• Title, Summary, Keyword: Shape optimization

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Shape Optimization of a Micro-Static Mixer (마이크로 믹서의 형상 최적화)

  • 한석영;김성훈
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.166-171
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    • 2004
  • In this study, shape optimization of micro-static mixer with a cantilever beam was accomplished for mixing the mixing efficiency by using successive response surface approximations. Variables were chosen as the length of cantilever beam and the angle between horizontal and the cantilever beam. Sequential approximate optimization method was used to deal with both highly nonlinear and non-smooth characteristics of flow field in a micro-static mixer. Shape optimization problem of a micro-static mixer can be divided into a series of simple subproblems. Approximation to solve the subproblems was performed by response surface approximation, which does not require the sensitivity analysis. To verify the reliability of approximated objective function and the accuracy of it, ANOVA analysis and variables selection method were implemented, respectively. It was verified that successive response surface approximation worked very well and the mixing efficiency was improved very much comparing with the initial shape of a micro-static mixer.

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Shape Optimization of Cavitator for a Supercavitating Projectile Underwater (초공동(超空洞) 하의 수중 주행체 캐비테이터 형상최적설계)

  • Choi, Joo-Ho
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.82-85
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    • 2008
  • When a projectile travels at high speed underwater, supercavitating flowarises, in which a huge cavity is generated behind the projectile so that only the nose, i.e., the cavitator, of the projectile is wetted, while the rest of it should be surrounded by the cavity. In that case, the projectile can achieve very high speed due to the reduced drag. Furthermore if the nose of the body is shaped properly, the attendant pressure drag can be maintained at a very low value, so that the overall drag is also reduced dramatically. In this study, shape optimization technique is employed to determine the optimum cavitator shape for minimum drag, given certain operating conditions. Simultaneous optimization technique is proposed for efficient cavitator shape optimization, in which the cavity and cavitator shape are determined in a single optimization routine.

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An Analysis of Femoral Bone Remodeling Using Topology Optimization Method

  • Choi J. B.
    • Journal of Biomedical Engineering Research
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    • v.26 no.6
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    • pp.365-372
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    • 2005
  • Topology optimization method has a great advantage and capability over a conventional shape optimization technique because it optimizes a topology as well as a shape and size of structure. The purpose of the present study, using topology optimization method with an objective function of minimum compliance as a mechanism of bone remodeling, is to examine which shape factors of femur is strongly related with the curvature of femoral shaft. As is expected, the optimized curvature increased definitely with neck angle among the shape factors and showed a similar trend with the measured curvature to neck angle. Therefore, the topology optimization method can be successfully applied in the analysis of bone remodeling phenomenon in the subsequent studies.

Study of Aerodynamic Design Optimization Using Genetic Algorithm (유전 알고리즘을 이용한 공력 형상 최적화 연구)

  • Kim S. W.;Kwon J. H.
    • Journal of computational fluids engineering
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    • v.6 no.3
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    • pp.10-18
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    • 2001
  • Genetic Algorithm(GA) is applied to aerodynamic shape optimization and demonstrated its merits in global searching ability and the independency of differentiability. However, applications of GA are limited due to slow convergence rate, premature termination, and high computing costs. The present aerodynamic designs such as wing shape optimizations using GA have seldom been applied because of high computing costs. This paper has two objects; improvement of the efficiency of GA and application of GA into aerodynamic shape optimization for 2D and 3D wings. The study indicates that GA can be applied to aerodynamic design and its performance is comparable to traditional design methods.

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Evaluation of Efficiency by Applying Different Optimization Method for Axial Compressor (최적화 방법에 따른 축류압축기의 효율평가)

  • Jang, Choon-Man;Abdus, Samad;Kim, Kwang-Yong
    • 유체기계공업학회:학술대회논문집
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    • pp.543-544
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    • 2006
  • Shape optimization of a transonic axial compressor rotor operating at the design flow condition has been performed using three-dimensional Navier-Stokes analysis and three different surrogate models: i.e.., Response Surface Method(RSM), Kriging Method, and Radial Basis Function(RBF). Three design variables of blade sweep, lean and skew are introduced to optimize the three-dimensional stacking line of the rotor blade. The object function of the shape optimization is selected as an adiabatic efficiency. Throughout the shape optimization of the rotor blade, the adiabatic efficiency is increased for the three different surrogate models. Detailed flow characteristics at the optimal blade shape obtained by different optimization method are drawn and discussed.

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Parametric Modeling and Shape Optimization of Offshore Structures

  • Birk, Lothar
    • International Journal of CAD/CAM
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    • v.6 no.1
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    • pp.29-40
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    • 2006
  • The paper presents an optimization system which integrates a parametric design tool, 3D diffraction-radiation analysis and hydrodynamic performance assessment based on short and long term wave statistics. Controlled by formal optimization strategies the system is able to design offshore structure hulls with superior seakeeping qualities. The parametric modeling tool enables the designer to specify the geometric characteristics of the design from displacement over principal dimensions down to local shape properties. The computer generates the hull form and passes it on to the hydrodynamic analysis, which computes response amplitude operators (RAOs) for forces and motions. Combining the RAOs with short and long-term wave statistics provides a realistic assessment of the quality of the design. The optimization algorithm changes selected shape parameters in order to minimize forces and motions, thus increasing availability and safety of the system. Constraints ensure that only feasible designs with sufficient stability in operation and survival condition are generated. As an example the optimization study of a semisubmersible is discussed. It illustrates how offshore structures can be optimized for a specific target area of operation.

The Aerodynamic Shape Optimization with Trust Region Methods (Trust Region 기법을 이용한 공력 형상 최적설계)

  • Lee, Jae-Hun;Jung, Kyung-Jin;Kwon, Jang-Hyuk
    • 한국전산유체공학회:학술대회논문집
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    • pp.130-133
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    • 2008
  • In this paper the trust region method is studied and applied in aerodynamic shape optimization. The trust region method is a gradient-based optimization method, but it is not as popular as other methods in engineering computations. Its theory will be explained for unconstrained optimization problems and a trust region subproblem will be solved with the dogleg method. After verifying the trust region method with analytical test problems, it is applied to aerodynamic shape design optimization and the performance of airfoil is improved successfully.

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Shape and size optimization of trusses with dynamic constraints using a metaheuristic algorithm

  • Grzywinski, Maksym;Selejdak, Jacek;Dede, Tayfun
    • Steel and Composite Structures
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    • v.33 no.5
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    • pp.747-753
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    • 2019
  • Metaheuristic algorithm is used to solve the weight minimization problem of truss structures considering shape, and sizing design variables. The cross-sectional areas of the line element in trusses are the design variables for size optimization and the changeable joint coordinates are the shape optimization used in this study. The design of plane and spatial truss structures are optimized by metaheuristic technique named Teaching-Learning-Based Optimization (TLBO). Finite element analyses of structures and optimization process are carried out by the computer program visually developed by the authors coded in MATLAB. The four benchmark problems (trusses 2D ten-bar, 3D thirty-seven-bar, 3D seventy-two-bar and 2D two-hundred-bar) taken from literature are optimized and the optimal solution compared the results given by previous studies.

Shape Optimization of a Stator Blade in a Single-Stage Transonic Axial Compressor (단단 천음속 축류압축기의 정익형상 최적설계)

  • Kim Kwang Yong;Jang Choon Man
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.5
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    • pp.625-632
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    • 2005
  • This paper describes the shape optimization of a stator blade in a single-stage transonic axial compressor. The blade optimization has been performed using response surface method and three-dimensional Navier-Stokes analysis. Two shape variables of the stator blade, which are used to define a stacking line, are introduced to increase an adiabatic efficiency. Data points for response evaluations have been selected by D-optimal design, and linear programming method has been used for an optimization on a response surface. Throughout the shape optimization of a stator blade, the adiabatic efficiency is increased to 5.8 percent compared to that of the reference shape of the stator. The increase of the efficiency is mainly caused by the pressure enhancement in the stator blade. Flow separation on the blade suction surface of the stator is also improved by optimizing the stator blade. It is noted that the optimization of the stator blade is also useful method to increase the adiabatic efficiency in the axial compressor as well as the optimization of a rotor blade, which is widely used now.

The size and shape optimization of plane trusses using the multi-levels method (다단계 분할기법에 의한 평면트러스의 단면치수 및 형상 최적화)

  • Pyeon, Hae-Wan;Oh, Kyu-Rak;Kang, Moon-Myung
    • Journal of Korean Society of Steel Construction
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    • v.12 no.5
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    • pp.515-525
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    • 2000
  • The purpose of this paper was to develop size & shape optimization programming algorithm of plane trusses. The optimum techniques applied in this study were extended penalty method of Sequential Unconstrained Minimization Techniques(SUMT) and direct search method with multi-variables proposed by Hooke & Jeeves. Upper mentioned two methods were used iteratively at each level of size and shape optimization routines. The design variables of size optimization were circular steel tube(structural member) diameter and thickness, those of shape optimization were joint coordinates, and the objective function was represented as total weight of truss. During the optimum design, two level procedures of size and shape optimization were interacted iteratively until the final optimum values were attained. At the previous studies about shape optimization of truss, the member sectional areas and coordinates were applied as design variables. So that they could not apply the buckling effect of compression member. In this paper, actual sizes of member and nodal coordinates are used as design variables to consider the buckling effect of compression member properly.

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