基于激光测振仪的兰姆波离面和面内位移检测.pdf

ww. llc hu.cemm
第48卷第8期
机械工程学报
Vo】.48No.8
2012年4月
JOURNAL OF MECHANICAL ENGINEERING
2012
DOI:10.390I/JME.2012.08.006
基于激光测振仪的兰姆波离面和面內位移检测
何存富郑阳周进节吴斌
(北京工业大学机械工程与应用电子技术学院北京100124)
摘要:激励模态和频响特性是超声导波传感器性能评估的两个重要指标,而传统的传感器,如压电传感器和电磁声传感器
( Electromagnetic acoustic transducer,EMAT)等,受自身带宽和模态选择性的影响,无法有效地实现这两个参数的评估。激光
测振仪可以测量结构中弹性波原始的离面和面内位移,且测量不受带宽的限制,因而是进行超声导波传感器激励模态测定和
频响特性测量的理想方法之ー。采用此种方法对一种周向一致激励兰姆波的EMAT进行测试,结果表明,此传感器在150
210kHz的范围内能激励产生出单一S0模态兰姆波,在50~150kHz范围内,A0模态与S0模态共存。利用激光测振仪检测
离面和面内位移的方法,是进行传感器评估和兰姆波接收的有效方法,在超声导波的非接触测量、高温波导体检测及弹性波
传播3D可视化方面也有广阔的应用前景
关键词:激光测振仪兰姆波离面位移面内位移电磁声传感器
中图分类号:TG52TB553
In-plane and Out-of-plane Displacement of Lamb Waves
Test with Laser Vibrometer
HE Cunfu ZHENG Yang ZHOU Jinjie WU Bin
(College of Mechanical Engineering and Applied Electronics Technology,
Beijing University of Technology, Beijing 100124)
Abstract: Excited modes and frequency response are two key parameters of ultrasonic guided wave transducers evaluating. However,
traditional transducers such as piezoelectric transducer and electromagnetic acoustic transucer(EMAT)cant measure these two
parameters efficiently because of the limit of frequency bandwidth and mode selection of themselves, Laser vibrometer can be
employed to measure the raw in-plane and out-of-plane displacement of elastic waves in the structure without the limit of bandwidth
Thus it could be one of the ideal methods to identity the excited modes and measure the frequency response curve. A kind of
omnidirecional lamb wave EMAT is been ineed by his m ho The results show that the transducer can produce purity S0 mode
in 150-200 KHZ and both A0 and $0 mode in 50-150 khz. It can be predicted that the method using laser vibrometer to detect the
widely used in no-contact measurement, high temperature testing and 3D visualization of elastic waves propagation(
in-plane and out-of-plane displacement is an efficient method of evaluating the transducer and receiving Lamb waves, and can be
Key words: Laser vibrometer Lamb wave Out-of-plane displacement In-plane displacement
Electromagnetic acoustic transducer(EMAT
评价超声导波激励传感器的性能和模态转换等研究
0前言
的关键问题,而利用传统的传感技术,无法准确测
量得出兰姆波的离面和面内位移。近年来,许多学
兰姆波广泛应用于对压力容器叫、船舰等常者利用激光测振仪对离面和面内位移进行测量,实
规板材结构和飞机机身、风力机叶片啊等复合材现兰姆波检测研究。 STASZEWSKI等?利用激光
料板的无损检测与结构健康监测中。兰姆波的离面测振仪测量板中的离面位移,进行A0模态兰姆波
和面内位移测量,是分析板中存在的兰姆波模态、的检测,试验证明其测量效果与压电晶片测量效果
致,是一种有效的检测兰姆波的手段,并利用三
*国家自然科学基金资助项目(10972014)20110630收到初稿,2011116
收到修改稿
台分布于不同位置的激光测振仪进行了兰姆波3D