*HEADING
 - ARRUDA-BOYCE HYPER-VISCOELASTICITY, VISCO ,LINEAR PERT. STEPS, CPE4H
*NODE
1,
2,10.
3,10.,5.,
4,0.,5.,
*ELEMENT,TYPE=CPE4H,ELSET=ONE
1,1,2,3,4
*SOLID SECTION,ELSET=ONE,MATERIAL=ARRUDA
1., 
*MATERIAL,NAME=ARRUDA
*HYPERELASTIC,ARRUDA-BOYCE,MODULI=INSTANTANEOUS
20., 7.
*VISCOELASTIC,TIME=PRONY
0.5,0.,3.
*AMPLITUDE,NAME=STEP
0.,1.,10.,1.
*BOUNDARY
1,1,2
2,2,2
4,1,1
*STEP,PERT
** Step 1: Initial linear perturbation
*STATIC
*BOUNDARY
1,1,2
2,2,2
4,1,1
3,1,1,.1
2,1,1,.1
*EL PRINT
S,E
*END STEP
*STEP,NLGEOM
** Step 2: Apply instantaneous uniaxial tensile stretch and allow to relax
*VISCO
2.,6.
*BOUNDARY,AMP=STEP
3,1,1,2.
2,1,1,2.
*EL PRINT,F=10
S,E
EE, 
CE, 
*END STEP
*STEP,PERT
** Step 3: Intermediate linear perturbation
*STATIC
*BOUNDARY
1,1,2
2,2,2
4,1,1
3,1,1,.1
2,1,1,.1
*EL PRINT
S,E
*END STEP
*STEP,NLGEOM
** Step 4: Continue stress relaxation
*VISCO 
2.,4.
*END STEP
*STEP,PERT
*STATIC
** Step 5: Multiple load cases
*LOAD CASE,name = "uniaxial tension-1"
*BOUNDARY
1,1,2
2,2,2
4,1,1
3,1,1,.1
2,1,1,.1
*END LOAD CASE
*LOAD CASE,name = "uniaxial tension-2"
*BOUNDARY
1,1,2
2,2,2
4,1,1
3,1,1,.2
2,1,1,.2
*END LOAD CASE
*LOAD CASE,name = "uniaxial tension-3"
*CLOAD
3,1,1000
2,1,1000
*END LOAD CASE
*EL PRINT
S,E
EE, 
*OUTPUT,FIELD
*NODE OUTPUT,VARIABLE=PRESELECT
*ELEMENT OUTPUT,VARIABLE=PRESELECT
*END STEP