Modal Analysis and Enhancement of Sound Insulation for a Commercialized Gasproof Window

• Main Authors: Bo-Wen Huang, 黃博文
• Other Authors: Chia-Chi Sung
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/32672523459996767989

碩士 === 國立臺灣大學 === 造船及海洋工程學研究所 === 87 === Modal analysis and active structural control experiment were performed, respectively, on a commercialized gasproof window to investigate the structural characteristics and enhance the sound isolation capability. The piezoelectric ceramics stuck on the glass surface were used as exciters and the accelerometers were used as sensors to carry out the modal testing. A dynamic signal analyzer (HP35665A) was employed for data acquisition and frequency response analysis. During the analysis, the exciters were fixed and the sensors were moved to obtain the required FRF matrix for the software STAR. The modal parameters, natural frequency, damping ratio and mode shapes, describing the dynamics of the structure, are the final outputs of the STAR. Secondly, the piezoceramics were used as actuators. In company with band-pass filter, phase shifter and power amplifier to compose a closed-loop control system to suppress structure vibrations. In the sound transmission control, an omni-directional speaker was used as the excitation. Instead of using accelerometers, different sets of piezoelectric ceramics were used as sensors. If the piezoceramic sensors and actuators are collocated their response will be in phase. The sound transmission loss is measured by sound intensity method.