Sparse Reconstruction and Damage Imaging Method Based on Uniform Sparse Sampling
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ISSN 1860-2134
Sparse Reconstruction and Damage Imaging Method Based on Uniform Sparse Sampling Pengfei Li1
Ying Luo1
Kan Feng1
Yang Zhou1
Chenguang Xu1
1
( National Center for International Research on Structural Health Management of Critical Components, Jiangsu University, Zhenjiang 212013, China)
Received 15 July 2020; revision received 10 September 2020; Accepted 15 September 2020 c The Author(s) 2020
ABSTRACT The full wavefield detection method based on guided waves can efficiently detect and locate damages relying on the collection of large amounts of wavefield data. The acquisition process by scanning laser Doppler vibrometer (SLDV) is generally time-consuming, which is limited by Nyquist sampling theorem. To reduce the acquisition time, full wavefield data can be reconstructed from a small number of random sampling point signals combining with compressed sensing. However, the random sampling point signals need to be obtained by adding additional components to the SLDV system or offline processing. Because the random sparse sampling is difficult to achieve via the SLDV system, a new uniform sparse sampling strategy is proposed in this paper. By using the uniform sparse sampling coordinates instead of the random spatial sampling point coordinates, sparse sampling can be applied to SLDV without adding additional components or offline processing. The simulation and experimental results show that the proposed strategy can reduce the measurement locations required for accurate signal recovery to less than 90% of the Nyquist sampling grid, and the damage location error is within the minimum half wavelength. Compared with the conventional jittered sampling strategy, the proposed sampling strategy can directly reduce the sampling time of the SLDV system by more than 90% without adding additional components and achieve the same accuracy of guided wavefield reconstruction and damage location as the jittered sampling strategy. The research results can greatly improve the efficiency of damage detection technology based on wavefield analysis.
KEY WORDS Scanning laser Doppler vibrometer, Lamb waves, Compressed sensing, Wavefield sparse reconstruction, Damage imaging
1. Introduction Lamb waves have received considerable attention in the fields of non-destructive testing (NDT) and structural health monitoring (SHM) because they are capable of traveling relatively long distances with low attenuation and sensitive to internal damage in plate-like structures [1–3]. As the most traditional Lamb waves detection method, distributed sensor arrays are often used to record acoustic emissions [4–8], which include single-ring [9], two-dimensional square arrays [10] and more complicated configurations [11]. While the above arrays can effectively obtain signals, the following disadvantages and limitations still exist in practical applications: (1) The sensors are usually connected to the specimen by cables, which easily influence wave propagation. Moreover, sensors and cables are vulnerable to
Corresponding author. E-mail: [email protected]
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