*HEADING
** 
** The problem is based on the Benchmark problem presented in Ch. 1.10.3:
** ACOUSTIC-STRUCTURAL INTERACTION IN AN INFINITE ACOUSTIC MEDIUM.
**
** However the acoustic and the structural mesh are changed, and
** so are the material properties whisch are now for steel and water
** respectively.
**
** The pressure results are identical to the STD results.
** The Std and Xpl problems using this mesh should replace
** the existing benchmark problems  
** 
*PREPRINT, ECHO=YES, MODEL=YES, HISTORY=YES
*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
*NSET,NSET=QA_TEST
P_OUT, 
****************************
*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
*****************************
*NFILL,NSET=ACOUSTIC
INNER,OUTER,20,100
**********************************
*ELEMENT,TYPE=SAX1,ELSET=BEAMS
2001, 25001,25002
*ELGEN,ELSET=BEAMS
2001,70,1,1
*ELEMENT,TYPE=SAX1,ELSET=STIFFNER
3001,55,65
4001,65,25060
5001,75,25048
6001,75,25040
******************
*ELEMENT, TYPE=ACAX4R,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,adjust=no
secondary,main
************************************
*MATERIAL,NAME=WATER
*DENSITY
1000.0, 
*ACOUSTIC MEDIUM,BULK MODULUS
2.25E9,
*ACOUSTIC MEDIUM,VOLUMETRICDRAG
0.63, 
*SOLID SECTION,MATERIAL=WATER,ELSET=ACOUSTIC
0.1,
*******************
*SHELL SECTION,MATERIAL=MAT1,ELSET=BEAMS
0.1
*SHELL SECTION,MATERIAL=MAT1,ELSET=STIFFNER
0.1
*MATERIAL,NAME=MAT1
*ELASTIC
207E9,0.3
*DENSITY
7800
*************************
*AMPLITUDE,DEFINITION=PERIODIC,NAME=SINE
1,628.3185,0,0.0
0.0,1.0
*ELSET,ELSET=OUTER,GENERATE
761,800,1
*SURFACE,NAME=OUTER
OUTER,S3
**********************
*STEP
*DYNAMIC,EXPLICIT,DIRECT
2.5e-5,0.003
*IMPEDANCE,NONREFLECTING=CIRCULAR
OUTER,I3,8.0
*BOUNDARY,AMP=SINE,TYPE=ACCEL
75,2,2,1.0E4
*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,NUMBER=1
*NODE OUTPUT,NSET=ACOUSTIC
POR
*NODE OUTPUT,NSET=QA_TEST
POR
*OUTPUT,HISTORY,freq=1
*NODE OUTPUT,NSET=out
U,V,A
*NODE OUTPUT,NSET=P_out
POR,
*END STEP