Abstract
Elastic-wave-based structural health monitoring technology has a broad application potential for its sensitivity and ability to achieve regional monitoring. For structures with large damping and specific shapes, the traditional damage monitoring method is limited by the sensor arrangement area and affected by low signal-to-noise ratios, so it is difficult to accurately locate the damage in a structure. To solve this problem, this paper proposed a damage monitoring method based on a sector piezoelectric sensor array for multiple signal classification algorithm. By arranging two sector piezoelectric sensor arrays that are suitable for a specific structure, the damage scattering array signal under the multi-excitation source was obtained and synthesized, the signal-to-noise ratios were improved, and the damage location accuracy was thus improved. The effectiveness of the method was verified by monitoring the damage in a circular bonded structure with a metal ring. Compared with the damage localization methods based on the traditional single excitation source multiple signal classification algorithm, path imaging and delay-sum imaging, this method can achieve better damage location and has a higher localization accuracy.
Highlights
High-reliability, high-performance structural safety services are of great importance to major or important mechanical equipment and infrastructure in fields such as aerospace, civil engineering, and rail transit
The focus array signal is used as the input of the multiple signal classification (MUSIC) algorithm to obtain the noise subspace and the steering vector space, the spatial spectrum is used to describe the orthogonality between them, and the damage location is realized by jointly searching the entire monitoring region
Using PZT A4 as the excitation source, the damage scattering array signal obtained by the difference between the reference signal received by array S and the damage signal was used as the input of the MUSIC algorithm
Summary
High-reliability, high-performance structural safety services are of great importance to major or important mechanical equipment and infrastructure in fields such as aerospace, civil engineering, and rail transit. A transmitter beamforming MUSIC damage imaging method based on a sector sensor array is proposed to perform damage monitoring of a special circular bonded structure In this method, according to the specific form of the circular bonded structure, the sector-shaped double sensor array is arranged, and the damage scattering array signal is superimposed at the search point according to the time delay rule to improve the SNRs. Through the eigenvalue decomposition of the covariance matrix of the superimposed sensor array signal, direction scanning is carried out on the structure, and the spatial spectrum of the monitoring area is constructed to locate the damage.
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