Experimental and numerical analysis of a test rig for structural testing of a full-scale aircraft wing

Complexities are involved in testing an aircraft structure, including its size, which is essential for determining cost and feasibility. This paper focuses on the novelty of investigating the use of a scaled-down version of a full-scale aircraft wing and a test rig to predict the test rig’s structural response to the wing’s loading condition, thereby improving design and modelling techniques for the test rig. This paper also presents a methodology for sizing the test rig and the aircraft wing to perform structural tests on the wing. Numerical and experimental models subjected to various load cases are compared. This study begins by justifying the use of finite element analysis (FEA) for relevant parts of the test rig. A detailed explanation of the sizing method and its overall effect on the test rig is also provided. The results indicate a substantial similarity between the numerical and experimental models with respect to the stresses and deformation of the test specimen.This publication has received funding from the European Union’s Horizon Europe research and innovation program under grant agreement No. 101102004; UKRIAerospac

A set-based design space exploration framework for hybrid-electric aicraft design

Engineering design is characterised by uncertainty caused by a lack of experience and information. The traditional approach focuses on iterating and refining an initial conceptual design, which often is similar to the final one. Although this method serves well in the case of evolutionary design, it is unsuitable for innovation. In fact, without a suitable initial starting point, many rework iterations may be required to correct early inadequate design decisions. In addition, it may be challenging to map the requirements directly onto the design space. This dissertation aims at developing a methodology to address this problem. The developed framework starts from the hypothesis, and the knowledge to carry out the mapping of requirements onto the input parameters is embedded in the simulation model, and hence no additional rules are required. Instead, a probabilistic surrogate model based on Gaussian processes is used in conjunction with Bayesian statistics to find and eliminate unfeasible areas of the design space. This selection criterion is used in a set-based design approach to explore pockets of the entire continuous design space. Finally, sets with a sufficient likelihood of satisfying the requirements are searched with a local multidisciplinary optimisation algorithm to recover the individual design points. This process reduced the computational cost of the design space exploration by 80% without sacrificing the number of alternative solutions. Thanks to the large amount of data obtained, it was possible to produce new knowledge on hybrid-electric aircraft design. Specifically, it was found that linear segments are sufficient for defining energy management strategies, and the reduction of NOx emissions and fuel consumption are associated with climb and cruise, respectively. Furthermore, when studying regional aircraft operating missions, it was found that partial recharge is necessary to maintain the design performance. However, this could reduce the duration of the battery. The battery ageing rate correlates with the EMS’s demand for electrical energy. Finally, it was found that the battery’s energy density is a determinant of the pack’s durability and the feasibility of HE aircraft. The rate of improvement in emissions and fuel consumption is non-linear, suggesting that investing in considerable technological improvements has better returns. Indeed, the required technological level will not be available until the 2040s without an exponential increment of the cell energy density.PhD in Aerospac

Cross-national radiomics validation using mammography to predict occult invasion in ductal carcinoma in situ

Background: Patients diagnosed with ductal carcinoma in situ (DCIS) may also have undetected invasive breast cancer. Radiomic features of calcifications at mammography can predict occult invasive disease among women diagnosed with DCIS at core-needle biopsy, which could affect treatment recommendations. However, the generalizability of these radiomic models must be tested before they are adopted in clinical practice. Purpose: To evaluate the generalizability of radiomic models based on mammography features to predict occult invasive cancer among women diagnosed with DCIS at core-needle biopsy from three national datasets. Materials and Methods: In this retrospective, cross-national study, digital mammograms from women diagnosed with DCIS at breast core-needle biopsy were collected in the United States, United Kingdom, and the Netherlands between January 1, 2000, and December 31, 2021. Only asymptomatic women who had calcifications but did not have associated masses, architectural distortions, or asymmetries were included. Radiomic models were developed using cross-validated logistic regression on each national dataset, then round-robin tested on the other datasets. Differences across the three datasets in terms of the upstaging rate, age, lesion size, and estrogen and progesterone receptor levels were assessed using Kruskal-Wallis or χ2 test. Results: The study included 1498 women (age range, 31–89 years; mean age, 59 years ± 9 [SD]), as follows: 696 women from the United States, 618 women from the United Kingdom, and 184 women from the Netherlands, with upstaging rates of 16.1%, 16.7%, and 14.1%, respectively. Internal cross-validation areas under the receiver operating characteristic curve (AUCs) were 0.675 (95% CI: 0.671, 0.679), 0.603 (95% CI: 0.567, 0.722), and 0.701 (95% CI: 0.697, 0.706) for the U.S., UK, and Netherlands datasets, respectively. The model that was trained on the U.S. dataset yielded cross-national validation AUCs of 0.604 (95% CI: 0.560, 0.648) and 0.682 (95% CI: 0.607, 0.757) for the UK and Netherlands datasets. Conclusion: Radiomic machine learning models were shown to have the potential to predict occult invasive cancer in women with DCIS across diverse settings.National Cancer InstituteRadiolog

Gust rejection in multirotor aircraft using sliding mode control

Multirotor aircraft are being used in many applications because of their mechanical simplicity and high manoeuvrability. Many potential applications of multirotor aircraft are in gusty and turbulent environ- ments, it is imperative for them to have a stable hovering as well as offer resistance to transient gusts and winds. Many research studies have been carried out with regards to control of the multirotor aircraft but not much work has been undertaken considering the aerodynamic effects impacting the aircraft, in particular the rotor tilt angle. As the Vertical Take Off and Landing (VTOL) aircrafts are light-weight, they are prone to gusty wind conditions and desired landing and hovering is a great challenge during these disturbances. In this research work, an analysis of the effect of rotor tilt on the stability and gust rejection properties is performed with a conceptual planar birotor initially and then extended to quadrotors. The gust rejection properties of multirotor aircraft are also examined using sliding mode control taking rotor tilt angle into account. Models of the aircraft were developed in MATLAB/Simulink to implement nonlinear dynamic equations of the multirotor vehicles. A range of rotor tilt angles have been considered and investigated for gust rejection through extensive simulation studies using Proportional-Integral-Velocity (PIV) control, Sliding Mode Control (SMC) of altitude, attitude and PIV position control and a complete SMC control of altitude, attitude and position control. The performance of the three controllers were compared through numerical simulations. It was found that the complete sliding mode controller is very robust at rejecting the gust and shows that the rotor tilt angle does not impact on the vehicle stability when used with SMC, even in the presence of parametric uncertainties and external disturbances. Finally, suggestions for further work based on this research are presented on further design and development of sliding mode controllers for di erent multirotor con gurations.PhD in Aerospac

Hybrid solvers for reactor modelling: matrix-based and matrix-free approaches on voxel-dominated meshes

Simulating neutronics and thermal hydraulics within nuclear reactor cores is computationally intensive, not only because of the complexity of the governing equations but also because of the intricate geometries involved. Solving the Boltzmann transport and Navier-Stokes equations for a full core representation typically relies on unstructured meshes, which, while highly flexible, can substantially increase computational costs regarding memory and solving time. Cartesian meshes with Finite Elements (FE) offer a faster alternative, potentially improving computational speed by an order of magnitude due to direct memory addressing. However, they necessitate finer grids to accurately capture the boundary details of non-Cartesian surfaces, which can offset these gains by increasing solver times. To address this challenge, a new meshing algorithm is proposed in conjunction with hybrid, matrix-based and matrix free, solver technologies. It employs a geometry-conforming boundary method using voxel-dominated Cartesian meshes. This method enables accurate boundary representation at arbitrary resolutions, which can be adjusted to resolve the physics to the desired level of accuracy rather than strictly to capture geometric detail. This is combined with a hybrid solver for fluid flows to different regions of a problem in order to increase efficiency when resolving the boundary. This article demonstrates the method’s application to Computational Fluids Dynamics (CFD) and neutronics problems relevant to reactor physics, showcasing its accuracy, convergence, numerical stability, and suitability for handling complex geometries.The author(s) declare that financial support was received for the research and/or publication of this article. Science and Technology Facilities Council (STFC) funded through grant: Parallel solvers for voxel-dominant meshes for the Boltzmann Transport Equation.Frontiers in Nuclear Engineerin

Measurement of strain and vibration, at ambient conditions, on a dynamically pressurised aircraft fuel pump using optical fibre sensors

Ever-increasing demands to improve fuel burn efficiency of aero gas turbines lead to rises in fuel system pressures and temperatures, posing challenges for the structural integrity of the pump housing and creating internal deflections that can adversely affect volumetric efficiency. Non-invasive strain and vibration measurements could allow transient effects to be quantified and considered during the design process, leading to more robust fuel pumps. Fuel pumps used on a high bypass turbofan engine were instrumented with optical fibre Bragg grating (FBG) sensors, strain gauges and thermocouples. A hydraulic hand pump was used to facilitate measurements under static conditions, while dynamic measurements were performed on a dedicated fuel pump test rig. The experimental data were compared with the outputs from a finite element (FE) model and, in general, good agreement was observed. Where differences were observed, it was concluded that they arose from the sensitivity of the model to the selection of nodes that best matched the sensor location. Strain and vibration measurements were performed over the frequency range of 0 to 2.5 kHz and demonstrated the ability of surface-mounted FBGs to characterise vibrations originating within the internal sub-components of the pump, offering potential for condition monitoring.United Kingdom Research and Innovation,113095; Engineering and Physical Sciences Research Council, EP/H02252X/1The authors acknowledge funding from the United Kingdom Research and Innovation (UKRI) through the support from Innovate UK, via the Aerospace Technology Institute (ATI) program, End-to-End Equipment Health Management (E2E EHM, Project Reference: 113095) [50] and by the Engineering and Physical Sciences Research Council (EPSRC), UK via a Platform Grant (EP/H02252X/1).Sensor

Fault diagnosis in time series data with application to railway assets

Emmanouilidis, Christos - Associate SupervisorThis thesis focuses on diagnosing incipient faults in railway train assets through large data sets. It investigates data mining methods to detect changes in big time series data to enable service by employing three case studies that separately investigate (1) the doors, (2) the engines, and (3) the wheels. Each case study comprises data with different characteristics: the first case study examining engines presents datasets with variable speed and load; the second case study examining door data highlights start-stop characteristics, with discontinuities in the data; and the third case study examining wheel data contains fast transitions from normal to slip behaviours in acceleration and deceleration. A time series architecture is proposed. It describes key steps for multivariate time series analysis and enables iterative improvement reusing results for the next iteration. A fault diagnosis is made for each case scenario, and procedures for synchronisation and alignment; pre-processing; and methods for feature extraction, classification or clustering are thus presented. For engine fault diagnosis, the proposed graphical method has the best performance. In the case of the door fault diagnosis, the K-nearest neighbours method has the best performance. In the wheel slip diagnosis case study, the combined wavelet and LSTM methods present the best accuracy. Limitations include data quality issues, key input data uncertainties, and applied classification deficiencies. The main challenges include big datasets that are desynchronised, wrongly time-indexed, noisy, redundant, and unlabelled; infrequent faults; the lack of monitoring in several subsystems; and incomplete or missing maintenance records.PhD in Manufacturin

Gimbal control of an airborne Pan-Tilt-Zoom camera for visual search

This paper presents the development of an optimized visual search algorithm for unmanned aerial vehicle (UAV) equipped with Pan-Tilt-Zoom cameras, designed to account for platform dynamics and disturbances. The study involves the design and evaluation of various gimbal control strategies to stabilize the camera’s orientation, ensuring effective area coverage despite UAV attitude changes. A comparative analysis of control methods, including Proportional–integral–derivative (PID), Disturbance Observer (DOB), Iterative Learning Control, Internal Model Control, Active Disturbance Rejection Control, and their combinations, highlights the importance of advanced controllers in maintaining camera stability under complex conditions such as coriolis, centripetal, and gyroscopic disturbances. The combination of PID and DOB provided superior disturbance rejection, making it a suitable choice for challenging flight scenarios. Additionally, an optimized coverage path planning algorithm was developed to maximize image coverage while minimizing flight time, turns, and overlap, taking into account field of view, resolution, and terrain constraints. Simulation results demonstrate the effectiveness of this approach, achieving full area coverage with enhanced efficiency. The framework developed in this study provides a solid foundation for reliable and precise UAV-based search operations, particularly in dynamic and complex environments.AIAA SCITECH 2025 Foru

Comparison of efficiencies in protectionist and liberal cabotage policies

This paper focuses on cabotage, which is a long-standing regulation that restricts coastal trade to domestic ships. As globalisation has grown, global trade organisations have pushed for the removal of these barriers to promote a competitive market environment. In this research, Data Envelopment Analysis (DEA) is used to evaluate and compare the efficiencies of countries which have protectionist and liberalised cabotage policies. To do this, maritime statistics in 2022 from the World Bank database are considered for 50 different countries. We find that both protectionist and liberal policies have advantages and disadvantages, but neither is inherently superior. In addition, cabotage policies must be structured according to each country’s conditions, and a delicate balance must be established between these policies, considering the dynamics of the global economy. This paper has also considered advantages and disadvantages by comparing countries that have different policies on cabotage, such as the UK and Türkiye, to show how cabotage regulations generate different perspectives created by their respective maritime pasts and geopolitics. In terms of an effective and competitive maritime industry, the study is one of the unique types of research that underlines the need for a cabotage strategy balanced between the liberalised and protectionist components.Maritime Policy & Managemen

Off-design performance control and simulation for gas turbine engines with sequential combustors

A gas turbine engine with a sequential combustion system has the potential to offer high cycle efficiency at moderate turbine entry temperatures. Consequently, it has one more degree of power setting control, which offers more flexible but also more complex control of engine off-design operations. In this paper, a novel simulation method for off-design thermodynamic performance of sequential combustion gas turbines has been introduced and a novel performance control schedule for part-load operations at various ambient conditions have been proposed aiming to keep the relative workloads between the two turbine sections constant. The proposed control schedule is simple and can be adapted easily. By applying the off-design performance control schedule to a model industrial gas turbine engine with two sequential combustors, the performance of the model engine is simulated at different part-load and at different ambient conditions. The results show that by applying the proposed off-design performance control schedule, the model sequential combustion gas turbine engine could operate effectively at different part-load operating conditions and at different ambient conditions with both turbine sections keeping nearly constant workload distributions.Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energ