• Transactions of the Korean Society of Mechanical Engineers A
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• 제30권5호
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• pp.585-594
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• 2006

The joined-wing is a new concept of the airplane wing. The fore-wing and the aft-wing are joined together in a joined-wing. The range and loiter are longer than those of a conventional wing. The joined-wing can lead to increased aerodynamic performance and reduction of the structural weight. In this research, dynamic response optimization of a joined-wing is carried out by using equivalent static loads. Equivalent static loads are made to generate the same displacement field as the one from dynamic loads at each time step of dynamic analysis. The gust loads are considered as critical loading conditions and they dynamically act on the structure of the aircraft. It is difficult to identify the exact gust load profile. Therefore, the dynamic loads are assumed to be (1-cosine) function. Static response optimization is performed for the two cases. One uses the same design variable definition as dynamic response optimization. The other uses the thicknesses of all elements as design variables. The results are compared.

• Composites Research
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• 제19권5호
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• pp.12-19
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• 2006

In this paper, conceptual structural design of the main wing for a small scale WIG(Wing in Ground Effect) among high speed ship projects, which will be a high speed maritime transportation system for the next generation in Rep. of Korea, was performed. The Carbon/Epoxy material was selected for the major structure, and the skin-spar with a foam sandwich structural type was adopted for improvement of lightness and structural stability. As a design procedure for the present study, firstly the design load was estimated through the critical flight load case study, and then flanges of the front and rear spars from major bending loads and the skin and the spar webs from shear loads were preliminarily sized using the netting rule and the rule of mixture. Stress analysis was performed by a commercial FEA code, NASTRAN. From the stress analysis results for the first designed wing structure, it was confirmed that the upper skin between the front spar and the rear spar was unstable fer the buckling. Therefore in order to solve this problem, a middle spar and the foam sandwich type structure at the skin and the web were added. After design modification, the structural safety and stability for the final design feature was confirmed. In addition to this, the insert bolt type structure with eight high strength bolts to fix the wing structure to the fuselage was adopted for easy assembly and removal as well as in consideration of more than 20 years fatigue life.

• Journal of the Korean Society for Aviation and Aeronautics
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• 제19권4호
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• pp.67-73
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• 2011

For loads analysis of airplane, applicable regulation should be determined. Then, loads conditions are prepared from the regulation. Modeling for aerodynamic, mass, and structure are performed. Panel method is usually adopted for aircraft loads analysis to obtain air loads. The ARGON which is a multidisciplinary fixed wing aircraft design software co-developed by the KARI and TsAGI are used for loads analysis. The ARGON can be utilized for flutter and stress analysis as well as for flight and ground loads analysis. In this paper, flight loads analysis for wing structural design of the regional aircraft at the conceptual design phase are performed with the ARGON. FAR 25 is used for the regulation for the load analysis. Shear force, bending moment and torsion diagrams for the wing and shear force and hinge moment for the aileron are presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.675-679
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• 2005

This paper deals with the problem of gust load alleviation in active control for the case that aeroelasticity takes place due to interaction between wing structure and aerodynamics on wing when aircraft meets gust during flight. Aeroservoelasticity model includes wing structure modeled in FEM, unsteady aerodynamics in minimum state approximate method, and models of actuator and sensors in state space. Based on this augmented model, digitally redesigned gust load alleviation system is designed in sampled-data control technique. From numerical simulation, this digital control system is effective to gust load on aircraft wing, which is shown in transient responses and PSD analysis to random gust inputs.

• Aerospace Engineering and Technology
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• 제12권1호
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• pp.1-9
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• 2013

In order to increase endurance flight efficiency of long endurance electric powered UAV with solar cell, the light weight airframe design techniques are important. In this paper, the design of the main wing of electric powered UAV manufactured using Mylar film and fiber reinforced composite was conducted in order to achieve weight reduction and structural integrity of the structure. The shape of spar and size were determined using beam theory analysis. The finite element analysis of the wing was performed under various load condition derived from flight environment of EAV-2H. Finally, the static strength test of the main wing was conducted to verify structural integrity. It was found that the developed main wing weigh less than 42% than the previous EAV-2 and the main wing passed static strength test under ultimate load.

• Journal of Aerospace System Engineering
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• 제9권2호
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• pp.19-24
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• 2015

Export basic trainer was designed to add armed configuration required by customer. Design configuration of main wing was changed to satisfy changed internal load caused by armed configuration. It was verified that design changed main wing airframe of export basic trainer satisfy the requirement through the structural detail analysis, structural ground test and flight test. This paper presents the durability test procensure and test result for the main wing of export basic trainer.

• Journal of the Korean Society for Aviation and Aeronautics
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• 제14권2호
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• pp.17-26
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• 2006

The flutter characteristics of all movable tail wing with honeycomb sandwich structure have been studied in this study. The present wing model has a airfoil cross section and the linear variation of spanwise thickness. Structural vibration analysis is performed based on the finite element method using sandwich and beam elements. Unsteady aerodynamic technique used on the doublet lattice method has been effectively used to conduct the frequency-domain flutter analyses. The parametric flutter studies have been performed for various structural design parameters. Computational results on flutter stability due to the variation of structural parameters are presented and its related characteristics are investigated through the comparison of results.

• Journal of the Society of Naval Architects of Korea
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• 제50권5호
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• pp.343-348
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• 2013

When a natural frequency of the trailing edge of a wing is close to a vortex shedding frequency, an amplitude of the edge oscillation becomes maximal; it makes intensive noise called singing. Motion of the trailing edge may also feedback to the vortex shedding so that self-sustained oscillation appears, and a resonant frequency is locked in some interval of the speed of the incident flow. In this study, we first evaluate main features of oscillating characteristics of the wing. Second we simulate fluid-structure interaction of the wing with a flap using a commercial code, ANSYS-CFX, and investigate lift characteristics in a frequency domain.

• International Journal of Aeronautical and Space Sciences
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• 제4권1호
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• pp.53-62
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• 2003

In this study, nonlinear aeroelastic characteristics of an supersonic missile wing with strong shock interferences are investigated. The missile wing model has a freeplay structural nonlinearity at its pitch axis. To practically consider the effects of freeplay structural nonlinearity, the fictitious mass method is applied to structural vibration analysis based on finite element method. Nonlinear aerodynamic flows with unsteady shock waves are also considered in supersonic flow regions. To solve the nonlinear aeroelastic governing equations including the freeplay effect, a modal-based coupled time-marching technique based on the fictitious mass method is used in the time-domain. Various aeroelastic computations have been performed for the nonlinear wing structure model. Linear and nonlinear aeroelastic analyses have been conducted and compared with each other in supersonic flow regions. Typical nonlinear limit cycle oscillations and phase plots are presented to show the complex vibration phenomena with simultaneous fluid-structure nonlinearities.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제32권3호
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• pp.74-81
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• 2004

In this study preliminary structural design has been performed to develop an all composite wing box for experimental aircraft(classified in FAR Part 21). Considerations on composite materials and their manufacturing process were taken into account throughout the design phase. Aerodynamic loads were estimated by using Shrenk method(NACA TM No 948) and FAR Part 23 Appendix A. The structural layout has been determined to carry effectively the critical loads and to maximize the benefit of composite structure. Maximum strain failure allowable and first ply failure criteria were applied for the sizing of major structural members. Finally, the designed composite wing box structure is presented in the form of drawings, which include material specifications, stacking sequences and joint design.