STEP
**
**
*STEP,NLGEOM,INC=500
Step 3: Biaxial Tension
*STATIC,DIRECT
.02, 1.7
*BOUNDARY,OP=NEW
FACE1,3
FACE3,2
FACE6,1
FACE4,1,1, 1.7
FACE5,2,2, 1.7
*ENERGY PRINT
*EL PRINT,FREQUENCY=500
S, 
E, 
*NODE PRINT,FREQUENCY=500
U,RF
*OUTPUT,FIELD, OP=ADD,FREQUENCY=1
*NODE OUTPUT
U
*OUTPUT,HISTORY,OP=ADD,FREQUENCY=1
*NODE OUTPUT, NSET=ALL
U,RF1,RF2
*END STEP
*STEP,NLGEOM,INC=20
Step 4: Unload
*STATIC,DIRECT
.1, 1.7
*BOUNDARY,OP=MOD
FACE4,1,1,
FACE5,2,2, 
*OUTPUT,FIELD, OP=NEW,FREQUENCY=0
*OUTPUT,HISTORY,OP=NEW,FREQUENCY=0
*END STEP
*STEP,NLGEOM,INC=500
Step 5: Planar Tension (Pure Shear)
*STATIC,DIRECT
.02, 1.8
*BOUNDARY,OP=NEW
FACE1,3
FACE3,2
FACE5,2 
FACE6,1
FACE4,1,1, 1.8
*ENERGY PRINT
*EL PRINT,FREQUENCY=500
S, 
E, 
*NODE PRINT,FREQUENCY=500
U,RF
*OUTPUT,FIELD, OP=ADD,FREQUENCY=1
*NODE OUTPUT
U
*OUTPUT,HISTORY,OP=ADD,FREQUENCY=1
*NODE OUTPUT, NSET=ALL
U,RF1,RF2
*END STEP