基于弯折频率变换的Lamb波高分辨率损伤成像  

High-resolution damage imaging of lamb waves based on warped frequency transform

作　　者：付尚琛[1] 石立华[1] 马丁[1] 蔡建[1] 

机构地区：[1]解放军理工大学电磁环境效应与光电工程国家级重点实验室,南京210007

出　　处：《振动与冲击》2014年第1期1-5,共5页Journal of Vibration and Shock

基　　金：国家自然科学基金项目(10872217)

摘　　要：Lamb波在结构健康监测中受到广泛关注,但其在传播过程中存在着多模和频散特性,不利于损伤定位和高分辨率成像。弯折频率变换(Warped Frequency Transform,WFT)通过构建合理的弯折映射可实现对频率轴的弯折。基于Lamb波群速度频散曲线设计弯折频率变换,则可用于Lamb波信号的处理。从直接补偿角度出发,利用WFT对传感信号进行频散抑制。提出了基于WFT的高分辨率损伤成像方法,利用有限元软件ABAQUS进行了带损伤铝板中Lamb波传播的仿真。仿真结果表明WFT能有效压缩频散的波包,通过该成像方法可实现高分辨率损伤成像。Lamb waves have received great attention in structural health monitoring （SHM）,but it is unfavourable in use due to its multi-mode character and dispersion effect,which impact the damage positioning and high-resolution imaging.Warped frequency transform （WFT）based on the group velocity dispersion curves of Lamb waves can be employed to process Lamb waves.Taking advantage of the direct dispersion compensation idea,WFT was adopted here to process the measured signals to suppress dispersion.A new method of high-resolution damage imaging was proposed based on WFT,and the propagation of Lamb waves in damaged aluminum plate was simulated by using finite element software ABAQUS.The results show that WFT can effectively compress dispersed wave-packets,and high-resolution damage imaging can be obtained by the proposed method.

关 键 词：LAMB波 频散补偿 弯折频率变换 损伤成像 

分 类 号：TP18[自动化与计算机技术—控制理论与控制工程] TN911.7[自动化与计算机技术—控制科学与工程]