Lamb wave-based subwavelength damage imaging using the DORT-MUSIC technique in metallic plates
Lamb wave-based subwavelength damage imaging using the DORT-MUSIC technique in metallic plates
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DOI：
10.1177/1475921715623359
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发表时间：
2016-01-01
影响因子：
6.6
通讯作者：
Yuan, Fuh-Gwo
中科院分区：
文献类型：
--
作者：
He, Jiaze;Yuan, Fuh-Gwo
提出了一种基于Lamb波的亚波长成像算法，该算法基于时反算子分解方法，结合空频域多信号分类成像条件，对金属板损伤进行了成像。在这项研究中，提出了一种混合非接触式检测系统，使用压电线性阵列的驱动和激光多普勒测振仪线扫描垂直于压电阵列的传感图像在铝板的损伤。在基于一阶玻恩近似的导波的背景下，在时间反演算子方法的分解中作为传递矩阵基础的入射波、反射波和反射波的物理学在数学上用公式表示。然后采用奇异值分解将实验测量的传递矩阵分解为三个矩阵，详细描述了从线性致动器阵列的入射波传播，从损伤的反射，以及随后针对每个小损伤朝向线性传感阵列的反射波。奇异值分解和多信号分类成像条件使得能够提供对损伤“反射率”的洞察并检测小于波长（亚波长）的损伤。由于该检测系统的灵活性，可以使用具有快速线扫描的较低频率兰姆波对相当大的区域进行成像。实验结果表明，硬件系统结合信号处理工具，如多信号分类时间反演算子分解（多信号分类时间反演）成像技术，可以提供稳健、高精度的成像结果，并可提供未知材料属性的损伤反射率估计。
A Lamb wave-based, subwavelength imaging algorithm is developed for damage imaging in a metallic plate based on a decomposition of the time-reversal operator method together with a multiple signal classification imaging condition in the space-frequency domain. In this study, a hybrid non-contact inspection system was proposed to image damage in an aluminum plate using a piezoelectric linear array for actuation and a laser Doppler vibrometer line-scan perpendicular to the piezoelectric array for sensing. The physics of incident waves, reflection, and reflected waves that underlie the transfer matrix in the decomposition of the time-reversal operator method is mathematically formulated in the context of guided waves based on the first-order Born approximation. Singular value decomposition is then employed to decompose the experimentally measured transfer matrix into three matrices, detailing the incident wave propagation from the linear actuator array, reflection from the damage, and followed by reflected waves toward the linear sensing array for each small damage. The singular value decomposition and multiple signal classification imaging condition enable providing insight on both the damage "reflectivity'' and detecting damage smaller than a wavelength (subwavelength). With the flexibility of this inspection system, a considerably large area can be imaged using lower frequency Lamb waves with rapid line-scans. The experimental results showed that the hardware system with a signal processing tools such as the decomposition of the time-reversal operator with multiple signal classification (time-reversal with multiple signal classification) imaging technique can provide robust, highly accurate imaging results as well as providing damage reflectivity estimation with unknown material properties.