Study on a Broadband Powerful Flextensional Transducer with a Tube-beam Coupling Structure

摘要

A new broadband flextensional transducer is described in this paper. The transducer consists of two tire-shaped steel end plates, a stack of piezoelectric rings as the driving element and a dual slotted convex aluminum shell coupled one end plate to the other. The structure of the transducer is similar to that of the Class Ш flextensional transducer with the difference of free-flooded type which could bring three main resonant modes including the cavity, the longitudinal and the radial to expand the working bandwidth effectively. The piezoelectric stack is made up of a dozen of axially polarized PZT-4 rings each with an outer diameter of 142 mm, an inner diameter of 122 mm and a thickness of 12 mm. The shell with an thickness of 7 mm has dual convex shape parts and each part is equally slotted into 12 slices with gaps of 4 mm in width. The transducer has a full size of 230 mm in height, 120 mm in inner diameter and 210 mm in outer diameter respectively. Finite element analysis about the performance of the transducer is done by ANSYS software which gives the results that the transmitting voltage response (TVR) is 134.8dB at the cavity resonant frequency of 2200 Hz and the difference of TVR is less than 10 dB in the frequency range from 2000 Hz to 9000 Hz. The minimum TVR is 127.6 dB at 3100 Hz and the maximum is 137.5 dB at the longitudinal resonant frequency of 6100 Hz.