隔音板聲音穿透損失之有限元素分析

FINITE ELEMENT ANALYSIS OF SOUND TRANSMISSION LOSS OF INSULATION PANELS

本研究建立一通用有限元素分析平台，以評估隔音板的隔音效能，考慮變壓器的典型電磁激振頻率120Hz及其倍頻，探討單片與雙片隔音板之厚度與布置位置的影響，並檢視氣腔共振與隔音板聲振耦合對聲音穿透損失（sound transmission loss，STL）之衝擊。經由收斂分析顯示本研究分析個案之隔音板、空氣腔體、與完美匹配層（perfectly matched layer，PML）的適當網格尺寸分別為0.05m、0.08m、與1.6m，以兼顧分析精確度與計算成本。相較於單片隔音板，在相同隔音板重量的情形下，具有適當空氣腔間隔之雙片隔音板的聲音穿透損失性能可提升高逾30 dB。 This study established a general-purpose finite element analysis platform to evaluate the effectiveness of sound insulation panels. Transformers with typical noisy components of electromagnetic excitation frequency 120Hz and its harmonics were considered. The effects of thickness and layout position of the single and dual sound insulation panels on the sound transmission loss (STL) were investigated, with the cavity resonance and structural/acoustic coupling being considered. The convergence analysis for this case study revealed the appropriate finite element mesh sizes for the insulation panel, the air cavity, and the perfectly matched layer (PML) were 0.05m, 0.08m, and 1.6m, respectively, in order to take into account both the analysis accuracy and computation cost. Compared to the case of a single panel with the same weight, the case of a set of dual-panel with an appropriate air space in between were demonstrated to be feasible of improving the performance of transmission loss over 30dB.