• Title/Summary/Keyword: topological optimization

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The Optimized Design Method of Vehicle for Weight-Reduction (무게절감을 위한 차량 최적 설계 기법)

  • Lee, Jeong-Ick
    • Korean Journal of Computational Design and Engineering
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    • v.12 no.5
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    • pp.376-381
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    • 2007
  • The geometric configuration in the weight-reduced structure is very required to be started from the conceptual design with low cost, high performance and quality. In this point, a structural-topological shape concerned with conceptual design of structure is important. The method used in this paper combines three optimization techniques, where the shape and physical dimensions of the structure and material distribution are hierachically optimized, with the maximum rigidity of structure and lightweight.

Evolutionary Approach for Traveling Salesperson Problem with Precedence Constraints

  • Moon, Chi-Ung;Yun, Young-Su
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2007.04a
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    • pp.305-308
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    • 2007
  • In this paper we suggest an efficient evolutionary approach based on topological sort techniques for precedence constrained TSPs. The determination of optimal sequence has much to offer to downstream project management and opens up new opportunities for supply chains and logistics. Experimental results show that the suggested approach is a good alternative to locate optimal solution for complicated precedence constrained sequencing as in optimization method for instance.

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A Hybrid ON/OFF Method for Fast Solution of Electromagnetic Inverse Problems Based on Topological Sensitivity

  • Kim, Dong-Hun;Byun, Jin-Kyu
    • Journal of Magnetics
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    • v.16 no.3
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    • pp.240-245
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    • 2011
  • A new hybrid ON/OFF method is presented for the fast solution of electromagnetic inverse problems in high frequency domains. The proposed method utilizes both topological sensitivity (TS) and material sensitivity (MS) to update material properties in unit design cells. MS provides smooth design space and stable convergence, while TS enables sudden changes of material distribution when MS slows down. This combination of two sensitivities enables a reduction in total computation time. The TS and MS analyses are based on a variational approach and an adjoint variable method (AVM), which permits direct calculation of both sensitivity values from field solutions of the primary and adjoint systems. Investigation of the formulations of TS and MS reveals that they have similar forms, and implementation of the hybrid ON/OFF method that uses both sensitivities can be achieved by one optimization module. The proposed method is applied to dielectric material reconstruction problems, and the results show the feasibility and effectiveness of the method.

Level Set Based Topological Shape Optimization Combined with Meshfree Method (레벨셋과 무요소법을 결합한 위상 및 형상 최적설계)

  • Ahn, Seung-Ho;Ha, Seung-Hyun;Cho, Seonho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.1
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    • pp.1-8
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    • 2014
  • Using the level set and the meshfree methods, we develop a topological shape optimization method applied to linear elasticity problems. Design gradients are computed using an efficient adjoint design sensitivity analysis(DSA) method. The boundaries are represented by an implicit moving boundary(IMB) embedded in the level set function obtainable from the "Hamilton-Jacobi type" equation with the "Up-wind scheme". Then, using the implicit function, explicit boundaries are generated to obtain the response and sensitivity of the structures. Global nodal shape function derived on a basis of the reproducing kernel(RK) method is employed to discretize the displacement field in the governing continuum equation. Thus, the material points can be located everywhere in the continuum domain, which enables to generate the explicit boundaries and leads to a precise design result. The developed method defines a Lagrangian functional for the constrained optimization. It minimizes the compliance, satisfying the constraint of allowable volume through the variations of boundary. During the optimization, the velocity to integrate the Hamilton-Jacobi equation is obtained from the optimality condition for the Lagrangian functional. Compared with the conventional shape optimization method, the developed one can easily represent the topological shape variations.

Weight Reduction Design and the Applications (하중 감량 설계와 적용)

  • Lee, Jeong-Ick
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.3
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    • pp.8-14
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    • 2007
  • The geometry in the weight reduction design is very required to be started from the conceptual design with low cost, high performance and quality. In this point, a topological shape fur optimization concerned with conceptual design of structure is important. The method used in this paper combines three optimization techniques, where the shape and physical dimensions of the structure and material distribution are hierachically optimized, with the maximum rigidity of structure and lightweight. As the applications, the technology of weight reduction design is applied on designs of aluminum control arm and inner panel of hood.

Shape Optimization of Energy Flow Problems Using Level Set Method (레벨 셋 기법을 이용한 에너지 흐름 문제의 형상 최적화)

  • Seung-Hyun, Ha;Seonho, Cho
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2004.10a
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    • pp.411-418
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    • 2004
  • Using a level set method we develop a shape optimization method applied to energy flow problems in steady state. The boundaries are implicitly represented by the level set function obtainable from the 'Hamilton-Jacobi type' equation with the 'Up-wind scheme.' The developed method defines a Lagrangian function for the constrained optimization. It minimizes a generalized compliance, satisfying the constraint of allowable volume through the variations of implicit boundary. During the optimization, the boundary velocity to integrate the Hamilton-Jacobi equation is obtained from the optimality condition for the Lagrangian function. Compared with the established topology optimization method, the developed one has no numerical instability such as checkerboard problems and easy representation of topological shape variations.

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Shape Optimization of Electromagnetic System using Level Set Method (전자기 시스템에서 Level Set Method를 이용한 최적화)

  • Kim, Young-Sun;Choi, Hong-Soon;Park, Il-Han;Lee, Ki-Sik
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.623-624
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    • 2008
  • We present a level set method for numerical shape optimization of electromagnetic systems. The level set method does not only lead to efficient computational schemes, but also is able to handle topological changes such as merging, splitting and even disappearing of connected components. The velocity field on boundaries is obtained by a shape derivative of continuum sensitivity analysis using the material derivative concept and an adjoint variable technique. Two numerical results of dielectric optimization between electrodes showed that the level set method is feasible and effective in solving shape optimization problems of electromagnetic systems.

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Level Set based Optimization of Electromagnetic System using Multi-Material (Level Set Method를 이용한 전자기 시스템의 다물질 최적설계)

  • Lee, Jang-Won;Shim, Ho-Kyung;Lee, Heon;Wang, Se-Myung
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.653-654
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    • 2008
  • This paper presents a topological shape optimization for electromagnetic system using a level set method. The optimization is progressed by updating the implicit level set function from the Hamilton-Jacobi equation. The up-wind scheme is used for numerical implementation of the Hamilton-Jacobi equation. In order to validate the proposed optimization, the core part of a C-core actuator is optimized by three cases using different materials; (single steel), (two steels), and (steel and magnet).

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The Examples of Weight Reduction Design-(2) (Weight Reduction Design의 선례-(2))

  • Lee, Jeong-Ick
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.6
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    • pp.97-104
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    • 2006
  • The geometric configuration in the weight reduction designis very required to be started from the conceptual design with low cost, high performance and quality. In this point, a structural-topological shape concerned with conceptual design of structure is important. The method used in this paper combines three optimization techniques, where the shape and physical dimensions of the structure and material distribution are hierachically optimized, with the maximum rigidity of structure and lightweight. As the results, the technology of weight reduction design is considered in designs of aluminum control arm and inner panel of door.

Application of the Parallelized Topology Optimization for the Dynamic Characteristics Improvement of a DVD Pickup Bobbin (DVD 픽업보빈의 동특성 개선을 위한 병렬위상 최적설계법 응용)

  • 김태수;김재은;김윤영
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.365-367
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    • 2002
  • A parallelized topology optimization is applied to the design of a DVD-pickup bobbin, for which the design objective is to maximize the fundamental frequency within a given mass limit. Unlike the existing serial topology optimization, the present method can deal with a large number of design variables, and thus can yield practical and realistic results. The structural member-sizing filter is also employed to control the topological complexity of the optimized bobbin structure.

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