Application and Research of Acoustic Characteristic of Foam Material

• Main Authors: Lei, Tzu-Hsuan, 雷梓煊
• Other Authors: Liu, Yu-Cheng
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/06734638735835216774

碩士 === 逢甲大學 === 電聲碩士學位學程 === 105 === In the field of noise control, porous foam is a common and simple approach applied in the factories to attenuate the noise from the mechanical vibrations. But how to do the accurate selections in the appropriate material to achieve the desired effect is the current problem because of rarely literatures to describe about that. The objective of this article is to study on the influence of porous foam, especially in the applications of factory. All the content mainly focused on flow resistivity of material. In the beginning, a simple measurement system complying with standard ISO 9053 is built up to acquire this parameter. All the testing results are compared with those coming from other standard system. With the aid of the standard Impedance Tube (Brüel & Kjær Type 4206T), after that, eight constants of each specified foam material applied in the Delany-Bazley theory are derived with MATLAB. Finally, the influence of flow resistivity are simulated with COMOSL software and discussed with muffler and factory case. Results show that flow resistivity of absorption material is indeed a important parameters especially in the applications and assessment of noise attenuation. The higher flow resistivity is, the larger transmission loss will be. With the aid of finite element simulation, the contributions of foam material in the noise attenuation will be predicated well. These results are well agreement with that from the measurement, especially in the lower frequency below 1.2 kHz.