Multi-damage detection with embedded ultrasonic structural radar algorithm using piezoelectric wafer active sensors through advanced signal processing

The embedded ultrasonic structural radar (EUSR) algorithm was developed by using piezoelectric wafer active sensor (PWAS) array to detect defects within a large area of a thin-plate specimen. EUSR has been verified to be effective for detecting a single crack either at a broadside or at an offside position. In this research, advanced signal processing techniques were included to enhance inspection image quality and detect multiple damage. The signal processing methods include discrete wavelet transform for signal denoising, short-time Fourier transform and continuous wavelet transform for time-frequency analysis, continuous wavelet transform for frequency filtering, and Hilbert transform for envelope extraction. All these signal processing modules were implemented by developing a graphical user-friendly interface program in LabVIEW. The paper starts with an introduction of embedded ultrasonic structural radar algorithm, followed with the theoretical aspect of the phased array signal processing method. Then, the mathematical algorithms for advanced signal processing are introduced. In the end, laboratory experimental results are presented to show how efficiently the improved EUSR works. The results are analyzed and EUSR is concluded to have been improved by using the advanced signal processing techniques. The improvements include: 1) EUSR is able to provide better image of the specimen under monitoring; 2) it is able to detect multi-damage such as several cracks; 3) it is able to identify different damage types.

[1]  Shu-Jen Steven Tsai.  Power Transformer Partial Discharge (PD) Acoustic Signal Detection using Fiber Sensors and Wavelet Analysis, Modeling, and Simulation , 2002 .

[2]  Khaled H. Hamed,et al.  Time-frequency analysis , 2003 .

[3]  M. O'Donnell,et al.  Delta-sigma oversampled ultrasound beamformer with dynamic delays , 1999, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[4]  Mathias Fink.  Time-reversal mirrors , 1993 .

[5]  J.L. Rose,et al.  Implementing guided wave mode control by use of a phased transducer array , 2001, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[6]  Shi-Chang Wooh,et al.  Three-dimensional beam directivity of phase-steered ultrasound , 1999 .

[7]  Alistair McNab,et al.  An array-based system for monitoring cracks in industrial plant at high temperatures , 1996 .

[8]  Lingyu Yu,et al.  Advanced signal processing for enhanced damage detection with embedded ultrasonic structural radar using piezoelectric wafer active sensors , 2005 .

[9]  W. E. Lawrie,et al.  Ultrasonic testing of materials: 2nd English Edition, translated from the 3rd German Edition, J. & H. Krautkrämer Springer-Verlag, Berlin, Heidelberg, New York (1977) 667 pp, $65.20, DM 148 , 1978 .

[10]  Lingyu Yu,et al.  Embedded Ultrasonic Structural Radar with Piezoelectric Wafer Active Sensors for Damage Detection in Cylindrical Shell Structures , 2004 .

[11]  Victor Giurgiutiu,et al.  Embedded-Ultrasonics Structural Radar for Nondestructive Evaluation of Thin-Wall Structures , 2002 .

[12]  Darryll J. Pines,et al.  Damage Interrogation Using a Phased Piezoelectric Sensor/Actuator Array: Simulation Results on Two Dimensional Isotropic Structures , 2003 .

[13]  Mark M. Derriso,et al.  Structural health monitoring using wavelet transforms , 2001, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[14]  Arata Masuda,et al.  A study of health monitoring systems of linear structures using wavelet analysis , 1997 .