一种高信噪比电磁声表面波传感器及在厚壁管道检测中的应用

发布时间：2019-07-09 10:52

【摘要】：为了提高在自激自收模式下接收信号的信噪比,自行研制一种不同结构配置的电磁声表面波传感器,分析其提高信噪比的机制及影响其信噪比的因素。在自激自收模式下,由于所研制的传感器中磁铁与线圈间存在间隔,降低了磁铁中超声波的影响,进而提高了信噪比。研究结果表明,接收信号的信噪比不仅与提离距离(磁铁与线圈的间隔)有关,而且与其中心频率成正相关关系。所研制的3个不同中心频率电磁声表面波传感器性能测试结果表明,其实测中心频率与设计值一致,其指向性与理论分析相吻合。采用所研制的表面波传感器对标准样块上不同深度的缺陷进行检测,试验结果表明,当缺陷深度约达表面波波长的1/4时,即可检测到该缺陷。进一步选用中心频率1.0 MHz的表面波传感器,实现了对厚壁管道上周向矩形槽、轴向矩形槽和平底孔3种类型缺陷的检测。
文内图片：

图片说明：钕铁硼永磁铁
[Abstract]:In order to improve the signal-to-noise ratio of the received signal in self-excited self-adduction mode, an electromagnetic surface acoustic wave sensor with different configuration is developed, and the mechanism of improving the signal-to-noise ratio and the factors affecting the signal-to-noise ratio are analyzed. In the self-excited self-charge mode, due to the gap between the magnet and the coil in the developed sensor, the influence of the ultrasonic wave in the magnet is reduced, and the signal-to-noise ratio is improved. The results show that the signal-to-noise ratio of the received signal is related not only to the lift-off distance (the spacing between the magnet and the coil), but also to its center frequency. The performance test results of three different center frequency electromagnetic surface acoustic wave sensors show that the center frequency is consistent with the design value, and the directivity is in agreement with the theoretical analysis. The surface wave sensor was used to test the defect of different depth on the standard sample block. The test results show that the defect can be detected when the defect depth is about 1/4 of the surface wave length. A surface wave sensor with a center frequency of 1.0MHz is further selected, and the detection of three types of defects of the thick-wall pipeline to the rectangular groove and the axial rectangular groove and the bottom hole of the flat bottom hole is realized.
【作者单位】：北京工业大学机械工程与应用电子技术学院;
【基金】：国家自然科学基金资助项目(51235001,11372016,51505013)
【分类号】：TP212

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