Roger M Groves

Roger M Groves
Delft University of Technology | TU · Aerospace Structures and Materials (ASM)

PhD

About

245
Publications
53,888
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1,539
Citations
Introduction
I lead a research group in Non-Destructive Testing (NDT) & Structural Health Monitoring (SHM). My personal research objective is to develop and demonstrate the next generation of NDT and SHM technologies & algorithms for (i) Automation of NDT in composite manufacturing for preventative quality assurance and (ii) Sensing and decision making for smart and efficient aircraft maintenance.
Additional affiliations
February 2005 - October 2008
Universität Stuttgart
Position
  • Senior Researcher
January 2001 - January 2005
Cranfield University
Position
  • Research Fellow

Publications

Publications (245)
Article
Full-text available
In this paper, with the final aim of shape sensing for a morphing aircraft wing section, a developed multimodal shape sensing system is analysed. We utilise the method of interrogating a morphing wing section based on the principles of both hybrid interferometry and Fibre Bragg Grating (FBG) spectral sensing described in our previous work. The focu...
Article
Full-text available
The unique sensing features of the tilted Fibre Bragg Grating (TFBG) as a single three-parameter optical sensor are demonstrated in this work, to monitor the manufacturing process of composite materials produced using Vacuum Assisted Resin Transfer Moulding (VARTM) process. Each TFBG sensor can measure simultaneously and separately strain, temperat...
Article
Full-text available
Automated fibre layup techniques are often applied for the production of complex structural components. In order to ensure a sufficient component quality, a subsequent visual inspection is necessary, especially in the aerospace industry. The use of automated optical inspection systems can reduce the inspection effort by up to 50 %. Laser line scan...
Article
Thick composite materials are commonly used as load-bearing structures in marine applications. Developing a suitable and sophisticated non-destructive testing (NDT) method for thick composites is an urgent challenge to improve the safety, reliability and maintenance of these structures. Digital shearography has become an important NDT technique for...
Article
Full-text available
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-Destructive...
Article
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 train...
Article
Strain-based structural health monitoring (SHM) relies on high performance strain sensing methods. Gold nanoparticle (NP) doped fibre optic sensors not only have the potential to increase the intensity of the backscattered signal to increase the signal to noise ratio but also have plasmon resonance peaks in the visible light range. The spectral pea...
Article
This study aims at improving shearography non-destructive testing (NDT) of deep defects in thick composites with thermal loading. Instead of conventional global heating (GH), the core idea is to apply novel spatially modulated heating (SMH) for shearography NDT. In this paper, the finite element method (FEM) has been used to advance shearography to...
Article
Full-text available
In this research the ageing of a silicone adhesive in a simulated space environment is monitored through an embedded three parameter tilted Fibre Bragg Grating (TFBG) sensor. Here, the silicone is used as an adhesive between two thin cover glasses, and the space environmental ageing is simulated by thermal cycles in high vacuum conditions (better t...
Article
Full-text available
The demand for efficient composite production processes is growing as the proportion of composites in modern aircraft increases. Particularly, thermoplastic composites are interesting for sustainability and cost efficiency. They can be manufactured using deposition methods, which involve heating by radiation in the visible and near-infrared spectra...
Article
"I am concerned and I am frustrated because I don't know what the alternates are...It clearly isn't racist; its economics. The real question you have to ask yourself is: Is this good orbad?"-Norman Rice, former Mayor of Seattle, On gentrification in that cityUrban America is in a state of crisis. A huge pool of America's resources is increasingly d...
Article
Full-text available
The aerospace industry has established the Automated Fiber Placement process as a common technique for manufacturing fibre reinforced components. In this process multiple composite tows are placed simultaneously onto a tool. Currently in such processes manual testing requires often up to 50% of the manufacturing duration. Moreover, the accuracy of...
Article
Full-text available
Automated Fibre Placement is a common manufacturing technique for composite parts in the aero-space industry. Therefore, a visual part inspection is required which often covers up to 50% of the actual production time. Moreover, the inspection quality of this manual step fluctuates significantly. A camera-based automated inline inspection is capable...
Article
Full-text available
In the aerospace industry, the Automated Fiber Placement process is an established method for producing composite parts. Nowadays the required visual inspection, subsequent to this process, typically takes up to 50% of the total manufacturing time and the inspection quality strongly depends on the inspector. A Deep Learning based classification of...
Article
Full-text available
In the aerospace industry, automated fibre laying processes are often applied for economical composite part fabrication. Unfortunately, the current mandatory visual quality assurance process takes up to 50% of the entire manufacturing time. An automised classification of manufacturing deviations using Neural Networks potentially improves the inspec...
Article
Full-text available
There has been an increase in the use of ultrasonic arrays for the detection of defects in composite structures used in the aerospace industry. The response of a defect embedded in such a medium is influenced by the inherent anisotropy of the bounding medium and the layering of the bounding medium and hence poses challenges for the interpretation o...
Article
Full-text available
Automated fibre layup techniques are widely used in the aviation sector for the efficient production of composite components. However, the required manual inspection can take up to 50 % of the manufacturing time. The automated classification of fibre layup defects with Neural Networks potentially increases the inspection efficiency. However, the ma...
Conference Paper
Automated fibre layup techniques are commonly used composite manufacturing processes in the aviation sector and require a manual visual inspection. Neural Network classification of defects has the potential to automate this visual inspection, however, the machine decision-making processes are hard to verify. Thus, we present an approach for visuali...
Article
Full-text available
In our previous research, a novel demodulation technique based on α-shape Delaunay triangulation (D-T) was developed to obtain the refractive index of the medium surrounding the optical fibre using the envelope of the cladding peaks from the spectrum of the tilted fibre Bragg grating (TFBG) sensor. This technique was demonstrated to be efficient, e...
Article
Full-text available
Optical fibre sensors and in particular fibre Bragg gratings (FBG) have received a lot of interest for Structural Health Monitoring in different application fields, such as aerospace, pipeline and civil engineering. FBGs are conventionally used to monitor strain and sometimes temperature. In this paper, we propose a new method for load monitoring o...
Article
Full-text available
This paper presents a study on trailing edge deflection estimation for the SmartX camber morphing wing demonstrator. This demonstrator integrates the technologies of smart sensing, smart actuation and smart controls using a six module distributed morphing concept. The morphing sequence is brought about by two actuators present at both ends of each...
Article
A conventional distributed fiber optic sensing system offers close to linear sensitivity along the fiber length. However gold nanoparticles (NP) have been shown to be able to enhance the contrast ratio to improve the quality of signal detection. The challenge in improving the contrast of reflected signals is to optimise the nanoparticle doping conc...
Article
Full-text available
Monitoring of extreme dynamic loadings on composite materials with high temporal and spatial resolution provides an important insight into the understanding of the material behaviour. Quantitative measurement of the surface strain at the first moments of the impact event may reveal the initiation of the failure mechanisms leading to damage. For thi...
Article
Full-text available
A simultaneous two-parameter single sensor based on weakly tilted Fibre Bragg Grating (TFBG), embedded in a 1 mm glass fibre/epoxy composite plate, is demonstrated to measure independently the temperature and strain variations induced in the material by the exposure to heating lamps. The spectrum of weakly TFBGs is composed of several peaks that ca...
Article
Full-text available
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 local-ize 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, but th...
Article
Full-text available
Ageing of historical documents often results in changes in the optical properties of the constituent materials. Imaging spectroscopy (IS) can be a valuable tool for monitoring of such changes, if the method fulfils two important conditions. Firstly, compared to natural ageing, the accumulated light dose from repeated measurements of the monitored d...
Presentation
Invited speaker for the Robotics in MRO panel. MRO companies are using a variety of robotic solutions to speed up the inspection and repair of aircraft. One of the more time-consuming tasks faced by aircraft maintenance, repair and overhaul (MRO) companies is inspecting the exterior of an aircraft to assess its required maintenance needs. An aircra...
Article
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 experiment...
Presentation
Full-text available
This video highlights the smart fibre optic sensing methodology developed and incorporated in the SmartX-Alpha wing. This video is a snippet of the SmartX-Alpha promotional video titled ''SmartX-Alpha active morphing wing continuous in-flight optimisation advanced technology demonstrator'' taken from https://www.youtube.com/watch?v=SdagIiYRWyA.
Presentation
Non-Destructive Inspection of Thick-Walled Composites
Presentation
This presentation describes the design and implementation of load monitoring and shape sensing technology for the SmartX morphing wing demonstrator with the objective to understand better the performance of the morphing wing. The fibre optic method presented in this work combines the hybrid interferometry and FBG spectral sensing principle as repo...
Conference Paper
S460 steel is increasingly used in civil engineering, especially in a harsh environment such as offshore structures [1]. Material damage is inevitable for structures subjected to static and dynamic loads during their technical life time. Thus, monitoring material damage is important for providing information regarding critical damage of in-service...
Presentation
A key feature of Spectral Domain-Optical Coherence Tomography (SD-OCT) is the axial resolution dependence on the inverse of the optical bandwidth of the light source. Due to this there are numerous constraints to deal with at the spectrometer design to ensure high-sensitivity, high-speed and a large spectral sensitivity range. Most of the time, one...
Conference Paper
Fibre Bragg Gratings (FBG) sensors consist of a local modulation of refractive index in the fibre core, which serves as a spectral filter for guided light. The grating period and refractive index are sensitive to external and internal strains/stresses and temperature perturbations of the structure in which they are embedded to. The continuous devel...
Article
Full-text available
Ultrasonic testing using arrays is becoming widely used to test composite structures in the Aerospace industry. In recent years, the Full Matrix Capture (FMC) technique has been implemented to extract the signals for post-processing to form an image. The inherent anisotropy and the layering of the structure pose challenges for the interpretation of...
Article
Full-text available
The concept of structural health monitoring has been introduced to ensure structural integrity during the design lifetime of a structure. The main objectives of structural health monitoring are to detect, locate, quantify, and predict any damage that occurs during this lifetime of the structure so that effective and efficient maintenance and repair...
Article
Full-text available
Reflective Tilted Fiber Bragg Grating (TFBG) sensors have intriguing sensing capabilities due to the resonance-peaks present in their transmitted spectrum. Previous works measured the external refractive index (ERI) in which the TFBG sensor is placed, by considering the wavelengths or the envelope of the cladding-modes resonances. In this paper, pr...
Conference Paper
The Automated Fiber Placement process is established in the aerospace industry for the production of composite components. This technique places several narrow material strips in parallel. Within current industrial Automated Fiber Placement processes the visual inspection takes typically up to 50 % of overall production time. Furthermore, inspectio...
Preprint
Full-text available
In this work, we will demonstrate the abilities of tilted Fibre Bragg Grating (TFBG) as single three-parameter optical sensor, in monitoring the curing process and the internal state of thin and thick glass/epoxy composites manufactured using vacuum assisted resin infusion process. The TFBG sensors are embedded between the layers of the composite m...
Preprint
Full-text available
In the last decades, the continuous development of composite and new advanced materials and their relevant applications in the aerospace structures lead, in parallel, to the study of more sophisticated structural health monitoring techniques. Fibre Bragg gratings are of interest as sensors for structural health monitoring of composite materials as...
Article
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 method...
Preprint
Full-text available
Reflective Tilted Fiber Bragg Grating (TFBG) sensors have intriguing sensing capabilities due to the resonance-peaks present in their transmitted spectrum. Previous works measured the external refractive index (ERI) in which the TFBG sensor is placed, by considering the wavelengths or the envelope of the cladding-modes resonances. In this paper, pr...
Article
Full-text available
A reliable damage diagnostic by ultrasonic guided wave (GW) based structural health monitoring (SHM) can only be achieved if the physical interactions between wave propagation, the SHM system and environmental factors are fully understood. The purpose of this research was to gain knowledge about the effects of high-amplitude low-frequency structura...
Poster
Update on the feasibility and successful demonstration of our novel hybrid optical sensing method for load monitoring of morphing wing sections by carrying out tests on a mock-up wing section.
Article
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 tend to...
Article
In the first of two articles presenting findings from a collaborative research project into Frans Hals’s working methods and materials, an analysis of his ‘Portrait of woman’ in the Gemäldegalerie, Berlin, using five different non-invasive techniques offers a benchmark for a technical understanding of his paintings that can be used to support attri...
Article
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 enabled the...
Conference Paper
Fibre Bragg gratings (FBGs) are obtained through a permanent and periodic refractive index modulation in the core of the single-mode optical fibre. For many years, they have been employed in telecommunication industry as a passive device for wavelength division multiplexing and dispersion compensation components, or in laser apparatus for laser fib...
Article
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 beam pr...
Conference Paper
Over the last several years hybrid laminar flow control has gained a lot of interest for drag reduction by boundary layer suction, using small holes at the leading edges of aircraft wings and tail elements. A lot of effort has been spent on drilling of small holes into different materials with diameters around 100 µm. This paper focuses on practica...
Conference Paper
Today’s aircraft are equipped with multiple sensors, which monitor the integrity of aircraft systems and support predictive maintenance to increase aircraft operability and safety. Al-though the tires are only functional in a small time frame during flight, tire failures can have a huge operational impact on both the aircraft and airport. The Airbus...
Article
In this paper we propose a novel approach to characterise barely visible transverse matrix cracks in composite structures using fibre Bragg grating optical sensors. Matrix cracks are one of the most prevalent types of damage in composite structures, and detecting them in the internal layers of composites has remained a challenge. In this paper, we...
Conference Paper
Composite materials are susceptible to barely visible impact damages (BVID) due to low-velocity impact. Therefore, an automated damage detection and quantification technique is highly desirable for quick inspection of large number of composite structures. Among various different non-destructive techniques (NDTs), active thermography NDT can be used...
Conference Paper
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 structu...