基于纵向超声导波管道非通透缺陷检测研究

Detection of non-penetrating defect in pipeline based on the longitudinal ultrasonic guided wave

管道经过长期服役后,由于磨损、腐蚀和意外损伤等原因,对管道正常运行产生危害。在实际工况中,小的腐蚀缺陷容易发展成腐蚀穿孔,浅层的小裂纹容易发展成穿透型裂纹,因此探究如何有效检测管道小宽度非通透缺陷是很有必要的。利用ANSYS有限元仿真软件模拟纵向模态导波对管道的周向和斜向非通透缺陷的检测,得到了周向非通透缺陷的反射系数曲线,并证实时间反转法可以显著提高导波对非通透斜裂纹的检测能力。还针对空管和充水管非通透斜裂纹的定位问题进行了研究,结果表明利用时间反转法可以得到缺陷较为精确的周向与轴向位置及大致形状。

The wear, corrosion and accidental damage will harm the normal usage of the pipeline after long term oper- ation. Under the practical working conditions, the small corrosion defects can be easily developed into corrosion perforation. Meanwhile, small crack in the shallow layer is likely to develop into a penetrating crack. Therefore, research on how to effectively detect the small defects in pipeline is necessary. In this paper, the longitudinal ultrasonic guide wave based detections of circumferential and oblique non-penetrating defects are simulated by ANSYS finite element simulation software. The reflection coefficient curves of circumferential non-penetrating defects are obtained. It is also proved that the time reversal method could considerably increase detection capability to the oblique non penetrating defects. This paper also investigates the localization problem of the oblique non penetrating defects in hollow pipeline and liquid-filled pipeline. The result indicates that by the time reversal method, the more accurate circumferential and axial positions and the approximate shape of the defect can be obtained.