Dynamic and acoustic characteristics of the bell type structure were analyzed numerically. The finite element method with 3-D general shell element was used to identify the natural frequencies and mode shapes of the structure. Mode shapes and stress distributions of a transient dynamic analysis were effectively displayed by using computer graphic technique. The results of this numerical study were in good agreement with those obtained from the experimental test of fast Fourier transform analyer. Vibrational modes, which effect the acoustic characteristics of the typical bell-type structure were found to be the first flexural mode (4-0 mode) and the second flexural mode (6-0 mode). Asymmetric effects by Dangjwas and acoustic holes gave rise to beat frequencies, and the Dangjwa was found to be most effective. When the impact load was applied to the bell, the stress concentration occured at the rim part of the bell. It was found that the bell type structure should be designed thickly at the rim part in order to prevent failure from impact loads.
[1]
A. Kalnins,et al.
Free Vibration of Rotationally Symmetric Shells
,
1964
.
[2]
A. Jones.
The Tones from Bells
,
1920
.
[3]
S. Timoshenko,et al.
THEORY OF PLATES AND SHELLS
,
1959
.
[4]
R N Arnold,et al.
Flexural vibrations of the walls of thin cylindrical shells having freely supported ends
,
1949,
Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.
[5]
W. Thomson.
Vibration Theory and Applications
,
1966
.
[6]
M. F. Rubinstein,et al.
Dynamics of structures
,
1964
.
[7]
A. Leissa,et al.
Vibration of shells
,
1973
.
[8]
Ichiro Aoki,et al.
Effect of Local Loading on the Acoustical Property of Japanese Bell
,
1970
.