In this paper, a vertical drop test of a full composite fuselage section of a regional aircraft has been presented. This test was performed to investigate the structural response of a prototype of a composite fuselage section as well as the biomechanical response of the anthropomorphic dummies under a vertical crash loading condition. The research activity, carried out within the framework of Metodi di CERtificazione e Verifica Innovativi ed Avanzati (CERVIA) ‡ ‡ project, allowed collecting suitable amount of data for the assessment of the reliability of numerical models. The test article consists of a composite fuselage section with a diameter of 3445 mm and a total length of 4750 mm. It includes all main structural components, the passengers, and the cargo floor structure. Fuselage section has been also equipped with an aeronautical three-seat row. The accelerations, recorded in different locations, demonstrate that the structure is able to absorb a considerable impact energy amount, thus to mitigate the acceleration levels induced to the passengers.
This work deals with the development of an improved numerical model, based on the explicit finite element method, aimed at investigating the energy absorption capabilities of a full-scale composite fuselage section of a regional aircraft and the related biomechanical injuries affecting the passengers. The experiment, conducted within the Italian national research project named "Innovative and Advanced Verification and Certification methods," consisted in a drop test of a fully equipped barrel performed at the Italian Aerospace Research Centre, according to the special conditions of the Federal Aviation Regulation Certification Specification 25. From a free-fall height of about 4 m, a ground contact impact velocity of 9.14 m∕s was measured. The numerical model has been developed faithfully to the experiment. Numerical analysis results, in terms of global deformations, failures, local accelerations, and biomechanical injuries, have been compared with the experimental ones to assess the prediction capability of the proposed numerical modeling procedure with a focus on improved crashworthy components for certification by analysis future purpose.
Traditional anti-icing/de-icing systems, i.e., thermal and pneumatic, in most cases require a power consumption not always allowable in small aircraft. Therefore, the use of passive systems, able to delay the ice formation, or reduce the ice adhesion strength once formed, with no additional energy consumption, can be considered as the most promising solution to solve the problem of the ice formation, most of all, for small aircraft. In some cases, the combination of a traditional icing protection system (electrical, pneumatic, and thermal) and the passive coatings can be considered as a strategic instrument to reduce the energy consumption. The effort of the present work was to develop a superhydrophobic coating, able to reduce the surface free energy (SFE) and the work of adhesion (WA) of substrates, by a simplified and non-expensive method. The developed coating, applied as a common paint with an aerograph, is able to reduce the SFE of substrates by 99% and the WA by 94%. The effects of both chemistry and surface morphology on the wettability of surfaces were also studied. In the reference samples, the higher the roughness, the lower the SFE and the WA. In coated samples with roughness ranging from 0.4 and 3 µm no relevant variations in water contact angle, nor in SFE and WA were observed.
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