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Use of dictionary learning for damage localization in complex structures

Nokhbatolfoghahai, A. (author), M. Navazi, H. (author), Groves, R.M. (author)

In this paper, to increase the performance of the sparse reconstruction method in real complex engineering structures an adaptive dictionary learning framework is proposed which updates the dictionary matrix, to allow improved compatibility with the complex structure. This proposed framework was developed by combining analytical modeling with...

journal article 2022

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Error analysis and reliability of zero-order Lamb mode inversion for waveguide characterization

Sabbadini, A. (author), Massaad Mouawad, J.M. (author), van Neer, P.L.M.J. (author), de Jong, N. (author), Verweij, M.D. (author)

In recent years, several fitting techniques have been presented to reconstruct the parameters of a plate from its Lamb wave dispersion curves. Published studies show that these techniques can yield high accuracy results and have the potential of reconstructing several parameters at once. The precision with which parameters can be...

journal article 2022

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From wave speed to cardiac stiffness

Sabbadini, A. (author)

Diastolic heart failure is one of the principal causes of death in Western countries, and there is currently no treatment available; prevention, on the other hand, may be possible, provided an early enough diagnosis. The worsening of diastolic functionality is associated with increased values of cardiac stiffness, which could therefore provide a...

doctoral thesis 2021

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High-precision Versatile Ultrasonic Flow Meters Based on Matrix Transducer Arrays

Massaad Mouawad, J.M. (author)

Ultrasonic flow meters are widely applied to measure flow in a variety of applications. The vast majority of ultrasonic flow meters are based on the measurement of the transit time of an acoustic pulse through the fluid. This can either be done in-line, by inserting a spool piece with ultrasonic transducers into the pipe carrying the fluid, or...

doctoral thesis 2021

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Perception modelling by invariant representation of deep learning for automated structural diagnostic in aircraft maintenance: A study case using DeepSHM

Adrianus Ewald, V. (author), Sridaran Venkat, Ramanan (author), Asokkumar, Aadhik (author), Benedictus, R. (author), Boller, Christian (author), Groves, R.M. (author)

Predictive maintenance, as one of the core components of Industry 4.0, takes a proactive approach to maintain machines and systems in good order to keep downtime to a minimum and the airline maintenance industry is not an exception to this. To achieve this goal, practices in Structural Health Monitoring (SHM) complement the existing Non...

journal article 2021

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Measurement of Pipe and Fluid Properties with a Matrix Array-based Ultrasonic Clamp-on Flow Meter

Massaad Mouawad, J.M. (author), van Neer, P.L.M.J. (author), van Willigen, D.M. (author), Sabbadini, A. (author), de Jong, N. (author), Pertijs, M.A.P. (author), Verweij, M.D. (author)

Current ultrasonic clamp-on flow meters consist of a pair of single-element transducers that are carefully positioned before use. This positioning process consists of manually finding the distance between the transducer elements, along the pipe axis, for which maximum signal-to-noise ratio (SNR) is achieved. This distance depends on the sound...

journal article 2021

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Acoustic emission source location using Lamb wave propagation simulation and artificial neural network for I-shaped steel girder

Cheng, L. (author), Xin, H. (author), Groves, R.M. (author), Veljkovic, M. (author)

Acoustic emission (AE) is often used for structural health monitoring (SHM) in the wide field of engineering structures and one of its most beneficial attributes is the ability to localize the damage/crack based on the AE events. The vast majority of ongoing work on AE monitoring focues on geometrically simple structures or a confined area,...

journal article 2021

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Evaluation of the sparse reconstruction and the delay-and-sum damage imaging methods for structural health monitoring under different environmental and operational conditions

Nokhbatolfoghahai, A. (author), Navazi, H. M. (author), Groves, R.M. (author)

In this paper, the performance of the sparse reconstruction (SR) and the delay-and-sun (DAS) methods for damage localization, were evaluated for various environmental and operational conditions, both numerically and experimentally. To assess these damage localization methods, a methodology based on the Taguchi method was used to make the...

journal article 2021

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

Falcetelli, F. (author), Venturini, Nicolas (author), Barroso Romero, M. (author), Martinez, Marcias J. (author), Pant, Shashank (author), Troiani, Enrico (author)

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...

journal article 2021

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Lamb Waves and Adaptive Beamforming for Aberration Correction in Medical Ultrasound Imaging

Mozaffarzadeh, M. (author), Minonzio, C.G. (author), de Jong, N. (author), Verweij, M.D. (author), Hemm, Simone (author), Daeichin, V. (author)

Phase aberration in transcranial ultrasound imaging (TUI) caused by the human skull leads to an inaccurate image reconstruction. In this article, we present a novel method for estimating the speed of sound and an adaptive beamforming technique for phase aberration correction in a flat polyvinylchloride (PVC) slab as a model for the human...

journal article 2020

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Using the hybrid DAS-SR method for damage localization in composite plates

Nokhbatolfoghahai, A. (author), Navazi, H. M. (author), Groves, R.M. (author)

In this paper, the hybrid Delay-And-Sum (DAS) with Sparse Reconstruction (SR) method was further developed for damage location in composite plates. In composite materials, anisotropy leads to some challenges in using conventional damage location methods, which are developed for isotropic materials. In the hybrid DAS-SR method, the DAS and SR...

journal article 2020

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Using passive and active acoustic methods for impact damage assessment of composite structures

Saeedifar, M. (author), Mansvelder, Jasmijn (author), Mohammadi, R. (author), Zarouchas, D. (author)

This study aims to use the passive and active acoustic-based health monitoring methods for impact damage assessment of composite structures. To this aim, a Carbon Fiber Reinforced Polymer (CFRP) composite plate was fabricated and subjected to a simulated low-velocity impact by performing repeated quasi-static indentation tests where a loading...

journal article 2019

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Use of delay and sum for sparse reconstruction improvement for structural health monitoring

Nokhbatolfoghahai, A. (author), Navazi, Hossein M. (author), Groves, R.M. (author)

To perform active structural health monitoring, guided Lamb waves for damage detection have recently gained extensive attention. Many algorithms are used for damage detection with guided waves and among them, the delay-and-sum method is the most commonly used algorithm because of its robustness and simplicity. However, delay-and-sum images...

journal article 2019

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Structural state awareness of composite structures by blending passive and active acoustic-based health monitoring methods

Zarouchas, D. (author), Saeedifar, M. (author)

This study aims to demonstrate the effectiveness of blending passive and active acoustic-based health monitoring methods to impact damage diagnostics of composite structures. The structural state awareness is introduced as a term to characterize the health condition that a structure is and how this condition can be quantified by blending...

conference paper 2019

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DeepSHM: A deep learning approach for structural health monitoring based on guided Lamb wave technique

Adrianus Ewald, V. (author), Groves, R.M. (author), Benedictus, R. (author)

In our previous work, we demonstrated how to use inductive bias to infuse a convolutional neural network (CNN) with domain knowledge from fatigue analysis for aircraft visual NDE. We extend this concept to SHM and therefore in this paper, we present a novel framework called DeepSHM which involves data augmentation of captured sensor signals...

conference paper 2019

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Experimental assessment of the influence of welding process parameters on Lamb wave transmission across ultrasonically welded thermoplastic composite joints

Ochôa, Pedro (author), Villegas, I.F. (author), Groves, R.M. (author), Benedictus, R. (author)

One of the advantages of thermoplastic composites relative to their thermoset counterparts is the possibility of assembling components through welding. Ultrasonic welding in particular is very promising for industrialization. However, uncertainty in the fatigue and fracture behaviour of composites is still an obstacle to the full utilisation...

journal article 2018

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Transducer Placement Option of Lamb Wave SHM System for Hotspot Damage Monitoring

Adrianus Ewald, V. (author), Groves, R.M. (author), Benedictus, R. (author)

In this paper, we investigated transducer placement strategies for detecting cracks in primary aircraft structures using ultrasonic Structural Health Monitoring (SHM). The approach developed is for an expected damage location based on fracture mechanics, for example fatigue crack growth in a high stress location. To assess the performance of the...

journal article 2018

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Residual stress effects of a fatigue crack on guided lamb waves

Martinez, M.J. (author), Pant, S (author), Yanishevsky, M (author), Backman, D (author)

Structural health monitoring has focused on the use of computational models to capture the effect of crack-like discontinuities on the behaviour of acoustic-ultrasonic signals. However, few models have taken into account the effect of geometric complexity in combination with residual stresses generated during the fatigue crack growth (FCG)...

journal article 2017

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Quantitative Assessment of Adhesively-bonded Joints Using Ultrasonic Guided Waves

Verze, M. (author)

Maintenance is a costly but vital part of an aircraft lifespan. Regulations demand scheduled and rigorous inspection to ensure safety and airworthiness in the long term. Studies estimate that up to a third of the total operational cost of an aircraft is spent in maintenance checks. Consequently, design choices are made to take into account these...

master thesis 2016

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Lamb Wave Propagation in Sandwich Composite Structures for the Detection of Impact Damage

Aaij, E. (author)

Lightweight composite sandwich structures are particularly susceptible to impact damage. Barely Visible Impact Damage (BVID) is known to affect the short and long term load bearing capacities of composite structures. Active acoustic Structural Health Monitoring (SHM) systems have the potential to detect such damages before they lead to...

master thesis 2016