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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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International Journal of Aeronautical and Space Sciences
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Journal DOI :
The Korean Society for Aeronautical & Space Sciences
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Volume & Issues
Volume 14, Issue 4 - Dec 2013
Volume 14, Issue 3 - Sep 2013
Volume 14, Issue 2 - Jun 2013
Volume 14, Issue 1 - Mar 2013
Selecting the target year
Development of an Engineering Education Framework for Aerodynamic Shape Optimization
Kwon, Hyung-Il ; Kim, Saji ; Lee, Hakjin ; Ryu, Minseok ; Kim, Taehee ; Choi, Seongim ;
International Journal of Aeronautical and Space Sciences, volume 14, issue 4, 2013, Pages 297~309
DOI : 10.5139/IJASS.2013.14.4.297
Design optimization is a mathematical process to find an optimal solution through the use of formal optimization algorithms. Design plays a vital role in the engineering field; therefore, using design tools in education and research is becoming more and more important. Recently, numerical design optimization in fluid mechanics, which uses computational fluid dynamics (CFD), has numerous applications in the engineering field, because of the rapid development of high-performance computing resources. However, it is difficult to find design optimization software and contents for educational purposes in aerospace engineering. In the present study, we have developed an aerodynamic design framework specifically for an airfoil, based on the EDucation-research Integration through Simulation On the Net (EDISON) portal. The airfoil design framework is composed of three subparts: a geometry kernel, CFD flow analysis, and an optimization algorithm. Through a seamless interface among the subparts, an iterative design process is conducted. In addition, the CFD flow analysis and the design framework are provided through a web-based portal system, while the computation is taken care of by a supercomputing facility. In addition to the software development, educational contents are developed for lectures associated with design optimization in aerospace and mechanical engineering education programs. The software and content developed in this study is expected to be used as a tool for e-learning material, for education and research in universities.
Static Aeroelastic Response of Wing-Structures Accounting for In-Plane Cross-Section Deformation
Varello, Alberto ; Lamberti, Alessandro ; Carrera, Erasmo ;
International Journal of Aeronautical and Space Sciences, volume 14, issue 4, 2013, Pages 310~323
DOI : 10.5139/IJASS.2013.14.4.310
In this paper, the aeroelastic static response of flexible wings with arbitrary cross-section geometry via a coupled CUF-XFLR5 approach is presented. Refined structural one-dimensional (1D) models, with a variable order of expansion for the displacement field, are developed on the basis of the Carrera Unified Formulation (CUF), taking into account cross-sectional deformability. A three-dimensional (3D) Panel Method is employed for the aerodynamic analysis, providing more accuracy with respect to the Vortex Lattice Method (VLM). A straight wing with an airfoil cross-section is modeled as a clamped beam, by means of the finite element method (FEM). Numerical results present the variation of wing aerodynamic parameters, and the equilibrium aeroelastic response is evaluated in terms of displacements and in-plane cross-section deformation. Aeroelastic coupled analyses are based on an iterative procedure, as well as a linear coupling approach for different free stream velocities. A convergent trend of displacements and aerodynamic coefficients is achieved as the structural model accuracy increases. Comparisons with 3D finite element solutions prove that an accurate description of the in-plane cross-section deformation is provided by the proposed 1D CUF model, through a significant reduction in computational cost.
Elite-initial population for efficient topology optimization using multi-objective genetic algorithms
Shin, Hyunjin ; Todoroki, Akira ; Hirano, Yoshiyasu ;
International Journal of Aeronautical and Space Sciences, volume 14, issue 4, 2013, Pages 324~333
DOI : 10.5139/IJASS.2013.14.4.324
The purpose of this paper is to improve the efficiency of multi-objective topology optimization using a genetic algorithm (GA) with bar-system representation. We proposed a new GA using an elite initial population obtained from a Solid Isotropic Material with Penalization (SIMP) using a weighted sum method. SIMP with a weighted sum method is one of the most established methods using sensitivity analysis. Although the implementation of the SIMP method is straightforward and computationally effective, it may be difficult to find a complete Pareto-optimal set in a multi-objective optimization problem. In this study, to build a more convergent and diverse global Pareto-optimal set and reduce the GA computational cost, some individuals, with similar topology to the local optimum solution obtained from the SIMP using the weighted sum method, were introduced for the initial population of the GA. The proposed method was applied to a structural topology optimization example and the results of the proposed method were compared with those of the traditional method using standard random initialization for the initial population of the GA.
Warping thermal deformation constraint for optimization of a blade stiffened composite panel using GA
Todoroki, Akira ; Ozawa, Takumi ;
International Journal of Aeronautical and Space Sciences, volume 14, issue 4, 2013, Pages 334~340
DOI : 10.5139/IJASS.2013.14.4.334
This paper deals with the optimization of blade stiffened composite panels. The main objective of the research is to make response surfaces for the constraints. The response surface for warping thermal deformation was previously made for a fixed dimension composite structure. In this study, the dimensions of the blade stiffener were treated as design variables. This meant that a new response surface technique was required for the constraints. For the response surfaces, the lamination parameters, linear thermal expansions and dimensions of the structures were used as variables. A genetic algorithm was adopted as an optimizer, and an optimal result, which satisfied two constraints, was obtained. As a result, a new response surface was obtained, for predicting warping thermal deformation.
Particle Swarm Assisted Genetic Algorithm for the Optimal Design of Flexbeam Sections
Dhadwal, Manoj Kumar ; Lim, Kyu Baek ; Jung, Sung Nam ; Kim, Tae Joo ;
International Journal of Aeronautical and Space Sciences, volume 14, issue 4, 2013, Pages 341~349
DOI : 10.5139/IJASS.2013.14.4.341
This paper considers the optimum design of flexbeam cross-sections for a full-scale bearingless helicopter rotor, using an efficient hybrid optimization algorithm based on particle swarm optimization, and an improved genetic algorithm, with an effective constraint handling scheme for constrained nonlinear optimization. The basic operators of the genetic algorithm, of crossover and mutation, are revisited, and a new rank-based multi-parent crossover operator is utilized. The rank-based crossover operator simultaneously enhances both the local, and the global exploration. The benchmark results demonstrate remarkable improvements, in terms of efficiency and robustness, as compared to other state-of-the-art algorithms. The developed algorithm is adopted for two baseline flexbeam section designs, and optimum cross-section configurations are obtained with less function evaluations, and less computation time.
Fatigue damage detection of CFRP using the electrical resistance change method
Todoroki, Akira ; Mizutani, Yoshihiro ; Suzuki, Yoshiro ; Haruyama, Daichi ;
International Journal of Aeronautical and Space Sciences, volume 14, issue 4, 2013, Pages 350~355
DOI : 10.5139/IJASS.2013.14.4.350
Electrical resistance change measurements were performed, to detect fatigue damage of a quasi-isotropic CFRP and cross-ply CFRP laminates. A four-probe method was used to measure the exact electrical resistance change. A three-probe method was used to measure the electrical contact resistance change, during long cyclic loading. The specimen side surface was observed using a video-microscope to detect damage. The measured electrical resistance changes were compared with the observed damage. The results of this study show that the electrical resistance increase of the quasi-isotropic laminate was caused by a delamination crack between
plies. Matrix cracking caused a small electrical resistance increase of the cross-ply laminate, but the decreased electrical resistance caused by the shear-plastic deformation impedes matrix-cracking detection.
Landing Stability Simulation of a 1/6 Lunar Module with Aluminum Honeycomb Dampers
Pham, Van Lai ; Zhao, Jun ; Goo, Nam Seo ; Lim, Jae Hyuk ; Hwang, Do-Soon ; Park, Jung Sun ;
International Journal of Aeronautical and Space Sciences, volume 14, issue 4, 2013, Pages 356~368
DOI : 10.5139/IJASS.2013.14.4.356
The Korea Aerospace Research Institute plans to launch a lunar module by 2025, and so is carrying out a preliminary study. Landing stability on the lunar surface is a key design factor of a lunar module. In this paper, a 1/6 scale model of a lunar module is investigated, for its landing stability on non-level surfaces. The lunar module has four tripod legs, with aluminum honeycomb shock absorbers in each leg strut. ADAMS
, the most widely used multi-body dynamics and motion analysis software, is used to simulate the module's lunar landing. Three types of dampers in the struts (rigid, viscous, and aluminum honeycomb dampers), and two types of lunar surfaces (rigid and elastic) are considered. The Sforce function is adopted, to model the aluminum honeycomb dampers. Details on the modeling and analysis of the landing stability of the 1/6 scale lunar module and the simulation results are provided in this paper.
Integrated Navigation Design Using a Gimbaled Vision/LiDAR System with an Approximate Ground Description Model
Yun, Sukchang ; Lee, Young Jae ; Kim, Chang Joo ; Sung, Sangkyung ;
International Journal of Aeronautical and Space Sciences, volume 14, issue 4, 2013, Pages 369~378
DOI : 10.5139/IJASS.2013.14.4.369
This paper presents a vision/LiDAR integrated navigation system that provides accurate relative navigation performance on a general ground surface, in GNSS-denied environments. The considered ground surface during flight is approximated as a piecewise continuous model, with flat and slope surface profiles. In its implementation, the presented system consists of a strapdown IMU, and an aided sensor block, consisting of a vision sensor and a LiDAR on a stabilized gimbal platform. Thus, two-dimensional optical flow vectors from the vision sensor, and range information from LiDAR to ground are used to overcome the performance limit of the tactical grade inertial navigation solution without GNSS signal. In filter realization, the INS error model is employed, with measurement vectors containing two-dimensional velocity errors, and one differenced altitude in the navigation frame. In computing the altitude difference, the ground slope angle is estimated in a novel way, through two bisectional LiDAR signals, with a practical assumption representing a general ground profile. Finally, the overall integrated system is implemented, based on the extended Kalman filter framework, and the performance is demonstrated through a simulation study, with an aircraft flight trajectory scenario.
Imperfection Parameter Observer and Drift Compensation Controller Design of Hemispherical Resonator Gyros
Pi, Jaehwan ; Bang, Hyochoong ;
International Journal of Aeronautical and Space Sciences, volume 14, issue 4, 2013, Pages 379~386
DOI : 10.5139/IJASS.2013.14.4.379
The hemispherical resonator gyroscope is a type of vibratory gyroscope, which can measure angle or angular rate, based on its operating mode. This paper deals with the case when the hemispherical resonator gyroscope is operated in angle measurement mode. In angle measurement mode, the resonator pattern angle precesses, with respect to the external rotation input, by the principle of the Coriolis effect, so that the external rotation can be estimated, by measuring the amount of precession angle. However, this pattern angle drifts, due to the manufacturing error of the resonator. Since the drift effect causes degradation of the angle estimation performance of the resonator, the corresponding drift compensation control should be performed, to enhance the estimation performance. In this paper, a mathematical model of the hemispherical resonator gyro is first introduced. By using the mathematical model, a nonlinear observer for imperfection parameter estimation, and the corresponding compensation controller are designed to operate hemispherical resonator gyros, as angle measurement sensors.
On the Assessment of Compressibility Effects of Two-Equation Turbulence Models for Supersonic Transition Flow with Flow Separation
Sung, Hong-Gye ; Kim, Seong-Jin ; Yeom, Hyo-Won ; Heo, Jun-Young ;
International Journal of Aeronautical and Space Sciences, volume 14, issue 4, 2013, Pages 387~397
DOI : 10.5139/IJASS.2013.14.4.387
An assessment of two-equation turbulence models, the low Reynolds k-
SST models, with the compressibility corrections proposed by Sarkar and Wilcox, has been performed. The compressibility models are evaluated by investigating transonic or supersonic flows, including the arc-bump, transonic diffuser, supersonic jet impingement, and unsteady supersonic diffuser. A unified implicit finite volume scheme, consisting of mass, momentum, and energy conservation equations, is used, and the results are compared with experimental data. The model accuracy is found to depend strongly on the flow separation behavior. An MPI (Message Passing Interface) parallel computing scheme is implemented.
Dense Spray Patternation using Optical Tomography
Cho, Seongho ; Park, Gujeong ; Yoon, Youngbin ;
International Journal of Aeronautical and Space Sciences, volume 14, issue 4, 2013, Pages 398~407
DOI : 10.5139/IJASS.2013.14.4.398
Optical tomography was used to measure the pattern of spray cross-section. The maximum-likelihood estimation (MLE) algorithm was used to reconstruct the spray cross-section from the measured transmission rate of the spray. A swirl-type injector was used to form an optically dense spray, and the test was carried out in a high-pressure chamber, to control the pressure condition of the test site. Before the experiment, the reliability of the MLE-based reconstruction algorithm was verified, by comparing it with a conventional filtered back projection reconstruction (FBP) method. The MLE algorithm showed superior reconstruction of the image. In the spray patternation experiment, the results of the optical tomography and optical line patternator, which uses Mie scattering signal information, were compared. While measuring the cross-section of optically dense spray, the intensity of the scattering signal had attenuated to an uncorrectable level, which led to incorrect spray pattern measurement by the optical line patternator. However, reliable results were obtained by optical tomography, under the same condition. Finally, the pattern of the optically dense spray was measured at various chamber pressures, of up to 3 MPa. As the chamber pressure increased, the hollow cone-shaped swirl spray shrank, and the attenuation coefficient value of the inner region increased.