ANSYS acoustic harmonic analysis

[marceljaner]

I am modeling the acoustic pressure inside a very thin pipe of air inside a titanium tube.
In theory, It should be an easy model to simulate with ansys APDL.
The problem is that, altought I put almost no damping, the acoustic wave is higly attenuated and I don't know what's wrong in the model.
If anyone has an idea i will apreciate it.
I pots the code below
Thank you


/PREP7
ANTYPE,HARM

ET,1,30,,0
ET,2,45

! MATERIAL PROPERTIES
DENS,1,1.225
SONC,1,343
MU,1,0

UIMP,2,EX,,,120E9
UIMP,2,DENS,,,4400
UIMP,2,NUXY,,,0.1
UIMP,2,DAMP,,,0.001


! DIMENSIONS
RAD=0.0012
LENGTH=0.023
RADM=0.0013

!CREATE THE GEOMETRY
K,1,0,0,0
K,2,0,0,LENGTH
CIRCLE,1,RAD,
L,1,2
AL,1,2,3,4
VDRAG,ALL,,,,,,5
CIRCLE,1,RADM,RAD
AL,14,15,16,17,1,2,3,4
VDRAG,7,,,,,,5


! MESH
XDIV=29
RDIV=1
CDIV=12
ESIZE,0.0005


TYPE,1
MAT,1
VSEL,S,VOLU,,1
VSWEEP,ALL

TYPE,2
MAT,2
VSEL,S,VOLU,,2
VSWEEP,ALL

VSEL,ALL

!BOUNDARY CONDITIONS AND LOADS
CSYS,1
NSEL ,X,RAD
ENODE
ESEL,r,type,,1
SF,all,FSI

CSYS,1
VSEL,S,VOLU,,1
NSLV,S,1
NSEL,R,LOC,Z,0
NSEL,R,LOC,X,0,RAD-RAD/10
ENODE
D,ALL,PRES,1


CSYS,1
VSEL,S,VOLU,,2
NSLV,S,2
NSEL,R,LOC,Z,0
NSEL,R,LOC,X,RADM
ENODE
D,ALL,UX,0


CSYS,1
VSEL,S,VOLU,,2
NSLV,S,2
NSEL,R,LOC,Z,LENGTH
NSEL,R,LOC,X,RADM
ENODE
D,ALL,UX,0




NALL
EALL
FINISH

/SOL
HARF,10000,10000
SOLVE

/POST1

SET,FIRST
/CONTOUR,ALL,18

VSEL,S,VOLU,,1
ESLV,S
PLNSOL,PRES