• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.3
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• pp.229-237
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• 2008

In this research, a MDO(multi-disciplinary design optimization) framework, which integrates aerodynamic and structural analysis to design an aircraft wing, is constructed. Whole optimization process is automated by a parametric-modeling approach. A CFD mesh is generated automatically from parametric modeling of CATIA and Gridgen followed by automatic flow analysis using Fluent. Finite element mesh is generated automatically by parametric method of MSC.Patran PCL. Aerodynamic load is transferred to Finite element model by the volume spline method. RSM(Response Surface Method) is applied for optimization, which helps to achieve global optimum. As the design problem to test the current MDO framework, a wing weight minimization with constraints of lift-drag ratio and deflection of the wing is selected. Aspect ratio, taper ratio and sweepback angle are defined as design variables. The optimization result demonstrates the successful construction of the MDO framework.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.5
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• pp.34-40
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• 2005

Most analyses and researches on Micro Aerial Vehicle(MAV) have focused upon propulsion, automatic control, aerodynamic configuration in low Reynolds number region, and miniaturization of telemetric parts. In the present study, a structural concept for MAV is designed by using the composite material suitable for light flight structures. In order to study the load path and stress state of the MAV, the load and structural analyses are simultaneously performed by the aeroelasticity module of MSC/NASTRAN. The stability derivatives of the MAV are obtained for three symmetric, two antisymmetric, and four unsymmetric maneuvering conditions. Although the aerodynamic theory in MSC/NASTRAN could not be proper for MAV analysis, it provides an traditional and effective tool for trim and load analyses and may be corrected with the results by more accurate theory or test. The results show that the inertial load due to payloads has a more effect on stress rather than the aerodynamic load.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.1
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• pp.91-98
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• 2011

In this study, we measure the aerodynamic forces acting on an AREX train in a crosswind by wind tunnel testing. A detailed test model scaled to 5% of the original and including the inter-car, under-body, and the bogie systems was developed. The aerodynamic forces on the train vehicles have been measured in a 4 m $\times$ 3 m test section of the subsonic wind tunnel located in Korea Aerospace Research Institute (KARI). The aerodynamic forces and moments of the train model on two different track models have been plotted for various yaw angles, and the characteristics of the aerodynamic coefficients have been analyzed at the experimental conditions.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.289-294
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• 2002

Unlike Tubular Steel Tower, This Composite Material Tower is a low-technology Component, whose design is easy to optimize, and which therefore during the design process-lends itself easily as an object for possible cost reduction at very little effort. This may come in useful as the cost of a tower usually significant part of the total cost of a structure. This paper is written by the Composite Materials Tower which loaded Complex loading in Off and On shore. This Composite Material Tower is made by the Method of Filament Winding, and the Component of Composite Material is used by the Roving RS220PE-535. When it loaded Complex trading, there is a results which is bigger than steel tower deflection. We controlled this 1a18e deflection by stiffeners which has thickness 20mm. At last, Off and On Shore Tower which used Composite Materials is compared with Off and On Shore Tower which used Steel.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.4
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• pp.29-37
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• 2003

Using a wind tunnel testing, the aerodynamic load characteristics of an elliptic airfoil was described. The experimental data was obtained for angles of attack $-20^{\circ}$ to $+20^{\circ}$ with $2^{\circ}$ increments at a chord Reynolds number of $0.99{\times}105$ and $2.48{\times}105$. For each test case, chordwise suction pressure distributions and wake surveys were obtained. Static pressure measurements were made over a 10 sec averaging time at a 10 Hz sampling rate. For each case, wake survey was conducted with a pilot-static probe at 1.0c downstream from the trailing edge at very fine spacing to resolve the wake velocity deficit profile. As can be expected, suction pressure coefficient was increased with angle of attack. The normal force, CNmax, appeared peak value at the incidence angle of $12^{\circ}~14^{\circ}$, and the significant increase in profile drag at this range of angles of attack.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.2
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• pp.115-120
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• 2014

In this study, a module is developed for modeling and analyzing dynamic behavior of a wind turbine using RecurDyn, which is a commercial multi-body dynamics software developed by FunctionBay, Inc. The wind turbine consists of tower, nacelle, hub and blades. Tower and blades are regarded as flexible bodies for considering elastic effect using beam theory and spring force. In this paper, a constant speed wind was assumed and aerodynamic force is modeled using BEM theory. Dynamic analysis applying this aerodynamic force is carried out. To verify the validity of analysis results, these results are compared to those of GH-Bladed which is a commercial software for analyzing wind turbine system distributed by Garrad Hassan.

• Journal of Aerospace System Engineering
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• v.13 no.1
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• pp.18-28
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• 2019

High speed vehicles are subjected to high thermal loadings due to aerodynamic heating during ascent and reentry. Since a thermal protection system panel is mechanically constrained, it may cause thermal buckling under excessive thermal loadings. The thermal buckling could disturb the field of flow and make aerodynamic characteristics unstable. It is thus necessary to design the thermal protection system panel to prevent thermal buckling. This study defines the analytical model of temperature distribution using the finite difference method for the thermal protection system panel with large temperature differences inside and outside. This paper proposes the approximate model of the thermal buckling characteristics for the thermal protection system panel through the use of the Ritz method. The validity of the present method was verified by comparing the results of the finite element analysis. Furthermore, this research performs the parametric analysis of the thermal buckling characteristics for the thermal protection system panel by using the approximate model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.9-16
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• 2017

In this paper, the aerodynamic design process of wind turbine blades is established. The optimization design strategy is presented and the constraints that must be reviewed during the aerodynamic design process are summarized. Based on this, this study developed a BEMT-based aerodynamic optimal design program that can be applied easily to actual work, not only for research purposes, but also can be integrated from the initial concept design stage to the final 3D shape detail design stage. The developed program AeroDA consisted of a concept design module, basic design module, optimal TSR module, local shape optimization module, performance analysis module, design verification module, and 3D shape generation module. Using the developed program, an improved design of the 5MW blade by NREL was made, and it was confirmed that this program could be used for design optimization. In addition, a 10kW blade aerodynamic design and turbine detailed performance analysis were carried out, and it was verified by a comparison with the commercial program DNVGL Bladed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.4
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• pp.336-343
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• 2014

Modern advanced-turboprop propellers are required to have high structural strength to cope with the thrust requirement at high speed. The high stiffness and strength carbon/epoxy composite material is used for the major structure and skin-spar-foam sandwich structural type is adopted for advantage in terms of the blade weight. As a design procedure for the present study, the structural design load is estimated through investigation on aerodynamic load and then flanges of spars from major bending loads and the skin from shear loads are sized using the netting rule and Rule of Mixture. In order to investigate the structural safety and stability, stress analysis is performed by finite element analysis code MSC. NASTRAN. It is found that current methodology of composite structure design is a valid method through the static structural test of prototype blade.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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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.