• Title, Summary, Keyword: Topology Optimization

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CAD Interface using Topology Optimization (위상최적설계 결과를 이용한 CAD 인터페이스)

  • Kim, Seong-Hoon;Min, Seung-Jae;Lee, Sang-Hun
    • Korean Journal of Computational Design and Engineering
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    • v.14 no.4
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    • pp.281-289
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    • 2009
  • Topology optimization has been widely used for the optimal structure design for weight reduction and high performance. Since the result of three-dimensional topology optimization is represented by the discrete material distribution in finite elements, it is hard to interpret from a design point of view. In this paper, the method for interpreting three-dimensional topology optimization resuIt into a series of cross-sectional curve representation is proposed and interfaced with the existing CAD system for the practical use. The concept of node density and virtual grid is introduced to transform element density values into grid density and material boundaries in each cross section are identified based on the element volume rate to satisfy the amount of material specified in the original design intent. Design exampIes show that three-dimensional topology result can be converted into a form of curve CAD model and the seamless interface with CAD software can be achieved.

Optimal Design of Dielectric shape and Topology using Smooth Boundary Topology Optimization Method (부드러운 경계 위상 최적설계기법을 이용한 유전체 형상 및 위상 최적설계)

  • Jeung, Gi-Woo;Choi, Nak-Sun;Kim, Nam-Kyung;Kim, Dong-Hun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.10
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    • pp.1936-1941
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    • 2009
  • This paper deals with a new methodology for topology optimization in which the topology of the design domain may change during the shape optimization process. To achieve this, the concept of the topological gradient is introduced to compute the sensitivity of an objective function when a small hole is drilled in the domain. Based on shape and topological sensitivity values, the shape and topology of the design domain may be simultaneously changed during design iterations if necessary. To verify the advantages and also to facilitate understanding of the method itself, two electrostatic design problems have been tested by using 2D finite element analysis: the first is the inverse problem of a simple dielectric model and the second is the rotor design of a MEMS actuator.

Reliability-Based Topology Optimization Based on Bidirectional Evolutionary Structural Optimization (양방향 진화적 구조최적화를 이용한 신뢰성기반 위상최적화)

  • Yu, Jin-Shik;Kim, Sang-Rak;Park, Jae-Yong;Han, Seog-Young
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.19 no.4
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    • pp.529-538
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    • 2010
  • This paper presents a reliability-based topology optimization (RBTO) based on bidirectional evolutionary structural optimization (BESO). In design of a structure, uncertain conditions such as material property, operational load and dimensional variation should be considered. Deterministic topology optimization (DTO) is performed without considering the uncertainties related to the design variables. However, the RBTO can consider the uncertainty variables because it can deal with the probabilistic constraints. The reliability index approach (RIA) and the performance measure approach (PMA) are adopted to evaluate the probabilistic constraints in this study. In order to apply the BESO to the RBTO, sensitivity number for each element is defined as the change in the reliability index of the structure due to removal of each element. Smoothing scheme is also used to eliminate checkerboard patterns in topology optimization. The limit state indicates the margin of safety between the resistance (constraints) and the load of structures. The limit State function expresses to evaluate reliability index from finite element analysis. Numerical examples are presented to compare each optimal topology obtained from RBTO and DTO each other. It is verified that the RBTO based on BESO can be effectively performed from the results.

Topology Optimization of a Vehicle's Hood Considering Static Stiffness (자동차 후드의 정강성을 고려한 위상 최적화)

  • Han, Seog-Young;Choi, Sang-Hyuk;Park, Jae-Yong;Hwang, Joon-Seong;Kim, Min-Sue
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.1
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    • pp.69-74
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    • 2007
  • Topology optimization of the inner reinforcement for a vehicle's hood has been performed by evolutionary structural optimization(ESO) using a smoothing scheme. The purpose of this study is to obtain optimal topology of the inner reinforcement for a vehicle's hood considering the static stiffness of bending and torsion simultaneously. To do this, the multiobjective optimization technique was implemented. Optimal topologies were obtained by the ESO method. From several combinations of weighting factors, a Pareto-optimal solution was obtained. Also, a smoothing scheme was implemented to suppress the checkerboard pattern in the procedure of topology optimization. It is concluded that ESO method with a smoothing scheme is effectively applied to topology optimization of the inner reinforcement of a vehicle's hood considering the static stiffness of bending and torsion.

Development of a Material Mixing Method for Topology Optimization of PCB Substrate (PCB판의 위상 최적화를 위한 재료혼합법의 개발)

  • Han, Seog-Young;Kim, Min-Sue;Hwang, Joon-Sung;Choi, Sang-Hyuk;Park, Jae-Yong;Lee, Byung-Ju
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.1
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    • pp.47-52
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    • 2007
  • A material mixing method to obtain an optimal topology for a structure in a thermal environment was suggested. This method is based on Evolutionary Structural Optimization(ESO). The proposed material mixing method extends the ESO method to a mixing several materials for a structure in the multicriteria optimization of thermal flux and thermal stress. To do this, the multiobjective optimization technique was implemented. The overall efficiency of material usage was measured in terms of the combination of thermal stress levels and heat flux densities by using a combination strategy with weighting factors. Also, a smoothing scheme was implemented to suppress the checkerboard pattern in the procedure of topology optimization. It is concluded that ESO method with a smoothing scheme is effectively applied to topology optimization. Optimal topologies having multiple thermal criteria for a printed circuit board(PCB) substrate were presented to illustrate validity of the suggested material mixing method. It was found that the suggested method works very well for the multicriteria topology optimization.

Topological optimized design considering dynamic problem with non-stochastic structural uncertainty

  • Lee, Dong-Kyu;Starossek, Uwe;Shin, Soo-Mi
    • Structural Engineering and Mechanics
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    • v.36 no.1
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    • pp.79-94
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    • 2010
  • This study shows how uncertainties of data like material properties quantitatively have an influence on structural topology optimization results for dynamic problems, here such as both optimal topology and shape. In general, the data uncertainties may result in uncertainties of structural behaviors like deflection or stress in structural analyses. Therefore optimization solutions naturally depend on the uncertainties in structural behaviors, since structural behaviors estimated by the structural analysis method like FEM need to execute optimization procedures. In order to quantitatively estimate the effect of data uncertainties on topology optimization solutions of dynamic problems, a so-called interval analysis is utilized in this study, and it is a well-known non-stochastic approach for uncertainty estimate. Topology optimization is realized by using a typical SIMP method, and for dynamic problems the optimization seeks to maximize the first-order eigenfrequency subject to a given material limit like a volume. Numerical applications topologically optimizing dynamic wall structures with varied supports are studied to verify the non-stochastic interval analysis is also suitable to estimate topology optimization results with dynamic problems.

Topology Optimization of Electromagnetic Systems with Two Materials (전자기 시스템에서 두 가지 물성치를 고려한 위상최적설계 기법)

  • Kang, Je-Nam;Wang, Se-Myung
    • Proceedings of the KIEE Conference
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    • pp.726-728
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    • 2002
  • The topology optimization of electromagnetic systems with two materials is investigated using the FEM. The design sensitivity equation for topology optimization is derived using the adjoint variable method and the continuum approach. The proposed method is applied to the topology optimization of C-core and compared to previous study with one material.

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Multi-domain Topology Optimization of Electromagnetic Systems (전자기 시스템 다영역 위상최적설계)

  • Wang, Se-Myung;Park, Seung-Kyu;Kang, Je-Nam
    • Proceedings of the KIEE Conference
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    • pp.705-707
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    • 2003
  • The design of multi-domain that considers all components of the electromagnetic systems such as air, iron, magnet, and coil is investigated using the topology optimization, interpolation method, and FEM. The design sensitivity equation for the topology optimization is derived using the adjoint variable method and the continuum approach. The proposed method is applied to the topology optimization of C-core actuator.

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Comparative Study on Reliability-Based Topology Optimization (신뢰성 기반 위상최적화에 대한 비교 연구)

  • Cho, Kang-Hee;Hwang, Seung-Min;Park, Jae-Yong;Han, Seog-Young
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.20 no.4
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    • pp.412-418
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    • 2011
  • Reliability-based Topology optimization(RBTO) is to get an optimal design satisfying uncertainties of design variables. Although RBTO based on homogenization and density distribution method has been done, RBTO based on BESO has not been reported yet. This study presents a reliability-based topology optimization(RBTO) using bi-directional evolutionary structural optimization(BESO). Topology optimization is formulated as volume minimization problem with probabilistic displacement constraint. Young's modulus, external load and thickness are considered as uncertain variables. In order to compute reliability index, four methods, i.e., RIA, PMA, SLSV and ADL(adaptive-loop), are used. Reliability-based topology optimization design process is conducted to obtain optimal topology satisfying allowable displacement and target reliability index with the above four methods, and then each result is compared with respect to numerical stability and computing time. The results of this study show that the RBTO based on BESO using the four methods can effectively be applied for topology optimization. And it was confirmed that DLSV and ADL had better numerical efficiency than SLSV. ADL and SLSV had better time cost than DLSV. Consequently, ADL method showed the best time efficiency and good numerical stability.