Plasmon resonance spectral peak shift due to morphing of gold nanoparticles for strain sensing

The plasmon resonance spectral peak of a gold spherical nanoparticle (NP) will shift when the NP shape is changed from sphere to spheroid. This may be used as a novel strain detection method with gold NPs embedded in a medium of different refractive index (RI). Applying a strain to the external medium will cause a change in the shape of the...

Light scattering by gold nanoparticles cured in optical adhesive at optical fibre interfaces

This study forms a part of the research in using nanoparticles (NPs) to increase the intensity of light scattering signal in the optical fibres. Increasing the intensity of the backscattered light signal in the optical fibres shows the potential to increase the signal-to-noise ratio in order to improve the sensitivity of the backscatter...

Simulation of ultrasonic array inspection of composites with side drilled holes

In this paper we ultrasonic signals from array transducers are simulated using the Thompson and Gray measurement model. The measurement model consists of a beam model, a system efficiency factor which characterizes the response of the electro-mechanical and electrical components of the system, and a flaw scattering model. To inspect layered...

Light scattering and rheological effects in an optical fibre coupled nanoparticle suspension

This study forms the first part of research into enhancing the forward and back scattering of light in an optical fibre using nanoparticles (NPs). This approach has the potential to enhance the sensitivity of optical fibre sensing by increasing the signal-to-noise ratio. The work described in this paper is focused on understanding the...

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

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...

Simultaneous position and displacement sensing using two fibre Bragg grating sensors

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...

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

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)...

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

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...

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

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...

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

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...

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

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...

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

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...

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

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...