Extraction of statistical properties of the point source response of a reverberant plate and application to parameter estimation (L)

Moulin, Emmanuel; Achdjian, Hossep; Assaad, Jamal; Leyla, Najib Abou; Hourany, K.; Zaatar, Y.

doi:10.1121/1.4750495

Cited by 6 publications

(5 citation statements)

References 13 publications

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“…An experimental validation of this distance estimation principle had been presented in a previous work [11]. We present here three examples of complete source localisation (Fig.…”

Section: B Source Localisationmentioning

confidence: 91%

“…An estimation of A can be performed by a curve fitting on the signal envelopes averaged over several realizations [11]. We show here an even more efficient solution, in terms of convergence towards the theoretical expectation.…”

Section: Ensemble Averaging In Reverberant Platesmentioning

confidence: 97%

“…As shown in a previous work [11], the following integral, computed from the first wavepacket of a received signal, provides an additionnal relation required for the parameter estimation:…”

Section: Application Examplesmentioning

confidence: 99%

“…See previous works for more details [10], [11]. As shown there, the mathematical expectation of the envelope is characterized by a decreasing exponential fonction of the form:…”

Section: Ensemble Averaging In Reverberant Platesmentioning

confidence: 99%

“…We exploit here a time-domain statistical description, presented in recent works [10], [11] and based on the imagesource method [12], [13], [10] used to estimate the average wavepacket distributions of waves propagating inside a reverberant plate [14].…”

Section: Introductionmentioning

confidence: 99%

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Prediction of average propagation characteristics in polygonal reverberant plates for experimental feature extraction

Achdjian

Moulin

Benmeddour

et al. 2012

2012 IEEE International Ultrasonics Symposium

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While exploitation of reverberant signals inside bounded media of low acoustic attenuation is customary in room acoustics, it is not so common in NDT&E. Yet, such diffuse signals potentially contain useful quantitative information about the medium and source(s) properties and are very sensitive to either localised or distributed structural changes. Provided proper data extraction techniques are available, it could therefore be advantageously exploited for structural characterisation using only a small set of sensors. Specifically, in this work, we aim at retrieving either information about the source position, or about the mechanical properties of a plate-shaped structure. A statistical time-domain description of the reverberant propagation in plates is developed using the image source method. The average density of received wavepackets due to multiple reflections at the medium boundaries is deduced from the spatial distribution of the image sources. Then, the mathematical expectation (or ensemble average) of the signal envelope or correlation function is theoretically derived, taking into account the dispersive nature of the plate wave (Lamb waves). The relationships between the reverberation properties and structural parameters such as the group velocity and the plate surface are thus explicitly expressed. A major point is that the reverberant behaviour is shown to be governed by a limited set of parameters, thus leading to a significant reduction of the problem complexity. First, by comparison with both numerical and experimental results, the model is shown to correctly predict the average reverberation behaviour of polygonal plates of various shapes and sizes. Then, by fitting the late envelopes of experimental signals to the theoretical expressions provided by the model, a number of terms involving the values of structural parameters can be estimated. Finally, by considering additional relations obtained from the early characteristics (treated in a deterministic manner) of the reverberation signals, it is shown possible to extract useful structural parameters. Possible practical applications in terms of structural characterisation and/or source localisation without any time measurement nor trigger synchronisation between the source and the receiver, and without the knowledge of the emitted signal are illustrated. These results show promising potential in the scope of blind parameter estimation or passive source or defect detection.

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“…An experimental validation of this distance estimation principle had been presented in a previous work [11]. We present here three examples of complete source localisation (Fig.…”

Section: B Source Localisationmentioning

confidence: 91%

Section: Ensemble Averaging In Reverberant Platesmentioning

confidence: 97%

“…As shown in a previous work [11], the following integral, computed from the first wavepacket of a received signal, provides an additionnal relation required for the parameter estimation:…”

Section: Application Examplesmentioning

confidence: 99%

“…See previous works for more details [10], [11]. As shown there, the mathematical expectation of the envelope is characterized by a decreasing exponential fonction of the form:…”

Section: Ensemble Averaging In Reverberant Platesmentioning

confidence: 99%