*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=CAX4R
 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, TYPE=ANISOTROPIC
 0.2,  0.2,  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
 UPPER,S3
*RIGID BODY,REF NODE=1000,
ANALYTICAL SURFACE=IMPACTOR
********************************************
*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.
********************************************
*NSET,NSET=QA_TEST
ALLN,
*********************
*STEP
 Apply gravity force.
*DYNAMIC,EXPLICIT
 ,5.
*FIXED MASS SCALING, FACTOR=10
*CONTACT PAIR,INTERACTION=ROUGH
 TARGET,IMPACTOR
*SURFACE INTERACTION,NAME=ROUGH
*FRICTION
 0.8,
*DLOAD,AMPLITUDE=RAMP
 PMASS,GRAV,9810.,0.,-1.,0.
*OUTPUT,FIELD,NUMBER INTERVAL=10,
VARIABLE=PRESELECT
*OUTPUT,FIELD,NUMBER INTERVAL=10
*NODE OUTPUT
 U,V,A,RF
*ELEMENT OUTPUT,ELSET=FOAM
 S,LE
*OUTPUT,HISTORY,TIME INTERVAL=1.0,VARIABLE=PRESELECT
*************************
*OUTPUT,FIELD,NUM=1
*NODE OUTPUT,NSET=QA_TEST
U,
***********************
*OUTPUT,HISTORY,TIME INTERVAL=0.1E-04
*NODE OUTPUT,NSET=PUNCH
 U,V,A,RF
*ELEMENT OUTPUT,ELSET=CENT
 MISES,LE22,S22
*END STEP
*********************************************
*STEP
 Apply dynamic load.
*DYNAMIC,EXPLICIT
 ,1.
*FIXED MASS SCALING
*DLOAD
 PMASS,GRAV,9810.,0.,-1.,0.
*CLOAD,AMPLITUDE=SINE
 1000,2
*END STEP
*********************************************
*STEP
 Remove load.
*DYNAMIC,EXPLICIT
 ,10.
*DLOAD
 PMASS,GRAV,9810.,0.,-1.,0.
*CLOAD,OP=NEW
*END STEP