彈性支承對複合材料板的振動與聲傳之影響研究

Abstract

因彈性支承對複合材料板的振動與聲傳具有重要的影響，本文將從實驗和理論兩方面來探討彈性支承對複合材料板之振動與聲傳的影響。實驗方面，利用不同寬度的玻璃纖維接腳做揚聲板的振動穩定性實驗，使揚聲器系統承受更大的瓦數，其中包括用12mm寬玻璃纖維彈性支承進行揚聲器承受不同功率的測試，結果顯示揚聲器可以承受到10瓦左右。若欲承受到15瓦時，則需用20mm寬玻璃纖維彈性支承才能達成。理論方面，利用有限元素軟體ANSYS來建立具不同彈性支承揚聲器的分析模式，由聲壓曲線的分析結果找出較為與實驗結果相符合的建模方式。另外，本文為了改善音質，在振動板上同時使用碳纖維與玻璃纖維兩種材料來加勁，讓其產生更佳的高音與低音效果，這種振動板的理論與實驗聲壓曲線亦相當吻合。

Because flexible supports may have great effects on vibration and sound radiation of composite plates, we will study these effects via experimental and theoretical approaches. In the experimental study, we conducted stability experiments of flat-panel speakers using different fiberglass flexible supports of different widths. With the aim of fabricating loudspeaker systems able to support higher power, we have been successful in using 12mm-wide fiberglass flexible supports in a loudspeaker to sustain 10 watts. If the loudspeaker is to sustain 15 watts, 20mm-wide fiberglass flexible supports must be used. In the theoretical study, we use ANSYS to construct the finite element model of the speaker in which the flexible supports are modeled by different types of elements. The vibration responses of the radiating plate are used in the first Rayleigh integral to find the SPL curve of the plate. The theoretical SPL curves of different flat-panel speakers have been determined and verified by the experimental ones. In addition, we use both carbon fiber and fiberglass to stiffen composite plates to produce sounds with higher sensitivity and better bass at the same time. The theoretical SPL curve of this type of speakers has also been validated by the experimental results.