Zheng Fei, Yuan Shenfang
Research Center of Structural Health Monitoring and Prognosis, State Key Laboratory of Mechanics and Control for Aerospace Structures, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016, China.
Sensors (Basel). 2024 Mar 15;24(6):1882. doi: 10.3390/s24061882.
Composite materials, valued in aerospace for their stiffness, strength and lightness, require impact monitoring for structural health, especially against low-velocity impacts. The MUSIC algorithm, known for efficient directional scanning and easy sensor deployment, is gaining prominence in this area. However, in practical engineering applications, the broadband characteristics of impact response signals and the time delay errors in array elements' signal reception lead to inconsistencies between the steering vector and the actual signal subspace, affecting the precision of the MUSIC impact localization method. Furthermore, the anisotropy of composite materials results in time delay differences between array elements in different directions. If the MUSIC algorithm uses a fixed velocity value, this also introduces time delay errors, further reducing the accuracy of localization. Addressing these challenges, this paper proposes an innovative MUSIC algorithm for impact imaging using a guided Lamb wave array, with an emphasis on time delay management. This approach focuses on the extraction of high-energy, single-frequency components from impact response signals, ensuring accurate time delay measurement across array elements and enhancing noise resistance. It also calculates the average velocity of single-frequency components in varying directions for an initial impact angle estimation. This estimated angle then guides the selection of a specific single-frequency velocity, culminating in precise impact position localization. The experimental evaluation, employing equidistantly spaced array elements to capture impact response signals, assessed the effectiveness of the proposed method in accurately determining array time delays. Furthermore, impact localization tests on reinforced composite structures were conducted, with the results indicating high precision in pinpointing impact locations.
复合材料因其刚度、强度和轻质特性在航空航天领域备受重视，需要对其进行冲击监测以确保结构健康，尤其是针对低速冲击。以高效定向扫描和易于传感器部署而闻名的MUSIC算法在该领域正日益受到关注。然而，在实际工程应用中，冲击响应信号的宽带特性以及阵列元件信号接收中的时延误差导致导向矢量与实际信号子空间之间存在不一致，影响了MUSIC冲击定位方法的精度。此外，复合材料的各向异性导致不同方向上的阵列元件之间存在时延差异。如果MUSIC算法使用固定速度值，这也会引入时延误差，进一步降低定位精度。针对这些挑战，本文提出了一种创新的使用导波兰姆波阵列进行冲击成像的MUSIC算法，重点在于时延管理。该方法专注于从冲击响应信号中提取高能、单频分量，确保跨阵列元件的精确时延测量并增强抗噪声能力。它还计算不同方向上单频分量的平均速度以进行初始冲击角度估计。然后，这个估计角度指导特定单频速度的选择，最终实现精确的冲击位置定位。实验评估采用等间距排列的阵列元件来捕获冲击响应信号，评估了所提方法在准确确定阵列时延方面的有效性。此外，还对增强复合材料结构进行了冲击定位测试，结果表明在精确确定冲击位置方面具有高精度。
