Finite Element Vibration Analysis and Modal Testing of Bells
Jahangir Ansari · 2006
When bells are manufactured by traditional methods, the ideal symmetries are usually all broken due to irregularity of shape, material properties, and local defects during the casting process. Therefore, the vibration analysis of bell type structures become complicated and sometimes predicting precise results is not possible. Lack of generalized mathematical representation of bell vibrations necessitates numerical and/or experimental methods to determine the vibration characteristics of these types of structures. Rapid advances in computer aided design and manufacturing technology, as well as the accuracy of the virtual instrumentation programs in recent years, cause the possibility of solving such complex vibration problems. In this study a finite element commercial package is used for vibration analysis. Modal simulation and LabView are used as well for experimental measurements of the first five natural frequencies. As an initial step toward more sophisticated situations and in order to reduce the complexity of the problem, the variation of the wall thickness only in the region of the soundbow is considered. Moreover, damping of any kind is neglected. The effect of the wall thickness (particularly soundbow thickness) on the first five musical modes is studied in detail. The experimental modal parameters obtained by impact testing were compared with corresponding analytical results obtained by the finite-element analysis.