• Structural Engineering and Mechanics
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• v.44 no.1
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• pp.35-49
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• 2012

A series of fatigue test were carried out on scarfed lap joints (SLJ) using in airfoil siding to explore the effect of structural details, such as rows of rivets, lap angles, on its fatigue performance. Finite element (FE) analysis was employed to explore the effect of lap angle on load transfer and the stress evolution around the rivet hole. At last, the fatigue lives were predicted by nominal stress approach and critical plane approach. Both of the test results and predicted results showed that fatigue life of SLJ was remarkably increased after introducing lap angle into the faying surface. Specimen with the lap angle of $1.68^{\circ}$ exhibits the best fatigue performance in the present study.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2005.05a
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• pp.302-305
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• 2005

To comply to demand for a development requirement of aircraft design part, the expert system builds up standard knowledge-base based on presently maintained expert knowledge and experience in aircraft structure material selection. It also builds up database based on aircraft design open data, and standard calculation module used for present design and analysis method. This system is developed using Visual Basic language. The expert system standardize aircraft structure material selection and can be applied to all type of elementary stage of aircraft structure design. It is working on Windows, which has a friendly interface and is convenient for debugging, maintenance and transplanting. Explanation of the structure and the function of the system was given in this paper.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.3
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• pp.267-281
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• 2012

This paper reviews the flight mechanics and control of birds and bird-size aircraft. It is intended to fill a niche in the current survey literature which focuses primarily on the aerodynamics, flight dynamics and control of insect scale flight. We review the flight mechanics from first principles and summarize some recent results on the stability and control of birds and bird-scale aircraft. Birds spend a considerable portion of their flight in the gliding (i.e., non-flapping) phase. Therefore, we also review the stability and control of gliding flight, and particularly those aspects which are derived from the unique control features of birds.

• Current Optics and Photonics
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• v.6 no.2
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• pp.171-182
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• 2022

A single-photon laser and mid-wave infrared (MWIR) common aperture optical system was designed and developed to detect and range a long-distance civil aviation aircraft. The secondary mirror of the Ritchey-Chretien (R-C) optical system was chosen as a dichroic lens to realize the design of a common aperture system for the laser and MWIR. Point spread function (PSF) ellipticity was introduced to evaluate the coupling efficiency of the laser receiving system. A small aperture stop and narrow filter were set in the secondary image plane and an afocal light path of the laser system, respectively, and the stray light suppression ability of the small aperture stop was verified by modeling and simulation. With high-precision manufacturing technology by single point diamond turning (SPDT) and a high-efficiency dichroic coating, the laser/MWIR common aperture optical system with a 𝜑300 mm aluminum alloy mirror obtained images of buildings at a distance of 5 km with great quality. A civil aviation aircraft detection experiment was conducted. The results show that the common aperture system could detect and track long-distance civil aviation aircraft effectively, and the coverage was more than 450 km (signal-to-noise ratio = 6.3). It satisfied the application requirements for earlier warning and ranging of long-range targets in the area of aviation, aerospace and ground detection systems.

• Advances in aircraft and spacecraft science
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• v.5 no.4
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• pp.477-498
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• 2018

The main goal of this article is to validate a methodological process in Actran MSC Software, that is based on the Finite Element Method, to evaluate the comfort in the cabin of a regional aircraft and to study the noise and vibrations reduction through the fuselage by the use of innovative materials. In the preliminary work phase, the CAD model of a fuselage section was created representing the typical features and dimensions of an airplane for regional flights. Subsequently, this model has been imported in Actran and the Sound Pressure Level (SPL) inside the cabin has been analyzed; moreover, the noise reduction through the fuselage has been evaluated. An important investigation and data collection has been carried out for the study of the aircraft cabin to make it as close as possible to a real problem, both in geometry and in materials. The mesh of the structure has been built from the CAD model and has been simplified in order to reduce the number of degrees of freedom. Finally, different fuselage configurations in terms of materials are compared: in particular, aluminum, composite and sandwich material with composite skins and poroelastic core are considered.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.5
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• pp.681-691
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• 2008

Taking into consideration both the inconveniences reported with current working uniform for the aircraft mechanics and the subjects' requirements mentioned in preceded survey, the researchers designed an ergonomic sample garments with improved motional flexibility and comfort. To improve motional flexibility, extra folds were added to the back of the garments to allow for ease of motion of limbs, so that the material would not be drawn up by the motion of the arms. Darts were added to the elbow, hip, the knee. Furthermore, by increasing the length of the waist centerline, the hip region would not be drawn up. For improved comfort, $CoolMax^{(R)}$ was used as lining material for the armpit and back region to discharge swear promptly. Subjects and panels were asked to evaluate the sample garment that followed an ergonomic design and pattern. According to the results, the sample garment was evaluated more highly than the existing working uniform in appearance and motional flexibility. The field tests by three aircraft mechanics working in the Office of Forestry were also demonstrated that the sample garment was advanced in terms of motional flexibility and comfort.

• Advances in aircraft and spacecraft science
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• v.10 no.2
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• pp.107-125
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• 2023

Drag reduction is significant research in aircraft design due to its effect on the cost of operation and carbon footprint reduction. Aircraft currently use conventional solid winglets to reduce the induced drag, adding extra structural weight. Fluidic on-demand winglets can effectively reduce drag for low-speed flight regimes without adding any extra weight. These utilize the spanwise airflow from the wingtips using hydraulic actuators to create jets that negate tip vortices. This study develops a computational model to investigate fluidic on-demand winglets. The well-validated computational model is applied to investigate the effect of injection velocity and angle on the aerodynamic coefficients of a rectangular wing. Further, the turbulence parameters such as turbulent kinetic energy (TKE) and turbulent dissipation rate are studied in detail at various velocity injections and at an angle of 30°. The results show that the increase in injection velocity shifted the vortex core away from the wing tip and the increase in injection angle shifted the vortex core in the vertical direction. Further, it was found that a 30° injection is efficient among all injection velocities and highly efficient at a velocity ratio of 3. This technology can be adopted in any aircraft, effectively working at various angles of attack. The culmination of this study is that the implementation of fluidic winglets leads to a significant reduction in drag at low speeds for low aspect ratio wings.

• Advances in aircraft and spacecraft science
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• v.4 no.4
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• pp.421-436
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• 2017

This paper presents the main outcomes of the preliminary development of the Anuloid, an innovative disk-shaped VTOL aircraft. The Anuloid has three main features: lift is provided by a ducted fan powered by a turboshaft; control capabilities and anti-torque are due to a system of fixed and movable surfaces that are placed in the circular internal duct and the bottom portion of the aircraft; the Coanda effect is exploited to enable the control capabilities of such surfaces. In this paper, results from flight mechanics are presented. The vertical flight dynamics were found to be desirable. In contrast, the horizontal flight dynamics of the aircraft shows both dynamic instability, and more importantly, insufficient pitch and roll control authority. Some recommendations and guidelines are then given aimed at the alleviation of such problems.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.2
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• pp.48-62
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• 2017

The purpose of this study was to analyze the influence of self-leadership of Korean aircraft mechanics on organizational effectiveness and to investigate whether safety culture has mediating effect. The theory of leadership, which has emerged since the 1940s, has been an important and key research issue in the social sciences for the last decade and has evolved as a brand-new theory through the theory of characteristics, the theory of behavior, and the theory of situation. The new leadership theory has been extended to charismatic leadership, transformative leadership, empowerment leadership, super leadership, and self-leadership of organizational members as a new flow leadership. On the other hand, there was a precedent study on the relationship between leadership and safety culture, and this study started with interest in the relationship between self-leadership, safety culture and organizational effectiveness. As a result, safety culture has been proved to play an moderating variable in the relationship between self-leadership of Korean aircraft mechanics and organizational effectiveness. Especially, among the sub-factors of the self-leadership, self-goal setting, self-reward, and natural reward have been shown to affect organizational effectiveness in combination with the sub-factors of the safety culture, learning culture and flexible culture.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.28 no.3
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• pp.12-17
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• 2020

Avionics is a compound word of aviation and electronics that began to be used in the late 1930s. In the components or sub-systems installed to the aircraft, avionics is something that works by electronic technology. In the past, the aircraft mate, the flight engineer, and the radar operators performed the work on board the aircraft but the modern aircraft have replaced these tasks with avionics. the aircraft mechanics who maintain and manage such complex aircraft must have expertise and technics with the development of avionics to maintain aircraft airworthiness. This paper is about the introduction of domestic avionics qualification system and the development of avionics maintenance technology. For this, the SWOT analysis is performed by identifying the internal and external environment. And recommend the strategy and direction of domestic avionics qualification and education system.