• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.24-29
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• 2013

A spacecraft radiator is a thermal control method to eject internally dissipated heat into the space generated from operation of unit boxes. The efficiency of thermal design may be improved by optimizing radiator design. In this paper, the optimization approach method of node-based radiator design was suggested which is to combine numerical thermal analysis with optimization algorithm. This method has meaning that it can be used practically to implement the spacecraft radiator design regardless of thermal analysis and optimization algorithm software and maintain the same basic concept of an ordinary radiator design approach based on node division of a thermal model. The overall analysis framework with thermal analysis and optimization algorithm would be presented.

• Nuclear Engineering and Technology
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• v.27 no.5
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• pp.803-810
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• 1995

핵연료 부품 설계개선 및 부품설계 최적화와 관련하여 Holddown Spring 설계해석 방법을 조사하고 기존 해석방법을 보완한 개선된 해석방법을 제시하였다. 이 개선된 스프링 해석방법을 이용하여 기존 17$\times$17 국산핵연료의 Holddown Spring 및 직선형 Holddown Spring 특성해석을 시도하여 시험결과와 비교하였다. 이들 해석결과 개선된 해석방법에 의한 스프링 특성의 예측은 시험값에 잘 일치함을 보인다. 또한 최대응력에 기초한 스프링 판 두께 최적화로써 직선형 스프링의 두께에 대한 최적화를 실시하여 그 특성을 검토하였다.

• Composites Research
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• v.23 no.6
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• pp.19-25
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• 2010

This paper describes the optimum design of bolt locations for metal joint parts of railway bogie frame made of glass fiber/epoxy 4-harness satin woven laminate composite and PVC foam core. The optimum design analysis was done by sub-problem approximation method using Ansys Parameter Design Language(APDL). The sub-modeling method was introduced to conduct the detailed recalculation for the only target parts and reduce calculating time. The structural analysis for composite bogie frame was performed according to JIS E 4207. The results showed that the optimum design analysis using sub-modeling method was able to obtain faster and more precise results than that of the entire model by the control of mesh size for the target parts, and the maximum Von-Mises stress has been reduced in comparison with its original dimensions due to the optimum design of bolt locations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.8
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• pp.695-702
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• 2012

In this study, Multi-fidelity analysis is performed to improve the accuracy of analysis result during conceptual design stage. Multidisciplinary Design Optimization(MDO) method is also considered to satisfy the total system requirements. Low-fidelity analysis codes which are based on empirical equations are developed and validated for analyzing the Unmanned Aerial Vehicle(UAV) which have unconventional configurations. Analysis codes consist of initial sizing, aerodynamics, propulsion, mission, weight, performance, and stability modules. Design synthesis program which is composed of those modules is developed. To improve the accuracy of the design method for UAV, Vortex Lattice Method is used for the strategy of MFA. Multi-Disciplinary Feasible(MDF) method is used for MDO technique. To demonstrate the validity of presented method, the optimization results of both methods are compared. According to those results, the presented method is demonstrated to be applicable to improve the accuracy of the analyses during conceptual design stage.

• Journal of Korean Society of Steel Construction
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• v.12 no.1 s.44
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• pp.93-102
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• 2000

Substructuring-based hierarchical approach for design analysis and optimization of structural frames is presented in this study. The conceptual framework of this method is in the hierarchical modeling for design processes as well as structural systems and the methodology combining substructuring analysis and multilevel optimization. Mathematical models for analysis and synthesis are established on the common basis of substructuring systems. Modularized behavioral analysis, design sensitivity analysis and optimization are linked and integrated on the mathematical and structural basis of substructuring. Substructures are coordinated with the active constraints for system level and the weight ratio criteria. Numerical examples for test frames show the validity and effectiveness of the present approach.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.10
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• pp.831-842
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• 2015

An optimization process was developed to improve mixed-flow pump performance. The optimization process was combined with CFX (a computational fluid dynamics (CFD) code) and HEEDS (an optimization code). CFX is a widely used CFD software for turbo machinery, whereas HEEDS, which uses the SHERPA algorithm, is a newly introduced optimization code. HEEDS can use a large number of optimization variables; thus, it is possible to effectively consider interaction effects. In this paper, an impeller model, which is already optimized with design of experiments (DOE), is used as the base model. The optimization process developed in this paper shows an improved design within an acceptable timeframe.

• Journal of the Korea Convergence Society
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• v.12 no.9
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• pp.161-168
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• 2021

As the demand for high speed and high precision increases in the field of machine tool, interest in stiffness and vibration of machine tool is increasing. However, it takes a lot of time to develop a detailed design of machine tool based on experience, and it is difficult to design appropriately. Recently, structural optimization using FEM are increasingly used in machine tool design. But, it is difficult to optimize in consideration of the vibration state of the structure since optimization through stress distribution of a structure is mainly used, In this paper, Static structural analysis, mode analysis, and harmonic analysis using FEM were conducted to optimize the head structure that has the most influence on machining in a 5-axis machine tool. It is proposed a topology optimization analysis method that considers both static stiffness and dynamic stiffness using objective function design.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.11-15
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• 2005

Compared with the conventional ground rocket launching, air-launching has many advantages. However, comprehensive and integrated system design approach is required because the physical geometry of air launch vehicle is quite dependent on the installation limitation of the mother plane. The system design has been performed using two different approaches: the sequential optimization and the multidisciplinary feasible(MDF) optimization method. Analysis modules include mission analysis, staging, propulsion analysis, configuration, weight analysis, aerodynamics analysis and trajectory analysis. MDF optimization shows better result than sequential optimization. As a result of system optimization, a supersonic air launching rocket with total mass of 1244.91 kg, total length of 6.18 m, outer diameter of 0.60 m and the payload mass of 7.5 kg has been successfully designed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.6
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• pp.34-48
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• 2004

In this paper an optimization algorithm is suggested to reduce the huge computation time in the optimum design of large structures, especially in spacecraft structures. It combines the coupled load analysis model using a constrained mode of component mode synthesis and the modal transient analysis. The computer simulation code is developed and evaluated in optimizing spacecraft platforms. The developed algorithm can alleviate the computational load with adequate accuracy. From the optimization of a spacecraft structural member, the characteristics of each structural member can be understood.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.12
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• pp.26-32
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• 2005

Compared with the conventional ground rocket launching, air-launching has many advantages. However, a comprehensive and integrated system design approach is required because the physical geometry of air launch vehicle is quite dependent on the installation limitation of the mother plane. The system design has been performed using two different approaches: the sequential optimization and the multidisciplinary feasible(MDF) optimization method. Analysis modules include mission analysis, staging, propulsion analysis, configuration, weight analysis, aerodynamics analysis and trajectory analysis. MDF optimization shows better results than the sequential optimization. As a result of system optimization, a supersonic air launching rocket with total mass of 1244.91kg, total length of 6.36m, outer diameter of 0.60m and the payload mass of 7.5kg has been successfully designed.