Broadband signal reconstruction for SHM: An experimental and numerical time reversal methodology

Structural Health Monitoring (SHM) aims to shift aircraft maintenance from a time-based to a condition-based approach. Within all the SHM techniques, Acoustic Emission (AE) allows for the monitoring of large areas by analyzing Lamb waves propagating in plate like structures. In this study, the authors proposed a Time Reversal (TR) methodology with the aim of reconstructing an original and unaltered signal from an AE event. Although the TR method has been applied in Narrow-Band (NwB) signal reconstruction, it fails when a Broad-Band (BdB) signal, such as a real AE event, is present. Therefore, a novel methodology based on the use of a Frequencies Compensation Transfer Function (FCTF), which is capable of reconstructing both NwB and real BdB signals, is presented. The study was carried out experimentally using several sensor layouts and materials with two different AE sources: (i) a Numerically Built Broadband (NBB) signal, (ii) a Pencil Lead Break (PLB). The results were validated numerically using Abaqus/CAETM with the implementation of absorbing boundaries to minimize edge reflections.

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A time reversal damage imaging method for structure health monitoring using Lamb waves

Chinese Physics B ◽

10.1088/1674-1056/19/11/114301 ◽

2010 ◽

Vol 19 (11) ◽

pp. 114301 ◽

Cited By ~ 6

Author(s):

Hai-Yan Zhang ◽

Ya-Ping Cao ◽

Xiu-Li Sun ◽

Xian-Hua Chen ◽

Jian-Bo Yu

Keyword(s):

Health Monitoring ◽

Time Reversal ◽

Lamb Waves ◽

Imaging Method ◽

Structure Health Monitoring ◽

Damage Imaging

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Shear-lag solution for excitation, sensing, and time reversal of Lamb waves for structural health monitoring

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x17711819 ◽

2017 ◽

Vol 29 (4) ◽

pp. 585-599 ◽

Cited By ~ 6

Author(s):

Santosh Kapuria ◽

Jitendra Kumar Agrahari

Keyword(s):

Structural Health Monitoring ◽

Health Monitoring ◽

Time Reversal ◽

Lamb Waves ◽

Shear Lag ◽

Structural Health

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Time reversal technique for health monitoring of metallic structure using Lamb waves

Ultrasonics ◽

10.1016/j.ultras.2009.05.002 ◽

2009 ◽

Vol 49 (8) ◽

pp. 696-705 ◽

Cited By ~ 76

Author(s):

R. Gangadharan ◽

C.R.L. Murthy ◽

S. Gopalakrishnan ◽

M.R. Bhat

Keyword(s):

Health Monitoring ◽

Time Reversal ◽

Lamb Waves ◽

Metallic Structure

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A Method for Acoustic Emission Source Identification Based on Optimisation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.413-414.793 ◽

2009 ◽

Vol 413-414 ◽

pp. 793-801 ◽

Cited By ~ 3

Author(s):

Andrew Spencer ◽

Keith Worden ◽

Gareth Pierce

Keyword(s):

Acoustic Emission ◽

High Cycle Fatigue ◽

Lamb Waves ◽

Acoustic Emissions ◽

Ultrasonic Waves ◽

Cycle Fatigue ◽

Simulation Approach ◽

Acoustic Emission Source ◽

Interaction Simulation ◽

Pencil Lead

When a metal or composite structure begins to fail, for example due to high cycle fatigue, acoustic emissions caused by the propagation of cracks give rise to bursts of ultrasonic waves travelling through the structure. The health of a structure can be monitored by means of sensors which detect these waves. Acoustic emissions are often generated in experiments by breaking a pencil lead against the surface of the structure in a standardised way but the forces that this imparts are not well understood at present. A Local Interaction Simulation Approach (LISA) algorithm has been implemented to simulate the propagation of ultrasonic waves. This code has been validated against experiments in previous work and has been shown to accurately reproduce the propagation of Lamb waves (including reflections and dispersion etc.) within thin-plate like structures. This paper deals with the use of the LISA code to characterise the forces associated with standard pencil lead breaks. The displacement due to waves emanating from a break is measured and a Differential Evolution (DE) optimisation scheme is used to find the optimal profile of forcing to match the simulation with experiment.

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Time Reversal Health Monitoring of a Composite Structure using Lamb Waves

50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference ◽

10.2514/6.2009-2380 ◽

2009 ◽

Cited By ~ 1

Author(s):

R Gangadharan ◽

Crl Murthy ◽

S Gopalakrishnan ◽

M R Bhat

Keyword(s):

Health Monitoring ◽

Time Reversal ◽

Composite Structure ◽

Lamb Waves

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Lamb waves time-reversal method using frequency tuning technique for structural health monitoring

10.1117/12.715450 ◽

2007 ◽

Cited By ~ 1

Author(s):

Buli Xu ◽

Victor Giurgiutiu

Keyword(s):

Structural Health Monitoring ◽

Health Monitoring ◽

Time Reversal ◽

Frequency Tuning ◽

Lamb Waves ◽

Structural Health

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Towards the Development of Predictive Models for the System Design and Modal Analysis of Acoustic Emission Based Technologies

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.518.396 ◽

2012 ◽

Vol 518 ◽

pp. 396-406 ◽

Cited By ~ 2

Author(s):

Miguel Angel Torres-Arredondo ◽

H. Jung ◽

Claus Peter Fritzen

Keyword(s):

Acoustic Emission ◽

Wave Propagation ◽

Modal Analysis ◽

Health Monitoring ◽

Guided Waves ◽

Lamb Waves ◽

Plate Theory ◽

Predictive Modelling ◽

Diagnostic Techniques ◽

Acoustic Energy

Acoustic Emission (AE) techniques are used for the structural health monitoring (SHM) of civil, aeronautic and aerospace structures. In order to depart from the traditional reliance on parameter based analysis, AE diagnostic techniques require the analysis of wave propagation phenomena and the use of predictive modelling tools to improve the monitoring capabilities and provide reliable health monitoring. Additionally, modal based techniques offer potential for optimization of sensor networks in terms of sensor placement and number of sensors, increased source location accuracy and to get an insight into the source mechanisms. If the modes of propagation can be recognised in the received AE signals, then it would be possible to discriminate between damage types. On that account, the present paper develops two methodologies that are useful tools for the investigation and design of wave propagation based SHM systems established upon modal analysis. Firstly, a higher order plate theory for modelling disperse solutions in elastic and viscoelastic fibre-reinforced composites is proposed in order to investigate the radiation and attenuation of Lamb waves in anisotropic media. Second, spectral flat shell elements are used for the simulation of guided waves in shell structures. Numerical simulations and experiments validate the models and demonstrate that material anisotropy has a strong influence on the velocities, attenuation and acoustic energy for the different modes of propagation. It is expected that the presented methodologies may contribute to offer a higher computational efficiency and simplicity in comparison to traditional methods, and enable the design shortening time and cost of development of Lamb wave based damage detection systems for a rapid transfer from laboratory to in-service structures.

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