Structural Health Monitoring of Thin Aluminum Plate Using Acoustic Sensors

Abstract:

SHM is defined as “an emerging technology that can be defined as continuous, autonomous, real time, in-service monitoring of the physical condition of a structure by means of embedded or attached sensors with minimum manual intervention” .SHM provides the ability of a system to detect adverse changes within a system’s structure to enhance reliability and reduce maintenance costs. There are different Non-Destructive techniques like acoustic emission, ultrasonic, acousto-ultrasonic, guided ultrasonic waves or Lamb waves which are nowadays investigated for the development of an efficient and user-friendly damage identification system. This paper deals with the latter which is based on Lamb wave propagation. It has been developed especially for distinguishing different kinds of damages. The Lamb wave-based active SHM method uses piezoelectric (PZT) sensors to transmit and receive Lamb waves in a thin Aluminum plate. The Lamb wave modes (AO &SO) travel into the structure and are reflected by the structural boundaries, discontinuities, and damage. By studying their propagation and reflection, the presence of defect in the structure is determined. Laboratory level experiments have been carried out on thin Aluminum plates with angular, horizontal and vertical defect. The obtained waveform is filtered to avoid unwanted noise & disturbances using Savitzky-Golay filtering. The filtered waveforms are compared to differentiate the defects. Short Time Fourier Transform has been carried out on the acquired waveform. This study provides significant insight into the problem of identifying localized damages in the structure using PZT and dispersion of signal after they interact with different types of damage. Those small defects like the horizontal one that may be nearly missed in time domain analysis can also be clearly identified in the STFT analysis. Moreover the occurrence of So mode is also clearly seen. Thus, Lamb waves generated by PZT sensors and time-frequency analysis techniques could be used effectively for damage detection in aluminum plate. This study has given a complete idea of the working and the basic requirements of SHM system.

• Periodical: Advanced Materials Research (Volumes 622-623)
• Pages: 1389-1395
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.622-623.1389
• Online since: December 2012
• Authors: R. Nishanth, K. Lingadurai, V. Malolan, Gowrishankar Wuriti, M.R.M. Babu
• Keywords: Lamb Wave, PZT, SHM, Transducer

References

[1] Hui-Ru Shih, Wilbur L. Walters, Wei Zheng, and Jessica Everett, Course Modules on Structural Health Monitoring with Smart Materials , -The Journal of science and technology Volume 35, Number 2, Winter (2009).

[2] R. Gangadharan, C.R.L. Murthy, S. Gopalakrishnan, M.R. Bhat, D. Roy Mahapatra, Characterization of cracks and delaminations using Pwas and lamb wave based time- frequency methods, - International journal on smart sensing and intelligent systems volume 3, number 4, (dec2010).

DOI: 10.21307/ijssis-2017-417

[3] Kevin k. tseng, Liangsheng Wang"Structural damage identification for thin plates using smart Piezoelectric transducers ", Computer Methods in Applied Mechanics and Engineering, Volume 194, Issues 27-29, 22 (July 2005), Pages 3192-3209.

DOI: 10.1016/j.cma.2004.08.007

[4] Israel Lopez, Nesrin Sarigul , A review of uncertainty flight vehicle structural damage monitoring, diagnosis and control: Challenges and opportunities, - Progress in , Volume 46, Issue 7, (October 2010), Pages 247-273.

DOI: 10.1016/j.paerosci.2010.03.003

[5] Victor Giurgiutiu, Structural Health Monitoring Using Pwas, - Springerlink books.

[6] J. Grabowskaa, M. Palaczb, M. Krawczuka, Damage identification by wavelet analysis, - Mechanical Systems and Signal Processing Volume 22, Issue 7, ( October 2008), Pages 1623-1635.

[7] Lamb H, On waves in an elastic plate, - Proceedings of the Royal Society of London Series A, v. 93, pp.114-128, (1917. ).

[8] V. T. Rathod and D. Roy Mahapatra, Lamb wave based monitoring of plate-stiffener deboding using a circular array of piezoelectric sensors, -International journal on smart sensing and intelligent systems volume 3, number 1, (March 2010).

DOI: 10.21307/ijssis-2017-377

[9] Young-Han Kim, Dae-HyunKim, Jung-HoHan, Chun-GonKim, Damage assessment in layered composites using spectral analysis and Lamb wave, Composites Part B: Engineering, Volume 38, Issues 7-8, (Oct 2007), Pages 800-809.

DOI: 10.1016/j.compositesb.2006.12.010

[10] J.L. Rose, Ultrasonic waves in solid media, - U.K. Cambridge University Press, pp.101-113. (1999).

[11] D. Roy Mahapatra, A. Singhal, and S. Gopalakrishnan, Lamb wave characteristics of thickness-graded piezoelectric IDT, - Ultrasonics, Volume 43, Issue 9, (October 2005), Pages 736-746.

DOI: 10.1016/j.ultras.2005.03.011

[12] Viktorov.I. A, Rayleigh and Lamb Waves, -Physical Theory and Applications. Plenum Press, New York, (1967. ).

[13] Brenner. N, Rader.C. (1976), A New Principle for Fast Fourier Transformation, -IEEE Acoustics, SpeechSignalProcessing 24 (3): 264266. doi: 10. 1109/TASSP. 1976. 1162805.

DOI: 10.1109/tassp.1976.1162805

[14] Lingyu Yu, Victor Giurgiutiu, In situ 2-D piezoelectric wafer active sensors arrays for guided wave damage detection, - Ultrasonics, Volume 48, Issue 2, (April 2008), Pages 117-134.

DOI: 10.1016/j.ultras.2007.10.008

[15] Joung-Man Park , Jin-Woo Kong , Dae-Sik Kim , Dong-JinYoon, Nondestructive damage detection and interfacial evaluation of single-fibers/epoxy composites using PZT, PVDF and P(VDF-TrFE) copolymer sensors, - Composites Science and Technology, Volume 65, Issue 2, (February 2005), Pages 241-256.

DOI: 10.1016/j.compscitech.2004.07.006

[16] Prasad. S, KumarV. R, Balasubramaniam K, and Krishna Moorthy C. V Imaging of defects in composite structures using guided ultrasonics, -Proceedings of the SPIE, volume 5062, pp.700-703, (2003).