*HEADING
Standard Acoustic 
*RESTART, WRITE
*PARAMETER
f=15
T1=0.005
omega=2*3.14159*f
*NODE, NSET=BACK_S
 1,  0.0, 0.0, 1.0
 3,  0.0, 0.0, 0.0
 7,  0.0, 1.0, 0.0
 5,  0.0, 1.0, 1.0
1010,0.0, 0.0, 0.5
1100,0.0, 1.0, 0.5
*NODE, NSET=FRONT_S
 2, 2.0, 0.0, 1.0
 4, 2.0, 0.0, 0.0
 8, 2.0, 1.0, 0.0
 6, 2.0, 1.0, 1.0
1030,2.0, 0.0, 0.5
1300,2.0, 1.0, 0.5
*NODE, NSET = CENTER_S
 101, 1.0, 0.0, 1.0
 102, 1.0, 0.0, 0.0
 103, 1.0, 1.0, 0.0
 104, 1.0, 1.0, 1.0
1020,1.0, 0.0, 0.5
1200,1.0, 1.0, 0.5
*NODE, NSET=BACK_F
 22, 2.0, 0.0, 1.0
 24, 2.0, 0.0, 0.0
 26, 2.0, 1.0, 1.0
 28, 2.0, 1.0, 0.0
1040,2.0, 0.0, 0.5
1400,2.0, 1.0, 0.5
*NODE, NSET=FRONT_F
 12, 3, 0.0, 1.0
 14, 3, 0.0, 0.0
 16, 3, 1.0, 1.0
 18, 3, 1.0, 0.0
1050,3.0, 0.0, 0.5
1500,3.0, 1.0, 0.5
*NODE
 99, 2.5, 0.5, 0.75
999, 2.5, 0.5, 0.25
*NSET, NSET=NODE2
FRONT_S,
*NSET, NSET=SOLID
FRONT_S,CENTER_S,BACK_S
*NSET, NSET=QA_TEST
NODE2
*NSET,NSET=ACOUS
BACK_F,FRONT_F
*ELEMENT, TYPE=C3D8R, ELSET=SOLID
1,1,1010,1100,5,101,1020,1200,104
2,1010,3,7,1100,1020,102,103,1200
3,101,1020,1200,104,2,1030,1300,6
4,1020,102,103,1200,1030,4,8,1300
*ELEMENT,TYPE=AC3D4, ELSET=FLUID 
 5,99, 12, 1050, 16
 6,99, 12, 1040, 1050
 7,99, 1040, 1500, 1050
 8,99, 16, 1050, 1500
 9,99, 1400, 1500, 1040
10,99, 16, 1500, 26
11,99, 26, 1500, 1400
12,99, 16, 26, 12
13,99, 12, 26, 22
14,99, 26, 1400, 22
15,99, 22, 1040, 12
16,99, 22, 1400, 1040
17, 999, 1050, 14, 1500
18, 999, 1050, 24, 14
19, 999, 24, 18, 14
20, 999, 1500, 14, 18
21, 999, 28, 18, 24
22, 999, 1500, 18, 1400
23, 999, 1400, 18, 28
24, 999, 1500, 1400, 1050
25, 999, 1050, 1400, 1040
26, 999, 1400, 28, 1040
27, 999, 1040, 24, 1050
28, 999, 1040, 28, 24
*SOLID SECTION, ELSET=SOLID, MATERIAL=ELAS
*MATERIAL, NAME=ELAS
*ELASTIC
207E9,0.3
*DENSITY
7800.0
*****
*SOLID SECTION, ELSET=FLUID, MATERIAL=FLUID
*MATERIAL, NAME=FLUID
*ACOUSTIC MEDIUM
2.25E9
*DENSITY
1000.0
**
*SURFACE,NAME=SOLID
3,S2
4,S2
*SURFACE,NAME=FLUID
14,S3
16,S3
26,S3
28,S3
*TIE,NAME=COUPLE
SOLID,FLUID
**
*BOUNDARY
BACK_S,1,3
**
*AMPLITUDE,NAME=SINE,DEF=PERIODIC
1,<omega>,0.0,0.0
0,1,0,0
**
** Step 1
**
*STEP, NLGEOM, INC=10000
*DYNAMIC,HAFTOL=1e05
0.001,<T1>
*BOUNDARY, AMP=SINE
FRONT_F,8,,1e10
*END STEP