超磁致伸缩单激励椭圆振动系统的设计

Design of giant magnetostrictive elliptical vibration system with single excitation

为了实现超声振动辅助加工,该文研制了一种超磁致伸缩单激励椭圆振动系统,其由超磁致伸缩换能器和结构不对称的弯曲振动变幅杆组成。利用各组件之间的连续边界条件,推导出超磁致伸缩换能器的频率方程,并根据Timoshenko理论设计了变幅杆。随后,利用有限元方法研究了变幅杆中的过渡圆弧对振动系统输出端头产生的椭圆轨迹的影响。振动系统的谐振频率设计值为20.486 kHz,在换能器的激励下,变幅杆产生纵向及横向振动。实验测试了振动系统的等效电阻抗、变幅杆端面处的纵向和横向振动振幅以及两者的相位差。结果表明,振动系统的实际谐振频率为20.7 kHz,带宽为187.5 Hz,纵向振幅稍大于横向振幅,多次测试后的纵横向振动的平均相位差为101◦。测试的谐振频率、变幅杆端头运动轨迹与计算结果相符。

A giant magnetostrictive single-excitation elliptical vibration system for ultrasonic vibration assisted machining was developed in this paper,which was composed of a giant magnetostrictive transducer and an asymmetric flexural vibration horn.Based on the continuous boundary conditions between the components,the frequency equation of the giant magnetostrictive transducer was derived,and the horn was designed based on Timoshenko theory.Then,the influence of the transition arc in the horn on the elliptical trajectory of the output end of the vibration system was studied by using the finite element method.The design value of the resonant frequency of the vibration system was 20.486 kHz,the horn produced longitudinal and transverse vibration under the excitation of the transducer.The equivalent electrical impedance of the vibration system,the longitudinal and transverse vibration amplitudes at the end face of the horn and the phase difference between them were tested experimentally.The results show that the resonance frequency of the vibration system was 20.7 kHz,the bandwidth was 187.5 Hz,the longitudinal amplitude was slightly greater than the transverse amplitude,and the average phase difference of the longitudinal and transverse vibration after multiple tests was 101◦.The measured resonance frequency and the movement track of the end of the horn were consistent with the calculated results.