Investigation of Sensor Placement in Lamb Wave-Based SHM Method

Abstract:

In this paper the investigation of a structural health monitoring method for thin-walled parts of structures is presented. The concept is based on the guided elastic wave propagation phenomena. This type of waves can be used in order to obtain information about structure condition and possibly damaged areas. Guided elastic waves can travel in the medium with relatively low attenuation, therefore they enable monitoring of extensive parts of structures. In this way it is possible to detect small defects in their early stage of growth. It is essential because undetected damage can endanger integrity of a structure. In reported investigation piezoelectric transducer was used to excite guided waves in chosen specimens. Dispersion of guided waves results in changes of velocity with the wave frequency, therefore a narrowband signal was used. Measurement of the wave field was realized using laser scanning vibrometer that registered the velocity responses at points belonging to a defined mesh. An artificial discontinuity was introduced to the specimen. The goals of the investigation was to detect it and find optimal sensor placement for this task. Determination of the optimal placement of sensors is a very challenging mission. In conducted investigation laser vibrometer was used to facilitate the task. The chosen mesh of measuring points was the basis for the investigation. The purpose was to consider various configuration of piezoelectric sensors. Instead of using vast amount of piezoelectric sensors the earlier mentioned laser vibrometer was used to gather the necessary data from wave propagation. The signals gather by this non-contact method for the considered network were input to the damage detection algorithm. Damage detection algorithm was based on a procedure that seeks in the signals the damage-reflected waves. Knowing the wave velocity in considered material the damage position can be estimated.

• Periodical: Key Engineering Materials (Volume 518)
• Pages: 174-183
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.518.174
• Online since: July 2012
• Authors: Pawel Malinowski, Tomasz Wandowski, Wiesław M. Ostachowicz
• Keywords: Damage Detection, Damage Localization, Elastic Wave, Lamb Wave, Nondestructive Testing (NDT), SHM, Structural Health Monitoring (SHM)

References

[1] Z. Su, L. Ye. Identification of damage using Lamb waves. Springer-Verlag, (2009).

[2] H. Lamb, On waves in an elastic plate, Proc. R. Soc. Lond. A 93 (1917) 114-128.

[3] J. L. Rose, Ultrasonic waves in solid media, Cambridge University Press Cambridge, (1999).

[4] P. Wilcox, Omni-directional guided wave transducer arays for the rapid inspection of large areas of palate structures, IEEE T. Ultrason. Ferr. 50 (2003) 699-709.

DOI: 10.1109/tuffc.2003.1209557

[5] K. Hongjoon, J. Kyungyoung, S. Minjea, K. Jaeyeol, A noncontact NDE method using a laser-generated focused-Lamb wave with enhanced defect detection ability and spatial resolution, NDT&E Int. 39 (2006) 312-319.

DOI: 10.1016/j.ndteint.2005.09.001

[6] K. Hongjoon, J. Kyungyoung, S. Minjea, K. Jaeyeol, Application of the laser-generated focused-Lamb wave for non-contact imaging of defects in plate, Ultrasonics 44 (2006) 1265-1268.

DOI: 10.1016/j.ultras.2006.05.080

[7] V. Giurgiutiu, Structural Health Monitoring with Piezoelectric Wafer Active Sensors, Academic Press, Amsterdam, (2008).

[8] W. Ostachowicz, P. Kudela, P. Malinowski, T. Wandowski, Damage localisation in plate-like structures based on PZT sensors, Mech. Syst. Signal Pr. 23 (2009) 1805-1829.

DOI: 10.1016/j.ymssp.2008.10.011

[9] P. Malinowski, T. Wandowski, I. Trendafilova, W. Ostachowicz, A phased–array–based method for damage detection and localization in thin plates. Struct. Health Monit. 8 (2009) 5-15.

DOI: 10.1177/1475921708090569

[10] W. Qiang and Y. Shenfang, Baseline-free imaging method based on new PZT sensor arrangements, J. Intel. Mat. Syst. Str. 20 (2009) 1663-1673.

DOI: 10.1177/1045389x09105232

[11] P. Malinowski, T. Wandowski, W. Ostachowicz, Damage detection potential of a triangular piezoelectric configuration, Mech. Syst. Signal Pr. 25 (2011) 2722–2732.

DOI: 10.1016/j.ymssp.2011.02.010

[12] W. J. Staszewski, K. Worden, R. Wardle, G. R. Tomlinson, Fail-safe sensor distributions for impact detection in composite materials, Smart Mater. Struct. 9 (2000) 298–303.

DOI: 10.1088/0964-1726/9/3/308

[13] M. Azarbayejani, A. I. El-Osery, K.K. Choi, M.M. Reda Taha, A probabilistic approach for optimal sensor allocation in structural health monitoring, Smart Mater. Struct. 17 (2008) 055019.

DOI: 10.1088/0964-1726/17/5/055019

[14] B.C. Lee, W.J. Staszewski, Sensor location studies for damage detection with Lamb waves, Smart Mater. Struct. 16 (2007) 399–408.

DOI: 10.1088/0964-1726/16/2/019

[15] L. Mallet, B.C. Lee, W.J. Staszewski, F. Scarpa, Structural health monitoring using scanning laser vibrometry: II. Lamb waves for damage detection. Smart Mater. Struct. 13 (2004) 261–269.

DOI: 10.1088/0964-1726/13/2/003

[16] W.J. Staszewski, S. Mahzan, R. Traynor, Health monitoring of aerospace composite structures – Active and passive approach. Composites Science and Technology 69 (2009) 1678–1685.

DOI: 10.1016/j.compscitech.2008.09.034

[17] M. Ruzzene, S.M. Jeong, T.E. Michaels, J.E. Michaels, B. Mi, Simulation and Measurement of Ultrasonic Waves in Elastic Pates Using Laser Vibrometry. Review of Quntitative Nondestructive Evaluation 24 (2005) 172–179.

DOI: 10.1063/1.1916675

[18] M. Ruzzene, 2007. Frequency–wavenumber domain filtering for improved damage visualization. Smart Mater. Struct. 16 (2007) 2116–2129.

DOI: 10.1088/0964-1726/16/6/014

[19] H. Sohn, D. Dutta, J.Y. Yang, P.M. Desimio, S.E. Olson, E.D. Swenson, A Wavefiled Imaging Technique for Delamination Detection in Composite Structures. Proceedings of the Fifth European Workshop on Structural Health Monitoring (2010) 1335–1340.

DOI: 10.1117/12.847316