PARAMETER OPTIMIZATION AND NUMERICAL CALCULATION FOR GIANT MAGNETOSTRICTIVE TRANSDUCER

In the study of piezoelectric ceramic transducers, a lot of high quality papers are published in journal NATUR. In this paper, a new type of transducers is developed with rare earth giant, magnetostrictive materials (GMM). The transducers are good at solving the ultrasonic nondestructive testing of the large components in concrete. For the transducers, the impedance characteristics, the vibration velocity and the stress of the rare earth GMM transducers are calculated by a new method of Four-Terminal Network Method (FTNM) combined with the Fourier Transform (FT). Experimental results prove that the results numerically calculated by the new method are correct. In addition, the pre-stress, the electrical parameters and the geometric dimensions are optimized, and thereafter, the rare earth Giant Magnetostrictive Transducer (GMT) with longitudinal vibration is developed based on the optimal parameters. The studied transducer has the advantages of the larger power, higher frequency and minimum residual vibration in nondestructive testing. The testing results show that the ultrasonic nondestructive detection of bridge and the massive concrete (length: 6m similar to 10m) with internal quality can be carried out.