Current Issue : January - March Volume : 2020 Issue Number : 1 Articles : 5 Articles
This paper evaluates possible applications for SMAs (Shape Memory Alloys) based on the\nrequirements in the field of aircraft interiors. The authors gather requirements regarding industry\nstandards and regulations by detailed literature research and lead user interviews. They develop a\nclassification scheme for SMA-based actuators, which consists of SMA-specific technical attributes\nand requirements. This classification scheme allows one to evaluate the feasibility of using SMAbased\nsystems in aircraft interiors. Furthermore, this paper clusters critical requirements and\ndiscusses solutions for limitations of SMAs in aircraft interiors. The authors identify critical and\nnoncritical requirements for the implementation of SMA-based actuators. They suggest solutions\nfor critical requirements in order to improve the possible range of applications for SMAs. The study\nexclusively regards the field of aircraft interiors and the currently existing industry standards and\nonly indirectly takes laws into account. The evaluated requirements and proposed solutions can be\ntransferred to other areas such as the automotive industry. This structured analysis of the feasibility\nof SMA-based systems in aircraft interiors is an innovative research work and, therefore, is valuable\nin order to benefit from the advantageous properties of SMAs....
A folding wing morphing aircraft should complete the folding and unfolding process of its wings while in flight. Calculating the\nhinge moments during the morphing process is a critical aspect of a folding wing design. Most previous studies on this problem\nhave adopted steady-state or quasi-steady-state methods, which do not simulate the free-flying morphing process. In this study,\nwe construct an aeroelastic flight simulation platform based on the secondary development of ADAMS software to simulate the\nflight-folding process of a folding wing aircraft. A flexible multibody dynamic model of the folding wing structure is established\nin ADAMS using modal neutral files, and the doublet lattice method is developed to generate aerodynamic influence coefficient\nmatrices that are suitable for the flight-folding process. The user subroutine is utilized, aerodynamic loading is realized in\nADAMS, and an aeroelastic flight simulation platform of a folding wing aircraft is built. On the basis of this platform, the flightfolding\nprocess of the aircraft is simulated, the hinge moments of the folding wings are calculated, and the influences of the\nfolding rate and the aircraftâ??s center of gravity (c.g.) position on the results are investigated. Results show that the steady-state\nmethod is applicable to the slow folding process. For the fast folding process, the steady-state simulation errors of the hinge\nmoments are substantially large, and a transient method is required to simulate the flight-folding process. In addition, the c.g.\nposition considerably affects the hinge moments during the folding process. Given that the c.g. position moves aft, the\nmaximum hinge moments of the inner and outer wings constantly increase....
SpaceFibre is an upcoming on-board high-speed communication protocol for space\napplications. It has been developed in collaboration with the European Space Agency to answer\nthe growing data-rate requirement of satellite payloads such as Synthetic Aperture Radars or\nhyper-spectral imagers. SpaceFibre offers a complete set of features (i.e., Fault Detection, Isolation\nand Recovery, and Quality of Service) that guarantees robust communication at the price of higher\ncomplexity. This article proposes an innovative modified implementation of the SpaceFibre standard:\nR-SpaceFibre. It has been designed to reduce hardware resources while keeping high data-rate\ncapability and flow control. Attention is given to the trade-off between Data link layer complexity\nreduction and protocol features. The proposed protocol is particularly suitable in scenarios where\nvery low bit error rate is foreseen and data integrity is not critical, for example in imaging instruments.\nThe main advantage is a reduction of more than 40% of logical resources required per single interface.\nR-SpaceFibre may be a suitable solution for several applications, such as low earth orbit CubeSats,\nwhich have strict requirements in terms of available logic resources, mass, volume and cost, and more\nrelaxed constraints in terms of upset immunity....
The tilt-rotor aircraft has often been proposed as a means to increase the maximum speed of the conventional helicopter. The tiltrotor\naircraft consists of three primary flight modes that are the helicopter flight mode in low forward speed flight, airplane flight\nmode in high forward speed flight, and conversion flight mode. The aim of this paper is to develop a nonlinear flight dynamics\nmathematical modeling method of tilt-rotor aircraft and investigate the dynamic stability characteristics of tilt-rotor aircraft.\nFirst, a nonlinear tilt-rotor aircraft flight dynamics model is developed. The trim and linearized results are present to verify the\nmodel. Then, using a numerical differentiation technique, the dynamic stability of the tilt-rotor aircraft is assessed. The results\nshow that the flight speed and nacelle angle would affect the magnitude and the trend of the aerodynamic derivatives. The\ndamping of the pitch short period mode and the Dutch roll mode is insensitive to flight speed while they could be affected by\nnacelle angle. In all flight modes, as flight speed increases, the natural modes become more stable....
The novel contribution in this manuscript is an expansion of the current state-of-the-art in\nthe geometric installation of control moment gyroscopes beyond the benchmark symmetric skewed\narrays and the four asymmetric arrays presented in recent literature. The benchmark pyramid\nsymmetrically skewed at 54.73 degrees mandates significant attention to singularity avoidance,\nescape, and penetration, while the most recent four asymmetric arrays are strictly useful in instances\nwhere space is available to mount at least one gyro orthogonal to the others. Skewed arrays of\ngyros and the research-benchmark are introduced, followed by the present-day box-90 and â??roofâ?\nconfigurations, where the roof configuration is the first prevalently used asymmetric geometry.\nSix other asymmetric options in the most recent literature are introduced, where four of the six options\nare obviously quite useful. From this inspiration, several dozen discrete options for asymmetric\ninstallations are critically evaluated using two figures of merit: maximum momentum (saturation)\nand maximum singularity-free momentum. Furthermore, continuous surface plots are presented to\nprovide readers with countless (infinite) options for geometric installations. The manuscript firmly\nestablishes many useful options for engineers who learn that the physical space on their spacecraft is\ninsucient to permit standard installations....
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