摘要
Lamb波损伤成像是结构健康监测领域的研究热点之一,然而由于Lamb波的频散特性,当传播距离增大时,Lamb波包很容易发生扩展和变形,从而严重影响成像结果的分辨率,因此,频散补偿是Lamb波损伤成像中急需解决的一个重要问题。本文针对传统频散补偿方法需要结构材料参数计算理论波数的局限性,提出了一种可利用较容易测得的相对波数的线性频散信号构建(LD-SC)方法。首先研究了LD-SC方法的原理和实现途径,给出了相对波数的测量过程并从理论上证明了基于相对测量波数的LD-SC可行性,然后在材料参数未知的玻璃纤维复合材料板中进行了验证实验,结果表明基于现场测得相对波数的LD-SC方法可有效消除Lamb波的频散效应,从而提高多损伤成像分辨率。
Lamb wave damage imaging is one of the most interesting research areas in structural health monitoring However,due to the dispersion of Lamb waves,the shape of Lamb wavepacket will distort when the propagation dis- tance increases. This significantly reduces the resolution of imaging. Therefore, dispersion compensation is a vital problem needing to be immediately resolved in Lamb wave damage imaging. With the limit that structural material pa- rameters are required for theoretical wavenumber calibration in traditional dispersion compensation techniques, a line- ar-dispersive signal construction （LD-SC） method allowing using easily-measured relative wavenumbers is presented in this paper. Both the theory and realization of LD-SC are studied. The relative wavenumber measuring process is given. Moreover, the feasibility of LD-SC with measured relative wavenumbers is theoretically demonstrated. Finally, a validation experiment is implemented in a glass fiber composite plate. Experimental results show that, with relative wavenumbers measured on-site, dispersion effect of Lamb waves can be efficiently removed by LD-SC method and therefore, the multi-damage imaging resolution can be improved.
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2013年第4期948-954,共7页
Chinese Journal of Scientific Instrument
基金
国家自然科学基金(11172053
10872217)
国家高技术研究发展计划863(2012AA040209)资助项目
关键词
结构健康监测
LAMB波
频散补偿
信号构建
损伤成像
分辨率
Structural health monitoring
Lamb waves
dispersion compensation
signal construction
damage imaging
resolution
