Broadband acoustic transducer driven by magnetostrictive composite rod and electrostrictive stack

An acoustic transducer consisting of a magnetostrictive Terfenol-D composite and electrostrictive PMN-PT stack connected in mechanical series is presented. A broadband velocity response is possible in this transducer when the two sections are connected in electrical parallel. A linearly coupled electromechanical model is formulated through mechanical vibrations, classical electroacoustics, and linear piezoelectricity and piezomagnetism. The linear model is used to analytically calculate the head mass velocity of the transducer in response to white noise voltage excitation. The analytical solutions are shown to correlate well with measurements, while providing a framework for calculation of material properties under the same dynamic conditions found during operation, as opposed to quasistatic conditions.