Tola Kassahun Demissie, Quoc Tran Dai, Yu Byoungjoon, Park Seunghee
School of Civil, Architectural Engineering and Landscape Architecture, Sungkyunkwan University, Suwon 16419, Korea.
Department of Convergence Engineering for Future City, Sungkyunkwan University, Suwon 16419, Korea.
Materials (Basel). 2020 Mar 21;13(6):1436. doi: 10.3390/ma13061436.
Corrosion detection using a pulsed laser scanning system can be performed via ultrasonic wave propagation imaging. This method outputs illustrations of the wave field within the host structure; thus, it can depict wave-corrosion area interactions. Additionally, post-processing can be performed to enhance the visualization of corroded areas. The wavefield energy computed using RMS (Root Mean Square) is a validated post-processing tool capable of displaying the location and area of corrosion-damaged regions. Nonetheless, to characterize corrosion, it is necessary to determine its depth. The measurement of depth in conjunction with that of the corroded area via the RMS distribution enables the determination of all dimensions of corrosion damage. Thereafter, the flaw severity can be evaluated. This study employed a wavefield within a plate on which corrosion was developed artificially to generate frequency-wavenumber dispersion curves. The curves were compared with their counterparts from a corrosion-free plate. Alternatively, they could be compared with dispersion curves drawn using the depth and material properties of a pristine plate via a computer program. Frequency-wavenumber pairs were extracted from the dispersion curves produced using the portion of the wavefield within the corroded area. These were inserted into the Rayleigh-Lamb equation, from which depths were calculated and averaged.
使用脉冲激光扫描系统进行腐蚀检测可通过超声波传播成像来实现。该方法输出主体结构内波场的图示；因此，它能够描绘波与腐蚀区域的相互作用。此外，可以进行后处理以增强腐蚀区域的可视化效果。使用均方根（RMS）计算的波场能量是一种经过验证的后处理工具，能够显示腐蚀损伤区域的位置和面积。然而，为了表征腐蚀情况，有必要确定其深度。通过RMS分布结合腐蚀区域的测量来确定深度，能够确定腐蚀损伤的所有尺寸。此后，可以评估缺陷的严重程度。本研究在一块人工产生腐蚀的平板内利用波场生成频率 - 波数色散曲线。将这些曲线与来自无腐蚀平板的对应曲线进行比较。或者，也可以将它们与通过计算机程序利用原始平板的深度和材料特性绘制的色散曲线进行比较。从使用腐蚀区域内波场部分生成的色散曲线中提取频率 - 波数对。将这些对代入瑞利 - 兰姆方程，从中计算深度并求平均值。
