Optimization of sound absorber: Design of sound absorber for the study of sound incidence in long narrow spaces such as corridors
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Sound and vibration (MPSOV), MSc
Publicerad
2024
Författare
Apadanda, Rushi Ganapathi
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Noise mitigation is of importance in areas where health and well-being of individuals
is needed and this is especially true in spaces such as schools were noise can hinder
learning and cognitive development of children. While acoustical treatment is often
focused on classrooms where children and teachers spend large amount of time, corridors
remain neglected despite their role in amplifying noise. Corridors with their
unique dimension, non-diffuse sound field and source for housing furniture pose a
challenge in sound proofing and hence an approach to optimise absorbers is needed
and to understand the impact of sound incident angle.
This thesis explores the design and optimization of a sound absorber system tailored
for such environments, with a focus on mitigating noise levels in school corridors.
The study investigates the performance of a resonant sound absorber, combining
a micro-perforated panel, air gap, and porous material, aimed at absorbing sound
in the mid-to-high frequency range 850 Hz-4000 Hz in diffuse and non-diffuse sound
field conditions.
Using theoretical modeling via the Transfer Matrix Method (TMM) and empirical
validation through free-field and diffuse-field measurements, the absorber’s performance
was analyzed under various sound incidence angles. The results demonstrate that the
designed system effectively absorbs sound, with a resonance peak at 2000 Hz. The study
also evaluates the impact of parameters such as porous material thickness, perforation
size, and air gap on the absorption coefficient for varied incident angle. While the absorber
achieved good efficiency, especially at the targeted resonance frequency, edge effects
were observed in finite-size samples, leading to overestimation of absorption coefficients
in certain cases.
This research highlights the importance of optimizing sound absorbers for nondiffuse
sound field environments like corridors, particularly at high frequency range, and offers
a practical solution for enhancing acoustic comfort in schools
Beskrivning
Ämne/nyckelord
sound absorber, school corridors, noise mitigation, micro-perforated panel, Transfer Matrix Method, acoustic treatment