Esposito, Antonio (2022) Modelling and experimental characterization of resonant panel sound absorbers. [Tesi di dottorato]
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| Tipologia del documento: | Tesi di dottorato |
|---|---|
| Lingua: | English |
| Titolo: | Modelling and experimental characterization of resonant panel sound absorbers |
| Autori: | Autore Email Esposito, Antonio antonio.esposito8@unina.it |
| Data: | 7 Dicembre 2022 |
| Numero di pagine: | 118 |
| Istituzione: | Università degli Studi di Napoli Federico II |
| Dipartimento: | Ingegneria Industriale |
| Dottorato: | Ingegneria industriale |
| Ciclo di dottorato: | 35 |
| Coordinatore del Corso di dottorato: | nome email Grassi, Michele michele.grassi@unina.it |
| Tutor: | nome email Romano, Rosario Aniello [non definito] |
| Data: | 7 Dicembre 2022 |
| Numero di pagine: | 118 |
| Parole chiave: | acoustics; room acoustics; panel absorbers; acoustic surface impedance |
| Settori scientifico-disciplinari del MIUR: | Area 09 - Ingegneria industriale e dell'informazione > ING-IND/11 - Fisica tecnica ambientale |
| Depositato il: | 08 Dic 2022 10:07 |
| Ultima modifica: | 09 Apr 2025 14:04 |
| URI: | http://www.fedoa.unina.it/id/eprint/14697 |
Abstract
The analytical modelling of the acoustic impedance of panel absorbers has been extensively addressed for the purpose of acoustic predictive analyses. Nevertheless, established approximate design equations rely on the assumption of pistonic plate motion, leading to significant errors with respect to finite sized samples, in which the flexural multimodal behaviour of the plate is predominant. In this thesis, an analytical expression of the surface averaged acoustic impedance of finite sized panel absorbers is obtained, by adding in series the impedance expression of vibrating plates of various shapes and edge constraints, excited by a transverse pressure load, to the acoustic impedance of a multilayered air cavity, calculated according to the impedance translation theorem. Such expressions were validated for normal sound incidence conditions, experimentally for the isolated clamped plate and numerically for the panel-cavity coupled system. Further numerical investigations were performed upon the effects of a porous layer inserted within the cavity as well as the response of a square panel absorber for conditions of spherical sound incidence in free field. The applicability of the proposed formulation as a boundary impedance condition in room acoustics FEM models was investigated for the case study of an existing room. Results in terms of sound pressure level frequency responses and T30 were compared against measured data at low frequencies for two different configurations of treatment, respectively showing reasonable deviations at low frequency. Since slight error increments were observed by increasing the number of panel absorbers in the room, further investigation is required by significantly increasing the surface area of acoustic treatment and refining calibration strategies of numerical models when accounting for unknown sources of acoustic damping. Nonetheless, results observed so far are promising towards the use of this methodology to bypass, when possible, the need of performing multiphysics FEM simulations which, in general, are extremely more expensive in terms of computational costs.
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