modelling of sound absorbing materials

Rahul_P1
Rahul_P1
Altair Employee
edited October 2020 in Community Q&A

Hello everyone,

I am a PhD student and my reasearch field is related to the vibro-acoustics of the passenger compartment.
In my current study I want to evaluate the SPL at the driver's ear location for a simplified passenger cabin with and without acoustic treatment. I performed an acoustic analysis in the frequency range from 0 to 300 Hz for the model without acoustic treatment and I obtained a SPL curve.Then I attached to the floor panel an cotton felt layer with thickness of 20 mm by using the CHACAB element with the associated property PACABS. When I comparing the SPL for the two model (with and without acoustic treatment) I observed that for some frequencies the SPL of the model with acoustic treatment is greater than the SPL of the model without acoustic treatment.

Is that right?

Please advice.

Thanks in advance!

Adrian

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Answers

  • Rahul_P1
    Rahul_P1
    Altair Employee
    edited May 2015

    HI,

    When you introduce acoustic absorber elements you remove locally energy from the model at each frequency. But that does not guarantee you, that at specific node (driver’s ear) the SPL is reduced.

    Thanks and regards

    Prakash Pagadala

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