作者：邱佳明, 丁汉绅, 王淑娟
作者单位：哈尔滨工业大学电气工程及自动化学院, 黑龙江 哈尔滨 150001
关键词：电磁超声换能器;脉冲电磁铁;测厚;移动性
摘要：
针对传统电磁超声换能器(electromagnetic acoustic transducer，EMAT）在钢板表面移动困难、探头易磨损等问题，提出利用脉冲电磁铁替代永磁铁为换能器提供偏置磁场的方法。该方法通过控制激励电流来控制脉冲电磁铁仅在超声体波发射接收瞬间激发脉冲磁场，提高换能器在试件表面多点测量时的移动性。通过对脉冲电磁铁励磁线圈、铁芯以及驱动电路的设计，使得脉冲磁场满足EMAT对于偏置磁场强度及维持时间的需求。为测试该脉冲电磁铁的性能，搭建电磁超声钢板测厚实验平台。结果表明：激励电流仿真值与实测值相似度达90%，脉冲电磁铁可产生峰值约0.8 T、维持时间120 s的脉冲磁场，以该方法设计的换能器可对50 mm厚钢板进行测厚同时具有良好的移动性。
Design of pulsed electromagnet for electromagnetic ultrasonic steel thickness gauging device
QIU Jiaming, DING Hanshen, WANG Shujuan
School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China
Abstract: Aiming at the problems of traditional EMAT(electromagnetic acoustic transducer) on steel plate surface such as difficulty in moving and damages of probe, a pulsed electromagnet is developed to provide bias magnetic field for the EMAT instead of a permanent magnet. By controlling the excitation current, the method controls the pulsed electromagnet to motivate pulsed magnetic field only at the moment when ultrasonic wave is transmitted and received, which improves the mobility of the transducer on the surface of specimen during multi-point measurement. Through the design of the excitation coil, iron core and driver circuit of the pulsed electromagnet, the pulsed magnetic field meets the requirements of EMAT on the strength and duration time of the bias magnetic field. To test the performance of the pulsed electromagnet, an electromagnetic ultrasonic steel thickness gauging platform is set up. The results show that the simulation values and the measured values of the current have a similarity of 90%, and the pulsed electromagnet can generate a pulsed magnetic field with about 0.8 T amplitude and 120 μs duration time. The transducer can gauge steel plate with 50 mm thickness and also has a good mobility.
Keywords: EMAT;pulsed electromagnet;thickness gauging;mobility
2018, 44(5): 77-82 收稿日期: 2018-02-10;收到修改稿日期: 2018-03-07
基金项目:
作者简介: 邱佳明(1994-),男,吉林长春市人,硕士研究生,专业方向为电磁超声脉冲电磁铁设计。
参考文献
[1] HIRAO M, OGI H. Electromagnetic acoustic transducers:noncontacting ultrasonic measurements using EMATS[M]. Berlin:Emats for Science&Industry,2017.
[2] FRANCISCO H V, STEVE D. Initial tests for designing a high temperature EMAT with pulsed electromagnet[J]. NDT&E International,2010(43):171-175.
[3] FRANCISCO H V, STEVE D. Preliminary tests to design anEMAT withpulsed electromagnet for hightemperature[C]//American Institute of Physics Conference Series,2009,1096(1):936-941.
[4] MIKHAILOV A V, GOBOV Y L. An electromagnetic-acousic transducer with pulsed biasing[J]. Russian Journal of Nondestructive Testing,2015,51(8):467-485.
[5] 张恒. 用于钢轨探伤的脉冲电磁式电磁超声体波换能器设计[D]. 哈尔滨:哈尔滨工业大学,2015.
[6] PEI C X, XIAO P, ZHAO S Q, et al. Development of a flexible film electromagnetic acoustic transducer for nondestructive testing[J]. Sensors and Actuators A:Physical,2017(258):68-73.
[7] 汪开灿,康磊,翟国富,等. 基于USB的电磁超声数据采集及分析系统的设计[J]. 无损检测,2010,32(10):825-828.
[8] JIAN X, STEVE D. Enhancement of EMAT and eddy current using a ferrite back-plate[J]. Sensors & Actuators A Physical,2007,136(1):132-136.
[9] 孙峥,李永虔,杨金旭,等. 管道内检测电磁超声在线测厚装置[J]. 中国测试,2017,43(2):69-72.
[10] ZHANG H, SU R L, WANG S J, et al. Design of bulk wave EMAT using a pulsed electromagnet[J].Nondestructive Evaluation,2014:242-246.
[11] 孙红霞. 基于Multisim8的二阶网络状态轨迹仿真分析[J]. 现代电子技术,2014,37(6):117-121.
[12] 张祖信. 脉冲磁场充磁的若干问题探讨[J]. 磁性材料及器件,2000,31(5):45-47.
[13] 王慧娟,李慧奇. 基于COMSOL Multiphysics的通电螺线管磁场分析[J]. 实验科学与技术,2014,12(6):31-35.
[14] 王淑娟,康磊,李智超,等. 电磁超声换能器三维有限元分析及优化设计[J]. 中国电机工程学报,2009(30):123-128.
[15] 周海强,杨占锋,李勇,等. 静态偏置磁场对铁磁材料电磁超声换能器信噪比的影响[J]. 无损检测,2014,36(10):25-28.
[16] 冯慈璋,马西奎. 工程电磁场导论[M]. 北京:高等教育出版社,2006:35-39.
