Numerical Evaluation and Experimental Test on a New Giant Magnetostrictive Transducer with Low Heat Loss Design

Giant magnetostrictive transducer with micro and nano precision has a wide application prospect in the field of remote sensing. However, excessive heat loss of components could generate during the energy conversion and transfer from electric energy to magnetic energy, and magnetic energy to mechanical energy, thereby affecting its long-term service and also reducing energy utilization. In this paper, a new magnetostrictive transducer is proposed and its excitation coil, internal and external magnetic circuit are optimized from the perspective of reducing heat loss. With the help of theoretical and finite element analysis, the response law between key parameters and heat loss of key components are summarized, which provides a basis for reducing heat loss. Finally, according to the optimization scheme, the prototype is processed, and the temperature rise and dynamic output performance of the transducer are tested by constructing an experimental setup. The results show that the transducer has a low temperature rise and good frequency response characteristics, which can provide support for long-time precise actuation on-orbit.

Особенности проведения неразрушающего контроля полимерных и композиционных материалов с использованием бесконтактной ультразвуковой стимуляции и лазерного вибросканирования

Until present, air-coupled (non-contact) ultrasonic excitation has not been routinely used in nondestructive testing of polymers and composites. It is believed that, by combining this stimulation technique with high-sensitive laser vibrometry, it would be possible to ensure acceptable quality of inspection avoiding any external influence on materials to be tested. This study is devoted to analyzing an ultrasonic inspection system including a non-contact magnetostrictive transducer and sa canning laser dopler vibrometer in application to nondestructive testing of polymeric and composite materials. The use of the magnetostrictor has ensured stimulation power high enough to detect hidden defects, provided that the experimental procedure has been appropriately optimized. The radiation pattern of the magnetostrictive device has been analyzed to demonstrate peculiarities of combining such type of ultrasonic emitters with a titanium waveguide.

Effect of Terfenol-D rod structure on vibration performance of giant magnetostrictive ultrasonic transducer

In this study, a giant magnetostrictive ultrasonic transducer was designed with Terfenol-D as the active material. The influence of different Terfenol-D rod structures on the performance of the giant magnetostrictive transducer was investigated. Finite element analysis was used to analyze the dynamics of the theoretical giant magnetostrictive transducer and to validate the design. Eddy current losses were simulated for Terfenol-D rods of various structures using finite element analysis in ANSYS Maxwell. Two different Terfenol-D rods were then fabricated with either slices along the axial direction or slit along the radial direction, then the impedance and amplitude of the magnetostrictive ultrasonic transducer composed of the two Terfenol-D rods were measured. The results suggest that sliced Terfenol-D rods can suppress eddy currents more effectively, resulting in higher energy conversion efficiency; therefore, the Terfenol-D rods of small giant magnetostrictive transducers should be sliced along the axial direction to suppress eddy currents, whereas radial slits should be adopted for the rods of large giant magnetostrictive transducers to ensure integrity of the Terfenol-D rod and avoid adverse effects on the vibration performance of the giant magnetostrictive transducer that are caused by cutting the rods.