• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.7
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• pp.716-726
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• 2010

In this research, design optimization of an aircraft wing has been performed using the fully automated Multidisciplinary Design Optimization (MDO) framework, which integrates aerodynamic and structural analysis considering nonlinear structural behavior. A computational fluid dynamics (CFD) mesh is generated automatically from parametric modeling using CATIA and Gambit, followed by an automatic flow analysis using FLUENT. A computational structure mechanics (CSM) mesh is generated automatically by the parametric method of the CATIA and visual basic script of NASTRAN-FX. The structure is analyzed by ABAQUS. Interaction between CFD and CSM is performed by a fully automated system. The Response Surface Method (RSM) is applied for optimization, helping to achieve the global optimum. The optimization design result demonstrates successful application of the fully automated MDO framework.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.6
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• pp.23-33
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• 2004

MDO framework, which provides multidisciplinary system design and optimization environment, requires integration of the analyses codes developed at various computer languages and operating systems, integration of CAD and DBMS, and development of complex GUI. Emphases must be given to the software modification and upgrades in conjunction with the analysis code addition and MDO method implementation. In this study, techniques about system integration and analysis code interface have been studied extensively, and the database design and communication methods which can handle the MDO methods like MDF and CO have been studied. Using the dedicated MDO framework developed for the air vehicle design, the multidisciplinary fighter aircraft wing design has been performed to demonstrate the efficiency and usefulness of the software. Optimum wing configuration is derived using the gradient-based optimization methods within thirty design iterations.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.210-218
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• 2003

MDO (multidisciplinary design optimization) technology has been proposed and applied to solve large and complex optimization problems where multiple disciplinaries are involved. In this research. an MDO problem is defined for automobile design which has crashworthiness analyses. Crash model which are consisted of airbag, belt integrated seat (BIS), energy absorbing steering system .and safety belt is selected as a practical example for MDO application to vehicle system. Through disciplinary analysis, vehicle system is decomposed into structure subspace and occupant subspace, and coupling variables are identified. Before subspace optimization, values of coupling variables at given design point must be determined with system analysis. The system analysis in MDO is very important in that the coupling between disciplines can be temporary disconnected through the system analysis. As a result of system analysis, subspace optimizations are independently conducted. However, in vehicle crash, system analysis methods such as Newton method and fixed-point iteration can not be applied to one. Therefore, new system analysis algorithm is developed to apply to crashworthiness. It is conducted for system analysis to determine values of coupling variables. MDO algorithm which is applied to vehicle crash is MDOIS (Multidisciplinary Design Optimization Based on Independent Subspaces). Then, structure and occupant subspaces are independently optimized by using MDOIS.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.2
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• pp.109-117
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• 2004

Optimization has been successfully applied to systems with a single discipline. As many disciplines are involved in coupled fashion, MDO (multidisciplinary design optimization) technology has been developed. MDO algorithms are trying to solve the coupled aspects generated from interdisciplinary relationship. In a general MDO algorithms, a large design problem is decomposed into small ones which can be easily solved. Although various methods have been proposed for MDO, the research is still in the early stage. This research proposes a new MDO method which is named as MDOIS (Multidisciplinary Design Optimization Based on Independent Subspaces). Many real engineering problems consist of physically separate components and they can be independently designed. The inter-relationship occurs through coupled physics. MDOIS is developed for such problems. In MDOIS, a large system is decomposed into small subsystems. The coupled aspects are solved via system analysis which solves the coupled physics. The algorithm is mathematically validated by showing that the solution satisfies the Karush-Kuhn-Tucker condition.

• The KSFM Journal of Fluid Machinery
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• v.12 no.5
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• pp.72-78
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• 2009

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.380-385
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• 2001

The paper presents a new multidisciplinary design optimization architecture using optimal sensitivity and coordination of interdisciplinary design variables. Original design problem is decomposed into a number of sub-problems that represent individual engineering analysis. The coupled effects between sub-problems are computed by interdisciplinary design variables. System level coordination is determined by optimal parameter sensitivity calculated by finite difference method. The proposed. MDO strategy is applied to a simplified model of rotorcraft blade design associated with structures and aerodynamic disciplines.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.209-217
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• 2002

This gaper discusses a multidisciplinary design optimization of the engine mounting system to improve the ride quality of a vehicle and to remove the possibility of the resonance between the powertrain system and vehicle systems. The driveline model attempts to support engine mount development by providing sufficient detail for design modification assessment in a modeling environment. Design variables used in this study are the locations, the angles and the stiffness of an engine mount system. The goal of the optimization is both decoupling the roll mode ova powertrain and minimizing the vibration transmitted to the vehicle including the powertrain, simultaneously. By applying forced vibration analysis for vehicle systems and mode decouple analysis for the engine mount system, it is shown that improved optimization result is obtained.

• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.187-190
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• 2005

In this study, the reliablility based design optimization is peformed for an aircraft wing. The flexiblility of the wing was assumed by considering the interaction modeled by static aeroelasticity between aerodynamic forces and the structure. For a multidisciplinary design optimization the results of aerodynamic analysis and structural analysis were included in the optimization formulation. The First Order Reliability Method(FORM) was employed to consider the uncertainty of the designed points.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.429-432
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• 2004

Multidisciplinary design optimization technique is applied to drum type washer in order to minimize the vibration of the cabinet. Dynamic analysis and structural analysis are carried out by using commercial programs to obtain the reliable responses. Analysis models are compared to the experimental responses and finally validated for further design. Two commercial programs are integrated by the design framework EMDIOS that provides interfaces to conveniently link between analyzers and performs design optimization. In this research we could obtain an optimum design that reduces the magnitude of amplitude by about 33% compared with the original design.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.12
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• pp.1150-1156
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• 2007

Multidisciplinary design optimization methodologies play an essential role in modern engineering design which involves many inter-related disciplines. These methodologies usually require very long computing time and design tasks are hard to finish within a specified design cycle time. Parallel processing can be effectively utilized to reduce the computing time. The research on the parallel computing performance of MDO methodologies has been just begun and developing. This study investigates performances of MDF, IDF, SAND and CO among MDO methodologies in view of parallel computing. Finally, the best out of four methodologies is suggested for parallel processing purpose.