摘要
针对板结构中裂纹方向识别及定量检测问题,提出了一种板结构兰姆波阵列复合成像方法。利用超声阵列采集的单模态兰姆波全矩阵数据,分别提取其幅值信息和极性信息,进行全聚焦成像和极性一致成像,并利用极性一致成像对全聚焦成像进行了加权处理;对全阵列进行子阵列划分,计算出各子阵列的特征矢量,并进行加权合成,得到矢量全聚焦成像;利用全聚焦成像的强度信息和矢量全聚焦成像的方向信息,综合得到兰姆波阵列的复合成像,并从中提取出缺陷的方向及空间分布范围等信息。实验结果表明,提出的兰姆波阵列复合成像方法可以很好地实现板中多个裂纹方向识别,其角度测量误差在20%以内。本文工作为裂纹缺陷识别及定量检测做了有益探索。
Aiming at the problem of the direction identification and quantitative detection of cracks in metal plate,a compound imaging method for plate structure is developed using array of Lamb waves. From the total matrix data of single mode Lamb waves acquired with ultrasonic array,the amplitude and sign information is extracted,which are used for total focus imaging and sign coherence imaging; and the sign coherence imaging is used to perform the weighted processing for the full focus imaging. The total array is divided into sub-arrays,the feature vector of each sub-array is calculated,and all of them are superimposed with weight to get the vector total focus imaging; Using the intensity information on the weighted total focus imaging and the direction information of the vector total focus imaging,the compound imaging is obtained,from which the orientation and dimension information of the crack is extracted. The experiment results demonstrate that the proposed compound imaging method using array of Lamb waves can achieve the orientation characteristic identification of multiple cracks in plate nicely,and the angle measurement errors is within 20%. The research provides a useful exploration for the crack defect identification and quantitative detection of metal plate.
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2016年第3期593-601,共9页
Chinese Journal of Scientific Instrument
基金
国家自然科学基金(11272017
11572010
51235001)项目资助
关键词
兰姆波
超声阵列
复合成像
裂纹
矢量全聚焦成像
全聚焦成像
Lamb wave
ultrasonic array
compound imaging
crack
vector total focus imaging
total focus imaging
