Aerotecnica Missili & Spazio最新文献

This study reports on the development of a new Blowdown-Induction Facility driven by two different Oxygen-Fueled Guns. The facility has been conceived and realized to simulate different flow conditions in the context of hypersonic sustained flight. Here the underlying principles are illustrated critically, along with a focused description of the various facility subsystems, their interconnections and the procedures specifically conceived to overcome some of the technical complexities on which this facility relies. Its performances are finally presented in relation to some prototype applications, together with an indication of the related limits, advantages and possible directions for future improvements.

Dynamic stall is a phenomenon affecting aerofoils in unsteady flows which is particularly relevant in the rotary-wing field. Semi-empirical models are simplified tools to simulate this phenomenon, especially during preliminary design phases and for aeroelastic assessments. However, they need a large number of tuning parameters to provide reliable estimations of unsteady airloads. To face this problem, a parameter identification procedure based on sequential resolutions of optimization problems using a genetic algorithm is developed and it is applied to the state-space formulation of a modified version of the so-called "Second Generation” Leishman-Beddoes model. The effects of the optimal parameters on the model prediction capabilities are discussed and the variability of the parameters with reduced frequency is studied. The estimations of the unsteady airloads obtained by applying the optimization of parameters show a great improvement in the correlation of the experimental data if compared to the predictions obtained by using the parameters provided in the literature, especially for pitching moments where the negative peaks are very well described. These improvements justify the need for optimization to set the parameters.

Unmanned flying-test bed aircraft are fundamental to experimentally prove and validate next-generation high-speed technologies, such as aeroshapes design, thermal protection materials, flight mechanics, and guidance–navigation–control in real flight conditions. During the test, the aircraft will encounter realistic operative conditions to assess the accuracy of new design choices and solutions. In this framework, the paper focuses on the longitudinal aerodynamic analysis of an experimental aircraft, with a spatuled forebody aeroshape, from subsonic up to hypersonic speeds. Computational flowfield analyses are carried out at several angles of attack ranging from 0 to 15º and for Mach numbers from 0.1 to 7. Results are reported in detail and discussed in the paper.

In this study, an on-working structural health monitoring system for impact detection on remote piloted vehicle (RPV) airplane is proposed. The approach is based on the propagation of Lamb waves in metallic structures on which Pb[Zr_xTi_1−x]O₃ (PZT) sensors are bonded for receiving vibrational signals due to impact events. The proposed method can be used to detect impacts in aerospace structures, i.e. skin fuselage and/or wing panels. After the detection, machine learning (ML) algorithms (polynomial regression and neural networks) are applied for processing the acquired ultrasounds waves in order to characterise the impacts, in terms of time of flight (ToF) and relative location. Several test cases are studied: the ML models are tested both without external noise (in laboratory) and introducing external RC engine vibration (on-working conditions). Furthermore, this work presents the implementation of a mini-equipment for acquisition and data processing based on Raspberry Pi. A good agreement between laboratory and in-flight results is achieved, in terms of distance between the actual and calculated impact location.

The work focuses on the study of the structural behaviour of a composite floor beam in the cargo area of a commercial aircraft subjected to static and dynamic loads (typical of hard or crash landing). Experimental tests have been performed in the laboratories of the Dept. of Industrial Engineering (UniNA) jointly with the development of numerical models suitable to correctly simulate the phenomenon through the LS-DYNA software. The definition of a robust numerical model allowed to evaluate the possibility of buckling triggering. The test article was equipped with potting supports on both ends of the tested beam, filling the pots with epoxy resin toughened with glass fiber nanoparticles. This allowed to uniformly load the beam ends in compression and to carry out the tests loading the specimen statically and dynamically, to observe the differences in the behaviour of the beam under two different types of applied load. The comparison between the numerical and the experimental results shows that the dynamic buckling was triggered by a quantitatively smaller load than in the static case. On the other hand, it is observed this phenomenon to postpone the failure of the structure, due to the significantly higher displacement with respect to the quasi-static case to reach that condition.

AlbaSat is a 2-Unit CubeSat which is being developed by a student team at the University of Padova. The Alba project aims to design, build, test, launch, and operate the first student CubeSat of the University of Padova, featuring four different payloads. The first goal is to collect data regarding the debris environment in Low Earth Orbit, the second goal is the study of the satellite vibrations, the third one is about CubeSat attitude determination through laser ranging technology, and the fourth goal concerns satellite laser and quantum communication. The Alba CubeSat mission has been selected by the European Space Agency to join the Fly Your Satellite! Design Booster program in December 2022. This paper presents the feasibility study of the Alba CubeSat mission reproduced in the framework of the “Space Systems Laboratory” class of Master of Science in Aerospace Engineering at the University of Padova. In the beginning, a mission requirements definition was conducted. After that, the mission feasibility was considered, with preliminary requirements verification to assess the ability of the spacecraft to survive the space environment, including compliance with Debris Mitigation Guidelines, ground station visibility and minimum operative lifetime evaluation. The Alba mission sets a base for a better understanding of the space environment and its interaction with nanosatellites, and an improvement of the accuracy of debris models. Furthermore, this paper, describing the educational experience and the results achieved, will provide a useful example for future students’ studies on CubeSat mission design.

Space electric propulsion represents a class of power-limited systems that utilize the interaction of electromagnetic fields with ionized inert gas propellants to generate thrust. This technology has emerged as a highly fuel-efficient and sustainable alternative to chemical propulsion systems, particularly for satellite constellations. However, the miniaturization potential of EP systems is impeded by certain limitations, necessitating the exploration of novel architectures. The high-efficiency multistage plasma thruster (HEMP-T) stands as a promising contender for stand-alone missions due to its employment of a cusped magnetic-field topology, which effectively mitigates plasma-wall interactions and enhances overall efficiency even at low thrust levels. Despite the growing interest in HEMP-Ts, there is a dearth of comprehensive and streamlined preliminary design procedures for these systems. Prior research has predominantly focused on extensive numerical analyses, neglecting the development of efficient and accessible design tools. To bridge this gap, this paper presents a novel preliminary design tool derived from integrating established analytical models available in the literature. The proposed design tool also incorporates an iterative procedure that refines geometric properties using a 2D magnetostatic solver. Through the application of this tool, a 4 mN HEMP thruster was analyzed. This finally exhibited a specific impulse of approximately 2000s and a good efficiency level of 23%. Also, the results obtained for a 10 mN application align closely with those achieved by other types of EP thrusters.

Within the global push towards environmental sustainability, the aviation industry is increasingly investigating electrification as a potential solution to reduce emissions and combat climate change. However, traditional battery integration faces significant drawbacks due to their limited energy and power densities, which negatively impact aircraft weight and performance. In this scenario, structural batteries are gaining interest, since they combine energy storage and load-bearing capabilities in multifunctional material structures, thus potentially eliminating barriers to the electrification of the air transport sector. While this novel technology holds immense potential, its integration raises new and unique airworthiness concerns. The present activity aims to support the development of aircraft certification requirements for structural batteries. Recognizing the dual nature of this technology, the proposed approach seeks to maintain or even enhance the current level of safety in both normal and emergency flight conditions.

In this work, the formation flight of the CubeSat cluster RODiO (Radar for Earth Observation by synthetic aperture DIstributed on a cluster of CubeSats equipped with high-technology micro-propellers for new Operative services) with respect to a small satellite in LEO (Low Earth Orbit) has been analyzed. RODiO is an innovative mission concept funded by the Italian Space Agency (ASI) in the context of the Alcor program. The small satellite is equipped with an antenna that allows it to function as a transmitter, whereas RODiO functions as a receiver. The extension of the virtual SAR (Synthetic Aperture Radar) antenna can be achieved by establishing an along-track baseline performing an orbital coplanar maneuver. Another interesting scenario is the possibility to create a cross-track baseline performing an inclination change maneuver. Such formation reconfiguration maneuvers can be achieved in relatively short times only by use of a high-thrust propulsion system, i.e., based on conventional chemical technologies. From the study of maneuvers, it is possible to identify the required ∆V (order of magnitude of 10 m/s), which represents an input parameter for the design of propulsion system. Among the different kinds of propulsion systems, a Hybrid Rocket Engine was chosen. Based on the previous experience acquired by Department of Industrial Engineering (University of Naples Federico II), the preliminary design of the thrust chamber for a Hybrid Rocket Engine based on Hydrogen Peroxide (91 wt%) of the 10 N-class could be carried out, whose dimensions meet the compactness requirements of the CubeSat (1.5 U, 2 kg).