摘 要
电磁超声换能器(EMAT)是一种基于电磁超声转换技术的新型电声转换器。同时，它也是一款集超声波发射、接收装置于一体的非接触型换能器。因为电磁超声波无损技术在进行作业的时候是不需要有介质耦合的，也无需对试件进行准备处理等诸多优点，故其检测时的温度可以高达1000℃，对一般的被探测的工件表面也无需经过特殊处理，可以直接进行无损处理，因此电磁超声换能器广泛的应用在超声无损检测技术领域中。
本课题主要是对电磁超声换能器的工作原理进行研究以及在现有的电磁超声换能器的基础上对其进行优化设计。结合国内外发表的文献为研究基础，对电磁超声换能器的研究现状进行调查分析，总结电磁超声换能器各参数对其转换效率的影响，针对现有研究中的不足对其进行优化设计。
关键词：毕电磁超声换能器；超声无损检测；调查分析；优化设计；
ABSTRACT
Electromagnetic acoustic transducer (EMAT) is a new type of electromagnetic acoustic transducer based on ultrasonic conversion technology. At the same time, it is also a set of ultrasonic emission, receiving device in one of the non – contact type transducer. Because electromagnetic ultrasonic non-destructive technique in homework is no need for coupling medium, there is no need to pretreatment of specimen and many other advantages, so detection of the temperature can be up to 1000 DEG C, the general detection of workpiece surface nor need after special treatment, can directly handle lossless, so electromagnetic ultrasonic transducer is widely used in ultrasonic nondestructive detection technology field.
This topic mainly studies the working principle of the electromagnetic ultrasonic transducer and its optimization design based on the existing electromagnetic ultrasonic transducer. Combined with the published at home and abroad in the literature is the foundation of the research, investigation and analysis of the current situation of the study on the electromagnetic ultrasonic transducer, influence on the conversion efficiency of the parameters of the electromagnetic ultrasonic transducer is summarized. For deficiencies in the current study to optimize the design.
Key Words：electromagnetic ultrasonic transducer;ultrasonic nondestructive testing;investigation and analysis;optimization design
目 录
1 绪论……………………………………………………….. 1
1.1课题研究背景……………………………………………. 1
1.2国内外研究进展………………………………………….. 1
1.3主要研究内容……………………………………………. 1
2 电磁超声换能器的工作方式……………………………………… 3
2.1电磁超声换能器的发射原理和接收原理………………………… 3
2.1.1洛伦兹力的工作原理…………………………………….. 3
2.1.2磁致伸缩力的工作原理…………………………………… 4
2.2电磁超声换能器常见的波…………………………………… 5
2.2.1电磁超声换能器常见的波…………………………………. 5
2.3 总结………………………………………………….. 6
3电磁超声换能器的硬件电路设计…………………………………… 9
3.1 激励电路………………………………………………. 9
3.1.1 信号发生电路…………………………………………. 9
3.1.2 功率放大电路…………………………………………. 9
3.1.3 吸收电路…………………………………………….. 9
3.1.4 阻抗匹配电路…………………………………………. 9
3.2 接收电路………………………………………………. 9
3.2.1 限幅电路…………………………………………….. 9
3.2.2 前置放大电路…………………………………………. 9
3.2.3 带通滤波电路…………………………………………. 9
3.2.4 主放大电路（信号处理）………………………………… 9
4 电磁换能器的实验研究………………………………………… 11
4.1兰姆波激发实验…………………………………………. 11
4.2表面波激发实验…………………………………………. 11
结 论…………………………………………………………………………………………………………….. 12
参考文献…………………………………………………………………………………………………………….. 13
致 谢…………………………………………………………………………………………………………….. 15
