*HEADING
Acoustic test - 1D Problem, Transient; A 4m long tube; from left to right,
a sound source, 3m is air, then 1m of a highly absorbent material, followed
by a rigid termination. [AC3D8R]
*PREPRINT,ECHO=NO,HISTORY=NO,MODEL=NO
**
***********************************************************
****To test different frequencies change the value here
*Parameter
f=100.0
T=1.0/f
omega=2*3.14159*f
*******************************
**
**   Mesh Generation
**
*NODE, Nset=ODB_NSET
    1, 0, 0,  0
  401, 4, 0,  0
  501, 0, 0, -2e-2
  901, 4, 0, -2e-2
 1001, 0, 2e-2,  0
 1401, 4, 2e-2,  0
 1501, 0, 2e-2, -2e-2
 1901, 4, 2e-2, -2e-2
*NGEN,NSET=ALL
    1,401
  501,901
 1001,1401
 1501,1901
*NSET,NSET=SAMPLE,GENERATE
 1,401
*NSET,NSET=LOAD
 1,1001,1501,501
*ELEMENT,TYPE=AC3D8R
 1,1,2,502,501,1001,1002,1502,1501
*ELGEN,ELSET=CHANNEL
 1,300
*ELEMENT,TYPE=AC3D8R
  301,301,302,802,801,1301,1302,1802,1801
*ELGEN,ELSET=ABSORB
  301,100
**
*NSET, NSET=INTERFACE
1301,1800,1801,301,302,801
*NSET, NSET=ODB_NSET
ODB_NSET, INTERFACE
*NSET, NSET=QA_TEST
ODB_NSET
**
************************************************
**    ** ELEMENT PROPERTIES **
**
*SOLID SECTION,MATERIAL=AIR,ELSET=CHANNEL
*SOLID SECTION,MATERIAL=ABSORB,ELSET=ABSORB
**
**
*MATERIAL,NAME=AIR
*DENSITY
 1.21,
*ACOUSTIC MEDIUM,BULK MODULUS
 0.1424E6,
**
**
*MATERIAL,NAME=ABSORB
*DENSITY
 1.21,
*ACOUSTIC MEDIUM,BULK MODULUS
 0.1424E6,
*ACOUSTIC MEDIUM,VOLUMETRIC DRAG
 1e4,
**
*AMPLITUDE,NAME=SINE,DEF=PERIODIC
1,<omega>,0.0,0.0
-1.0,0,0,0
*STEP
*DYNAMIC,EXPLICIT
,<T>
**
** Prescribe outward acceleration of 1e-2 at node LOAD.
*CLOAD,AMP=SINE
 LOAD,8,-1E-2
**
*OUTPUT,FIELD,NUM=1
*NODE OUTPUT
POR,
*NODE OUTPUT,NSET=QA_TEST
POR,
***OUTPUT,HISTORY,FREQ=10
***NODE OUTPUT,NSET=ODB_NSET
** POR,
*ENDSTEP