Study of sound absorption using acoustic impedance tube

• Main Author: Tan, Ting Yew
• Other Authors: Huang Xiaoyang
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/77639
• Institution: Nanyang Technological University

This report presents the process of using micro-perforated plates and the impedance tube to study sound absorption coefficient. The theory behind the formulas to analyse sound absorption coefficient has been explained. The factors affecting it include perforation ratio, thickness, materials and air cavity. Samples were manufactured by external vendor and tested by the author using the Brüel & Kjær impedance tube. Results and data were gathered and graphs were plotted to illustrate the data. It has been proven that low perforation ratio yields better sound absorption coefficient, thinner samples can absorb sound energy better, Aluminium is a better sound absorbing material than Polycarbonate and Bakelite and air cavity of 30mm is optimal for better sound absorption coefficient. The process of designing the samples, experimental setup and results are presented in this report.