超磁致伸缩换能器预应力优化设计方法研究

为优化超磁致伸缩换能器的工作性能、提高输出振幅,基于预应力对磁致伸缩效应的作用机理,建立了饱和磁致伸缩系数与预应力的关系模型。提出磁致伸缩灵敏度的概念,建立其与预应力和外磁场强度之间关系的理论模型。以超声换能器输出振幅最大为目标,提出以磁致伸缩平均灵敏度最大为准则的最佳预应力值确定方法。实验结果表明:随着预应力的增大,磁致伸缩平均灵敏度存在极大值,该预应力可在一定驱动磁场强度下获得最大的超声振幅,由此验证了磁致伸缩灵敏度模型的正确性和最佳预应力确定方法的可行性。提出的最佳预应力模型对超磁致伸缩换能器设计中预应力的选择具有指导意义,有助于大振幅超磁致伸缩换能器的设计及应用。

Research on the Optimization Design Method of Prestress for Giant Magnetostrictive Transducer

In order to improve the performance and amplitude of a giant magnetostrictive transducer, this paper establishes a mathematical model of saturation magnetostrictive coefficient and prestress based on the mechanism of the effect of prestress on a giant magnetostrictive. We put forth the concept of magnetostrictive sensitivity and proposed a theoretical model of magnetostrictive sensitivity, external magnetic field intensity and prestress. In order to maximize the amplitude of the ultrasonic transducer, we selected the optimal prestress with the criteria of the optimal average magnetostrictive sensitivity. The experimental results showed that average magnetostrictive sensitivity exists optimal value with increasing prestress, and maximum ultrasonic amplitude was obtained under a certain magnetic field, thereby verifying the validity of the model of magnetostrictive sensitivity and the feasibility of the optimal prestress method. The proposed model of optimal prestress has guiding significance for the choice of prestress, design, and application of a giant magnetostrictive transducer.