*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
1000,1,2
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,TYPE=SURFACE
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,Convert Sdi=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,SECONDARY=TARGET,MAIN=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,SECONDARY=TARGET
**CONTACT FILE,SECONDARY=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=1000,UNSYMM=YES,Convert Sdi=YES
Apply dynamic load.
*DYNAMIC,HAFTOL=4000.,APPLICATION=QUASI
.01,1.
*CLOAD,AMPLITUDE=SINE
1000,2
*BOUNDARY, OP=NEW
BOT,1,2
CENTER,1
1000,1
1000,6
*END STEP
********************************************
*STEP,NLGEOM,INC=1000,UNSYMM=YES,Convert Sdi=YES
Remove load.
*DYNAMIC,HAFTOL=4000.,APPLICATION=QUASI
.01,10.,,0.1
*CLOAD,OP=NEW
*END STEP