Acoustic amplification utilizing stepped-thickness piezoelectric circular cylindrical shells

This paper presents a new approach to amplify the acoustic field generated by a uniform thickness piezoelectric cylindrical shell by introducing a stepped thickness variation at predetermined axial locations. The acoustic field and corresponding mode shapes of a uniform thickness piezoelectric tube are analyzed first and then, axial thickness variations are machined within the specified designed regions of the tube. The machining leads to the formation of thin-walled regions in the tube which localize the vibration amplitude within the machined spaces with higher amplitude. This results in a conspicuous increase of approximately 85% on average in the strength of the resultant acoustic field, though both specimens the uniform and stepped-thickness tubes have the same power consumption. The results of the simulations and experiments are in good agreement.