• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.353.1-353
• /
• 2002

Impulse response of a slightly asymmetric cylindrical shell is derived. Receptance method is applied to obtain the vibration mode and natural frequency of the slightly asymmetric cylindrical shell. Impulse response model is used to identify the vibration beat characteristics of King Song-Dok Bell. The theretical mode is compared and verified by the measured mode of King Song-Dok Bell. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.1161-1168
• /
• 2002

Vibration and sound characteristics of King Song-Dok Bell are measured and the modal property is investigated. The effect of striking position and modal property on the beat characteristics is examined. It is first found that the beat characteristics are quite different according to the position on the bell surface and clear beat is periodically generated on the circumference. It turns out that in King Song-Dok Bell, striking Dangjwa(the present striking position) makes a beat in the first vibration mode, as well as it produces very clear beat in the second vibration mode.

• Journal of the Korea Society for Simulation
• /
• v.14 no.4
• /
• pp.69-76
• /
• 2005

To investigate the characteristics of the sound-pipe on the top of King Song-Dok bell, using computer simulation, the throat impedance was evaluated for the straight pipe and conical pipes with varying taper angles. When sound propagates in a rigid walled, unflanged circular pipe with wavelength larger than radius, the acoustic motion is planar, much as in a bar. The incident sound waves are reflected at the end of pipe and some of them are transmitted. The reflection coefficient and radiation impedance of the sound-pipe of King Song-Dok bell were calculated, and the results demonstrated that the high frequency sound is radiated through the sound-pipe. It behaves like a frequency filter.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11b
• /
• pp.498-504
• /
• 2002

Vibration beat phenomenon is theoretically investigated on a slightly asymmetric cylindrical shell, which is a simplified model of Korean bell. Mode pairs of the slightly asymmetric shell are obtained by receptance analysis and impulse response of the shell is derived using modal expansion and Laplace transform. Based on the impulse response model, beat mapping method is proposed to explain the reason that the beat of a bell vibration shows periodic distribution on the circumference. Beat characteristics of King Song-Dok Bell are explained in detail using the beat map and the measured modal data.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.7
• /
• pp.534-541
• /
• 2002

Vibration and sound characteristics of King Song-Dok Bell are ivesigated. Natural frequencies. vibration modes and beat period of the bell are precisely measured. The effect of striking position and the position of nodal lines on the beat characteristics is examined. It is first found that the beat characteristics are quote different according to the position on the bell surface and clear beat is periodically generated on the circumference. It turns out that in King Song-Dok Bell, Dangjwa(the present striking position) is located at the position which makes a beat in the first vibration mode, as welt as it produces very clear beat In the second vibration mode.

• The Journal of the Acoustical Society of Korea
• /
• v.37 no.5
• /
• pp.378-386
• /
• 2018

The present paper suggests the original form of the bell pavilion for the King Song-Dok bell which is one of the precious national treasure of Korea. In order to this, many literatures were reviewed including both historical and acoustical references. As the results, the model of the bell pavilion for the King Song-Dok bell is suggested as follows considering acoustical characteristics of the King Song-Dok bell and the traditional Korean bells ; 1) The bell pavilion has the rumbling puddle beneath the bell on the ground floor for resonance of sound 2) Many lumbers are used for columns and beams rather than boards since natural frequencies of the bell are 64 Hz and 168 Hz so that the sound absorption of the low frequency sound may not be occurred. 3) Only some boards may be used for the area between upper and middle molding of lintel in order to prevent of direct sunlight and sea breeze since this type of structure were used for bell pavilion of the same age. 4) Square form with the odd number of 3 or 5 Kans is adopted for bell pavilion considering the weight and the size of the bell which had been used traditionally 5) Finally, half-hipped structure is used for the roof of the bell pavilion which was the predominant form of the age.

• The Journal of the Acoustical Society of Korea
• /
• v.16 no.6
• /
• pp.41-47
• /
• 1997

Beating phenomenon which is generated by two closely located natural frequencies is one of research tenet for King Song-Dok bell. In this paper, we investigate the vibration shape of these natural frequencies using very extensive experimental data. Vibration signals are sampled at 108 points around the bell using accelerometers. Measured signals are anlayzed in time and frequency domain. Twelve natural shapes under 800Hz are plotted.

• The Journal of the Acoustical Society of Korea
• /
• v.16 no.5
• /
• pp.60-67
• /
• 1997

the famous King Song-dok Bell which was cast in A.D. 771, during Silla dynasty has significant xize of concave cavity which acts as Helmholtz resonator on the ground. To see the effect of this cavity and the bell's internal acoustic cavity on radiating sound of bell, three dimensional measurement of internal sound field was performed. In this paper, the dtail measurement procedure and results are carefully addressed. The effect of the cavity on the radiating sound of bell is investigated using simple and physically representative model. A new size of cavity is proposed.

• The Journal of the Acoustical Society of Korea
• /
• v.16 no.6
• /
• pp.19-24
• /
• 1997

The acoustic characteristics of the sound-pipe of King Song-Dok bell, which is located on the top, are investigated by experiment and simulation. The experimental results;reflection coefficient, and radiation impedance, demonstrate that the sound-pipe is capable of radiating high frequency(above 300Hz) sound; it behave as damper. It is also found that a waveguide model well presens the acoustic characteristics of the sound-pipe.

• The Journal of the Acoustical Society of Korea
• /
• v.16 no.4
• /
• pp.94-100
• /
• 1997

In order to investigate the radiation of sound from the King Song-Duk bell, we measured the sound pressure around the bell at every 30$^{\circ}$ using a microphone line array which was composed of 30 microphones separated by 15cm;total number of measurement point was 360. The sound field was estimated by using cylindrical acoustic holography. The spectrum of measured sound pressure demonstrates that it is almost like white noise in the very beginning, but in 10 seconds two close frequency components(64.06Hz, 64.38Hz) remain and make a famous beating. This beating sound is often believed to make unique sound of the King Song-Duk bell. The mode shapes of that frequency components are the same except that one is rotated by 45$^{\circ}$ from the other. This phenomenon occurs at the other pairs of components are the same except ones in very high frequency range where the mode shapes are rather complex.