Research on Acoustic Emission Source Location Imaging in Aluminum Alloy Plate-type Structure
Research on Acoustic Emission Source Location Imaging in Aluminum Alloy Plate-type Structure
复制标题
铝合金板式结构声发射源定位成像研究
DOI：
10.1520/jte20180831
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发表时间：
2020-07
影响因子：
1.2
通讯作者：
Jun Hong
中科院分区：
文献类型：
--
作者：
Shaofeng wang;Daorui wang;Jianguo Wang;Hailing Wang;Guang Xu;Jun Hong
时反聚焦成像技术常用于板状结构上声发射源的定位。由于原始声发射信号的色散模式引起的计算误差，有时声发射源位于其真实的位置的邻近区域，伪声发射源将聚焦在声发射源的位置图像中。本研究的目的是如何有效地避免伪声发射源的聚焦。因此，在这篇文章中，香农小波变换与“Morlet”母小波被用来分离S0模式从原始AE信号。基于时间反转聚焦原理，对孤立S0模的模值曲线进行了时间反转、时间延迟和在监测区域内各网格点叠加的处理。声发射源位于叠加曲线峰值最大的网格点处。利用叠加曲线的峰值来定义每个网格点的像素值，实现对监测区域的成像。验证实验在600 mm × 600 mm的监测区域中进行，该监测区域位于尺寸为1，200 mm × 1，200 mm × 3 mm的5052铝合金板上。与传统的基于到达时间差（TDOA）计算的正方形定位方法相比，定位精度得到了提高，最大径向误差小于30 mm。此外，所提出的定位方法具有一定的能力，以克服板的尺寸和局部曲率的影响。
The time reversal focusing and imaging technique is often used to locate the acoustic emission (AE) source on a plate-type structure. Because of the computational error caused by the dispersive modes of the raw AE signal, the AE source is sometimes located in the adjacent region of its real position and the pseudo-AE source will be focused in the location image of the AE source. This study is interested in how to effectively avoid the focusing of the pseudo-AE source. Thus, in this article, a Shannon wavelet transform with “Morlet” mother wavelet was used to isolate S0 modes from raw AE signals. The modulus value curves of the isolated S0 modes were treated by time reversal, time delay, and superposition at every grid point in the monitoring area, based on the time reversal focusing principle. The AE source was located at a certain grid point where the peak of the superposition curve is maximal. The monitoring area imaging was realized by defining every grid point’s pixel value with the peak of the superposition curves. The validating experiment was done in a 600 mm by 600 mm monitoring area which is on a 5052 aluminum alloy plate with dimensions of 1,200 mm by 1,200 mm by 3 mm. Comparing with the traditional square location method based on time difference of arrival (TDOA) calculation, the localization accuracy was improved and the maximal radial error is lower than 30 mm. Furthermore, the proposed localization method has a certain ability to overcome the effect of the plate size and local curvature.