超声的电磁脉冲激发方式的探讨

Discussion on excitation of ultrasound by electromagnetic pulse

主要研究了一种新的电磁超声激发方法-脉冲电磁超声的激发,旨在提高电磁超声换能器的磁声转换效率,解决其灵敏度低以及热效应的不良影响等问题。设计制作了脉冲电磁超声的激发装置。通过实验验证,该方式超声信号强度较强,激发装置发热量小。最后分析了超声波信号的激发强度与初始电压、电容容值等因素的关系,认为线圈中铁芯的加入在一定程度上可以提高磁声转换的效率。但目前产生的超声波信号频率仍在低频范围内,在今后的研究中还将进一步考虑采用信号压缩等方法来提高频率。

A new excitation mode of electromagnetic ultrasound, the excitation of pulsed electromagnetic ultrasound, is investigated. This conducts to enhancing the conversion efficiency of magnetism to ultrasound, improving the sensitivity and avoiding the adverse influence of thermal effect. The excitation device of pulsed electromagnetic ultrasound is developed. Experiments verify that the signal intensity of ultrasound is enhanced with little heat generated. In the end, the connection of acoustic signal＇ s intensity with the initial voltage and the capacitance value is analyzed. It is indicated that adding an iron core can enhance the conversion efficiency of magnetism to ultrasound to a certain extent. But the ultrasonic signal that can currently be excited is still in the range of low frequency. Therefore, the method of signal compression will be taken into account to heighten the frequency in the further research.