• Title, Summary, Keyword: Shape optimization

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Shape Design Optimization Using Isogeometric Analysis (등기하 해석법을 이용한 형상 최적설계)

  • Ha, Seung-Hyun;Cho, Seon-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.21 no.3
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    • pp.233-238
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    • 2008
  • In this paper, a shape design optimization method for linearly elastic problems is developed using isogeometric approach. In many design optimization problems for practical engineering models, initial raw data usually come from a CAD modeler. Then, designers should convert the CAD data into finite element mesh data since most of conventional design optimization tools are based on finite element analysis. During this conversion, there are some numerical errors due to geometric approximation, which causes accuracy problems in response as well as design sensitivity analyses. As a remedy for this phenomenon, the isogeometric analysis method can be one of the promising approaches for the shape design optimization. The main idea of isogeometric approach is that the basis functions used in analysis is exactly the same as the ones representing the geometry. This geometrically exact model can be used in the shape sensitivity analysis and design optimization as well. Therefore the shape design sensitivity with high accuracy can be obtained, which is very essential for a gradient-based optimization. Through numerical examples, it is verified that the shape design optimization based on an isogeometic approach works well.

Lightweight Crane Design by Using Topology and Shape Optimization (위상최적설계와 형상최적설계를 이용한 크레인의 경량설계)

  • Kim, Young-Chul;Hong, Jung-Kie;Jang, Gang-Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.7
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    • pp.821-826
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    • 2011
  • CAE-based structural optimization techniques are applied for the design of a lightweight crane. The boom of the crane is designed by shape optimization with the shape of the cross section of the boom as the design variable. The design objective is mass minimization, and the static strength and dynamic stiffness of the system are set as the design constraints. Hyperworks, a commercial analysis and optimization software, is used for shape and topology optimization. In order to consistently change the shape of the elements of the boom with respect to the change in the shape of its cross section, the morphing function in Hyperworks is used. The support of the boom of the original model is simplified to model the design domain for topology optimization, which is discretized by using three-dimensional solid elements. The final result after shape and topology optimization is 19% and 17% reduction in the masses of the boom and support, respectively, without a deterioration in the system stiffness.

Study of the Shape Optimization in Spline FEM Considering both NURBS Control Point Positions and Weights as Design Variables (NURBS 제어점의 위치 및 가중치를 설계변수로 하는 스플라인 유한요소법 기반 형상최적설계 연구)

  • Song, Yeo-Ul;Hur, Jun Young;Youn, Sung-Kie
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.4
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    • pp.363-370
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    • 2014
  • A new NURBS-based shape optimization method is proposed. Most shape optimization studies consider only control point positions as design variables. Some shape optimization processes present problems with mesh quality and convergence when control points are constrained to a limited space. If the weights of the control points are regarded as additional design variables, it should be possible to attain a better degree of shape control. In this study, positions and weights of NURBS control points are used as design variables, and a shape optimization algorithm incorporates position optimization and weight optimization steps. This method is applied to shape optimization benchmarking problems to verify its advantages.

Shape Optimization of a Thomson Coil Actuator for Fast Response Using Topology Modification

  • Li, Wei;Koh, Chang-Seop
    • Journal of Electrical Engineering and Technology
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    • v.7 no.1
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    • pp.58-63
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    • 2012
  • The shape optimization of a Thomson coil actuator used in an arc eliminator is done for fast response by adopting topology modification method. The displacement of the plate in a fixed calculation time is taken as the objective function. The objective function and contribution factor are calculated by using an adaptive equivalent circuit method which has been proved accurate and efficient. Both shape optimization and performance analysis are accomplished based on the segmentation of plate. Through the refinement of the sensitive segments a precise optimal plate shape can be obtained. The effectiveness of the proposed method is proved by the comparison of results before and after the shape optimization.

Aerodynamic Shape Optimization of the Impulse Turbine using Numerical Analysis (수치해석을 이용한 충동형 터빈의 공력형상 최적화)

  • Lee E. S.;Seol W. S.
    • 한국전산유체공학회:학술대회논문집
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    • pp.191-196
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    • 2005
  • For the improvement of aerodynamic performance of the turbine blade in a turbopump for the liquid rocket engine, the optimization of turbine profile shape has been studied. The turbine in a turbopump in this study is a partial admission of impulse type, which has twelve nozzles and supersonic inflow. Due to the separated nozzles and supersonic expansion, the flow field becomes complicates and shows oblique shocks and flow separation. To increase the blade power, redesign of the blade shape using CFD and optimization method was attempted. The turbine cascade shape was represented by four design parameters. For optimization, genetic algorithm based upon non-gradient search has been selected as a optimizer. As a result, the final blade has about 4 percent more blade power than the initial shape.

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AERODYNAMIC SHAPE OPTIMIZATION OF THE SUPERSONIC IMPULSE TURBINE USING CFD AND GENETIC ALGORITHM (CFD와 유전알고리즘을 이용한 초음속 충동형 터빈의 공력형상 최적화)

  • Lee E.S.
    • Journal of computational fluids engineering
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    • v.10 no.2
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    • pp.54-59
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    • 2005
  • For the improvement of aerodynamic performance of the turbine blade in a turbopump for the liquid rocket engine, the optimization of turbine profile shape has been studied. The turbine in a turbopump in this study is a partial admission of impulse type, which has twelve nozzles and supersonic inflow. Due to the separated nozzles and supersonic expansion, the flow field becomes complicate and shows oblique shocks and flow separation. To increase the blade power, redesign ol the blade shape using CFD and optimization methods was attempted. The turbine cascade shape was represented by four design parameters. For optimization, a genetic algorithm based upon non-gradient search hue been selected as an optimizer. As a result, the final blade has about 4 percent more blade power than the initial shape.

Shape Optimization of a Thomson Coil Actuator for Fast Response Using Topology Modification

  • Li, Wei;Koh, Chang-Seop
    • Journal of Electrical Engineering and Technology
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    • v.7 no.3
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    • pp.330-335
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    • 2012
  • The shape optimization of a Thomson coil actuator used in an arc eliminator is done for fast response by adopting topology modification method. The displacement of the plate in a fixed calculation time is taken as the objective function. The objective function and contribution factor are calculated by using an adaptive equivalent circuit method which has been proved accurate and efficient. Both shape optimization and performance analysis are accomplished based on the segmentation of plate. Through the refinement of the sensitive segments a precise optimal plate shape can be obtained. The effectiveness of the proposed method is proved by the comparison of results before and after the shape optimization.

Shape Optimization for Reinforced Concrete Culvert (철근콘크리트 암거의 형상 최적화)

  • Kim, Kee-Dae
    • Journal of the Korean Society of Industry Convergence
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    • v.5 no.3
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    • pp.261-268
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    • 2002
  • In this paper, the shape optimization is considered over the upper slab of reinforced concrete culvert. The sequential linear programming method (SLP) is used as a rational approach to this shape optimization. To make a comparison between the arch shaped member and the straight member for the upper slab, the culverts with 5~20m earth height were adopted. It is shown that the optimum rise/span is about 7%-13%, and the arch shaped member is more cheap (over 10%) than the straight member for the construction cost.

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Shape Optimization of a Thomson coil Actuator of Arc Eliminator Using Topology Modification (Topology Modification을 이용한 Thomson coil Actuator의 형상 최적화)

  • Li, Wei;Jeong, Young-Woo;Koh, Chang-Seop
    • Proceedings of the KIEE Conference
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    • pp.774_775
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    • 2009
  • The shape optimization of a Thomson coil actuator used in an arc eliminator is done for fast response by adopting topology modification method. The performance of the actuator is analyzed by using an equivalent circuit method. Both shape optimization and performance analysis are accomplished based on the segmentation of plate. The effectiveness of the proposed method is proved by the comparison of results before and after the shape optimization.

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Reliability-Based Shape Optimization Under the Stress Constraints (응력 제한조건하의 신뢰성 기반 형상 최적설계)

  • Oh, Young-Kyu;Park, Jae-Yong;Im, Min-Gyu;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.469-475
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    • 2010
  • The objective of this study is to integrate reliability analysis into shape optimization problem using the evolutionary structural optimization (ESO) in the application example. Reliability-based shape optimization is formulated as volume minimization problem with probabilistic stress constraint under minimization max. von Mises stress and allow stress. Young's modulus, external load and thickness are considered as uncertain variables. In order to compute reliability index, four methods, i.e., reliability index approach (RIA), performance measure approach (PMA), single-loop singlevector (SLSV) and adaptive-loop (ADL), are used. Reliability-based shape optimization design process is conducted to obtain optimal shape satisfying max. von Mises stress and reliability index constraints with the above four methods, and then each result is compared with respect to numerical stability and computing time.