| Summary: | 碩士 === 國立屏東科技大學 === 機械工程系所 === 97 === This work aims to discuss the sound characteristics correlated to the structural vibration modes of the copper gong with oval navel. First, the finite element (FE) model of the copper gong in free boundary is constructed to perform theoretical modal analysis so as to determine the modal parameters, including natural frequencies and corresponding mode shapes. Also, the microphone is used to measure the percussion sound response of the copper gong. The sound frequency spectrum can then be obtained and revealed peak frequencies that are related to structural vibration modal frequencies for certain types of structural modes. Base on the identified measured peak frequencies the FE model can be adjusted to fit the structural modal frequencies with the experimental measurement. Furthermore, the harmonic response analysis of the copper gong is also performed to obtain the frequency response function (FRF) similar to the practical percussion process.
By the use of recording tools in computor,the percussion sound of the gong can be recorded and analyzed by the developed analysis program.The sound spectra between theoretical analysis and experimental measurement reveal similar characteristics .Finally,the geometry modification of copper gong is carried out by finite element analysis to determine the dominant modal frequencies. The sound simulation program is adoptedmto study the sound response of different geometries of copper gongs.This week develops the analytical and experimental approaches to realize the sound characteristics of the gong. The methodology can also be applied to other percussion instruments.
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