*HEADING
 YEOH MODEL WITH MULLINS EFFECT
*RESTART,WRITE,FREQUENCY=5
*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
*HYPERELASTIC, YEOH
1.326,-0.326,0.1319,7.25E-4,0.0,0.0
*MULLINS EFFECT
1.1,100.
*STEP,NLGEOM,INC=20
Step 1: Hydrostatic Tension
*STATIC,DIRECT
0.1, 1
*BOUNDARY,OP=NEW
FACE1,3
FACE3,2
FACE6,1
FACE4,1,1,2.
FACE5,2,2,2.
FACE2,3,3,2.
*EL PRINT,FREQUENCY=1
SINV
**NE
*NODE PRINT,FREQUENCY=1
U,RF
*OUTPUT,FIELD, FREQUENCY=1
*ELEMENT OUTPUT
S,
E,
*OUTPUT,HISTORY,FREQUENCY=1
*NODE OUTPUT, NSET=ALL
U,RF
*END STEP
*STEP,NLGEOM,INC=20
Step 2: Unload
*STATIC,DIRECT
0.1,1
*BOUNDARY,OP=NEW
FACE1,3
FACE3,2
FACE6,1
FACE4,1,1,0.0
FACE5,2,2,0.0
FACE2,3,3,0.0
*END STEP
*STEP,NLGEOM,INC=20
Step 3: Reload
*STATIC,DIRECT
0.1,1
*BOUNDARY,OP=NEW
FACE1,3
FACE3,2
FACE6,1
FACE4,1,1,3.
*END STEP
*STEP,PERTURBATION
*STATIC
*BOUNDARY,OP=NEW
FACE1,3
FACE3,2
FACE6,1
FACE4,1,1,0.1
*OUTPUT,FIELD, FREQUENCY=1
*ELEMENT OUTPUT
S,
E,
*OUTPUT,HISTORY,FREQUENCY=1
*NODE OUTPUT, NSET=ALL
U,RF
*END STEP
*STEP,NLGEOM,INC=20
Step 4: unload
*STATIC,DIRECT
0.1,1
*BOUNDARY,OP=NEW
FACE1,3
FACE3,2
FACE6,1
FACE4,1,1,0.0
*END STEP