• 제목, 요약, 키워드: Shape design sensitivity

검색결과 299건 처리시간 0.029초

경계요소법을 이용한 2 차원 복수 영역 열전도 고체의 형상 설계 민감도 해석 (Shape Design Sensitivity Analysis of Two-Dimensional Thermal Conducting Solids with Multiple Domains Using the Boundary Element Method)

  • 이부윤;임문혁
    • 한국정밀공학회지
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    • v.20 no.8
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    • pp.175-184
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    • 2003
  • A method of the shape design sensitivity analysis based on the boundary integral equation formulation is presented for two-dimensional inhomogeneous thermal conducting solids with multiple domains. Shape variation of the external and interface boundary is considered. A sensitivity formula of a general performance functional is derived by taking the material derivative to the boundary integral identity and by introducing an adjoint system. In numerical analysis, state variables of the primal and adjoint systems are solved by the boundary element method using quadratic elements. Two numerical examples of a compound cylinder and a thermal diffuser are taken to show implementation of the shape design sensitivity analysis. Accuracy of the present method is verified by comparing analyzed sensitivities with those by the finite difference. As application to the shape optimization, an optimal shape of the thermal diffuser is found by incorporating the sensitivity analysis algorithm in an optimization program.

박판구조물의 방사소음에 대한 형상 설계민감도 해석 (Shape Design Sensitivity Analysis For The Radiated Noise From Thin body)

  • 이제원;왕세명
    • 한국소음진동공학회:학술대회논문집
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    • pp.90-95
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    • 2001
  • A continuum-based shape design sensitivity analysis (DSA) method is presented for the acoustic radiation from thin body. The normal derivative integral formulation is employed as an analysis formulation and differentiated directly by using material derivative to get the acoustic shape design sensitivity. In the acoustic sensitivity formulation, derivative coefficients of the structural normal velocities on the surface are required as the input. Thus, the shape design sensitivities of structural velocities on the surface with respect to the shape change are also calculated with continuum approach. A simple disk is considered as a numerical example to validate the accuracy and efficiency of the analytical shape design sensitivity equations derived in this research. This research should be very helpful to design an application involving thin body and to change its acoustic characteristics.

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Configuration sensitivity analysis of mechanical dynamics

  • Bae, Daesung
    • 한국공작기계학회논문집
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    • v.10 no.1
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    • pp.112-119
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    • 2001
  • Design sensitivity is an important is an important device in improving a mechanical system design. A continuum design consists of the shape and orientation design. This research develops the shape and orientation design sensitivity method. The configura-tion design variables of multibody systems define the shape and orientation changes. The equations of motion are directly differentiated to obtain the governing equations for the design sensitivity. The governing equation of the design sensitivity is formulated as an over determined differential algebraic equation and treated as ordinary differential equations on mani-folds. The material derivative of a domain functional is performed to obtain the sensitivity due to shape and orientation changes. The configuration design sensitivities of a fly-ball governor system and a spatial four bar mechanism are obtained using the proposed method and are validated against those obtained from the finite difference method.

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등기하 해석법을 이용한 형상 최적 설계 (Shape Design Optimization using Isogeometric Analysis Method)

  • 하승현;조선호
    • 한국전산구조공학회:학술대회논문집
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    • pp.216-221
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    • 2008
  • Shape design optimization for linear elasticity problem is performed using isogeometric analysis method. In many design optimization problems for real engineering models, initial raw data usually comes from CAD modeler. Then designer should convert this CAD data into finite element mesh data because conventional design optimization tools are generally based on finite element analysis. During this conversion there is some numerical error due to a geometry approximation, which causes accuracy problems in not only response analysis but also design sensitivity analysis. As a remedy of this phenomenon, the isogeometric analysis method is one of the promising approaches of shape design optimization. The main idea of isogeometric analysis is that the basis functions used in analysis is exactly same as ones which represent the geometry, and this geometrically exact model can be used shape sensitivity analysis and design optimization as well. In shape design sensitivity point of view, precise shape sensitivity is very essential for gradient-based optimization. In conventional finite element based optimization, higher order information such as normal vector and curvature term is inaccurate or even missing due to the use of linear interpolation functions. On the other hands, B-spline basis functions have sufficient continuity and their derivatives are smooth enough. Therefore normal vector and curvature terms can be exactly evaluated, which eventually yields precise optimal shapes. In this article, isogeometric analysis method is utilized for the shape design optimization. By virtue of B-spline basis function, an exact geometry can be handled without finite element meshes. Moreover, initial CAD data are used throughout the optimization process, including response analysis, shape sensitivity analysis, design parameterization and shape optimization, without subsequent communication with CAD description.

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The 3D Shape Optimal Design of Transformer Tank Shield by Using Parameterized Design Sensitivity Analysis

  • Yao, Ying-Ying;Ryu, Jae-Seop;Koh, Chang-Seop;Xie, Dexin
    • 대한전기학회:학술대회논문집
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    • pp.80-83
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    • 2002
  • A 3D shape optimization algorithm integrates the geometric parameterizationi 3D F.E. performance analysis, steepest descent method with design sensitivity and mesh relocation method. The design sensitivity of the surface nodal points is also systematically converted into that of the design variables for the application to parameterized optimization. The proposed algorithm is applied to the optimum design of tank shield model of transformer and the effectiveness is proved.

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SENSITIVITY ANALYSIS OF A SHAPE CONTROL PROBLEM FOR THE NAVIER-STOKES EQUATIONS

  • Kim, Hongchul
    • Korean Journal of Mathematics
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    • v.25 no.3
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    • pp.405-435
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    • 2017
  • We deal with a sensitivity analysis of an optimal shape control problem for the stationary Navier-Stokes system. A two-dimensional channel flow of an incompressible, viscous fluid is examined to determine the shape of a bump on a part of the boundary that minimizes the viscous drag. By using the material derivative method and adjoint variables for a shape sensitivity analysis, we derive the shape gradient of the design functional for the model problem.

초공동(超空洞) 유동 문제의 형상 설계민감도 해석 (Shape Design Sensitivity Analysis of Supercavitating Flow Problem)

  • 최주호;곽현구
    • 대한기계학회논문집A
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    • v.28 no.9
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    • pp.1320-1327
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    • 2004
  • An efficient boundary-based technique is developed for addressing shape design sensitivity analysis in supercavitating flow problem. An analytical sensitivity formula in the form of a boundary integral is derived based on the continuum formulation for a general functional defined in potential flow problems. The formula, which is expressed in terms of the boundary solutions and shape variation vectors, can be conveniently used for gradient computation in a variety of shape design in potential flow problems. While the sensitivity can be calculated independent of the analysis means, such as the finite element method (FEM) or the boundary element method (BEM), the FEM is used for the analysis in this study because of its popularity and easy-to-use features. The advantage of using a boundary-based method is that the shape variation vectors are needed only on the boundary, not over the whole domain. The boundary shape variation vectors are conveniently computed by using finite perturbations of the shape geometry instead of complex analytical differentiation of the geometry functions. The supercavitating flow problem is chosen to illustrate the efficiency of the proposed methodology. Implementation issues for the sensitivity analysis and optimization procedure are also addressed in this flow problem.

단조공정에서 민감도법을 이용한 예비 성형체 설계 (Preform Design for Forging by the Sensitivity Method)

  • 심현보;노현철;손기찬
    • 한국소성가공학회:학술대회논문집
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    • pp.180-185
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    • 2001
  • The sensitivity method has been applied to find perform shape that results in the desired shape after forging. As a 2D example, initial shape of specimen for the cylinder shape without barrelling after forging has been found. The method is then applied to various shapes of 3D free forging and initial shapes of the corresponding specimens after forging have been found successfully. The sensitivity method is proven to be an effective and accurate tool for the preform design.

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민감도법을 이용한 자유단조 공정의 예비성형체 설계 (Preform Design by the Sensitivity Method)

  • 심현보;노현철;서의권
    • 소성가공
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    • v.10 no.4
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    • pp.294-301
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    • 2001
  • The sensitivity method has been applied to find perform shape that results in the desired shape after foring. As a 2D example, initial shape of specimen for the cylinder shape without barrelling after forging has been found. The method is then applied to various shapes of 3D free forging and initial shapes of the corresponding specimens after forging have been found successfully The sensitivity method is proven to be an effective and accurate tool for the preform design.

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정식화를 이용한 3차원 구조물의 형상 최적설계 (Variational Formulation for Shape Optimization of Spatial Beam Structures)

  • 최주호;김종수
    • 한국전산구조공학회:학술대회논문집
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    • pp.123-130
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    • 2002
  • A general formulation for shape design sensitivity analysis over three dimensional beam structure is developed based on a variational formulation of the beam in linear elasticity. Sensitivity formula is derived based on variational equations in cartesian coordinates using the material derivative concept and adjoint variable method for the displacement and Von-Mises stress functionals. Shape variation is considered for the beam shape in general 3-dimensional direction as well as for the orientation angle of the beam cross section. In the sensitivity expression, the end points evaluation at each beam segment is added to the integral formula, which are summed over the entire structure. The sensitivity formula can be evaluated with generality and ease even by employing piecewise linear design velocity field despite the bending model is fourth order differential equation. For the numerical implementation, commercial software ANSYS is used as analysis tool for the primal and adjoint analysis. Once the design variable set is defined using ANSYS language, shape and orientation variation vector at each node is generated by making finite difference to the shape with respect to each design parameter, and is used for the computation of sensitivity formula. Several numerical examples are taken to show the advantage of the method, in which the accuracy of the sensitivity is evaluated. The results are found excellent even by employing a simple linear function for the design velocity evaluation. Shape optimization is carried out for the geometric design of an archgrid and tilted bridge, which is to minimize maximum stress over the structure while maintaining constant weight. In conclusion, the proposed formulation is a useful and easy tool in finding optimum shape in a variety of the spatial frame structures.

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