bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concepts for integrating electrical energy storage into CFRP laminate structures for aeronautic applications
Authors: Laurin Frédéric , Beutl Alexander , Jiang Qixiang , Kühnelt Helmut 
Published: June 2023

Abstract
The CleanSky2 THT project SOLIFLY is developing further structural batteries for aeronautical applications. This paper presents the concepts of structural integration and the methodology to evaluate the impact of structural battery integration on the mechanical properties of CFRP solid laminates considering the size and shape of the structural battery insert as well as its location through the laminate thickness. A fully parameterised, computationally efficient numerical strategy for finite element simulation has been implemented to evaluate the mechanical properties and, for the first time, the onset of matrix damage as the cell geometry and integration location are varied. The first mechanical characterisation data of SB cell components and cell prototypes were obtained thanks to multi-instrumented tensile tests using digital image correlation and acoustic emission. An initial assessment of the advantages and trade-offs of the SB integration concepts with respect to functionally separated components is discussed.
Functional and Safety Challenges of Hydrogen Fuel Cell Systems for Application in Electrified Regional Aircraft
Authors: Kazula Stefan , Staggat Martin , Graaf Stefanie de 
Published: June 2023

Abstract
This paper identifies potential weaknesses and challenges of hydrogen fuel cell systems as main energy provider for electrified aircraft propulsion and presents potential solutions. The general design, operating principles and main characteristics of hydrogen-fuelled low-temperature polymer electrolyte membrane fuel cell systems (PEMFCSs) are described. The safety assessment process in aviation according to Aerospace Recommended Practices ARP4754A and selected methods according to ARP4761 are introduced. The functions of fuel cell systems in electrified aircraft powertrains are analysed in functional structure trees on aircraft, powertrain and fuel cell system level. By means of a Functional Hazard Analysis (FHA), potential malfunctions and their effects are investigated and their severity is evaluated. Critical failure modes are identified and requirements for acceptable failure probabilities are stipulated. Solution options to mitigate failure effects are stated. The results of the mentioned analyses reveal design challenges associated with the application of fuel cell systems in electrified aircraft propulsion, for instance, concerning functional independence as well as solutions for cold start conditions, heat transfer and lightweight design. Furthermore, safety challenges arise due to the utilisation of cryogenic hydrogen as fuel and the high amount of electric energy.
Fault-tolerant switched reluctance motor propulsion system for eVTOLs
Authors: Biczyski M , Sehab R , Whidborne J F , Krebs G , Luk P C K 
Published: June 2023

Abstract
eVTOLs are receiving a lot of attention as a potential solution to urban air mobility challenges. Many configurations are multirotors, which are open loop unstable, therefore very susceptible to actuator failures. Due to their usually short mission duration (20-30 min), fault-tolerance of the propulsion system is of greater importance then reliability. Thus, novel approaches to enhance this capability are required. This study proposes a new fault-tolerant propulsion system using 4-phase switched reluctance motors. It is designed for an 8-10 kg scale multirotor eVTOL, to replace redundant coaxial brushless DC motors with a single fault-tolerant drive. Acknowledging the role of fault-tolerant control algorithms, the propulsion system is validated in terms of the loss of effectiveness metric, typically used in the evaluation of control solutions. The switched reluctance motor propulsion system was found to be highly resilient to open phase and current sensor faults, but susceptible to position sensor faults. This can, however, be mitigated with sensorless control solution. Extending the findings to full-scale eVTOLs is also discussed.
In-situ identification of ice accumulation profile and vibration response at composite blades under various icing conditions
Authors: Filippatos Angelos , Schwab Simon , Tzortzinis Georgios , Madia Evgenia , Gude habil. Maik 
Published: June 2023

Abstract
Icing challenges the safety and performance of wind turbines in low temperature environments. Detailed information on the amount and location of ice on rotor blades can facilitate decision making and mitigate hazardous effects. Therefore, a better understanding of the relation between ice accumulation and frequency response is required. Small scale experiments are conducted employing rotor blade specimens, experiencing natural icing of different configuration in terms of temperature and ice extent. The ice distribution is measured with a high-resolution laser scanner, and an algorithm based on alpha shapes is developed to determine the growth of the ice volume. Experimental modal analyses are performed periodically during the icing process, detecting consequent effects in the corresponding frequency spectra. The collected data is assessed regarding its suitability for an ice detection system and serves as a starting point for further developments.
Health monitoring of the shaft bearings in a micro turbojet based on vibration analysis
Authors: Przysowa Radoslaw , Majewski Paweł , Ślęczek Jakub , Grundas Dariusz , Wachłaczenko Michał 
Published: June 2023

Abstract
In a recently implemented aerial target, the propulsion system consists of two JetCat micro turbojet engines. Due to the limited durability of the rotor support bearings, the engine operation time has been limited to two hours or two flights. In addition, after each flight, an engine bench test with vibration measurement is required. The adopted maintenance system is also labor-intensive and costly due to obligatory shaft bearing inspections performed frequently in the repair shop. These problems result from the limitations of the available high-speed bearing technology and the high rotor loads related to aircraft maneuvers in the air. The goal of the work is to develop a method for assessing the health of the main shaft bearings in the micro turbojet based on vibration signals. Methods known from full-scale jet engines were adapted for monitoring the health of the main shaft bearings. An accelerometer and rotational speed sensor were mounted on the engine. Vibration and other parameters of the engine were measured and analyzed, and then symptoms of damage were sought. The vibrations of seven JetCat engines were analyzed, selecting the one for further destructive testing. In all three axes X, Y and Z, the vibration components related to the rotational frequency and its orders are dominant, especially EO2 and EO3 related to rotor dynamics. Continuous engine vibration monitoring is a promising way of extending engine life and avoiding the deficiencies of microturbines related to their size and low-cost technology. The obtained results indicate that the tested JetCat engines have a life reserve, which has so far been used to a small extent.
Prognostics of aerospace electromechanical actuators: comparison between model-based metaheuristic methods
Authors: Baldo L , Dalla Vedova M D L , Querques I , Maggiore P 
Published: June 2023

Abstract
Electro-Mechanical Actuators (EMAs) deployment as aircraft flight control actuators is an imperative step towards more electric concepts, which propose an increased electrification in aircraft subsystems at the expense of the hydraulic system. Despite the strong benefits linked to EMAs adoption, their deployment is slowed down due to the lack of statistical data and analyses concerning their often-critical failure modes. Prognostics and Health Management (PHM) techniques can support their adoption in safety critical domains. A very promising approach involves the development of model-driven prognostics methodologies based on metaheuristic bio-inspired algorithms. Evolutionary (Differential Evolution (DE)) and swarm intelligence (particle swarm (PSO), grey wolf (GWO)) methods are approached for PMSM based EMAs. Furthermore, two models were developed: a reference, high fidelity model and a monitoring, low fidelity counterpart. Several failure modes have implemented: dry friction, backlash, short circuit, eccentricity and proportional gain. The results show that these algorithms could be employed in pre-flight checks or during the flight at specific time intervals. Therefore, EMA actual state can be assessed and PHM strategies can provide technicians with the right information to monitor the system and to plan and act accordingly (e.g. estimating components Remaining Useful Life (RUL)), thus enhancing the system availability, reliability and safety.
Bird strike simulation on a bonded Ti/CFRP leading edge of an engine fan blade
Authors: Papadopoulos Kosmas , Floros Ioannis , Tserpes Konstantinos 
Published: June 2023

Abstract
Bird strike represents a critical loading scenario for aeronautical structures, especially for engine fan blades. It is, therefore, of great importance both to protect the leading edge of the fan blade from impact damage and to be able to detect impact damage directly. In the present study, an explicit finite element (FE) model was developed using the LS-DYNA software to simulate bird strike on the leading edge of a CFRP fan blade protected by an adhesively bonded Ti layer. The model accounts for damage on the CFRP blade through a progressive damage modeling scheme and for debonding through a cohesive zone modeling scheme but not for damage on the Ti layer. For the modeling of the bird, the smooth particle hydrodynamics (SPH) method was used, due to the large deformations that were expected. Using the model, a parametric study on the effects of bird mass and impact energy was performed. The numerical results show that impact damage depends more on impact velocity than the bird mass. In all cases, debonding of the tip of the leading edge was predicted, while for combinations of small bird mass and large impact velocity a more extensive debonding of the protective layer was predicted. Regarding damage in the CFRP, only matrix cracking on the leading edge has been predicted. Aiming to assess the effectiveness of FBGs to detect debonding of the Ti layer due to bird strike, an FBG network has been modeled into the bondline and a study was performed on the correlation of the measured strains with impact damage.
Lumped parameters multi-fidelity digital twins for prognostics of electromechanical actuators
Authors: Quattrocchi Gaetano , Dalla Vedova Matteo D.L. , Berri Pier Carlo 
Published: June 2023

Abstract
The growing affirmation of on-board systems based on all-electric secondary power sources is causing a progressive diffusion of electromechanical actuators (EMA) in aerospace applications. As a result, novel prognostic and diagnostic approaches are becoming a critical tool for detecting fault propagation early, preventing EMA performance deterioration, and ensuring acceptable levels of safety and reliability of the system. These approaches often require the development of various types of multiple numerical models capable of simulating the performance of the EMA with different levels of fidelity. In previous publications, the authors already proposed a high-fidelity multi-domain numerical model (HF), capable of accounting for a wide range of physical phenomena and progressive failures in the EMA, and a low-fidelity digital twin (LF). The LF is directly derived from the HF one by reducing the system degrees of freedom, simplifying the EMA control logic, eliminating the static inverter model and the three-phase commutation logic. In this work, the authors propose a new EMA digital twin, called Enhanced Low Fidelity (ELF), that, while still belonging to the simplified types, has particular characteristics that place it at an intermediate level of detail and accuracy between the HF and LF models. While maintaining a low computational cost, the ELF model keeps the original architecture of the three-phase motor and the multidomain approach typical of HF. The comparison of the preliminary results shows a satisfactory consistency between the experimental equipment and the numerical models.
Evolution of the Tactical Separation System to support the Integrated Mission Management System in the COAST project
Authors: Vito V Di , Torrano G , Cerasuolo G , Ferrucci M 
Published: June 2023

Abstract
This paper refers to the developments of the single pilot enabling technologies that are designed, implemented and validated in the Clean Sky funded project COAST (Cost Optimized Avionics SysTem). The target industry domain of such technologies is the aviation segment of Small Air Transport (SAT), referring specifically to commuter category vehicles (5 to 19 pax), under the EASA CS-23 regulation. Among the several technologies that have been designed, developed and demonstrated in flight, there is the Tactical Separation System (TSS), which reached TRL 6 in 2021 thanks to successful flight demonstration. It represents fundamental decision-making support system, able to assist the single pilot in the management of the separation task, under delegation of the separation responsibility to the pilot by the ATC. Nevertheless, in order to properly integrate and enhance the individual enabling technologies for single pilot operations, in the COAST project a unique Integrated Mission Management System (IMMS) is being designed. It constitutes a further technological advancement to support more effective and safe management of situations of pilot’s incapacitation during the flight, under single pilot operations, and a relevant step forward towards more autonomous aircraft. To support the IMMS implementation, therefore, the Tactical Separation System is currently subject to proper evolution, in order to include specific functionalities that will be needed as part of the IMMS. This paper outlines the main outcomes from the design and demonstration of the Tactical Separation System as individual technology. After that, it describes the IMMS and the specific role that the tactical separation functionality will play in such framework. Finally, the paper reports the evolved TSS version design currently ongoing in the COAST project, with specific focus on the implementation of the tactical traffic clustering functionality.
Tackling different aspects of drone services utilizing technologies from cross-sectional industries
Authors: Purucker P , Reis R JN , Larsen M , Ryabokon A , Giovagnola J , Filho E , Reil C , Höß A , Barreto Guerra JP , Molina M , Duarte Penna S , Politi E 
Published: June 2023

Abstract
Enabling autonomous and Beyond Visual Line of Sight (BVLOS) operation of Unmanned Aerial Vehicles (UAVs) in the Very Low Level (VLL) airspace requires further advancement of technologies such as sensing the environment or secure and reliable communication. This paper addresses these challenges by presenting solutions developed within the project Airborne Data Collection on Resilient System Architectures (ADACORSA). Here, findings from cross-sectional areas such as the automotive industry are being further enhanced to fulfill the demands of aviation, in particular for use in the UAV domain. The developed technologies include an advanced Ethernet-based deterministic network for reliable onboard communication, a multi-sensor architecture for sensing the spatial environment as well as a multi-link communication gateway that provides reliable communication to the ground and a secure handover architecture.
Design and SITL Performance of an online Distributed Target Estimation for UAV Swarm
Authors: Lizzio Fausto Francesco , Primatesta Stefano , Guo Haoyu , Guglieri Giorgio 
Published: June 2023

Abstract
In this paper, an online distributed target estimation for a swarm of Unmanned Aerial Vehicles in formation flight is considered. In particular, a flocking algorithm is employed to handle the formation task, while a Distributed Kalman Filter in the Information form is used to perform the estimate of a mobile target state. Software-In-The-Loop simulations are carried on in the ROS/Gazebo environment to illustrate the coupling between the formation and the estimation tasks. Moreover, the influence of swarm connectivity in the estimation process is analyzed, showing the benefits of information fusion.
Analysis of the impact of GNSS disruptions on aircraft operations at Romanian airports
Authors: Ivan Antonia Nicoleta , Pandele Constantin Alexandru , Ionescu Bianca , Grigorie Teodor Lucian 
Published: June 2023

Abstract
In the transition towards space-based air navigation, the reliance on Global Navigation Satellite Systems (GNSS) is increasing. However, GNSS disruptions and interference can cause GPS loss in the cockpit. The purpose of this paper is to assess the impact of GNSS vulnerabilities, especially interference, on aircraft operations. The data used for this analysis was collected by GNSS monitoring stations installed at two Romanian airports, specifically selected due to their proximity to possible interference sources. In order to obtain relevant results, the entire assessment is based on the scenario in which all the flights at the airport are using GNSS as their primary means of navigation. Therefore, the flights that could have possibly been affected were identified and the operational impact of interference was assessed. This study emphasises the importance of GNSS monitoring at airports in order to reduce the negative effects of GNSS disruptions on the safe and efficient operations of aircraft.
Integrating ATM and air transport into multimodal transport system for Door-to-Door travel: the X-TEAM D2D project proposed approach
Authors: Vito V Di , Dziugiel B , Meincke P A , Mota M Mujica , Bagamanova M , Duca G , Russo R , Montaquila R V , Cerasuolo G , Maczka M , Mazur A , Naser F , el Makhloufi A , Proietti S 
Published: June 2023

Abstract
The project X-TEAM D2D (Extended ATM for Door-to-Door Travel) has been funded by SESAR JU in 2020 and completed its activities in 2022, pursuing and accomplishing the definition, development and initial assessment of a Concept of Operations (ConOps) for the seamless integration of ATM and air transport into an overall intermodal network, including other available transportation means (surface, water), to support the door-to-door connectivity, in up to 4 hours, between any location in Europe. The project addressed the ATM and air transport, including Urban Air Mobility (UAM), integration in the overall transport network serving urban and extended urban (up to regional level) mobility, specifically identifying and considering the transportation and passengers service scenarios expected for the near, medium and long-term future, i.e. for the project baseline (2025), intermediate (2035) and final (2050) time horizons. In this paper, the main outcomes from the project activities are summarized, with particular emphasis on the studies about the definition of future scenarios and use cases for the integration of the vertical transport with the surface transport towards integrated intermodal transport system and about identification of the barriers towards this goal. In addition, an outline is provided on the specific ConOps for the integration of ATM in intermodal transport infrastructure (i.e. the part of the overall ConOps devoted to integration of different transportation means) and on the specific ConOps for the integration of ATM in intermodal service to passengers (i.e. the specific component of the ConOps devoted to design of a unique service to passengers). Finally, the main outcomes are summarized from the validation of the proposed ConOps through dedicated simulations.
Operational Concepts for Urban Air Mobility deployment in the next decades
Authors: Di Vito V , Dziugiel B , Melo S , ten Thije J , Duca G , Liberacki A , Hesselink H , Giannuzzi M , Menichino A , Witkowska-Koniecz A 
Published: June 2023

Abstract
Urban Air Mobility development and deployment into future cities is gaining increasing and relevant interest in the last years, as a new mobility form suitable to meet the future greener, scalable and efficient mobility targets needed to solve the issues today’s big cities are facing in terms of traffic congestion as well as related environmental consequences. In this framework, the ASSURED UAM (Acceptance, Safety and Sustainability Recommendations for Efficient Deployment of UAM) project has been funded by H2020 and is ongoing, with the main objective of providing cities with knowledge concerning deployment of UAM services and definition of necessary standards and recommendations assuring common acceptance, safety and sustainability within integrated metropolitan transport system for three time horizons (2025, 2030 and 2035). In the project, dedicated activities have been carried out to develop operational concepts for Urban Air Mobility (UAM) deployment in the next decades. The main results from these activities are presented in this paper, which namely includes the main project outcomes in terms of: the identification of the most relevant and promising technologies that can enable the UAM implementation over the next decades, taking into account the current technological trends and perspectives; the outline of the regulatory framework in which the UAM will be shaped in the next decades; the definition of the most relevant aspects and constraints affecting the UAM deployment from the point of view of integration of such new mobility form in the cities infrastructures; the outline of the foreseen UAM concept of operations and definition of the most relevant use case that are expected to be implemented in the cities over the three time horizons considered in the project, i.e. 2025, 2030 and 2035.
Artificial Situational Awareness Assessment of a Novel ATC Support System
Authors: Tukarić I , Samardžić K , Radišić T , Vetter C 
Published: June 2023

Abstract
This paper presents the application of an existing situational awareness framework to a newly developed artificial intelligence system to determine its awareness level. The system incorporates diverse automation techniques - knowledge graph, expert rules, machine learning - for gaining situational awareness and applying it in the field of air traffic control. Since the system was developed to serve as a foundation for exploring automation and artificial situational awareness, the primary result of this work is the system’s overall awareness level assessment and the identification of sub-systems that may be improved for additional awareness. The framework used was chosen in the fundamental project documents and its use proved beneficial as it enabled the demonstration of how general guidelines can be interpreted for a specific system. It also informed possible routes for improvement of the process. Highest priority awareness-related improvements are those dealing with robustness, whose implementation would substantiate the current awareness assessment. The system is shown to be on the highest awareness level conditionally, considering its proof-of-concept level. The high level reached by the system is contingent on awareness concept and condition interpretations. With the appropriate assessment of the system, implementation in an operational environment is more feasible.