Nowadays, the development of techniques capable of numerically predicting the sound field within the passenger compartment of a car produced by the sound system has become fundamental to automotive design and innovation. In this context, the reliability of such numerical models is crucial in order to ensure their correct use. The use of numerical models that are reliable enough not to require experimental prototypes (at least in part) considerably simplifies the automotive production chain and speeds up design. The procedure implemented in this thesis will not take into account noises from outside the passenger compartment or noises that do not depend on vibrations from the system's loudspeakers. Moreover, in this context only a part of the entire procedure required for the development of the complete predictive model will be discussed, i.e. the one concerning high-frequency emission. The different approaches offered in the literature will be discussed, with their relative advantages and drawbacks. Having identified ray tracing as the main method of analysis, the necessary inputs and boundary conditions, as well as the achievable outputs, will be discussed in detail, with particular attention to the characterisation of the interior surfaces of the passenger compartment and their effect on the simulation results. To complete the thesis, an experimental campaigns will be set out, providing data to validate the numerical models developed in Comsol Multiphysics on the basis of the theoretical discussions. The analysis of these data and the related discussions will constitute the conclusion of the thesis and the starting point for further investigation and future developments in this field.
Al giorno d'oggi, lo sviluppo di tecniche in grado di predire numericamente il campo sonoro generato all'interno dell'abitacolo di un'autovettura prodotto dall'impianto audio è diventato fondamentale per la progettazione e l'innovazione automobilistica. In questo contesto, l'affidabilità di tali modelli è fondamentale per garantirne il corretto utilizzo. L'uso di modelli numerici sufficientemente affidabili da non richiedere prototipi sperimentali (almeno in parte) semplifica notevolmente la catena di produzione automobilistica e accelera la progettazione. La procedura implementata in questa tesi non terrà conto dei rumori provenienti dall'esterno dell'abitacolo o di quelli che non dipendono dalle vibrazioni degli altoparlanti dell'impianto. Oltretutto, in questo contesto verrà approfondita solo una parte dell'intera procedura necessaria per lo sviluppo del modello predittivo completo, ovvero quella relativa all'emissione ad alta frequenza. Verranno discussi i diversi approcci proposti in letteratura, con i relativi vantaggi e svantaggi. Individuato il ray tracing come metodo principale di analisi, verranno discussi in dettaglio gli input e le condizioni al contorno necessarie, nonché gli output che è possibile ottenere, con particolare attenzione alla caratterizzazione delle superfici interne dell'abitacolo e al loro effetto sui risultati della simulazione. A completamento della tesi, verrà impostata una campagna sperimentale che fornirà i dati per validare i modelli numerici sviluppati in Comsol Multiphysics sulla base delle trattazioni teoriche. L'analisi di questi dati e le relative discussioni costituiranno la conclusione della tesi e il punto di partenza per ulteriori indagini e sviluppi futuri in questo campo.
High-frequency model analysis for car cabin sound prediction
COSTA, GABRIELE
2023/2024
Abstract
Nowadays, the development of techniques capable of numerically predicting the sound field within the passenger compartment of a car produced by the sound system has become fundamental to automotive design and innovation. In this context, the reliability of such numerical models is crucial in order to ensure their correct use. The use of numerical models that are reliable enough not to require experimental prototypes (at least in part) considerably simplifies the automotive production chain and speeds up design. The procedure implemented in this thesis will not take into account noises from outside the passenger compartment or noises that do not depend on vibrations from the system's loudspeakers. Moreover, in this context only a part of the entire procedure required for the development of the complete predictive model will be discussed, i.e. the one concerning high-frequency emission. The different approaches offered in the literature will be discussed, with their relative advantages and drawbacks. Having identified ray tracing as the main method of analysis, the necessary inputs and boundary conditions, as well as the achievable outputs, will be discussed in detail, with particular attention to the characterisation of the interior surfaces of the passenger compartment and their effect on the simulation results. To complete the thesis, an experimental campaigns will be set out, providing data to validate the numerical models developed in Comsol Multiphysics on the basis of the theoretical discussions. The analysis of these data and the related discussions will constitute the conclusion of the thesis and the starting point for further investigation and future developments in this field.File | Dimensione | Formato | |
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2024_12_Costa_Tesi.pdf
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2024_12_Costa_Executive Summary.pdf
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https://hdl.handle.net/10589/229905