抄録
An automatically performing bell system, which informed the specified time with music, has many types of bell configuration and arrangement. The first requirement for the bell system is to tune the fundamental resonance frequencies of each bell to an equal temperament of scale. Finite Element Method was used to determine the natural frequency and mode shape of the axisymmetric bell. Experimental evaluation was also carried out to examine the existence of the orthogonal mode which frequency is close to the fundamental frequency. Boundary Element Method(BEM) was applied to investigate the acoustic radiation properties of bell's eigen mode. Based on this results, bell is approximated by the point sound source with specific radiation directivity. Moreover, wave form of sound pressure radiated from the vibrating bell is calculated by this point sound source approximation and compared with the detailed BEM analysis.
