*HEADING
IMPEDANCE PROPERTY  [AC3D6]
***************************
*PARAMETER
f=100.0
T=5/f
omega=2*3.14159*f
***************************
*NODE, Nset=ODB_NSET
1, 
41,,10.
1001,1.
1041,1.,10.
2001,,,1.
2041,,10.,1.
3001,1.,,1.
3041,1.,10.,1.
*NGEN,NSET=ALL_NODES
1,41
1001,1041
2001,2041
3001,3041
*ELEMENT,TYPE=AC3D6,ELSET=ALL_ELEMENTS
1,1,3,2003,1001,1003,3003
2,1,2003,2001,1001,3003,3001
*ELGEN,ELSET=ALL_ELEMENTS
1,20,2,2
2,20,2,2
*ELSET,ELSET=LINER5
2, 
*MATERIAL,NAME=AIR
*DENSITY
1.293, 
*ACOUSTIC MEDIUM,BULK MODULUS
1.42176e5, 
*SOLID SECTION,MATERIAL=AIR,ELSET=ALL_ELEMENTS
*IMPEDANCE PROPERTY,NAME=IMPED
0.0,2.332317E-3
*NSET,NSET=RECRD,GEN
1,41
*NSET,NSET=DRIVEN_NODES
41,1041,2041,3041
**
*NSET, NSET=MID
23, 1023, 33, 1033, 13, 1013
*NSET, NSET=ODB_NSET
ODB_NSET, MID
*AMPLITUDE,NAME=SINE,DEF=PERIODIC
1,<omega>,0.0,0.0
0,1,0,0
*STEP
*DYNAMIC,EXPLICIT
,<T>
*BULK VISCOSITY
0.000,
*IMPEDANCE,prop=IMPED
LINER5,I5
*BOUNDARY, AMP=SINE
DRIVEN_NODES,8,,1.
*OUTPUT,FIELD,NUM=1
*NODE OUTPUT
POR,
*OUTPUT,HISTORY,FREQ=1
*NODE OUTPUT,NSET=ODB_NSET
 POR,
*ENDSTEP