*HEADING
 Acoustic test - 1D Problem, SS-DIRECT.
 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. 
*PREPRINT,ECHO=NO,HISTORY=NO,MODEL=NO
*RESTART,WRITE
***********************************************************
**
**
**   Mesh Generation
**
*NODE, Nset=ODB_NSET
    1,0,
  401,4,
*NGEN,NSET=ALL
   1,401
*NSET,NSET=QA_TEST,GENERATE
 1,401,10
*NSET,NSET=LOAD
 1,
*ELEMENT,TYPE=AC1D3
 1,1,2,3
*ELGEN,ELSET=CHANNEL
 1,150,2
*ELEMENT,TYPE=AC1D3
  151,301,302,303
*ELGEN,ELSET=ABSORB
  151,50,2
**
**
************************************************
**    ** 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,
**
**
**
*************************************************
**
*Elset,Elset=ODB_ESET
CHANNEL, ABSORB
**
**
*Nset, Nset=ODB_NSET
ODB_NSET, ALL, QA_TEST
**
**
*STEP
*STEADY STATE DYNAMICS,DIRECT,FREQUENCY SCALE=LINEAR
 100,1100,3,1
**
** Prescribe outward volume acceleration of 100 at node LOAD
*CLOAD
 LOAD,8, -1e2
**
*NODE PRINT, NSET=QA_TEST
 POR,PPOR,
*EL PRINT,FREQUENCY=0
*ENERGYPRINT
*OUTPUT,FIELD
*NODE OUTPUT,NSET=QA_TEST
 POR,
*ELEMENT OUTPUT
ACV,INTEN,GRADP,ENER,ELEN,ELEDEN
*OUTPUT,HISTORY
*NODE OUTPUT,NSET=QA_TEST
 POR,
*ENERGY OUTPUT
ALLSE,ALLKE,ALLWK,ALLVD
*ENDSTEP
**
**
*STEP
*FREQUENCY,NORM=MASS,EIGENSOLVER=LANCZOS, SIM=NO
50,,,50
*NODE PRINT,F=0
*EL PRINT,F=0
*OUTPUT,FIELD,Frequency=0
*END STEP
**
**
*STEP
*STEADY STATE DYNAMICS,SUBSPACE PROJECTION,FREQUENCY SCALE=LINEAR,INTERVAL=RANGE
 100,1100,3,1
**
** Prescribe outward volume acceleration of 100 at node LOAD
*SELECT EIGENMODES,GENERATE
1,45
*CLOAD
 LOAD,8, -1e2
**
*NODE PRINT, NSET=QA_TEST
 POR,PPOR,
*EL PRINT,FREQUENCY=0
*energyprint
*OUTPUT,FIELD,VARIABLE=PRESELECT,OP=ADD,FREQUENCY=9999
*OUTPUT,FIELD, OP=ADD
*NODE OUTPUT,NSET=QA_TEST
 POR,
*ELEMENT OUTPUT,ELSET=ABSORB
ACV,INTEN,GRADP
*OUTPUT,HISTORY
*NODE OUTPUT,NSET=QA_TEST
 POR,
*ENERGY OUTPUT
ALLSE,ALLKE,ALLWK,ALLVD
*ENDSTEP