Staff publications (SATM)

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Open Access
A review of material-related mechanical failures and load monitoring-based structural health monitoring (SHM) technologies in aircraft landing gear
(MDPI, 2025-03-20) Deng, Kailun; Ompusunggu, Agusmian Partogi; Xu, Yigeng; Skote, Martin; Zhao, Yifan
The aircraft landing gear system is vital in ensuring the aircraft’s functional completeness and operational safety. The mechanical structures of the landing gear must withstand significant operational forces, including repeated high-intensity impact loads, throughout their service life. At the same time, they must resist environmental degradation, such as corrosion, temperature fluctuations, and humidity, to ensure structural integrity and long-term reliability. Under this premise, investigating material-related mechanical failures in the landing gear is of great significance for preventing landing gear failures and ensuring aviation safety. Compared to failure investigations, structural health monitoring (SHM) plays a more active role in failure prevention for aircraft landing gears. SHM technologies identify the precursors of potential failures and continuously monitor the operational or health conditions of landing gear structures, which facilitates condition-based maintenance. This paper reviews various landing gear material-related failure investigations. The review suggests a significant portion of these failures can be attributed to material fatigue, which is either induced by abnormal high-stress concentration or corrosion. This paper also reviews a series of load monitoring-based landing gear SHM studies. It is revealed that weight and balance measurement, hard landing detection, and structure load monitoring are the most typical monitoring activities in landing gears. An analytical discussion is also presented on the correlation between reviewed landing gear failures and SHM activities, a comparison of sensors, and the potential shift in load-based landing gear SHM in response to the transition of landing gear design philosophy from safe life to damage tolerance.
Open Access
Traffic prediction with shared causal inference in ORAN computing continuum
(IEEE, 2024-12-08) Guo, Weisi; Cordiez, Theophile
Data-driven proactive network optimisation is critical for 5G advanced and 6G, allowing operators to dynamically allocate cellular spectrum reuse in anticipating for demand surges. Current approaches to traffic prediction are largely temporal correlation based. We know causal inference of key factors can help to improve prediction accuracy for spike traffic events and identify pathways to improve services. Current causal inference identify stationary independent variables, but real environments have open challenges: (i) dynamic and heterogeneous causal maps, (ii) cascade partially observable variables, and/or (iii) have coupled / confounding relationships. Currently there is no research that dynamically configures the causal relationship according to emerging real-time data and shares inference outcomes across the data sharing and computing continuum of Open-RAN (ORAN) architecture. Here, we use both real cellular network traffic and social event triggers to perform nonlinear causal inference as an rApp: Predictability Improvement (PI), Conditional Mutual Information (CMI), and Convergent Cross Map (CCM). This causal knowledge is then shared across the ORAN to be embedded in traffic prediction xApps: hard causal embedding to Recurrent Neural Network (RNN) and soft causal feature embedding to a Gaussian Processes (GP). The results show a significant accuracy improvement (93-99%) over baseline non-causal correlated prediction (76-94%) and blind multi-variate approaches (87-95%). This work paves the way to causal proactive network optimisation.
Open Access
International collaboration
(The Foundation for Science and Technology, 2025-03-01) Neale, Geoffrey
Open Access
Numerical predictions of Low-Reynolds-Number propeller aeroacoustics: comparison of methods at different fidelity levels
(MDPI, 2025-02-18) Huang, Guangyuan; Sharma, Ankit; Chen, Xin; Riaz, Atif; Jefferson-Loveday, Richard
Low-Reynolds-number propeller systems have been widely used in aeronautical applications, such as unmanned aerial vehicles (UAV) and electric propulsion systems. However, the aerodynamic sound of the propeller systems is often significant and can lead to aircraft noise problems. Therefore, effective predictions of propeller noise are important for designing aircraft, and the different phases in aircraft design require specific prediction approaches. This paper aimed to perform a comparison study on numerical methods at different fidelity levels for predicting the aerodynamic noise of low-Reynolds-number propellers. The Ffowcs-Williams and Hawkings (FWH), Hanson, and Gutin methods were assessed as, respectively, high-, medium-, and low-fidelity noise models. And a coarse-grid large eddy simulation was performed to model the propeller aerodynamics and to inform the three noise models. A popular propeller configuration, which has been used in previous experimental and numerical studies on propeller noise, was employed. This configuration consisted of a two-bladed propeller mounted on a cylindrical nacelle. The propeller had a diameter of D=9″ and a pitch-to-diameter ratio of P/D=1, and was operated in a forward-flight condition with a chord-based Reynolds number of Re=4.8×104, a tip Mach number of M=0.231, and an advance ratio of J=0.485. The results were validated against existing experimental measurements. The propeller flow was characterized by significant tip vortices, weak separation over the leading edges of the blade suction sides, and small-scale vortical structures from the blade trailing edges. The far-field noise was characterized by tonal noise, as well as broadband noise. The mechanism of the noise generation and propagation were clarified. The capacities of the three noise modeling methods for predicting such propeller noise were evaluated and compared.
Open Access
Coriolis massflow measurement errors due to inhomogeneous entrained particles: an analytical model
(Elsevier, 2025-06) Wernli, Stephan; Huber, Lilach Goren; Avdelidis, Nicolas P.; Rieder, Alfred
The Coriolis mass flow meter is a critical instrument used in various industries for the precise measurement of mass flow rate and density of a fluid. Despite its widespread use, the impact of entrained particles within the fluid can significantly affect the accuracy of the meter, leading to potential errors and inefficiencies. Previous calculations of the mass flow errors assumed that the entrained particles are uniformly distributed along the axis of the measurement tube. In this paper we extend the analytical investigation of the measurement errors beyond the previous work to the regime of non-uniform density distribution of the entrained particles. We provide a clear analysis of the contributions of various physical effects in this regime to the mass-flow measurement error.
Open Access
Influence of thermal contrast and limitations of a deep-learning based estimation of early-stage tumour parameters in different breast shapes using simulated passive and dynamic thermography
(Elsevier, 2025-04) Moraes, M. F. B.; Sfarra, Stefano; Fernandes, Henrique; Figueiredo, Alisson A. A.
To enhance diagnostic sensitivity compared to passive thermography, thermal stress can be applied to the breast surface with the temperatures being measured in the thermal recovery phase, a process called dynamic thermography. This study aims to evaluate the limitations of both passive and dynamic thermography in estimating early-stage tumour parameters across different breast shapes and how to improve the results. Three breast models with thermoregulation were solved numerically using COMSOL Multiphysics®. A neural network developed in PyTorch was used to estimate breast tumour location and size. The estimates obtained using each approach were compared, and the effects of thermal contrast, noise, and tumour depth range were analysed. Dynamic thermography provided the most accurate estimates compared to passive thermography, with mean error reductions that reached up to 33.25%. Additionally, the number of estimates with errors higher than 10% was up to 48.42% lower. Tumour radius showed the lowest noise threshold, providing the highest estimations errors. Adding deeper tumours to the datasets caused mean error increases of up to 51.27%. Thus, this work contributes by comparing both types of thermography, analysing thermal aspects of the temperature data that influences the neural network's estimation process, and suggesting alternatives to improve its accuracy.
Open Access
Recovery from startle and surprise: a survey of airline pilots' operational experience using a startle and surprise management method
(Elsevier, 2025-05-01) Vlaskamp, Daan; Landman, Annemarie; van Rooij, Jeroen; Blundell, James
A significant safety challenge airline pilots contend with is the possibility of experiencing startle and surprise. These are cognitive-emotional responses that may temporarily impair performance and that have contributed to multiple fatal loss of control events. Several self-management methods exist that are intended to facilitate recovery from startle and surprise, but these have only been tested in simulator experiments. The current study addresses this research gap by surveying the perceptions of 239 airline pilots on the utility and benefit of a method which they use in operational practice– the “Reset Method”. Overall, the survey results revealed that pilots felt the method improved mental preparedness, and reduced stress. A reported reason for not applying the method was the urge to act quickly. In addition, not all steps of the method were applied equally, and some pilots found the method difficult to fit into the existing procedures of several time-critical scenarios (e.g., aircraft upsets and emergency landings). We recommend training self-management methods in scenarios which carry the most risk of negative effects of startle and surprise. We also recommend instilling awareness of the ‘startle paradox': self-management techniques are most difficult to apply in situations where they are most beneficial. Method shortening and simplification may facilitate application. Future research should focus on refining the method's implementation, addressing the startle paradox, and understanding the transferability of startle and surprise management methods to other safety critical industries defined by complex sociotechnical interactions.
Open Access
The ‘hangar of the future’ for sustainable aviation
(Cambridge University Press (CUP), 2024-11) Plastropoulos, Angelos; Fan, Ip-Shing; Avdelidis, Nicolas P.; Angus, Jim; Maggiore, John; Atkinson, Helen
Sustainability is becoming a major strategic driver within the aviation industry, which has moved from providing primarily economic benefits to delivering the ‘triple bottom line’, including social and environmental impact as well as financial performance. Sustainable aviation is also being tracked by the International Civil Aviation Organisation (ICAO) Global Collation for Sustainable Aviation. Operations and Infrastructure is an important near-term opportunity to deliver sustainability benefits. Digital Technologies, Integrated Vehicle Health Management (IVHM) and Maintenance Repair and Overhaul (MRO) play a prominent role in implementing these benefits, with a particular focus on operational efficiencies. As part of this, the sustainable smart hangar of the future is a concept that is becoming more and more important in forming the future of the aviation industry. The Hangar of the Future is an excellent opportunity for innovation, combining the progress in manufacturing, materials, robotics and artificial intelligence technologies. Succeeding in developing a hangar with these characteristics will provide us with potential benefits ranging from reduced downtime and costs to improved safety and environmental impact. This work explores some of the key features related to the sustainable smart hangar of the future by discussing research that takes place in DARTeC’s (Digital Aviation Research and Technology Centre) hangar led by the IVHM Centre in Cranfield. Additionally, the paper touches on some longer-term aspirations.
Open Access
Battery pack technological considerations for hybrid-electric regional aircraft feasibility
(Cambridge University Press (CUP), 2025-01-01) Spinelli, Andrea; Krupa, Gustavo P.; Kipouros, Timoleon; Laskaridis, Panos; Berseneff, Boris
This paper presents a study of the effects of the durability and level of energy storage technology on energy management strategies and the performance of hybrid electric turboprops. The results highlight the key role of battery energy density on the durability of the battery pack and the viability of the concept of hybrid electric aircraft. Additionally, the trade-off between zero-day environmental compatibility and battery lifetime is identified, caused by the size of the pack. The effective energy density would decrease with the aging of the cells, leaving a significant inert mass and increasing fuel consumption. Optimal energy management strategies are suggested in light of this new information. Higher specific energy of the pack would mitigate this aspect, along with a reduction in fuel consumption and NOx emissions. Indeed, the improvement of environmental compatibility was found to be nonlinear with a positive rate, suggesting high returns in investing in great improvements in energy density over a gradual increase. This result relates to the results of the statistical technological forecast presented in this study, which, without an increase in funding, predicts the availability of the specific energy required to match the fuel-only baseline in the 2040–2050 decade.
Open Access
Assessment of hydrogen storage and pipelines for hydrogen farm
(MDPI, 2025-02-27) Alssalehin, Esmaeil; Holborn, Paul; Pilidis, Pericles
This paper presents a thorough initial evaluation of hydrogen gaseous storage and pipeline infrastructure, emphasizing health and safety protocols as well as capacity considerations pertinent to industrial applications. As hydrogen increasingly establishes itself as a vital energy vector within the transition towards low-carbon energy systems, the formulation of effective storage and transportation solutions becomes imperative. The investigation delves into the applications and technologies associated with hydrogen storage, specifically concentrating on compressed hydrogen gas storage, elucidating the principles underlying hydrogen compression and the diverse categories of hydrogen storage tanks, including pressure vessels specifically designed for gaseous hydrogen containment. Critical factors concerning hydrogen gas pipelines are scrutinized, accompanied by a review of appropriate compression apparatus, types of compressors, and particular pipeline specifications necessary for the transport of both hydrogen and oxygen generated by electrolysers. The significance of health and safety in hydrogen systems is underscored due to the flammable nature and high diffusivity of hydrogen. This paper defines the recommended health and safety protocols for hydrogen storage and pipeline operations, alongside exemplary practices for the effective implementation of these protocols across various storage and pipeline configurations. Moreover, it investigates the function of oxygen transport pipelines and the applications of oxygen produced from electrolysers, considering the interconnected safety standards governing hydrogen and oxygen infrastructure. The conclusions drawn from this study facilitate the advancement of secure and efficient hydrogen storage and pipeline systems, thereby furthering the overarching aim of scalable hydrogen energy deployment within both energy and industrial sectors.
Open Access
Brief review of vibrothermography and optical thermography for defect quantification in CFRP material
(MDPI, 2025-03-16) Hidayat, Zulham; Avdelidis, Nicolas P.; Fernandes, Henrique
Quantifying defects in carbon-fiber-reinforced polymer (CFRP) composites is crucial for ensuring quality control and structural integrity. Among non-destructive evaluation techniques, thermography has emerged as a promising solution for defect detection and characterization. This literature review synthesizes current advancements in active thermography methods, with a particular focus on vibrothermography and optical thermography, in identifying defects such as delaminations and BVID in CFRP composites. The review evaluates state-of-the-art techniques, highlighting the advanced applications of optical thermography. It identifies a critical research gap in the integration of vibrothermography with advanced image-processing methods, such as computer vision, which is more commonly applied in optical thermography. Addressing this gap holds significant potential to enhance defect quantification accuracy, improve maintenance practices, and ensure the safety of composite structures.
Open Access
Emerging decision-making for transportation safety: collaborative agent performance analysis
(MDPI, 2025-01-15) Maguire-Day, Jack; Al-Rubaye, Saba; Warrier, Anirudh; Sen, Muhammet A.; Whitworth, Huw; Samie, Mohammad
This paper addresses the challenge of improving decision-making capabilities and safety in autonomous vehicles (AVs) using Agent-Based Modelling (ABM). The study evaluates ABM’s effect on Advanced Driver Assistance Systems (ADASs) in challenging driving situations, like lane merging, by incorporating it into a simulation framework designed for autonomous vehicles. Identifying emergent behaviours that enhance safety and efficiency, verifying the efficacy of ABM in AV decision-making, and investigating the function of hardware acceleration to enable practical application in ADASs are some of the major achievements. According to the simulation results, ABM can greatly improve AV performance, providing a practical and scalable means of enhancing safety in future transportation systems.
Open Access
Vertical-horizontal actor collaboration in governance network: a systematic review
(Springer, 2024-12-01) Hendra, Oke; Prasojo, Eko; Fathurrahman, Reza; Pilbeam, Colin
This research proposes a categorization framework to analyse multi-actor collaboration variations in governance network. It examines both vertical (government levels) and horizontal (sectors) interactions. This study reviewed 92 academic articles, adhering to the PRISMA methodology and utilizes 2 × 2 and "who-how-what" frameworks to capture the breadth of vertical-horizontal collaboration arrangements. The study identifies a rise in multi-actor collaborations and a dominance of qualitative research. It exposes research gaps: limited cross-sectoral and international actor studies, and under-researched sectors beyond environment. The proposed framework, capturing actors, levers, purposes, and context, aims to guide future research on vertical-horizontal actor collaboration in governance network.
Open Access
Temperature-dependent solid material properties of GRCop-42 for an additively manufactured liquid rocket engine LOx cooling channel
(University of Miskolc, 2024-11-06) Monokrousos, Nikos; Könözsy, László; Pachidis, Vassilios; Sozio, Ernesto; Rossi, Federico
Recent technological developments in the field of Additive Manufacturing (AM) provide a number of opportunities for the utilisation of high-performance copper alloys for aerospace applications. The additively manufactured LOx/LNG DemoP1 aerospike engine demonstrator designed by Pangea Aerospace is a characteristic example based on the Direct Metal Laser Sintering (DMLS) technology. The aerospike engine thrust chamber and LOx cooling channels are manufactured using GRCop-42 material powder, a Cu-Cr-Nb based copper alloy developed by the National Aeronautics and Space Administration (NASA) for the regenerative cooling technology of high thermal demand thrust chambers and nozzles. In the current work temperature-dependent correlations are derived for the density, specific heat capacity at constant pressure and thermal conductivity of the GRCop-42 material. The correlations for the solid material properties are then introduced into the ANSYS Fluent 2023 R2 Computational Fluid Dynamics (CFD) package and their capabilities are investigated for the characterisation of the flow-field characteristics of the LOx flow in the cooling channel. The numerical solution of the coolant flow in the AM cooling channel is compared against experimental data of the DemoP1 engine demonstrator. The main objective of this study is to provide a realistic physical description of the temperature-dependent properties of the AM solid material in high heat flux applications where the material properties are mostly considered as constant in previous studies.
Open Access
CFD modelling and simulation on a lambda wing at subsonic speed
(American Institute of Aeronautics and Astronautics (AIAA), 2025-01-06) Prince, Simon A.; Rana, Zeeshan A.; Di Pasquale, Davide; Podwojewski, Claude; Zielinski, Tomas
This paper presents and discusses the results of a study at subsonic airspeed of the aerodynamic characteristics of the Swept Wing Flow Test (SWIFT) lambda wing configuration, which was undertaken as part of the NATO AVT-298 Task Group activity on “Reynolds Number Scaling Effects on Swept Wing Flows”. While the task group studied the aerodynamics of this unconventional wing shape across the subsonic and transonic Mach number, and a wide range of Reynolds numbers via cryogenic testing in the NASA NTF wind tunnel, this paper focuses only on the Mach 0.2 conditions at a Reynolds number, based on mean chord, of 2.5 million, for which the model was tested at the ARA Transonic Wind Tunnel in the UK. Various fidelity CFD methods were employed for comparison with experimental data, over a pitch sweep from -4 to 20 degrees angle of attack, including the Viscous Full Potential (VFP) method, RANS, Unsteady RANS and Delayed Detached Eddy Simulation (DDES). The results for this case, highlight the complex 3D stall, initiating inboard, associated with this class of swept wing, which is very different from that seen on conventional swept, tapered wings typically seen on civil transport aircraft, which tends to initiate towards the tip. While the results show that, of the RANS turbulence models tested, the k-omega SST turbulence model most effectively predicted the experimental data, but none of the linear eddy viscosity models could resolve the benign stall characteristics captured in the experiment. Only the DDES method was found to effectively predict the post stall characteristics to some degree of accuracy. The VFP method generated results in a fraction of the time (seconds compared with hours), required for higher fidelity CFD solution, and was found to provide data with equivalent accuracy to RANS based methods for pre-stall conditions.
Open Access
Impact of whale tubercles on the aerodynamics characteristics of F1 front wing - adjoint optimization
(American Institute of Aeronautics and Astronautics (AIAA), 2025-01-06) Toprakoglu, Fidel; Ozyumruoglu, Ismet; Rana, Zeeshan A.; Di Pasquale, Davide
This research aimed to investigate the impact of varying tubercles frequency and amplitudeon the leading edge of a double-element Formula One (F1) front wing at two different ride heights in the pre-stall regime. A bio-inspired tubercle distribution was implemented, varying in amplitude and frequency across the span. Computational simulations were performed at 30m/s using the κ − ω SST model. The results showed that implementing bio-inspired tubercles on front wings did not improve aerodynamic efficiency at any ride height. The clean leading-edge model consistently achieved the highest lift-to-drag ratio at both ride heights. Configurations with various tubercle amplitude presented different results: for low-amplitude tubercles, the down force increased compared to the baseline at the cost of increased drag. Models with higher amplitude tubercles led to significant down force reduction due to flow separation, further diminishing aerodynamic performance. Variations in tubercle frequency had minimal impact on aerodynamic performances. Among the tubercle configurations tested, the model with the lowest amplitude and the fewest tubercles achieved the highest aerodynamic efficiency.
Open Access
Aerodynamics of high-bypass-ratio aeroengine nacelles: numerical and experimental investigation
(American Institute of Aeronautics and Astronautics (AIAA), 2025-03-12) Tejero, Fernando; MacManus, David; Sanchez-Moreno, Francisco; Schreiner, Deneys; Hill, Andrea; Sheaf, Christopher; Ramirez-Rubio, Santiago
This work presents a numerical and experimental investigation of the nacelle aerodynamics for high-bypass- ratio aeroengines. A conventional nacelle that is representative of a current standard, and a compact design that is envisaged for future aeroengines, were optimized with an existing computational method. Both nacelles were tested in a large-scale transonic wind tunnel. For the first time, the aerodynamic benefits of compact nacelles are demonstrated through an experimental test campaign. Measurements and computational fluid dynamics (CFD) simulations confirmed the drag reduction of compact configurations across a wide range of operating points with different flight Mach numbers, mass-flow capture ratios, and angles of attack. For midcruise conditions with a Mach number of 0.85, this was a drag reduction of 8.5% and 8.8% for the measurements and CFD, respectively. These benefits are similar to an isolated optimization, that is, not installed in the wind tunnel, which confirmed the capabilities of the method to identify the drag benefit of compact designs. Relative to the measurements, the main aerodynamic characteristics on the nacelles were captured by CFD in terms of isentropic Mach number distributions and shock location. This work provides a quantitative evaluation for the use of CFD within an industrial setting for nacelle design and analysis.
Open Access
Enhancing quadrotor resilience in outdoor operations with real-time wind gust measurement by using LiDAR
(World Scientific Publishing, 2025-03-12) Latif, Zohaib; Whidborne, James F.; Bhatti, Aamer Iqbal; Shahzad, Amir; Samar, Raza
Unmanned Aerial Vehicles (UAVs) encounter wind gusts during outdoor operations, impacting their position holding, particularly for quadrotors. This vulnerability is amplified during the autonomous docking to outdoor charging stations. The integration of real-time wind preview information for UAV gust rejection control has become more feasible with advances in remote wind sensor technologies like LiDAR. In this study, a ground-based LiDAR system is proposed to predict wind gusts at the landing site of quadrotors. The acquired wind preview data are subsequently utilized by the Model Predictive Control (MPC) to effectively mitigate disturbances. To validate the proposed methodology, a nonlinear simulation environment has been established using LiDAR data collected from comprehensive field tests. The results demonstrate a notable improvement in the system performance compared to benchmark results. This research underscores the practical utility of real-time wind preview information, facilitated by LiDAR technology, in enhancing the overall operational resilience of UAVs, especially quadrotors, during challenging environmental conditions.
Open Access
Potential for energy recovery of a nonadiabatic subsonic airfoil
(American Institute of Aeronautics and Astronautics (AIAA), 2025) Lister-Symonds, Joseph E.; Mutangara, Ngonidzashe E.; Lamprakis, Ioannis; Sanders, Drewan S.
This paper investigates the effect of wall temperature and flow conditions on the potential for energy recovery of the NACA0012 airfoil. A work–energy balance has been derived from the governing equations for moving control volumes for a body in dynamic equilibrium, aerodynamically decoupled from its propulsive source. The formulation has been applied to an extensive test matrix of computational fluid dynamics cases, with steady level flight imposed and wall temperature, angle of attack, Reynolds number, and Mach number varied independently. The decomposition of the wake energy shows explicitly that the near-field work of the body manifests as global energy constituents, viscous dissipation, and baroclinic work. The analysis identifies the conditions and underlying mechanisms that minimize and maximize the potential for energy recovery, revealing that there are synergistic opportunities for tightly coupled airframe and propulsor configurations with waste heat to reject.
Open Access
Composite material defect segmentation using deep learning models and infrared thermography
(Universidade Federal do Rio Grande do Sul, 2025-02-20) Garcia Vargas, Iago; Fernandes, Henrique
For non-destructive assessment, the segmentation of infrared thermographic images of carbon fiber composites is a critical task in material characterization and quality assessment. This study focuses on applying image processing techniques, particularly adaptive thresholding, alongside neural network models such as U-Net and DeepLabv3 for infrared image segmentation tasks. An experimental analysis was conducted on these networks to compare their performance in segmenting artificial defects from infrared images of a carbon-fibre reinforced polymer sample. The performance of these models was evaluated based on the F1-Score and Intersection over Union (IoU) metrics. The findings reveal that DeepLabv3 demonstrates superior results and efficiency in segmenting patterns of infrared images, achieving an F1-Score of 0.94 and an IoU of 0.74, showcasing its potential for advanced material analysis and quality control.