• Title, Summary, Keyword: Continuum sensitivity

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A Study on a Novel Method for Electromagnetic Force Computation based on Continuum Design Sensitivity Analysis (연속체 설계 민감도해석을 이용한 새로운 전자기력 계산방법에 관한 연구)

  • Kim Dong-Hun
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.6
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    • pp.287-293
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    • 2005
  • Equations have been derived for computing electromagnetic forces by using the Continuum Design Sensitivity Analysis based on the Continuum Mechanics and the Virtual Work Principle. The resultant expressions have similar terms relating to the Korteweg-Holmholz force density, Maxwell Stress Tensor and Magnetic Charge Method but numerical implementation of the proposed scheme leads to efficient calculation and improved accuracy. In addition, the method can be easily applied to computing the magnetic force distribution as well as the global force. Results show the aforementioned advantages in comparison with the conventional methods.

The Reduction of Harmonic Dynamic Response of Plate Structure Using Continuum Design Sensitivity Analysis (연속법에 의한 설계민감도를 이용한 판구조물의 조화진동저감)

  • 이재환;이광한
    • Journal of KSNVE
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    • v.6 no.1
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    • pp.27-34
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    • 1996
  • In this paper, design sensitivity of vibration displacement and acceleration is computed and design sensitivity, the derivative information of responses with respect to design perameters, is used as a design guidance tool to reduce the vibration. First, the harmonic vibration analysis of deck and simplified ship structures is performed by finite element method and secondly continuum disign sensityivity for excessive dynamic response is computed by continuum method. Both the direct and modal frequency response methods for the finite element analysis are adopted. Sensitivities of structural components such as upper plate, side wall, bilge, bottom plate are compared and the reductionof vibration is obtained by the proper increase of thickness of each component.

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A New Unified Design Environment for Optimization of Electric Machines Based on Continuum Sensitivity and B-Spline Parametrization

  • Kim, Min-Ho;Lee, Hyang-Beom;Kim, Hyeong-Seok;Byun, Jin-Kyu
    • Journal of Electrical Engineering and Technology
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    • v.6 no.4
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    • pp.513-518
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    • 2011
  • In this paper, a unified design environment is developed for the optimization of electric machines based on continuum sensitivity. For electromagnetic (EM) system analysis, COMSOL scripting environment is used. Optimization module is developed by MATLAB programming, which can be combined with COMSOL script commands. The modules are combined into one MATLAB project, and iteration process necessary for the optimization of EM system can be performed efficiently. During the design process, visual feedback of the current design status is given to the designer. In addition, the B-Spline parametrization of the nodal points is implemented to obtain smooth boundary of the device. The developed software is applied to the problem of finding uniform flux density distribution at the air gap of an electromagnet to verify its feasibility and effectiveness.

Global Acoustic Design Sensitivity Analysis using Direct BEM and Continuum DSA (직접 경계요소법과 연속계 설계민감도 해석법을 이용한 소음 설계 민감도 해석)

  • 왕세명;이제원
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.81-87
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    • 1998
  • In this paper, a global acoustic design sensitivity analysis (DSA) of field point pressure with respect to structural sizing design variables is developed. Firstly acoustic sensitivity is formulated and implemented numerically. And it is combined with continuum structural sensitivity to obtain the global acoustic, design sensitivity. For this procedure, GASA (global acoustic design sensitivity analyzer) has been developed. A half scale of automobile cavity model is considered in this paper. In order to confirm accuracy of the results of global acoustic DSA obtained by GASA, it is compared with the result of central finite difference method. In order to reduce computation time, Rayleigh approximated solution is evaluated and compared with the solution which used every nodal velocities. Also the acoustic optimization procedure is performed using design sensitivities. From these numerical studies, it can be shown that global acoustic DSA is a useful tool to improve acoustic problems.

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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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Design Sensitivity Analysis of Coupled Thermo-elasticity Problems

  • Choi Jae-yeon;Cho Seonho
    • Journal of Ship and Ocean Technology
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    • v.8 no.3
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    • pp.50-60
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    • 2004
  • In this paper, a continuum-based design sensitivity analysis (DSA) method is developed for the weakly coupled thermo-elasticity problems. The temperature and displacement fields are described in a common domain. Boundary value problems such as an equilibrium equation and a heat conduction equation in steady state are considered. The direct differentiation method of continuum-based DSA is employed to enhance the efficiency and accuracy of sensitivity computation. We derive design sensitivity expressions with respect to thermal conductivity in heat conduction problem and Young's modulus in equilibrium equation. The sensitivities are evaluated using the finite element method. The obtained analytical sensitivities are compared with the finite differencing to yield very accurate results. Extensive developments of this method are useful and applicable for the optimal design problems incorporating welding and thermal deformation problems.

Optimization Design of a Dielectric Lowpass Filter based on Continuum Design Sensitivity Analysis in Frequency Domain (주파수 영역에서 연속체 민감도법을 이용한 유전체 저대역 필터 최적 설계)

  • Choi, Nak-Sun;Jeung, Gi-Woo;Kim, Nam-Kyung;Byun, Jin-Kyu;Kim, Dong-Hun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.8
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    • pp.1388-1393
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    • 2010
  • This paper presents a new methodology for designing a dielectric waveguide filter with the cutoff frequency of 2.4 GHz based on the continuum design sensitivity analysis. An analytical sensitivity formula is derived in frequency domain and then unified program architecture applicable to the optimal design of high-frequency devices is proposed. A three-dimensional dielectric resonator used in waveguide filters has been tested to illustrate the validity of the proposed method.

Design Sensitivity Analysis of Coupled MD-Continuum Systems Using Bridging Scale Approach (브리징 스케일 기법을 이용한 분자동역학-연속체 연성 시스템의 설계민감도 해석)

  • Cha, Song-Hyun;Ha, Seung-Hyun;Cho, Seonho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.3
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    • pp.137-145
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    • 2014
  • We present a design sensitivity analysis(DSA) method for multiscale problems based on bridging scale decomposition. In this paper, we utilize a bridging scale method for the coupled system analysis. Since the analysis of full MD systems requires huge amount of computational costs, a coupled system of MD-level and continuum-level simulation is usually preferred. The information exchange between the MD and continuum levels is taken place at the MD-continuum boundary. In the bridging scale method, a generalized Langevin equation(GLE) is introduced for the reduced MD system and the GLE force using a time history kernel is applied at the boundary atoms in the MD system. Therefore, we can separately analyze the MD and continuum level simulations, which can accelerate the computing process. Once the simulation of coupled problems is successful, the need for the DSA is naturally arising for the optimization of macro-scale design, where the macro scale performance of the system is maximized considering the micro scale effects. The finite difference sensitivity is impractical for the gradient based optimization of large scale problems due to the restriction of computing costs but the analytical sensitivity for the coupled system is always accurate. In this study, we derive the analytical design sensitivity to verify the accuracy and applicability to the design optimization of the coupled system.

Study on Configuration Design Sensitivity of Noise & Vibration (소음/진동의 컨피규레이션 설계 민감도 연구)

  • 왕세명;기성현
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.192-198
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    • 1997
  • In the concurrent engineering, the CAD-based design model is necessary for multidisciplinary analysis and for computer-aided manufacturing (CAM). A shape and configuration design velocity field computation of structure has been developed using a computer-aided design (CAD) tool, Pro/ENGINEER. The design Parameterization with CAD tool is to characterize the change in dimensions and movements of geometric control points that govern the shape/orientation of the structural boundary. The boundary velocity is obtained by using a CAD-based finite difference method and the domain velocity field is obtained from finite element analysis (FEA) using the boundary displacement method. In this paper, the continuum configuration DSA for NVH problem, which requires the shape velocity field and the orientation velocity field at the same time, is developed using linear shape functions. For validation of continuum design sensitivity coefficients, design sensitivity coefficients are compared with the coefficients computed using by the finite difference method.

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Optimization of Iron Core Structure for Controlling Induced Electric Field Distribution Using the Continuum Design Sensitivity Analysis (CDSA) (설계 민감도법을 이용한 유도 전기장 분포 제어를 위한 철심구조 최적화 연구)

  • Park Joon-Goo
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.55 no.8
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    • pp.397-400
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    • 2006
  • An optimized iron core structure of stimulating coil are presented in order to control the induced electric field distribution using the Continuum Design Sensitivity Analysis (CDSA) combined with a commercially available generalized finite element code (OPERA). The results show that a Figure-Of-Eight (FOE) coil as well as a circular coil with the proposed iron core structure can increase induced electric field intensity by more than two times and make better field localization, compared with those of existing stimulation coil with a air core. After considering manufacturing constraints, a practical iron core structure based on the proposed optimized one is proposed and its performance is analyzed.