*Heading
** Benchmark: Steel shell submerged in water, resonances
**
*Parameter
r1 = 1.3
rm = -r1
** Number of Acoustic Layers
NL = 6
** Number of Acoustic Nodes circumferentially (max = 99)
NC = 73
** Number of Acoustic Elements circumferentially
EC = NC-1
N0 = 100*NL+1
NN = 100*NL+NC
E0 = 100*(NL-1)
EN = E0+NC-1
I0 = E0+100
IN = EN+100
I1 = N0+1
** Number of Shell Nodes circumferentially
NS = 73
** Number of Shell Elements circumferentially
ES = NS-1
** Maximum frequency of interest - for example, choose 3000.00
Fmax = 1100.00
**
*Preprint, echo=NO, model=ye, history=NO, contact=NO
** PARTS
**
*Part, name=acax
*Node
    1,  0.0, -1.0, 0.0
 <NC>,  0.0,  1.0, 0.0
  100,  0.0,  0.0, 0.0
*NGEN,LINE=C,nset=inside
 1,<NC>,1,,0.0,0.0,0.0, 0.0,0.0,1.0
*Node
 <N0>,  0.0, <rm>
 <NN>,  0.0, <r1>
*NGEN,LINE=C,nset=outside
 <N0>,<NN>,1,,0.0,0.0,0.0, 0.0,0.0,1.0
*NFILL
inside,outside,<NL>,100
*Element,type=acax4,elset=eall
1,1,101,102,2
*Elgen,elset=eall
1, <EC>, 1, 1, <NL>, 100, 100
*Element,elset=acin,type=acinax2
<I0>,<I1>,<N0>
*Elgen,elset=acin
<I0>,<EC>,1,1
*Solid Section, elset=eall, material=water
1.,
*Solid Section, elset=acin, material=water,refnode=100
1.,
****
*elset,elset=acaxinner,gen
1,<EC>
*elset,elset=acaxouter,gen
<E0>,<EN>
*surface,name=inner
acaxinner,s4
*surface,name=outer
acaxouter,s2
*End Part
**  
**  
*Part, name=Shell
*NODE,NSET=LOADPOS
 1,  0.0, -1.0
*NODE,NSET=LOADNEG
 <NS>, 0.0,  1.0
*NGEN,LINE=C
 1,<NS>,1,,0.0,0.0,0.0, 0.0,0.0,1.0
*ELEMENT,TYPE=SAX1
 1,1,2
*ELGEN,ELSET=EALL
 1,<ES>
*SHELL SECTION,MATERIAL=Steel,ELSET=EALL
 0.01,3
*End Part
**
** ASSEMBLY
**
*Assembly, name=Assembly
**
*Instance, name=Shell, Part=Shell
*End Instance
**
*Instance, name=acax, part=acax
*End Instance
**  
*Surface, type=ELEMENT, name=ShellOuter
shell.eall,sneg
******
*Tie, name=Constraint-2, adjust=yes, no rotation
acax.Inner,shellOuter
*End Assembly
** 
** MATERIALS
**
*MATERIAL,NAME=Steel
*DENSITY
 7647.,
*ELASTIC
 1.8509E+11, 0.3
*Material, name=water
*Acoustic Medium
 2.12812e+09,
*Density
997.,
****************************
*STEP
REAL EIGENANALYSIS
*frequency,acoustic=on,norm=ma
,36.0, <Fmax>
**
*OUTPUT, FIELD
*NODE OUTPUT
U,POR
*END STEP
*****************************
*STEP
COMPLEX EIGENANALYSIS
*COMPLEXFREQUENCY
, 
*OUTPUT, FIELD
*NODE OUTPUT
U,POR
*END STEP
*****************************