Sound transmission loss studies on aerogel sandwich composites

• Main Author: Cai, Xingfang
• Other Authors: Sunil Chandrakant Joshi
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/61710
• Institution: Nanyang Technological University

Loud noises from aircraft engines can be a nuisance for people living near the vicinity of an airport. With the increase in commercial aircraft traffic, there has been an increase in emphasis on noise attenuation research to reduce aircraft noise pollution. Acoustic liners are widely used in the inlets and outlets of the engine nacelles for their ability to absorb sound to suppress acoustic radiation within the engine. The liners along the walls of engine nacelle inlets and aft-fan ducts are made of sound absorbing materials that attenuate acoustic waves due to viscous and thermal dissipation. Hence, the understanding of the acoustic properties of the sound absorbing material used as the liner is essential for the noise control of engine mufflers. For the research into novel materials for acoustic liners, the possibility of using aerogel composites as the liner material is being studied in the project. Aerogel has many remarkable physical properties such as low bulk density, low thermal conductivity and low sound velocity, which makes it appropriate as a material for acoustic liners in aircraft engines. To improve its structural strength for use in the aerospace applications, aerogel composites in the form of honeycomb sandwich structure were fabricated for the study to investigate the acoustic properties.