Intensive ultrasonic waves can be generated based on the magnetostriction effect. These waves are used in many industries such as engineering, agriculture, and food industry. In this study, nickel as a naturally abundant magnetostrictive material was used in the core of a magnetostrictive transducer. This study aimed to investigate the influence of core geometry on the behavioral performance of the magnetostrictive ultrasonic transducer. The results showed that slightly stretching (elongating) the cross-section of the core increases the maximum radial and longitudinal magnetostrictive forces. Moreover, in tapered cores, by increasing the cone angle up to 30°, the maximum radial magnetostrictive force increased and then decreased. By increasing the cone angle, the maximum longitudinal magnetostrictive force and the coil required voltage almost linearly decreased. A proper ultrasonic transducer should have maximum sound pressure variations in the medium (sample). Thus, the variations of the magnetostrictive force in the longitudinal direction (Z axis) should be maximized. The results indicated that the conical core with a cone angle of 30° has the highest variations of magnetostrictive force in the Z-direction.

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