*HEADING
** 
*PREPRINT, ECHO=NO, MODEL=NO, HISTORY=NO
*NODE,NSET=BEAMS,SYSTEM=C
      25001,4.0,90.0,0.0
      25071,4.0,-90.0,0.0
********************************
*NODE,NSET=STIFFNER
55,0.0,-2.0
65,1.0,-2.0
75,3.0,-1.1
*****
*NGEN,NSET=BEAMS,LINE=C
 25001,25071,1,,0,0,0,0,0,-1
*NSET,NSET=OUT
 25001, 25071, 25036,75
*NSET,NSET=P_OUT
1,21,41,1001,1021,1041 
****************************
*NODE,NSET=INNER,SYSTEM=C
1,4.0,90.0,0.0
41,4.0,-90.0,0.0
*NGEN,NSET=INNER,LINE=C
1,41,1,,0,0,0,0,0,-1
*****************************
*NODE,NSET=OUTER,SYSTEM=C
2001,8.0,90.0,0.0
2041,8.0,-90.0,0.0
*NGEN,NSET=OUTER,LINE=C
2001,2041,1,,0,0,0,0,0,-1
*****************************
** USE "*nmap" TO CREATE ELLIPTICAL
** OUTER BOUNDARY
*NMAP,NSET=OUTER,TYPE=RECTANGULAR
** points a, b, c: see documentation
0,0,0, 1,0,0,
0,1,0
** stretch factors for x, y, z:
1.00,1.2,1.00
*****************************
*NFILL,NSET=ACOUSTIC
INNER,OUTER,20,100
**********************************
*ELEMENT,TYPE=B21,ELSET=BEAMS
2001, 25001,25002
*ELGEN,ELSET=BEAMS
2001,70,1,1
*ELEMENT,TYPE=B21,ELSET=STIFFNER
3001,55,65
4001,65,25060
5001,75,25048
6001,75,25040
******************
*ELEMENT, TYPE=AC2D4,ELSET=ACOUSTIC
1,1,2,102,101
*ELGEN, ELSET=ACOUSTIC
1,40,1,1,20,100,40
****************************
*ELGEN,ELSET=SECONDARY
1,40,1,1
*SURFACE, TYPE=ELEMENT, NAME=SECONDARY
SECONDARY,S1
*SURFACE,TYPE=ELEMENT,NAME=MAIN
BEAMS,SPOS
*TIE,NAME=COUPLING
SECONDARY,MAIN
************************************
*MATERIAL,NAME=WATER
*DENSITY
1000.0, 
*ACOUSTIC MEDIUM,BULK MODULUS
2.25E9,
*SOLID SECTION,MATERIAL=WATER,ELSET=ACOUSTIC
0.1,
*******************
*BEAM SECTION,MATERIAL=MAT1,ELSET=BEAMS,SECTION=RECT
0.1,0.1
*BEAM SECTION,MATERIAL=MAT1,ELSET=STIFFNER,SECTION=RECT
0.1,0.1
*MATERIAL,NAME=MAT1
*ELASTIC
207E9,0.3
*DENSITY
7800
*************************
*ELSET,ELSET=OUTER,GENERATE
761,800,1
*SURFACE,NAME=OUTER
OUTER,S3
**********************
*STEP,INC=1000
*STEADY STATE DYNAMIC,DIRECT
1.0,7.0,2,1
*IMPEDANCE,NON=E
OUTER,I3,   9.6,0.5527708,0,0,0,0,1,0
*CLOAD
55,2,100.0
*BOUNDARY
25001,1,1,0.0
25071,1,1,0.0
25001,6,6,0.0
25071,6,6,0.0
55,1,1,0.0
55,6,6,0.0
*ENERGYPRINT
*OUTPUT,FIELD,FREQ=1
*NODE OUTPUT,NSET=BEAMS
U,
*NODE OUTPUT,NSET=ACOUSTIC
POR,
*ELEMENTOUTPUT,ELSET=ACOUSTIC
ENER,ELEN,INTEN
*OUTPUT,HISTORY,FREQ=1
*NODE OUTPUT,NSET=BEAMS
U,V,A
*END STEP
*STEP,INC=1000
*STEADY STATE DYNAMIC,DIRECT
1.0,7.0,2,1
*IMPEDANCE,NONREF=E,OP=NEW
*SIMPEDANCE,OP=NEW,NONREF=E
OUTER,9.6,0.5527708,0,0,0,0,1,0
*CLOAD
55,2,100.0
*BOUNDARY
25001,1,1,0.0
25071,1,1,0.0
25001,6,6,0.0
25071,6,6,0.0
55,1,1,0.0
55,6,6,0.0
*OUTPUT,FIELD,FREQ=1
*NODE OUTPUT,NSET=BEAMS
U,
*NODE OUTPUT,NSET=ACOUSTIC
POR,
*ELEMENT OUTPUT, ELSET=ACOUSTIC
ENER,ELEN,INTEN
*OUTPUT,HISTORY,FREQ=1
*NODE OUTPUT,NSET=BEAMS
U,V,A
*END STEP

****************************
*STEP,INC=1000
*Frequency, eigensolver=Lanczos, acoustic coupling=on, normalization=MASS
100, , 3000., -1.0, , 
*IMPEDANCE,NONREFLECTING=ELLI,OP=NEW
*SIMPEDANCE,NONREFLECTING=ELLI,OP=NEW
OUTER,9.6,0.5527708,0,0,0,0,1,0
*OUTPUT,FIELD,FREQ=1
*NODE OUTPUT,NSET=BEAMS
U
*NODE OUTPUT,NSET=ACOUSTIC
POR,
*END STEP
************************