Browsing by Author "Pontillo, Alessandro"
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Item Open Access A Benchtop Flight Control Demonstrator - Data and Code(Cranfield University, 2019-09-10 09:28) Duran, Joris; Whidborne, James; Pontillo, Alessandro; alejandro Carrizales rodriguez, MartinCodes and data for "A benchtop flight control demonstrator" J R Duran, J F Whidborne, M Carrizales Rodriguez, A Pontillo International Journal of Mechanical Engineering Education Published online July 27, 2019 doi: 10.1177/0306419019852688CodesFlight-Desk-Control-Demonstrator-master.zip - GUI on a computer programmed in JAVA - PID Controller for ArduinoExperimental Results- Test open loop.xls- Test P.xls- Test PID.xlsFluent CFD Fileswindtunnel.casWindtunnel.jouWindtunnel_refine.meshdatJavaFoil filescriptJaveFoilMicrosoft Excel Windtunnel design worksheetWind Tunnel Design V2.xlsmCATIA CAD filesCAD-CATIA.zipMSc DissertationDuran JR. Flight Desk Control Demonstrator. MSc dissertation, Cranfield University, Bedfordshire, U.K., 2018. Available at: http://dspace.lib.cranfield.ac.uk/handle/1826/14154Item Open Access Active stall flutter suppression for a revised Leishman/Beddoes model(American Society of Civil Engineers, 2023-12-25) Zheng, Junruoyu; Pontillo, Alessandro; Chen, Lejun; Whidborne, James F.This paper proposes a nonlinear disturbance observer (NDO) based sliding mode control (SMC) method to the problem of stall flutter suppression for a revised Leishman/Beddoes (L/B) model. To capture accurate aerodynamic characteristics whilst reducing the plant model mismatch, the dynamics of the separation point and the shift of the aerodynamic centre are analysed to improve the structure of the L/B model. Based on this revised L/B model, an active flutter suppression problem which includes aerodynamic disturbances and actuator dynamics is addressed. The inclusion of the actuator dynamics means that the aerodynamic disturbance from the flow separation, induced by the revised L/B model, is considered as an ‘unmatched’ disturbance. To counteract the effect of unmatched disturbances, an NDO-based sliding mode control scheme is applied to suppress stall flutter and to ensure rapid reference tracking performance in both steady and unsteady flow conditions. Simulation results show the improvements of the proposed revised L/B model via a comparative analysis. In addition, the efficacy of the proposed stall flutter suppression scheme is demonstratedItem Open Access Aeroelastic scaling for flexible high aspect ratio wings(AIAA, 2019-12-31) Yusuf, Sezsy; Pontillo, Alessandro; Weber, Simone; Hayes, David; Lone, MudassirThis paper provides an overview of the work conducted as part of the Cranfield BEAmReduction and Dynamic Scaling (BeaRDS ) programme, which aims to develop a methodologyfor designing, manufacturing and testing of a dynamically scaled High Aspect Ratio (HAR)Wing inside Cranfield 8’x6’ wind tunnel. The aim of this paper is to develop a methodologythat adopts scaling laws to allow experimental testing of a conceptual flexible-wing planformas part of the design process. Based on the Buckinghamπtheorem, a set of scaling lawsare determined that enable the relationship between a full-scale and sub-scale model. Thedynamically sub-scaled model is manufactured as a combination of spar, skin, and addedmass representing the stiffness, aerodynamic profile, and aeroelastic behaviour respectively.The spar was manufactured as a cross-sectional shape using Aluminium material, while theskin was manufactured using PolyJet technology. Compromises due to the manufacturingprocess are outlined and lessons learned during the development of the sub-scaled model arehighlighted.Item Open Access Data for: Ground Vibration Testing of a High Aspect Ratio Wing with Revolving Clamp(Cranfield University, 2022-12-01 09:17) Dessena, Gabriele; Ignatev, Dmitrii; Whidborne, James; Pontillo, Alessandro; Zanotti Fragonara, Luca33rd Congress of the International Council of the Aeronautical Sciences (ICAS). Abstract: The advancements in the aeronautical industry and research on materials and manufacturing methods in the last 70 years have been shifting the paradigm of wing design to high aspect ratio flexible wings. These wings can show a varying behaviour in different operating conditions, as per the nature of their geometry and materials. This work proposes a case study of a high aspect ratio flexible wing in order to study the effect of operating conditions on its structural properties. To test different operating conditions on the ground, a revolving clamp is designed to attach the specimen to a clamp-on shaker. A clear relationship between the wing’s modal properties, and so structural properties, and the angle the clamp sets is found.Item Open Access Flexible high aspect ratio wing: Low cost experimental model and computational framework(AIAA, 2018-01-13) Pontillo, Alessandro; Hayes, David; Dussart, Gaétan X.; Lopez Matos, Guillermo E.; Carrizales, Martin A.; Yusuf, Sezsy Y.; Lone, Mohammad M.Aircraft concepts of tomorrow, such as high aspect ratio wing aircraft, are far more integrated between technical disciplines and thus require multidisciplinary design approaches. Design tools able to predict associated dynamics need to be developed if such wing concepts are to be matured for use on future transport aircraft. The Cranfield University Beam Reduction and Dynamic Scaling ( BeaRDS) Programme provides a framework that scales a conceptual full size aircraft to a cantilevered wing model of wind tunnel dimensions, such that there is similitude between the static and dynamic behaviour of the model and the full size aircraft. This process of aeroelastically scaled testing combines the technical disciplines of aerodynamics, flight mechanics and structural dynamics, to provide a means by which future concept aircraft can be de-risked and explored . Data acquisition from wind tunnel testing can then be used to validate fluid-structure interaction frameworks that model the aeroelastic effect on the flight dynamics of the aircraft. This paper provides an overview of the BeaRDS methodology, and focuses on the Phase I of the programme, being the development of a reduced Cranfield A-13 aircraft cantilevered wing, to mitigate risk associated with the manufacturing and instrumentation app roach. It is shown that a low cost acquisition system of commercial Inertial Measurement Units (IMUs) can measure the response of the wing within the desired frequency range. Issues associated with the Phase I testing are discussed, and methods are proposed for the Phase II programme that allow these problems to be resolved for a larger scale flexible wing with active control surfaces.Item Open Access Ground vibration testing of a flexible wing: a benchmark and case study(MDPI, 2022-08-10) Dessena, Gabriele; Ignatyev, Dmitry I.; Whidborne, James F.; Pontillo, Alessandro; Zanotti Fragonara, LucaBeam-like flexible structures are of interest in many fields of engineering, particularly aeronautics, where wings are frequently modelled and represented as such. Experimental modal analysis is commonly used to characterise the wing’s dynamical response. However, unlike other flexible structure applications, no benchmark problems involving high-aspect-ratio flexible wings have appeared in the open literature. To address this, this paper reports on ground vibration testing results for a flexible wing and its sub-assembly and parts. The experimental data can be used as a benchmark and are available to the aeronautical and structural dynamics community. Furthermore, non-linearities in the structure, where present, were detected. Tests were performed on the whole wing as well as parts and sub-assembly, providing four specimens. These were excited with random vibration at three different amplitudes from a shaker table. The modal properties of a very flexible high-aspect-ratio wing model, its sub-assembly and parts, were extracted, non-linear behaviour was detected and the experimental data are shared in an open repository.Item Open Access Ground vibration testing of a high aspect ratio wing with revolving clamp(ICAS, 2022-11-28) Dessena, Gabriele; Ignatyev, Dmitry I.; Whidborne, James F.; Pontillo, Alessandro; Zanotti Fragonara, LucaThe advancements in the aeronautical industry and research on materials and manufacturing methods in the last 70 years have been shifting the paradigm of wing design to high aspect ratio flexible wings. These wings can show a varying behaviour in different operating conditions, as per the nature of their geometry and materials. This work proposes a case study of a high aspect ratio flexible wing in order to study the effect of operating conditions on its structural properties. To test different operating conditions on the ground, a revolving clamp is designed to attach the specimen to a clamp-on shaker. A clear relationship between the wing’s modal properties, and so structural properties, and the angle the clamp sets is found.Item Open Access High aspect ratio wings on commercial aircraft: a numerical and experimental approach(Cranfield University, 2019-12-20) Pontillo, Alessandro; Lone, Mudassir M.; Whidborne, James F.The aim of this work is to assess the aeroelastic response to gust of a flexible high aspect ratio wing (HARW) single-aisle commercial aircraft and to design a viable open-loop Gust Load Alleviation (GLA) system. Aeroservoelastic assessment was carried out by adopting the low-fidelity Cranfield Accelerated Aircraft Load Model (CA2LM ) aeroelastic framework. Wind tunnel testing of two flexible wing models was carried out to assess the limitations of low-fidelity numerical frameworks in modelling highly flexible structures. The numerical work firstly focused on upgrading the CA2LM framework by including the non-linear aerodynamic effects of spoiler deflection into the low-fidelity model. The novel method was able to locally change the wing lift distribution evaluated with strip theory by combining ESDU 14004 experimental data with the numerical estimation. Finally, the aeroelastic response of the High Aspect Ratio Technology ENabler (HARTEN) concept aircraft to gust input was carried out for a single flight condition (h=26000 ft and v=200 m/s) and for two different structural configurations: rigid wing and flexible wing structure. Tuned discrete gust analysis, as specified in CS-25, was adopted in this analysis. Results showed that tuned gust is able to excite flexible wing dynamics along with the rigid-body dynamics, having a detrimental impact on aircraft performance. Finally, an open-loop GLA system was designed to alleviate Wing Root Bending Moment (WRBM) increment due to gust load. The GLA deflected spoilers and ailerons for a fixed amount of time (hold time) once a specific vertical load factor was crossed. An optimization algorithm was used to optimize parameters such as control surfaces deflection, hold time and load factor threshold. Several configurations of the GLA were evaluated. The optimal GLA configuration was able to alleviate WRBM from a minimum of 2.4% to a maximum of 8.1% with respect to the non-alleviated scenario. Two wind tunnel models were built with the common spar and skin configuration, while a novel approach for the skin manufacturing was introduced: the skin was 3D printed with PolyJet technology which allowed to provide a continuous aerodynamic shape removing the typical gaps necessary for flexible models to allow wing bending, limiting the impact of the skin to less than 12.5% of the overall model stiffness. The first model was tested in the Cranfield Weybridge wind tunnel at 27 m/s (Re = 3.5e5) and α = 6 ◦ . The model span was 0.840 m and Aspect Ratio AR = 12. The model was successfully tested to prove the ability of the skin to retain the aerodynamic shape and sustain the load under large deformation, reaching a max wingtip displacement of 32% of the model span. The second model was tested in the Cranfield 8x6 ft wind tunnel in the speed range of 20 m/s to 40 m/s (3.1e5 < Re < 6.2e5) at −2 ◦ < α < 8 ◦ . The model span was 1.5 m and AR = 18.8. The main result showed that in the most severe aerodynamic load scenario (v = 40 m/s and α = 8 ◦ ), the spanwise force coefficient accounted for 10% of the wing overall CL and was 2.5 times higher than CD . The overall damping was also estimated for different velocities at α = 6 ◦ , reaching a maximum of 26.9% at 35 m/s and a minimum of 17.8% at 20 m/s, with aerodynamic damping accounting for a minimum of 61% to a maximum of 74% of the overall damping. Maximum displacement of the wing tip was 13.7% of the model span (0.21 m). In both tests a low-cost acquisition system built with off-the-shelf components was used. The system was based on Raspberry Pi board able to acquire accelerations and rotations from four MPU6050 IMU boards, with the main benefit being the small size of the sensors, which were able to fit within tiny volumes typical of HARW wind tunnel models.Item Open Access New solutions for old problems(Cranfield University, 2018-10-18 10:05) Pontillo, Alessandro3 Minute Thesis presented at the Cranfield Doctoral Network Annual Event, September 2018.Highly flexible structures are now a common scenario in the aeronautic industry due to the adoption of slender and longer wings in order to reduce drag and increase the overall aircraft efficiency. Such configuration brings new challenges as structural dynamics now overlaps flight dynamics. Testing is then more important than ever. The Cranfield BEam Reduction and Dynamic Scaling (BEARDS) programme aims to provide a numerical and experimental tool able to dynamically scale-down a full aircraft and to test it successfully in the wind tunnel. Being able to predict static response along with structure dynamics, allows either universities and industry to mitigate the risk of testing bigger and more expensive models. The presentation will focus on the BEARDS methodology, results obtained from tests already done in the Weybridge wind tunnel and on the future of the programme with the new designed eXperimental Beards (XB-2) model.Item Open Access Noise-robust modal parameter identification and damage assessment for aero-structures(Emerald, 2024-12-16) Dessena, Gabriele; Civera, Marco; Pontillo, Alessandro; Ignatyev, Dmitry I.; Whidborne, James F.; Zanotti Fragonara, LucaPurpose Ground vibration testing is critical for aircraft design and certification. Fast relaxed vector fitting (FRVF) and Loewner framework (LF), recently extended to modal parameter extraction in mechanical systems to address the computational challenges of time and frequency domain techniques, are applied for damage detection on aeronautically relevant structures. Design/methodology/approach FRVF and LF are applied to numerical datasets to assess noise robustness and performance for damage detection. Computational efficiency is also evaluated. In addition, they are applied to a novel damage detection benchmark of a high aspect ratio wing, comparing their performance with the state-of-the-art method N4SID. Findings FRVF and LF detect structural changes effectively; LF exhibits better noise robustness, while FRVF is more computationally efficient. Practical implications LF is recommended for noisy measurements. Originality/value To the best of the authors’ knowledge, this is the first study in which the LF and FRVF are applied for the extraction of the modal parameters in aeronautically relevant structures. In addition, a novel damage detection benchmark of a high-aspect-ratio wing is introduced.Item Open Access Verification of a low fidelity fast simulation framework through RANS simulations(Springer, 2019-07-22) Carrizales, Martin A.; Dussart, Gaétan; Portapas, Vilius; Pontillo, Alessandro; Lone, MudassirVerification and validation of simulation models are critical steps in engineering. This paper aims at verifying the suitability of reduced order aerodynamic models used in an aeroservoelastic framework designed to analyze the flight dynamics of flexible aircraft, known as the Cranfield Accelerated Aircraft Loads Model. This framework is designed for rapid assessment of aircraft configurations at the conceptual design stage. Therefore, it utilizes or relies on methods that are of relatively low fidelity for high computational speeds, such as modified strip theory coupled with Leishmann–Beddoes unsteady aerodynamic model. Hence, verification against higher order methods is required. Although low fidelity models are widely used for conceptual design and loads assessments, the open literature still lacks a comparison against higher fidelity models. This work focuses on steady-trimmed flight conditions and investigates the effect of aerodynamic wing deformation under such loads on aerodynamic performance. Key limitations of the reduced order models used, namely fuselage and interference effects, are discussed. The reasons for the overall agreement between the two approaches are also outlined.