The most important feature of bells is their sound. Their clarity and beauty depend, first of all, on the bell’s geometry - particularly the shape of its profile and the mechanical properties of alloy. Bells are the castings that work by emitting sound in as-cast state. Therefore all features that are created during melting, pouring, solidification and cooling processes will influence the bell's sound. The mechanical properties of bronze depend on the quality of alloy and microstructure which is created during solidification and depend on its kinetics. Hence, if the solidification parameters influence the alloy’s properties, how could they influence the frequencies of bell`s tone? Taking into account alterable thickness of bell's wall and differences in microstructure, the alloy's properties in bell could be important. In the article authors present the investigations conducted to determine the influence of cooling kinetics on microstructure of bronze with 20 weight % tin contents.
The most important feature of bells is their sound. Its clarity and beauty depend, first of all, on the bell’s geometry - particularly the shape of its profile, but also on the quality of alloy used to its cast. Hence, if the melting and pouring parameters could influence the alloy’s properties, what influence they would have on the frequencies of bell’s tone. In the article authors present their own approaches to find answers on that and more questions.
The aim of this paper is to present methods of digitally synthesising the sound generated by vibroacoustic systems with distributed parameters. A general algorithm was developed to synthesise the sounds of selected musical instruments with an axisymmetrical shape and impact excitation, i.e., Tibetan bowls and bells. A coupled mechanical-acoustic field described by partial differential equations was discretized by using the Finite Element Method (FEM) implemented in the ANSYS package. The presented synthesis method is original due to the fact that the determination of the system response in the time domain to the pulse (impact) excitation is based on the numerical calculation of the convolution of the forcing function and impulse response of the system. This was calculated as an inverse Fourier transform of the system’s spectral transfer function. The synthesiser allows for obtaining a sound signal with the assumed, expected parameters by tuning the resonance frequencies which exist in the spectrum of the generated sound. This is accomplished, basing on the Design of Experiment (DOE) theory, by creating a meta-model which contains information on its response surfaces regarding the influence of the design parameters. The synthesis resulted in a sound pressure signal in selected points in space surrounding the instrument which is consistent with the signal generated by the actual instruments, and the results obtained can improve them.