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Response to Acoustic Excitation

Response to Acoustic Excitation

Response to Acoustic Excitation

(OP)
hi
what is the best way to model a cylindrical structure that will undergo SPL of 150db for 15 minutes?
i have a Ansys FEM modal analysis of the structure to 3000Hz.
i was thinking of working out the pressure from the 150db SPL and applying this to the external
surfaces of the structure and performing a response spectrum analysis to determine peak stresses.
for example, 150db, Pref=2e-5, so 150=20log(Prms/2e-5)
-> Prms = 632Pa
-> P=632 x sqrt(2) = 893Pa, is the pressure i would use.

does this seem sensible?
is there another better way of doing this?
also without doing a time domain transient type analysis what is the best way of
accounting for the 15 minutes duration?

the other option i was thinking was a fluid-structure analysis, with the fluid elements surrounding the structure and applying the 150db to the fluid & seeing what the response of the structure was.
but again i'm not sure how to 'apply the 150db load' to the fluid?

anyway might be an interesting discussion!
thanks!
jas

RE: Response to Acoustic Excitation

1) yes, but are you sure it is just the external surfaces?

2) don't think so

3) by looking at the s/n curve of your material

4) sounds unnecessarily complicated to me

Cheers

Greg Locock

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RE: Response to Acoustic Excitation

Stupid question:

Do you have ANSYS Multiphysics?  If the answer is yes, then you have acoustic fludi elements that have coupled pressure/displacement degrees of freedom.  I have done acoustic FSI analysis in ANSYS before.   It's been probably four years since I touched it so I can't give you much help in that regard but there is info in the ANSYS documentation that will point you in the right direction.   

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