bluuebunny/crossref_metadata_2025_split huggingface dataset:
Meshfree Methods of Airframe Stress Analysis
Authors: Kalutskiy N S 
Published: January 2021

Abstract
Present-day meshfree methods of numerical computer analysis of structures have been analyzed in this article. Principal mathematical ratios used in meshfree methods have been provided. Building of a shape function, one of the principal problems of the meshfree method, has been discussed, and an algorithm for the building of a shape function by using polynomial basis functions has been proposed. The algorithm developed has been tested on solving an elementary problem. The Conclusion section of this article contains solution results of a practically important problem of mechanical stress concentrations in a typical aircraft stringer. Comparative analysis of the accuracy of the results obtained by the conventional FEM and the meshfree method proposed has been conducted.
Recycling of Critical Raw Materials from Hydrogen Chemical Storage Stacks (PEMWE), Membrane Electrode Assemblies (MEA) and Electrocatalysts
Authors: Moschovi A M , Zagoraiou E , Polyzou E , Yakoumis I 
Published: January 2021

Abstract
The increase in energy demands for the establishment of a modern digital era has resulted in the significant limitation of the energy sources. The depletion of energy reserves drew attention to alterative renewable energy sources that can satisfy the energy requirements in an environmentally friendly way. Hydrogen is an ideal chemical energy storage. Proton exchange membrane water electrolysis (PEMWE) is a promising technology as a green source of high-purity hydrogen. For that reason, PEMWE devices are already used in aerospace to produce oxygen for the crew on the Space Stations. The use of Critical Raw Materials (CRMs, especially Pt and Ir) and high cost materials in the PEMWE systems compromises their economic feasibility. It is necessary to implement End-of-Life (EoL) strategies that optimise the recovery of CRMs within feasible and environmentally friendly processes. In this paper an overview of the existing technologies for recycling of Membrane Electrode Assembles and electrocatalysts from PEMWE systems are revealed. MONOLITHOS has developed a novel optimized hydrometallurgical method for high PGMs recovery from spent automotive catalysts. This work aims to describe how this method can be applied to the EoL phase of PEMWE to improve techno-environmental and techno-economical performance of CRMs recovery.
Conceptual design and parametric structural modeling of a FWAV biomimetic flapping wing
Authors: Rayhan Saiaf Bin 
Published: January 2021

Abstract
Flapping wing air vehicle is the latest technological achievement of the aviation industry, which is still maturing as a miniature of large aircraft before finally achieving the finest development. By mimicking the nature, parametric structural modeling of a flapping wing, made of composite membrane and aluminum alloy support beam is numerically investigated adopting commercial FE code Ansys. A flapping cycle is divided into twelve segments, and for each segment, the maximum stress, first ply failure and the deformation are studied. It is found that the fiber orientation angle has the highest impact on the structural properties during a flapping cycle, where improper stacking sequence will cause failure to the wing. Moreover, increasing the ply thickness has a positive impact on the overall structural performance of the model. Finally, appropriate support beam orientation can further improve the structure by increasing the stiffness and reducing the maximum stress significantly without increasing the overall weight of the wing.
On Unsteady Flow Analysis of a Round Spike Blunt Nose Afterbody in Mach 6 Flow
Authors: Vashishtha A , Khurana S 
Published: January 2021

Abstract
An aerospike, in front of a blunt body, has largely been deemed as a key passive control device for effectively reducing the wave drag and aerodynamic heating associated with high-speed flows. In addition, it has been reported that the presence of a spike brings in unsteadiness in the form of oscillation and pulsation to the flow characteristics. Past researchers, having investigated mainly the aerothermodynamic coefficients, have hinted towards the suppressing of such oscillations with the use of a round nose spike over a sharp spike, though a thorough and a concrete result is yet to be established together with offering a detailed explanation of the flow physics and its dependence on the spike’s geometric characteristics (spike-length to afterbody-diameter ratio, L/D). Numerical investigation has been carried out using axisymmetric Navier-Stokes laminar flow solver at hypersonic Mach number of 6.0. A round-tip spike with a flat face cylindrical afterbody have been simulated for spike length ratios of L/D = 0.5 – 2.0, with spike diameter to-afterbody diameter (d/D) of 0.1. The behavior and subsequent control of flow pulsation for a round (hemispherical) spike with varying L/D-ratio has been established.
Aeroelastic optimisation of manufacturable tow-steered composite wings with cruise shape constraint and gust loads
Authors: Wang Zhijun , Peeters Daniël , Roel De Breuker 
Published: January 2021

Abstract
In the structural design of aircraft wings, aeroelastic tailoring is used to control the aeroelastic deformation to improve the aerostructural performance by making use of directional stiffness. Recently, tow-steered composites, where the fibre angles continuously vary within each ply, have been proven to have the potential to further expand the advantages of aeroelastic tailoring. This work extends TU Delft aeroelastic tailoring framework PROTEUS by introducing a lay-up retrieval step, so that it can be used for the conceptual design of tow-steered composite wing structures. In the extended framework, aeroelastic tailoring and lay-up retrieval are sequentially and iteratively performed to take static and dynamic loads, manufacturing and cruise shape constraints into consideration. The first step is carried out using PROTEUS, in which the lamination parameters and thickness of the wing sections are optimised under manoeuvre and gust load conditions. Further, for ensuring optimal aircraft performance in cruise flight conditions, the jig twist distribution is allowed to be optimised to maintain a desired prescribed cruise shape. In the second step, the stacking sequence, including minimum steering radius constraint, is retrieved. Since the lamination parameters cannot be matched exactly during the retrieval step, the constraints are checked, and tightened to take the performance loss during retrieval into account. The first step is repeated until all constraints are satisfied after fibre angle retrieval. To demonstrate the usefulness of the proposed optimisation framework, it is applied to the design of the NASA Common Research Model (CRM) wing, of which the objective is minimizing wing mass subjected to aerostructural design constraints, such as aeroelastic stability, aileron effectiveness, material strength and buckling load.
Repair & maintenance by Metal Additive Manufacturing process on Titanium alloy parts
Authors: Lhabitant Solène , Badouaille Florimont , Remache Djamel , Cohen Guillaume , Toufine Alain 
Published: January 2021

Abstract
The CRO2
project* deals with both the aircrafts’ parts repair & maintenance and the Additive Manufacturing by metal powder Directed Energy Deposition **.
Repairing parts in the aerospace industry is a potential application for additive manufacturing technologies. It’s thus possible to reduce operating losses and to avoid waste of costly and strategic raw materials. CRO2 proposes a pre-industrial development to rebuild lost shapes and functions of Ti64 alloys structures as example in air bled piping. Laser Metal Deposition (DED) process was used for Ti64 parts manufacturing. Tensile and fatigue tests were performed on several samples to characterize the AM material. The mechanical properties of the tested samples are comparable to those of the laminate Ti64 and their microstructure is typical of additive manufacturing. The reliability of the proposed technique, compared to welding repairs’ process, has been successfully demonstrated using aircraft environmental qualification tests at high temperature and pressure carried out on thin representative pipings.

(*) CRO2: Cost Repair Overhaul Optimization

(**) DED AM: Directed Energy Deposition Additive Manufacturing
SPARE project – improvement of continuous compression moulding process for the production of thermoplastic composite beams
Authors: Angiuli Riccaro , Dell’Anno Federica , Cosma Leonardo , Raganato Umberto , Passaro Alessandra 
Published: January 2021

Abstract
In recent years, thermoplastic matrix composites have seen an increasing interest from the research and development sector due to the versatility of use and the wide potential in sectors such as automotive, aeronautics and transport. Furthermore, the thermoplastic matrix allows the use of simpler, faster and automatable production cycles and joining systems. As part of the SPARE project, the continuous compression moulding process (CCM) was upgraded using as numerical simulation, monitoring via infrared thermography and induction welding. Thanks to these innovations, the CCM process can ensure savings in terms of production costs, reduction of waste and a higher level of automation, the proposed work will illustrate the activities carried out during the project. The numerical simulation was used to analyze the heating process and verify its uniformity in order to identify the best configuration to obtain uniform heating, infrared thermography, on the other hand, was used to continuously monitor the temperate of the laminate at the entrance and exit of the compaction zone and to measure the process temperature and the degree of uniformity.
Finally, at the end of the production process, a tool was developed for the induction welding of the laminates for the construction of complex beams with a T or H cross section.
Virtual testing activities for the development of a hybrid thermoplastic composite material for the NHYTE project
Authors: Dotoli Rosario , Gerardi Antonio , Polydoropoulou Panagiota , Lampeas George , Pantelakis Spiros , Carpio Rovira Alfonso 
Published: January 2021

Abstract
Designing composite structures with a good level of confidence and accuracy requires access to allowables values. The allowables generation is extremely time and cost consuming. In fact, various layups, experimental tests and environmental conditions have to be taken into account for each material to be characterized. Moreover, each test configuration needs many repetitions to obtain a statistical evaluation of the mechanical property. A robust alternative to reduce the experimental time and costs is the use of virtual allowables calculated and predicted thanks to advanced multiscale simulations. This paper deals with the activities of virtual testing carried out in the European NHYTE Project for the development and characterization of a hybrid thermoplastic composite material for the aerospace sector. The main aim has been to reduce tests and risk associated with the use of the hybrid composite in aerospace structures. This can be achieved by lowering the probability of failure of primary structures through the use of A-basis or B-basis strength allowables as design values. For this purpose, coupons of the hybrid thermoplastic composite have been accurately analysed using virtual tests. Starting from a micromechanics approach and taking into account the different constituents (PEEK matrix, PEI films and fibre reinforcement), a material model has been implemented; then it has been propagated to different scales until the element level. For virtual testing to be useful in the certification process, this numerical model has been validated by a synergic approach, correlating the simulation results with the experimental data carried out by Applus+ Laboratory. At the end, it has been possible to demonstrate that the resulting models are an excellent tool to speed up the certification process for complex structures, as required in the Aeronautical industry.
Advanced Acoustic Emission Source Location in Aircraft Structural Testing
Authors: Grigg S , Featherston C A , Pearson M , Pullin R 
Published: January 2021

Abstract
Acoustic emission (AE) is an in situ Structural Health Monitoring (SHM) technique, where a structure is monitored for the ultrasonic waves produced due to crack growth. A major challenge with AE when applied to aircraft, and other complex structures, is that wave propagation is significantly affected by stiffeners, holes, thickness changes and other complexity. This reduces the accuracy of traditional source location techniques, that are based on a singular propagating wave speed. The Delta-T method enables higher levels of accuracy by mapping the structure and accounting for these changes. In this work AE monitoring equipment was installed on a section of an aluminium Airbus A320 wing. Location trials showed the Delta-T technique improved the average error from 85mm to 23mm, for artificial Hsu-Nielson sources, compared to the commercial standard technique. Testing under fatigue however demonstrated the challenges encountered when inspecting 3D structures (due to multiple signal paths) with significant levels of background noise. Of two cracks identified in the structure, the first of these was successfully detected and located, whilst the other was missed due to high machine noise and unrepresentative loading.
Preliminary studies of flight sensoring for loads and aeroelastic parameters estimation of the NGCTR-TD wing
Authors: Cardozo A , Beretta J , Paletta N , Adden S , Belardo M , Chiariello A , Di Palma L 
Published: January 2021

Abstract
The paper presents the preliminary analyses carried out to estimate the accelerom-eters and strain gauges optimal configuration for the in-flight natural modes and internal loads identification of the Next Generation Civil Tilt Rotor Technology Demonstrator (NGTCTR-TD) wing.
The optimal accelerometers’ configuration has been achieved with the aeroelastic model by taking into account the modal displacements of the targeted natural modes, requirements of space availability and accessibility. A further analysis has been set up to estimate the accel-eration peak on the wing by using a continuous turbulence model with a von Karman power spectral density.
The optimal strain gauges’ configuration has been achieved as a subset of an initial layout by using the Skopinski methodology, where quality ratios and percentual errors lead to the identification of redundant and irrelevant measurements. This approach aims to recover the flight loads on the wing from an optimal set of strain measurements during flight. The present work has been a numerical study. A verification of the final Load Evaluation Matrix (LEM) has been performed using a set of validation load cases.
Methods of analyzing isolated and ducted fixed-pitch propellers under non-axial inflow conditions
Authors: Cerny M , Faust J , Breitsamter C 
Published: January 2021

Abstract
Currently, a growing interest for the propulsion of unmanned aerial vehicles (UAVs) can be recognized. To adress this, small-scale fixed-pitched propellers are analyzed in this work, both in isolated and ducted configurations. Due to their flight envelope, UAVs are likely to operate at highly inclined inflow conditions and even under reversed inflow, having a major influence on the flow field around a propeller. In order to investigate this influence, all analyses are performed at a range of inflow angles from αdisc = 0° to 180° relative to the propeller axis. This paper employs different numerical techniques and compares them regarding their capability of showing the influence of non-axial inflow on propeller configurations. Wind tunnel experiments are performed measuring the forces and visualizing the flow field with PIV as well as steady and unsteady RANS simulations are applied to study details of the flow field.
Study on a twin-fuselage transport airplane model in a low speed wind tunnel
Authors: Chernousov V I , Krutov A A , Pigusov E A 
Published: January 2021

Abstract
This paper presents the results of experimental studies of the twin-fuselage transport airplane model at the cruising configuration in the T-102 TsAGI low-speed wind tunnel. The researched twin-fuselage transport airplane is a tri-engine transport aircraft intended for transportation of cargo weighted up to 40 tons at a distance up to 3000 km with speed 700-740 km/h. The aerodynamic configuration has the two fuselages distributed under high-wing, and a “TT” – shaped tail. The research purpose was the determination of the aerodynamic characteristics of the twin-fuselage transport airplane model without engine nacelles and assessment of the twin-fuselage layout impact on control surfaces efficiency. The effect of installing an external cryogenic fuel tank under the wing between the fuselages of the model was considered too.
Sustainability: key to enable next generation supersonic passenger flight
Authors: Hardeman A B , Maurice L Q 
Published: January 2021

Abstract
The 2020 global Covid-19 pandemic has shocked the aviation system to its core, showcasing what the loss of this economic engine can do to the world’s economies and societies. This crisis also presents an opportunity to create new capabilities and outlooks. Commercial supersonic flight is one such capability. The availability of advanced computational designs and propulsion systems, new materials, route optimization and alternative fuels means that supersonic aviation can be part of that future in a sustainable manner.
Boom’s ultimate goal is to mainstream supersonic air travel and make it accessible to millions of passengers per year. Long-term projections of business-class airline demand suggest a total market of 1,000 to 2,000 commercial supersonic aircraft operating on more than 500 primarily transoceanic routes that will benefit from speeds twice as fast as today’s aircraft.
Given the increased focus on mitigating aviation’s environmental impact, bringing a new aircraft to market in the 2020s requires a careful focus on sustainability. To ensure public acceptance supersonic aircraft manufacturers and operators will have to proactively engage with stakeholders to address their concerns and focus on integrating sustainability solutions across their business strategies.
Boom is the first commercial aviation OEM to build sustainability into its aircraft programmes from day one, ensuring that sustainability considerations form an integral part of every aspect of the production process. A sustainability commitment to cover every step in the aircraft development cycle, from design and test through in-service operations and end-of-life recycling is key to successfully reintroduce commercial supersonic flight in the years ahead.
Conceptual design of a novel Unmanned Ground Effect Vehicle
Authors: Papadopoulos C , Mitridis D , Yakinthos K 
Published: January 2021

Abstract
In this work, a methodology for the conceptual design of a combined Box-wing and Blended-Wing-Body unmanned aerial platform, which exploits the ground effect, is presented. Ground Effect Vehicles (GEVs) are aircrafts or aerial vehicles capable of flying very close to the surface of water areas, being a promising alternative to ships and seaplanes operating in closed seas. In order to exploit the air cushion that is formed underneath, GEVs have low Aspect Ratio wings. Thus, the Blended-Wing-Body (BWB) layout configuration is an appealing choice due to the large available body surface. On the other hand, a tailless vehicle having the BWB layout is facing challenging stability issues, especially in a turbulent and highly volatile environment as the one close to the sea level. Therefore, the addition of the Box wing configuration, namely a continuous-surface nonplanar wing formation with no wing tips, is deemed beneficiary as a way to overcome the stability challenges and eliminate the wingtip vortices. The combination of these two prominent platforms leads to improved aerodynamic performance and eventually, a reduced fuel consumption. The design methodology starts by the estimation of the most important design parameters, such as aspect ratio, sweep angle, and taper ratio, which are continuously refined in an iterative computational framework during the conceptual design phase. In an initial approach, the flight scenario with no ground effect interference is studied, with the use of both analytical calculations and computational fluid dynamics simulations. The results from the conceptual design phase indicate that the UGEV configuration has a considerable potential as an alternative to ships or seaplanes, based on its ability to carry larger payload than seaplanes and deliver it faster than ships.
Geometry Model and Approach for Future Blisk LCA
Authors: Fricke Kilian , Gierlings Sascha , Ganser Philipp , Venek Tommy , Bergs Thomas 
Published: January 2021

Abstract
Air traffic is expected to double over the next 20 years and Flightpath 2050 targets to a 70 % reduction of CO2 and a 90 % reduction of NOx. Optimization of future aircraft engines often is dominantly driven by a focus on the reduction of fuel burn and emissions during operation. To identify additional environmental improvement potential a full Life Cycle Analysis (LCA) shall be aspired also including Materials, Processes and Resources, Manufacture and Production, Lifetime Services as well as Reuse, End-of-Life and Recycling. Core engine components, for example integral rotors, are comprised of Titanium-or Nickel-alloys and require complex manufacturing processes.
A geometry design model of a compressor blisk is introduced which is employed as basis for a future LCA approach focusing on materials, processes and resources as well as manufacture and production. The model is a carrier for challenging manufacturing features such as large blade twist, high aspect ratio and small blade gaps. In addition to the geometry model, a first set of multiple technology scenarios and their process chains will be introduced which will serve as base for a future LCA.
Selecting figures of merit for a hybrid-electric 50-seat regional aircraft
Authors: Moebs N , Eisenhut D , Bergmann D , Strohmayer A 
Published: January 2021

Abstract
In the course of the aircraft design process for a hybrid-electric aircraft, a number of configuration alternatives have to be assessed. In addition, novel propulsion concepts have to be compared to a conventional reference aircraft. These comparisons are carried out by means of suitable figures of merit, adapted to a reference mission. This work will give insight into the process of identifying suitable figures of merit for a 50-seat hybrid-electric regional aircraft, which was carried out in the Horizon 2020 project FutPrInt50. Coming from a thorough perspective, a down-selection leads to a graspable number of parameters which are categorized in regard to the environment, to the airline desirability, and to the introduction of hybrid-electric aircraft. Those figures of merit, like emissions and operating costs, are gathered in an objective function which can support an overall evaluation of the aircraft design. This offers a detailed, yet transparent assessment of the various designs.