*HEADING
 DYNAMIC LOADING OF AN ELASTOMERIC, VISCOELASTIC 
 FOAM BLOCK
**************************************************
** Step 1: Apply a gravity load on the point mass 
   of the punch in a visco step and let the foam 
   relax fully.
** Step 2: Apply a sinusoidal half-wave force on 
   the punch and measure the displacement, velocity
   and acceleration response in a dynamic step.
** Step 3: After removing the force, continue 
   measuring the dynamic response.
** (Units: N, mm, sec)
**************************************************
*PREPRINT,MODEL=YES,HISTORY=NO
*RESTART,WRITE
*NODE
  1,    0., 300.
 19,    0.,   0.
 481, 300., 300.
 499, 300.,   0.
 601, 600., 300.
 619, 600.,   0.
*NSET,NSET=N1
 1, 
*NSET,NSET=N19
 19, 
*NSET,NSET=N481
 481, 
*NSET,NSET=N499
 499, 
*NFILL,NSET=TOP,BIAS=.85
 N1,N481,12,40
*NGEN,NSET=TOP
 481,601,40
*NFILL,NSET=BOT,BIAS=.85
 N19,N499,12,40
*NGEN,NSET=BOT
 499,619,40
*NFILL,NSET=ALLN,BIAS=.9
 TOP,BOT,9,2
*NSET,NSET=CENTER,GENERATE
 1,19
*ELEMENT,TYPE=CAX4
 1,3,43,41,1
*ELGEN,ELSET=FOAM
 1,15,40,10,9,2,1
*ELSET,ELSET=CENT,GENERATE
 1,141,10
 61,69
*ELSET,ELSET=ETOP,GENERATE
 1,101,10
*ELSET,ELSET=UPPER,GEN
 1,141,10
*NODE,NSET=PUNCH
 1000,0.,500.
*ELEMENT,TYPE=MASS,ELSET=PMASS
 1001,1000
*MASS,ELSET=PMASS
 0.2, 
*SOLID SECTION,ELSET=FOAM,MATERIAL=FOAM,
ORIENTATION=RECT
*ORIENTATION,NAME=RECT,SYSTEM=RECTANGULAR
 1.,0.,0., 0.,1.,0.
 3,0.
******************************************
*MATERIAL,NAME=FOAM
*HYPERFOAM,N=2,TEST DATA INPUT,POISSON=0.0,
MODULI=INSTANTANEOUS
*UNIAXIAL TEST DATA
 -.0217,   -.05
 -.0317,   -.10
 -.0367,   -.15
 -.0402,   -.20                              
 -.0433,   -.25
 -.0467,   -.30
 -.0504,   -.35
 -.0542,   -.40
 -.0604,   -.45
 -.0668,   -.50
 -.0759,   -.55
 -.0909,   -.60
 -.1083,   -.65
 -.1410,   -.70
 -.1933,   -.75
 -.2896,   -.80
*SIMPLE SHEAR TEST DATA      
  .0140, .08, .0046
  .0334, .16, .0166
  .0533, .24, .0366
  .0853, .32, .0573
  .1280, .40, .0817
  .1653, .48, .1098
  .2080, .56, .1394
  .2560, .64, .1666
  .2987, .72, .1904
*VISCOELASTIC,TIME=RELAXATION TEST DATA
*SHEAR TEST DATA,SHRINF=0.5000
 1.0000, 0.0001
 0.9695, 0.001
 0.9417, 0.002
 0.8722, 0.005
 0.7913, 0.010
 0.7043, 0.020
 0.6233, 0.050
 0.5736, 0.100
 0.5271, 0.200
 0.5013, 0.500
 0.5000, 1.000
*DENSITY
 1.E-11, 
*********************************************
*BOUNDARY
 BOT,1,2     
 CENTER,1
 1000,1
 1000,6
*********************************************
*SURFACE,TYPE=SEGMENTS,NAME=IMPACTOR
 START,141.42,641.42
 CIRCL,-1.,300.,0.,500.
*SURFACE,TYPE=ELEMENT,NAME=TARGET
 ETOP,S3
*RIGID BODY,REF NODE=1000,
ANALYTICAL SURFACE=IMPACTOR
*CONTACT PAIR,INTERACTION=ROUGH
 TARGET,IMPACTOR
*SURFACE INTERACTION,NAME=ROUGH
*FRICTION
 0.8,
*********************************************
*AMPLITUDE,NAME=RAMP,VALUE=RELATIVE
** Ramp to full load in 2 sec
 0.,0., 2.,1., 10.,1.
*AMPLITUDE,NAME=SINE,DEFINITION=PERIODIC,
VALUE=ABSOLUTE
** Force amplitude=5000 N of a half-sine wave
** for a 1 sec period
 1,3.1416,0.,0.
 0.,-5000.
*********************************************
*STEP,NLGEOM,INC=100,UNSYMM=YES
 Apply gravity force.
*VISCO,CETOL=0.01
.01,5.
*DLOAD,AMPLITUDE=RAMP
 PMASS,GRAV,9810.,0.,-1.,0.
*OUTPUT,FIELD,FREQUENCY=10
*CONTACT OUTPUT,SLAVE=TARGET,MASTER=IMPACTOR,
VARIABLE=PRESELECT
*NODE OUTPUT
 U,V,A,RF
*ELEMENT OUTPUT,ELSET=FOAM
 S,LE
*OUTPUT,HISTORY,FREQUENCY=1
*NODE OUTPUT,NSET=PUNCH
 U,V,A,RF
*ELEMENT OUTPUT,ELSET=CENT
 MISES,LE22,S22
*PRINT,CONTACT=YES
*ENERGY PRINT,FREQUENCY=5
*ENERGY PRINT,ELSET=FOAM,FREQ=5
*ENERGY PRINT,ELSET=CENT,FREQ=5
*CONTACT PRINT,SLAVE=TARGET
**CONTACT FILE,SLAVE=TARGET,FREQUENCY=10
*EL PRINT,FREQUENCY=20,ELSET=CENT                                          
 S, 
 SINV, 
 LE, 
 EE, 
 CE, 
 LOADS, 
*NODE PRINT,FREQUENCY=20
 U, 
 CF,RF
*END STEP
********************************************
*STEP,NLGEOM,INC=200,UNSYMM=YES
 Apply dynamic load.
*DYNAMIC,HAFTOL=4000. 
 .01,1.
*DLOAD
 PMASS,GRAV,9810.,0.,-1.,0.
*CLOAD,AMPLITUDE=SINE
 1000,2
*END STEP
********************************************
*STEP,NLGEOM,INC=300,UNSYMM=YES
 Remove load.
*DYNAMIC,HAFTOL=4000.,INITIAL=NO
 .01,10.
*DLOAD
 PMASS,GRAV,9810.,0.,-1.,0.
*CLOAD,OP=NEW
*END STEP