*HEADING
ACOUSTIC/STRUCTURAL ANALYSIS VERIFICATION
FULLY COUPLED CASE
*RESTART,WRITE,FREQUENCY=999
*NODE,NSET=ALLN
*ELEMENT,TYPE=AC1D2,ELSET=FLUID
*ELEMENT,TYPE=MASS,ELSET=MASS
*ELEMENT,TYPE=SPRING1,ELSET=SPRING
*ELEMENT,TYPE=DASHPOT1,ELSET=DASHPOT
*ELEMENT,TYPE=ASI1,ELSET=INTER
*SOLID SECTION,MATERIAL=FLUID,ELSET=FLUID
*MATERIAL,NAME=FLUID
*DENSITY
0.4008,
*ACOUSTIC MEDIUM,BULK MODULUS
*ACOUSTIC MEDIUM,VOLUMETRIC DRAG
*MASS,ELSET=MASS
4.,
*SPRING,ELSET=SPRING
1,
1.0,
*DASHPOT,ELSET=DASHPOT
1,
0.08,
*INTERFACE,ELSET=INTER
*IMPEDANCE PROPERTY,NAME=RAS
*BOUNDARY
10, 8,
20, 2, 3
*STEP
*FREQUENCY, eigensolver=lanczos
2, ,
*MODAL FILE
*END STEP
*STEP
*STEADY STATE DYNAMICS,SUBSPACE PROJECTION,INTERVAL=RANGE, FREQUENCY SCALE=LINEAR
0.,.3,31,0.
*IMPEDANCE
1,I2,RAS
*CLOAD
20,1,1.0
*NODE PRINT,SUMMARY=NO
U1,POR,PU1,PPOR
*EL PRINT,FREQUENCY=999,ELSET=SPRING
S,E
*NODE FILE
U,POR,PU,PPOR
*OUTPUT,FIELD,OP=NEW
*NODE OUTPUT
U,POR,
*OUTPUT,HISTORY,OP=NEW
*NODE OUTPUT,NSET=ALLN
U,POR,
*END STEP
*STEP
*STEADY STATE DYNAMICS, DIRECT,FREQUENCY SCALE=LINEAR
0.,.3,31,0.
*IMPEDANCE
1,I2,RAS
*CLOAD
20,1,1.0
*END STEP
*STEP
*FREQUENCY, eigensolver=lanczos, acoustic coupling=off
2, ,
*MODAL FILE
*END STEP
*STEP
*STEADY STATE DYNAMICS,SUBSPACE PROJECTION,INTERVAL=RANGE, FREQUENCY SCALE=LINEAR
0.,.3,31,0.
*IMPEDANCE
1,I2,RAS
*CLOAD
20,1,1.0
*NODE PRINT,SUMMARY=NO
U1,POR,PU1,PPOR
*EL PRINT,FREQUENCY=999,ELSET=SPRING
S,E
*NODE FILE
U,POR,PU,PPOR
*OUTPUT,FIELD,OP=NEW
*NODE OUTPUT
U,POR,
*OUTPUT,HISTORY,OP=NEW
*NODE OUTPUT,NSET=ALLN
U,POR,
*END STEP