Aerotecnica Missili & Spazio最新文献

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).

Future space transportation systems will heavily rely on predicting and understanding Boundary Layer Transition (BLT) during atmospheric entry, especially in the hypersonic phase. Several transition models compatible with RANS solvers have been proposed. However, the majority of them have been developed for low-speed flows, and attempts to extrapolate them to the hypersonic regime are documented in only a limited number of studies, specifically focusing on simplified geometries.This paper focuses on evaluating prediction capabilities for such models on complex 3D geometries int he hypersonic regime, using the International Boundary Layer Transition (BOLT) Flight Experiment as a test case.

The Aerospace Program at the Malta College of Arts, Science and Technology (MCAST) is a research and development program that focuses on addressing challenges in the aerospace industry, in particular, but not exclusively, in the field of protection of aerospace structures and systems from space debris impacts. This paper provides a comprehensive overview of the program, including five main projects currently under development. The first project presents a collaboration between MCAST and the University of Padova to develop a single-stage Light-Gas Gun impact facility in Malta, with operational ranges which could be complementary to other impact laboratories in Europe. The second project focuses on the study of 3D-printed Kevlar shields for aerospace applications; the outcome of this project will be the development of repair strategies for aviation structures and efficient novel small satellite shields. The third project addresses the issue of fragmentation of brittle materials for aerospace following a hypervelocity impact. The fourth project presents MCAST's participation in Malta's third space bioscience experiment, led by the University of Malta, the experiment investigated how microgravity affects the behavior of foot ulcer microbiomes in Type 2 Diabetes Mellitus patients. Finally, the paper discusses the ASTROBEAT project, that will be on board of the International Space Station, marking a significant milestone for the MCAST aerospace program; the project results from a collaboration with the South East Technological University (SETU), Ireland, and aims to explore the application of the cold-welding phenomenon for spacecraft repair. It will lead to the development of an experimental test rig to apply custom repair patches of different materials to pre-damaged metallic structures and monitor its performance. The projects presented in this paper reflect MCAST's commitment to contribute to the advancement of the aerospace industry and offer new opportunities for research, development, and commercialization. Furthermore, the importance of the MCAST Aerospace Program is relevant since Malta in 2024 will upgrade its status in the framework of the ESA Plan for European Cooperating States (PECS).

We present FLEW, an in-house high-fidelity solver for direct numerical simulation (DNS) of turbulent compressible flows over arbitrary shaped geometries. FLEW solves the Navier–Stokes equations written in a generalized curvilinear coordinate system, in which the surface coordinates are non-orthogonal, whereas the third axis is normal to the surface. Spatial discretization relies on high-order finite-difference schemes. The convective terms are discretized using an hybrid approach, combining the near-zero numerical dissipation provided by central approximations with the robustness of weighted essentially non-oscillatory (WENO) schemes, required to capture shock waves. Central schemes are stabilized using a skew-symmetric-like splitting of convective derivatives, endowing the solver with the energy-preserving property in the inviscid limit. The maximum order of accuracy is eighth for central schemes (also used for viscous terms discretization) and seventh for WENO. The code is oriented to modern high-performance computing (HPC) platforms thanks to message passing interface (MPI) parallelization and the ability to run on graphics processing unit (GPU) architectures. Reliability, accuracy and robustness of the code are assessed in the low-subsonic, transonic and supersonic regimes. We present the results of several benchmarks, namely the inviscid Taylor–Green vortex, turbulent curved channel flow, transonic laminar flow over a NACA 0012 airfoil and turbulent supersonic ramp flow. The results for all configurations proved to be in excellent agreement with previous studies.

This work presents the development of an OpenFOAM solver aimed at correctly predicting dynamics of concentrated suspensions when subjected to non-uniform shear flows. The newly implemented solver is able to predict the behavior of a heterogeneous mixture whose characteristics depend on the solid particle local concentration. To simulate such behavior, the conservation equation expressing the time variation of the particle volume fraction has been implemented in OpenFOAM; this was achieved by modifying a pre-existing solver, pimpleFoam, which discretizes the Navier–Stokes system of equation through the PIMPLE algorithm. As a first step, the formulation of the momentum equation has been adapted to correctly solve cases with non-Newtonian fluids. Successively, the Krieger’s correlation has been used to model the viscosity variation in the domain to take in account heterogeneous particle distributions. Finally, the iterative cycle for the solution of the migration equation has been included within the time loop. The above-mentioned code has been successfully validated by comparing the numerical results with the measured data provided by experiments reported in literature.

This paper presents BEA (Buoy Eau Air), an innovative multi-unmanned vehicle system to address the issue of marine traffic endangering scuba diving and free diving. Scuba diving is a popular recreational activity with over 6 million active participants worldwide. Boat drivers may fail to recognize universal markers due to a variety of factors, such as inattention, unfamiliarity with dive zones, or poor visibility. In addition, some boat drivers may deliberately speed too close to dive zones, unaware of the dangers they pose to divers. This risk is particularly pronounced in popular dive destinations like Malta, where boat traffic can be heavy. Divers in these areas are often more vulnerable to collisions. To mitigate these risks, the proposed system consists of an Unmanned Aerial Vehicle (UAV), an Unmanned Surface Vehicle (USV), and an Unmanned Underwater Vehicle (UUV), which work in synergy to monitor and protect divers. The UAV monitors the surface of the sea near the dive zone for any traffic, while the USV tracks the UUV, communicates with the other unmanned vehicles, and provides a takeoff/landing surface for the UAV. The USV can also be used to tow divers and equipment to and from the shore. Finally, the UUV tracks the diver and warns them if it is unsafe to surface. The paper provides an overview of the system’s design and architecture, as well as algorithms for boat detection, precision landing, and UUV tracking. Preliminary tests on a prototype have shown that the system is suitable for the intended application. The BEA system is the first in the world to use a multi-drone system to create a geo-fence around the diver and monitor the area within it. This has the potential to significantly improve diver safety with real-time alerts, providing also assistance with navigation, towing of divers and emergency response.