Papers by Keyword: Aircraft

Abstract: The work aimed to obtain zirconium diboride ZrB₂ and silicon carbide SiC based ultra-high temperature ceramics, which have improved properties due to the unique morphology of starting ultrafine homogeneous composite powders. Such properties make it possible to use the product as thermal protection materials of hypersonic aircraft. The novelty of the research is the use of methods that lead to relevant selection of sintering additives/dopants and obtaining a fine microstructure, as well as the combined effect of these factors. Boron carbide B₄C, graphite powder, carbon black, and graphene structures are used as sintering additives. ZrB₂ nano powders with different stoichiometry and graphene nanostructural inclusions are produced and then their nanopowder ceramic composites with SiC are made by vacuum hot-pressing method at 1700–1750°C. The following key properties of powders and ceramics were determined: morphology, elemental and phase compositions, particle size distribution, relative density, hardness, and flexural strength and modulus.

Abstract: LVD Company NV and Kawasaki Heavy Industries, ltd. developed the cutting-edge, high performance CNC press brake [1] for high accuracy/precision bending of approx.10m (L) by 2.5m (W) size aircraft skins. Those skin sheets have complex shapes which include mainly machine milled thickness reduction area called pockets, thickness tapers, cutouts for the windows and doors. Due to those characters, the materials have large thickness variation between less than 2 mm and more than 11 mm in a single skin sheet. Here in this paper, the overview of this intelligence press brake equipment and its forming process are described. The materials with complex shapes described above can be bent accurately including material edges with the features of the press brake which are the synchronized material handling system, 210 numbers of variable punches, the special die suitable for the variable punches, the curvature measurement devices, and an automated bending mechanism with curvature feedback /feedforward. In addition, cardboard-like-filler jigs which are used to make thickness variations flat in a traditional bending process and shims to adjust regional press strokes can be eliminated, which reduce significant process time and product quality without worker’s superior skills. As a result, full automation of accurate bending process of aircraft skins have been achieved.

Abstract: The presented study demonstrates the possibility of an analytical approach called the multi-optional hybrid-effectiveness functions uncertainty measure conditional optimization doctrine. This method is applied in order to obtain the known, therefore considered proven, solutions by-passing the entirely probabilistic approach. It is made in application to the stochastic process measures determination. Supposedly, the process is developing in the aircraft engine system’s element (the state condition of its material). The solution is found in the framework of the entropy paradigm. It helps assess the newly emerged materials applications rationality and the novelty technologies implementations expediency on condition of the operational options uncertainty.

Abstract: This paper is focused on the use of special composite materials for the construction of aircraft components. It focuses on measuring and testing the strength of reinforced composite materials used in damaged aircraft parts repairs. To determine the layer required to repair a part of the aircraft, it is necessary to know the strength limit of the material and its parts. The article describes experimental measurements of manufactured composite samples that have been subjected to tensile stress. Aim of the performed tensile tests was to determine the maximum tensile stress that the composite materials are able to transmit until they are damaged. Measurement determining the maximum stress level is important to ensure the required safety of the aircraft structure on which the composite structure was repaired.

Abstract: The use of steel in aerospace manufacture continues to decrease, owing in part to the sustainability and mechanical properties of fibers which have higher strength in minimum weight than steel. This study was defined to evaluate the mechanical properties of high-performance fibers, especially aramid, in terms of composite to be part of aircraft' wings called CN-235. The reinforcements were pre-impregnated by the materials manufacturers, under heat and pressure, with a pre-catalysed resin. Then the layering of aramid prepregs was carried with a dry lay-up process and cured in the autoclave at a temperature of 125°C and pressure of 3 bar for 90 minutes. The aramid composite was cured in various grain directions and examined in mechanical tests such as tensile, compression, and interlaminar shear strength tests. The result showed an insignificant difference between 0 and 90 degrees of grain direction in aramid composite in any properties. The strength of aramid composite with 90 degrees of grain direction has a higher value in the compression test (less than 5%) while having lower value in tensile and interlaminar shear tests.

Abstract: Composite material is widely used to maintain damaged structures of aircraft. The 3D finite element model of composite cement maintenance for aircraft is established by finite element method software ANSYS Workbench. The structural characteristics and usage status of the composite cement maintenance model is analyzed, and then the optimal structural parameters of the composite patch are obtained, including the length, width and thickness. The results show that the composite cement maintenance method could effectively restore the rigidity, and improve the strength of the structure. Furthermore, the optimal design for composite patch ensures safety of aircraft, economics of maintenance, and operability of repair methods.

Abstract: As a special functional and structural material, the rare metal beryllium has been widely applied in many key areas due to its excellent nuclear properties, optical properties and physical properties such as low density, high specific stiffness, high specific strength, and excellent thermal properties. This article systematically reviews application of beryllium in strategic nuclear energy, high-energy physics, inertial navigation systems, aircraft structural components, optical systems and commercial fields. The paper also examines how beryllium promoted technological advances and improved the facilities performance in its applications fields. Beryllium plays an important role in the development of nuclear technology, defense, and aerospace, which make beryllium become a strategic and critical engineering material. The paper provides a reference for scientists and technicians to employ beryllium in more fields.

Abstract: Although aircraft carriers operating in the seas have developed considerably from a constructive point of view, naval aviation continues to face significant challenges due to short runways, often in motion or unpredictable weather conditions, as a rule. This paper aims to analyze the concept of aircraft's rapid deceleration to landing, as well as to study the dynamic behavior of the aircraft restraint system used by aircraft carriers.

Abstract: The paper studies the possibility of applying the coatings produced by cold spraying, for the protection and repair of aircraft structural elements of aluminum alloy against corrosion damage during service of aircrafts. Mechanical tests were carried out on samples, made of aircraft alloy 1163RDTV, and repaired by cold spraying after corrosion damage. It is shown that the coating production via cold spraying on corrosively damaged areas can restore the strength characteristics of the sample in the elastic region of deformation diagrams. The preliminary results of the influence of cyclic loading on repaired by cold spraying samples were also obtained. It is shown that the characteristics of durability increased by factor 1.67 in comparisons with the sample that was not repaired after corrosion damage.

Abstract: The application of composites in aircraft was introduced. And compare composites with metal materials. The conclusions referring to the impact test on composite laminates and impact damage characteristics of composite laminates, were summarized by referring to a large number of literature. This investigation shows: composite material is more suitable for the preparation of the overall structure; the research of impact damage test on composites mainly concentrated in the layer order; layer direction and low-energy impact test; and there are clear division and judgment method of four kinds of damage body by studying characteristics of impact damage.Keyword: aircraft; composites; impact damage