- 學位論文
具簡諧倍頻聲音特性之半圓管型打擊樂器設計與製作
Design Analysis and Verification of Half Cylindrical Tube with Harmonic Sound for Percussion Instrument
摘要
一般的弦樂器都可發現簡諧倍頻音之聲音特性，亦即樂器發出的泛音與基音有整數倍率的關係，因而具有良好的聲音特性，而打擊樂器之結構要設計出有簡諧倍頻音是相當有挑戰性的。本研究主要開發不同音階之具簡諧倍頻音半圓管型新型打擊樂器組，由於在竹製打擊樂器半圓管型結構經初步聲音量測評估，此結構具有接近簡諧倍頻音之聲音特性，值得探究與應用發展；透過理論分析與實驗之手法探討半圓管型結構振動與敲擊聲音之關聯性，並設計出新型半圓管型打擊樂器組。因此本研究使用適當管徑之不銹鋼管，並搭配不同的管件厚度進行半圓管型結構設計，同步進行半圓管型之模態分析，以獲得理論之模態參數，由結構之自然頻率與對應之模態振型可探討預測其聲音特性。由聲振耦合分析以及實際聲音量測分析，進行此半圓管型聲音響應預測之驗證；最後利用參數化之有限元素模型，設計完成一組涵蓋兩個八度音簡諧倍頻音半圓管型半圓管型打擊樂器組，且基音頻率與標準音階互相對應，其誤差皆在3%以內，達到具簡諧倍頻音半圓管型之設計，此新型打擊樂器為具有商品化潛力的打擊樂器。本研究所建立的分析與實驗技術，將有助於深耕我國樂器產業的設計研發能力。
並列摘要
Harmonic sound effect, i.e. the overtone frequencies with integer ratios with respect to the fundamental frequency, is known for good sound quality and can be observed in string types of musical instruments. For percussion instruments, the design on the structure that can produce harmonic sound is challenging. This work aims to develop the half cylindrical tube producing harmonic sound and manufacture a set of tubes containing different musical notes as the new type of percussion instrument. The conceptual design of half cylindrical tube with harmonic sound is inspired from sound measurement of traditional bamboo wind chimes and percussion instruments. The basic geometry pattern may come from the wisdom and experience of people and is very likely and worthy to investigate. This work employs engineering analysis and experimental techniques to study the relations between structural vibration characteristics and percussion sound, and so forth to design the new type of percussion instrument composed by the half cylindrical tubes. This work uses the stainless steel tubes via engineering evaluation to select the proper diameters and thickness of the hollow tubes. The finite element model is constructed and performed theoretical modal analysis (TMA) to obtain structural modal parameters. Structural natural frequencies and corresponding mode shapes can then be used to predict the percussion sound. The vibro-acoustic coupling analysis and sound measurement are also conducted, respectively, to verify the predicted sound response. In design process, the parametric geometry model is adopted to complete the design of hollow tubes for different musical notes’ requirement of frequencies. This work completes the optimum design and manufacture of the new percussion instrument for half cylindrical tubes and meets the design goals. A set of half cylindrical tubes containing two octaves with full and semi-notes is fabricated and potentially commercialized. The analysis and experimental approaches developed in this work can enhance the R&D ability for domestic musical instrument industry.