• Title/Summary/Keyword: Shape design sensitivity

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

  • 이제원;왕세명
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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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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Shape Design Sensitivity Analysis of Two-Dimensional Thermal Conducting Solids with Multiple Domains Using the Boundary Element Method (경계요소법을 이용한 2 차원 복수 영역 열전도 고체의 형상 설계 민감도 해석)

  • 이부윤;임문혁
    • Journal of the Korean Society for Precision Engineering
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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.

Shape Design Sensitivity Analysis for Stability of Elastic Structures (탄성 구조물의 안정성을 고려한 형상설계민감도해석)

  • Choi, Joo-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.1
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    • pp.76-83
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    • 2006
  • This paper addresses the method for the shape design sensitivity analysis of the buckling load in the continuous elastic body. The sensitivity formula for critical load is analytically derived and expressed in terms of shape variation, based on the continuum formulation of the stability problem. Though the buckling problem is more efficiently solved by the structural elements such as beam and shell, the elastic solids are considered in this paper because the solid elements can be used in general for any kind of structures whether they are thick or thin. The initial stress and buckling analysis is carried out by the commercial analysis code ANSYS. The sensitivity is computed by using the mathematical package MATLAB using the results of ANSYS. Several problems including straight and curved beams under compressive load, ring under pressure load, thin-walled section and bottle shaped column are chosen to illustrate the efficiency of the presented method.

Shape Design Sensitivity Analysis for Stability of Elastic Structure (탄성 구조물의 안정성을 고려한 형상설계 민감도해석)

  • Choi Joo-Ho;Yang Wook-Jin
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.841-846
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    • 2006
  • This paper addresses the method for the shape design sensitivity analysis of the buckling load in the continuous elastic body. The sensitivity formula for critical load is analytically derived and expressed in terms of shape variation, based on the continuum formulation of the stability problem. Though the buckling problem is more efficiently solved by the structural elements such as beam and shell, the elastic solids are considered in this paper because the solid elements can be used in general for any kind of structures whether they are thick or thin. The initial stress and buckling analysis is carried out by the commercial analysis code ANSYS. The sensitivity is computed by using the mathematical package MATLAB using the results of ANSYS. Several problems including straight and curved beams under compressive load, ring under pressure load, thin-walled section are chosen to illustrate the efficiency of the presented method.

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Shape Design Sensitivity Analysis of Thermal Conduction Problems using Commercial Software ANSYS (상용 소프트웨어 ANSYS를 이용한 열전도문제의 형상설계 민감도 해석)

  • Choe, Ju-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.3
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    • pp.645-652
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    • 2000
  • A method for shape design sensitivity analysis is proposed utilizing commercial software ANSYS for thermal conduction problems. While the sensitivity formula is derived analytically by introduing adjoint variable concept, sensitivity calculation in practice as well as the primal and adjoint solution of thermal conduction is performed using the ANSYS very easily. Since the formula always takes boundary integral form, sensitivity evaluation in ANSYS requires a little more addition of post-processing routine which involves evaluation of boundary variable from the obtained solution. Though the BEM has been used as a better tool for this purpose, the present study shows it can also be calculated using any kind of analysis code such as ANSYS since the formula is based on analytic nature. Therefore the present study provides a new and efficient way of optimization which was not possible before using commercial software. The usefulness of the method is illustrated via a weight minimization problem of thermal diffuser.

Shape Design Sensitivity Analysis of Dynamic Crack Propagation Problems using Peridynamics and Parallel Computation (페리다이나믹스 이론과 병렬연산을 이용한 균열진전 문제의 형상 설계민감도 해석)

  • Kim, Jae-Hyun;Cho, Seonho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.4
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    • pp.297-303
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    • 2014
  • Using the bond-based peridynamics and the parallel computation with binary decomposition, an adjoint shape design sensitivity analysis(DSA) method is developed for the dynamic crack propagation problems. The peridynamics includes the successive branching of cracks and employs the explicit scheme of time integration. The adjoint variable method is generally not suitable for path-dependent problems but employed since the path of response analysis is readily available. The accuracy of analytical design sensitivity is verified by comparing it with the finite difference one. The finite difference method is susceptible to the amount of design perturbations and could result in inaccurate design sensitivity for highly nonlinear peridynamics problems with respect to the design. It turns out that $C^1$-continuous volume fraction is necessary for the accurate evaluation of shape design sensitivity in peridynamic discretization.

Shape Design Sensitivity Analysis Case of the Valves installed in the Hydraulic Driving Motor (사판식 구동모터에 장착된 밸브의 설계변수 민감도 해석 사례)

  • Noh, Dae-Kyung;Jang, Joo-Sup
    • Journal of the Korea Society for Simulation
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    • v.22 no.3
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    • pp.81-87
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    • 2013
  • This paper is about study how to decrese surge pressure that is occurred in excavator driving motor. We used computer simulation program SimulationX. It is also about the way finding design problem and approaching a solution through interpreting shape design sensitivity analysis. Programmes are below. First of all, finding shape fault by analyzing dynamic behavior of valves installed in hydraulic driving motor which is designed now. And drawing variable which is considered sensitive to improve dynamic efficiency among a lot of shape variables. Then, targeting that variable and examining dynamic efficiency stabilization tendency with controlling it. Finally, suggesting the most effective tuning method through variable combination as there are a lot of sensitive variables.

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

  • Choi, Joo-Ho;Kwak, Hyun-Gu;Grandhi, R.V.
    • Transactions of the Korean Society of Mechanical Engineers A
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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.

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

  • Choi, J.H.;Gwak, H.G.;Grandhi, R.
    • Proceedings of the KSME Conference
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    • pp.1047-1052
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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-touse 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 and optimization procedure are addressed in this flow problem.

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Shape Design Sensitivity Analysis for Interface Problem in Axisymmetric Elasticity

  • Choi, Joo-Ho;Lee, Boo-Youn;Han, Jung-Suk
    • Journal of Mechanical Science and Technology
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    • v.14 no.2
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    • pp.197-206
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    • 2000
  • A boundary integral equation method in the shape design sensitivity analysis is developed for the elasticity problems with axisymmetric non-homogeneous bodies. Functionals involving displacements and tractions at the zonal interface are considered. Sensitivity formula in terms of the interface shape variation is then derived by taking derivative of the boundary integral identity. Adjoint problem is defined such that displacement and traction discontinuity is imposed at the interface. Analytic example for a compound cylinder is taken to show the validity of the derived sensitivity formula. In the numerical implementation, solutions at the interface for the primal and adjoint system are used for the sensitivity. While the BEM is a natural tool for the solution, more generalization should be made since it should handle the jump conditions at the interface. Accuracy of the sensitivity is evaluated numerically by the same compound cylinder problem. The endosseous implant-bone interface problem is considered next as a practical application, in which the stress value is of great importance for successful osseointegration at the interface. As a preliminary step, a simple model with tapered cylinder is considered in this paper. Numerical accuracy is shown to be excellent which promises that the method can be used as an efficient and reliable tool in the optimization procedure for the implant design. Though only the axisymmetric problem is considered here, the method can be applied to general elasticity problems having interface.

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