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Lamb wave detection in prepreg composite materials with fibre Bragg grating sensors

Miesen, N. (author), Mizutani, Y. (author), Groves, R.M. (author), Sinke, J. (author), Benedictus, R. (author)

This paper demonstrates that existing Structural Health Monitoring (SHM) techniques have potential during the production phase in addition to their application for maintenance and for in-flight monitoring. Flaws occur during composite fabrication in industry, due to an imperfect process control and human errors. This decreases production...

conference paper 2011

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Signal processing in optical coherence tomography for aerospace material characterization

Liu, P. (author), Groves, R.M. (author), Benedictus, R. (author)

Based on a customized time-domain optical coherence tomography (OCT) system, a series of signal processing approaches have been designed and reviewed. To improve demodulation accuracy and image quality, demodulation approaches such as median filter, Hilbert transform, and envelope detector were investigated with simulated as well as experimental...

journal article 2013

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Optical coherence elastography for measuring the deformation within glass fiber composite

Liu, P. (author), Groves, R.M. (author), Benedictus, R. (author)

Optical coherence elastography (OCE) has been applied to the study of microscopic deformation in biological tissue under compressive stress for more than a decade. In this paper, OCE has been extended for the first time, to the best of our knowledge, to deformation measurement in a glass fiber composite in the field of nondestructive testing. A...

journal article 2014

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Simulation and detection of flaws in pre-cured CFRP using laser displacement sensing

Miesen, N. (author), Sinke, J. (author), Groves, R.M. (author), Benedictus, R. (author)

The novelty of the research is the detection of different types of flaws in the prepreg carbon fibre-reinforced fibres (CFRP) layup compared to in cured products. This paper presents the development of a new method for in situ detection of prepreg CFRP production flaws combining laser displacement sensors and analytical modelling. Experimental...

journal article 2015

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Lamb wave dispersion time-domain study using a combined signal processing approach

Ochoa, P. (author), Groves, R.M. (author), Benedictus, R. (author)

Ultrasonic Lamb wave techniques are described as one of the most encouraging developments for structural health monitoring of aerospace composite structures. The reliability of those techniques is highly dependent on the quality of signal processing algorithms capable of extracting useful information out of complex responses. When damage...

conference paper 2015

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Experimental characterisation of Lamb wave propagation through thermoplastic composite ultrasonic welds

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

Ultrasonic welding is a very promising technique for joining thermoplastic composite (TpC) components in aircraft primary structures [1, 2]. The potential introduction of new lightweight structures in civil aviation has been driving the change towards condition-based maintenance (CBM) as an alternative to the regular inspection interval approach...

abstract 2016

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Modelling of ultrasonic beam propagation from an array through transversely isotropic fibre reinforced composites using Multi Gaussian beams

Anand, C. (author), Shroff, S. (author), Groves, R.M. (author), Benedictus, R. (author)

Ultrasonic arrays are used for non-destructive evaluation of structures for aerospace and other applications. With the increase in the usage of fibre-reinforced composites in aerospace structures, this evaluation becomes complex due to the effects of attenuation and reflection from the layer boundaries in composite laminates. Hence there is...

conference paper 2017

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Reliability Analysis of an Ultrasonic Guided Wave Based Structural Health Monitoring System for a Carbon Fibre Reinforced Thermoplastic Torsion-box

Ochôa, Pedro (author), Groves, R.M. (author), Benedictus, R. (author)

Certification is the key step towards the implementation of structural health monitoring (SHM) as part of condition based maintenance programmes of aircraft fleets. That can only be accomplished by demonstration of system performance in multiple scenarios and in a statistically relevant way. This paper describes a fully computational approach...

conference paper 2017

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

Ewald, Vincentius (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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Incorporating Inductive Bias into Deep Learning: A Perspective from Automated Visual Inspection in Aircraft Maintenance

Ewald, Vincentius (author), Goby, Xavier (author), Jansen, Hidde (author), Groves, R.M. (author), Benedictus, R. (author)

The near-term artificial intelligence, commonly referred as ‘weak AI’ in the last couple years was achieved thanks to the advances in machine learning (ML), particularly deep learning, which has currently the best in-class performance outperforming other machine learning algorithms. In the deep learning framework, many natural tasks such as...

conference paper 2018

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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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Full-scale testing of an ultrasonic guided wave based structural health monitoring system for a thermoplastic composite aircraft primary structure

Ochôa, Pedro (author), Groves, R.M. (author), Benedictus, R. (author)

This paper describes the test campaign of an ultrasonic guided wave (GW) based structural health monitoring system (SHM) deployed on a full-scale stiffened panel of a thermoplastic composite horizontal stabilizer torsion box. The diagnostic capabilities of the SHM system were successfully evaluated by testing barely-visible impact damage of...

conference paper 2018

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Design and Experimental Assessment of a Multi-spherical Composite- Overwrapped Pressure Vessel for Cryogenic Storage

Tapeinos, I. (author), Rajabzadeh, Aydin (author), Zarouchas, D. (author), Groves, R.M. (author), Koussios, S. (author), Benedictus, R. (author)

In the field of cryogenic storage, the medium inside the pressure vessel is in a liquid state and thus is incompressible. Therefore the storage tank should be designed in a way, that makes the best possible use of the available space within an aircraft. A composite-overwrapped pressure vessel (COPV) based on intersecting spheres (multi-sphere)...

conference paper 2018

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Evaluation of the mechanical performance of a composite multi-cell tank for cryogenic storage: Part II – Experimental assessment

Tapeinos, I. (author), Rajabzadeh, Aydin (author), Zarouchas, D. (author), Stief, Malte (author), Groves, R.M. (author), Koussios, S. (author), Benedictus, R. (author)

This study focuses on the understanding of the thermal and structural behavior of an innovative Type IV multi-spherical composite-overwrapped pressure vessel through an experimental assessment that consists of hydrostatic testing at ambient conditions and pressure cycling with a cryogenic medium (LN₂). During hydro-burst testing at...

journal article 2019

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Systematic multiparameter design methodology for an ultrasonic health monitoring system for full-scale composite aircraft primary structures

Ochôa, Pedro (author), Groves, R.M. (author), Benedictus, R. (author)

The successful utilization of guided wave-based structural health monitoring (SHM) for detailed quantitative diagnostic of damage in composite aircraft primary structures depends on the excitation frequency, geometry, and positioning of the piezoelectric transducers. This study proposes a novel methodology to consistently define those parameters...

journal article 2019

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Diagnostic of manufacturing defects in ultrasonically welded thermoplastic composite joints using ultrasonic guided waves

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

This article presents research about the propagation of ultrasonic guided waves in ultrasonically welded thermoplastic composite joints. The goal of the study was to understand the effect of weld manufacturing defects on guided wave transmission across the joint. Triangular energy-directors integrated into the lower composite adherends...

journal article 2019

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

Ewald, Vincentius (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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Simultaneous position and displacement sensing using two fibre Bragg grating sensors

Nazeer, N. (author), Groves, R.M. (author), Benedictus, R. (author)

Over the years, many shape sensing methods have been developed with technologies including optical fibre, PZT and fringe projection. Among them, optical fibres have gained a lot of attention due to their unobtrusive nature when either surface mounted or embedded in the structure. Optical fibre Bragg gratings (FBG) are currently employed for...

conference paper 2019

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Multi-modal fibre optic shape sensing for the SmartX morphing wing demonstrator (PPT)

Nazeer, N. (author), Groves, R.M. (author), Benedictus, R. (author)

PowerPoint presentation

other 2020

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Simulation of ultrasonic beam propagation from phased arrays in anisotropic media using linearly phased multi-Gaussian beams

Anand, C. (author), Delrue, Steven (author), Jeong, Hyunjo (author), Shroff, Sonell (author), Groves, R.M. (author), Benedictus, R. (author)

Phased array ultrasonic testing is widely used to test structures for flaws due to its ability to produce steered and focused beams. The inherent anisotropic nature of some materials, however, leads to skewing and distortion of the phased array beam and consequently measurement errors. To overcome this, a quantitative model of phased array...

journal article 2020