*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
*NSET,NSET=N1
*NSET,NSET=N19
*NSET,NSET=N481
*NSET,NSET=N499
*NFILL,NSET=TOP,BIAS=.85
N1,N481,12,40
*NGEN,NSET=TOP
*NFILL,NSET=BOT,BIAS=.85
N19,N499,12,40
*NGEN,NSET=BOT
*NFILL,NSET=ALLN,BIAS=.9
TOP,BOT,9,2
*NSET,NSET=CENTER,GENERATE
*ELEMENT,TYPE=CAX4
*ELGEN,ELSET=FOAM
*ELSET,ELSET=CENT,GENERATE
*ELSET,ELSET=ETOP,GENERATE
*ELSET,ELSET=UPPER,GEN
*NODE,NSET=PUNCH
*ELEMENT,TYPE=MASS,ELSET=PMASS
*MASS,ELSET=PMASS
0.2,
*SOLID SECTION,ELSET=FOAM,MATERIAL=FOAM,
ORIENTATION=RECT
*ORIENTATION,NAME=RECT,SYSTEM=RECTANGULAR
******************************************
*MATERIAL,NAME=FOAM
*HYPERFOAM,N=2,TEST DATA INPUT,POISSON=0.0,
MODULI=INSTANTANEOUS
*UNIAXIAL TEST DATA
*SIMPLE SHEAR TEST DATA
*VISCOELASTIC,TIME=RELAXATION TEST DATA
*SHEAR TEST DATA,SHRINF=0.5000
*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,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=1000,UNSYMM=YES,Convert Sdi=YES
Apply dynamic load.
*DYNAMIC,HAFTOL=4000.,APPLICATION=TRANSIENT FIDELITY
.01,1.
*DLOAD
PMASS,GRAV,9810.,0.,-1.,0.
*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.,INITIAL=NO,APPLICATION=TRANSIENT FIDELITY
.01,10.
*DLOAD
PMASS,GRAV,9810.,0.,-1.,0.
*CLOAD,OP=NEW
*END STEP