Kazys R, Mazeika L, Barauskas R, Raisutis R, Cicenas V, Demcenko A
Ultrasound Institute, Kaunas University of Technology, Studentu str. 50, Kaunas LT-51368, Lithuania.
Ultrasonics. 2006 Dec 22;44 Suppl 1:e1127-30. doi: 10.1016/j.ultras.2006.05.152. Epub 2006 Jun 9.
The objective of the research presented here is the investigation of the interaction of guided waves with welds, defects and other non-uniformities in steel plates loaded by liquid. The investigation has been performed using numerical simulation for 2D and 3D cases by the finite differences method, finite element method and measurement of 3D distributions of acoustic fields. Propagation of the S(0) mode in a steel plate and its interaction with non-uniformities was investigated. It was shown that using the measured leaky wave signals in the water loading of the steel plate and by application of signal processing, the 3D ultrasonic field structure inside and outside of the plate can be reconstructed. The presence of leaky wave signals over the defect caused by the mode conversion of Lamb waves has been proved using the numerical modelling and experimental investigations. The developed signal and data processing enables to visualise dynamics of ultrasonic fields over the plate, and also to estimate spatial positions of defects inside the steel plates.
本文所呈现的研究目标是探究在液体加载的钢板中，导波与焊缝、缺陷及其他不均匀性之间的相互作用。该研究通过有限差分法、有限元法对二维和三维情况进行数值模拟，并测量声场的三维分布来开展。研究了S(0)模式在钢板中的传播及其与不均匀性的相互作用。结果表明，利用钢板水加载过程中测得的泄漏波信号并应用信号处理方法，可以重建钢板内部和外部的三维超声场结构。通过数值建模和实验研究，证实了由兰姆波模式转换引起的缺陷上方存在泄漏波信号。所开发的信号和数据处理方法能够可视化钢板上超声场的动态变化，还能估计钢板内部缺陷的空间位置。
