激光超声波零滞后互相关特性的金属损伤成像  

Metal damage imaging based on laser ultrasonic zero-lag cross-correlation characteristics

作　　者：欧海峰 朱凯然[1] 仵杰[1] 王波[1] OU Haifeng;ZHU Kairan;WU Jie;WANG Bo(School of Electronic Engineering, Xi’an Shiyou University, Xi’an 710065, China)

机构地区：[1]西安石油大学电子工程学院,西安710065

出　　处：《中国科技论文》2021年第12期1299-1306,共8页China Sciencepaper

基　　金：国家重大科研仪器研制项目(11927801);陕西省教育厅科研计划重点项目(18JS094);西安石油大学研究生创新与实践能力培养项目(YCS18213094)。

摘　　要：为了在激光超声检测技术中快速定位金属材料的表面损伤位置并精确估计损伤尺寸,对激光超声波零滞后互相关(zero-lag cross-correlation,ZLCC)特性的金属材料表面损伤成像进行了研究。首先,通过激光超声波检测仪对表面带有损伤的铝板材料进行检测,对检测到的时间、空间域超声波场做频率波数域分析并引入窗函数滤波,将入射波与反射波分离。其次,对入射波和反射波做互相关运算,获得检测区域内各点ZLCC值,提取出损伤区域的ZLCC值划分若干区间并统计各区间内的ZLCC值个数,选择95%置信区间对应的值作为降噪阈值。最后,对降噪后的数据进行成像。实验结果表明:所提方法能够对金属材料存在的表面损伤进行精确定位和尺寸估计,与最大幅值法相比,所提方法具有更高的检测精度。In order to quickly locate the surface damage location of metal materials and accurately estimate the damage size in laser ultrasonic testing technology,the surface damage imaging of metallic materials based on the characteristics of ultrasonic zero-lag cross-correlation(ZLCC)was studied.Firstly,the metallic material with surface damage was detected by a laser ultrasonic detector.The detected time-space domain ultrasonic field was subjected to frequency-wavenumber analysis and perform window function filtering,to separate the forward and backward waves.Then,the cross-correlation operation was performed on the incident and reflected wave to obtain the ZLCC value of each point in the detection region;The ZLCC value of the damage region was extracted;Several intervals was divided;The number of ZLCC values was counted in each interval,the value corresponding to the 95%confidence interval was selected as the noise reduction threshold.Finally,image the data after noise reduction.The experimental results show that the proposed method can accurately locate and estimate the size of the surface damage of metal materials.Compared with the maximum amplitude method,the proposed method has higher detection accuracy.

关 键 词：无损检测技术 金属损伤检测 激光超声检测 零滞后互相关 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]