Visualization and Modal Analysis of Guided Waves from a Defect in a Pipe
Visualization and Modal Analysis of Guided Waves from a Defect in a Pipe
复制标题
DOI：
10.1143/jjap.48.07gd06
复制
发表时间：
2009-07
影响因子：
1.5
通讯作者：
M. N. Salim;T. Hayashi;M. Murase;S. Kamiya
中科院分区：
文献类型：
--
作者：
M. N. Salim;T. Hayashi;M. Murase;S. Kamiya
许多商业导波管道检测技术使用轴对称扭转模式T（0，1）以及纵向振动L（0，2）模式作为入射波，因为扭转模式具有低衰减和非色散的显著特性。然而，从管道中的缺陷反射波包含许多模式以外的入射扭转模式，和复杂的反射波传播有时会阻止我们定位缺陷的领域。因此，我们进行了可视化的导波传播周围的整个圆周的管道，以解释反射波的行为，从缺陷发生在管道检测。在这项研究中，大量的RF信号测量在许多位置上的弯曲表面的管道进行了使用激光多普勒测振仪（LDV）和6轴机械臂，扫描了两个管道的弯曲表面的圆周和倾斜的缺陷。从缺陷的导波传播的可视化示出了平面内和平面外振动，以分析当使用轴对称扭转模式T（0，1）作为管道检测中的入射波时，在这些缺陷周围的管道中发生的模式转换。
Many commercial guided wave pipe inspection techniques use an axisymmetric torsional mode T(0,1) as well as a longitudinally vibrating L(0,2) mode as incident waves since the torsional mode has prominent characteristics of low attenuation and nondispersion. However, reflected waves from defects in a pipe contain many modes other than the incident torsional mode, and the complex reflected wave propagation sometimes prevents us from locating defects in the field. Therefore, we carried out a visualization of guided wave propagations around the full circumference of pipes to explain the behavior of reflected waves from defects that occur in pipe inspections. In this study, a large number of RF signal measurements at many locations on the curved surfaces of pipes were performed using a laser Doppler vibrometer (LDV) and a 6-axis robot arm that scanned over the curved surfaces of two pipes with circumferential and oblique defects. The visualizations of guided wave propagations from defects are shown for both in- and out-of-plane vibrations to analyze the mode conversions that occur in pipes around these defects when using the axisymmetric torsional mode T(0,1) as an incident wave in pipe inspections.