Study on the driving element of gourd transducer

A class III flextensional transducer also called gourd transducer because of its particular shape mainly consists of a driving element, two end plates and a specially designed shell coupling one end plate to the other. Using multiple-mode-coupling design technique, the transducer could achieve better broadband working performance with fine qualities such as low frequency, high power, high efficiency and low cost than traditional flextensional transducer within limited size and weight conditions. The driving element of a gourd transducer is commonly made up of piezoelectric ceramic. In recent years, rare-earth giant magnetostrictive materials such as Terfenol-D is becoming more and more attractive because of its high strain and energy density, low Young's modulus and sound velocity. All of these attributes make it suitable for low frequency, high power and broadband transducer applications. The performance of a gourd transducer under different driving mode is studied in this paper. The driving element is made up of single piezoelectric material, single magnetostrictive material and the union of them respectively. Using finite element analysis, the transmitting current/voltage response of transducer for each mode are simulated and compared in detail. The transducer with piezoelectric driver has the largest maximum source level. The transducer with magnetostrictive driver has higher sound power in low frequency range compared with the projector with piezoelectric driver. Also the transducer with hybrid magnetostrictive-piezoelectric drivers could achieve the best balance between high sound power and broad working bandwidth.