Design Analysis of Metallophone Bar Base on Percussion Sound Characteristics

• Main Authors: Ming-Hsien Hsieh, 謝明憲
• Other Authors: Bor-Tsuen Wang
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/97262965429600518672

碩士 === 國立屏東科技大學 === 機械工程系所 === 97 === The metallophone is one of percussion instruments. The percussion sound of a metalophone consists of the fundamental frequency and overtone frequencies that are related to the vibration modes of the metallophone. This work presents the geometry design of the metallophone with C chord sound characteristics. The Bezier’s curve formulation is adopted to generate smooth curves so as to construct the finite element model of the metallophone. By performing modal analysis the natural frequencies and mode shapes can be obtained. The sound generation mechanism can be interpreted by mode shape patterns. This work designs two types of metallophones that can generate the C chord sound. Both aluminum and stainless steel materials are used to shape the designed metallophones. The microphone is used as the sensor to measure the percussion sound and characterize the modal properties of the metallophones. The sound spectrum can be obtained and identified those peak frequencies that are used to correlate and adjust the finite element model. Results show that the finite element model can be well calibrated. The finite element model is then adopted to carry out geometry design modification. The scaled thickness and geometry shapes can change the modal properties in a scale relation. This work establishes the design method for the C chord metallophone and validates the design by experimental measurements. The developed methodology will be beneficial to the design of specific types of metallophones, in particular for different chord combinations.