• Title, Summary, Keyword: Shape design sensitivity

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Optimal Shape Design of Magnetic Actuators for Magnetic and Dynamic Characteristic Improvement

  • Yoo, Jeong-Hoon;Jung, Jae-Yeob;Hong, Hyeok-Soo
    • Journal of Magnetics
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    • v.16 no.3
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    • pp.268-270
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    • 2011
  • This study introduces a new topology optimization scheme combing the genetic algorithm (GA) with the on/off sensitivity method for the magnetic actuator core and the armature design. The design process intended to maximize the first eigen-frequency of the armature part and the magnetic actuating force acting on the armature simultaneously. GA based optimal design was carried out to obtain the initial structure and the modified on/off sensitivity method was succeeded to accelerate the design process. Final results show tens of percent improvement in actuating force as well as the first eigen-frequency of the armature.

Adjoint Variable Method Combined with Complex Variable for Structural Design Sensitivity (보조변수법과 복소변수를 연동한 설계 민감도 해석 연구)

  • Kim, Hyun-Gi;Cho, Maeng-Hyo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.3
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    • pp.243-250
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    • 2009
  • The adjoint variable method can reduce computation time and save computer resources because it can selectively provide the sensitivity information for the positions that designers wish to measure. However, the adjoint variable method commonly employs exact analytical differentiation with respect to the design variables. It can be cumbersome to precisely differentiate every given type of finite element. This trouble can be overcome only if the numerical differentiation scheme can replace this exact manner of differentiation. But, the numerical differentiation scheme causes of severe inaccuracy due to the perturbation size dilemma. For assuring the accurate sensitivity without any dependency of perturbation size, this paper employs a complex variable that has been mainly used for computational fluid dynamics problems. The adjoint variable method combined with complex variables is applied to obtain the shape and size sensitivity for structural optimization. Numerical examples demonstrate that the proposed method can predict stable sensitivity results and that its accuracy is remarkably superior to traditional sensitivity evaluation methods.

Novel Mesh Regeneration Method Using the Structural Deformation Analysis for 3D Shape Optimization of Electromagnetic Device (전자소자의 3차원 형상최적화를 위한 구조변형 해석을 이용한 새로운 요소망 변형법)

  • Yao Yingying;Jae Seop Ryu;Chang Seop Koh;Dexin Xie
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.52 no.6
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    • pp.247-253
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    • 2003
  • A novel finite element mesh regeneration method is presented for 3D shape optimization of electromagnetic devices. The method has its theoretical basis in the structural deformation of an elastic body. When the shape of the electromagnetic devices changes during the optimization process, a proper 3D finite element mesh can be easily obtained using the method from the initial mesh. For real engineering problems, the method guarantees a smooth shape with proper mesh quality, and maintains the same mesh topology as the initial mesh. Application of the optimum design of an electromagnetic shielding plate shows the effectiveness of the presented method.

Isogeometric Shape Design Optimization of Structures under Stress Constraints (응력 제한조건을 갖는 구조물의 아이소-지오메트릭 형상 최적설계)

  • Ahn, Seung-Ho;Kim, Min-Geun;Cho, Seon-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.3
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    • pp.275-281
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    • 2010
  • In this paper, the design optimization of structures with stress constraints is performed using isogeometric shape optimization method. The stress constraints have an important role in design optimization problems since stress concentration could result in structural failure. To represent exact geometry in analysis, the isogeometric analysis method uses the same basis functions as used in the CAD geometry. The geometrically exact model can be used in both stress and design sensitivity analyses so that it can yield more precise optimal design than finite element one. Through numerical examples, the isogeometric approach turns out to be effective in shape optimization problems under stress constraints.

Stator Slot Shape Optimization of Induction Motors for Iron Loss Reduction (철손 저감을 위한 유도전동기 고정자 슬롯 형상 최적화)

  • Park, S.B.;Lee, H.B.;Park, I.H.;Chung, T.K.;Hahn, S.Y.
    • Proceedings of the KIEE Conference
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    • pp.150-152
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    • 1994
  • In this paper, the optimum shape design of stator slot of induction motors for iron loss reduction is proposed. To obtain the flux distribution in induction motors, 2-D finite element method with voltage source is employed. The iron loss is calculated from the iron loss data given by the iron manufacturer. To calculate the sensitivity of iron loss to shape variation, the sensitivity analysis of discrete approach is used. The proposed algorithm is applied to a 3-phase squirrel cage induction motor. The nodes at stator slot boundary of the induction motor are defined as design parameters. By controlling these parameters under the constant volume of iron, we can minimize the iron loss. Furthermore, the stator copper loss is reduced by increasing the slot area. So the stator slot area is determined at the point that the summation of iron loss and copper loss of stator is minimized. Since the constraint of constant volume of iron is nonlinear to the design parameters, the Gradient Projection method is used as an optimization algorithm.

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Shape Optimization for Magnetic Pole Piece of PM MRI using Nonlinear Parameterized Sensitivity Analysis (매개화된 민감도 해석에 의한 PM MRI의 Pole Piece 형상 최적화)

  • Ryu, Jae-Seop;Koh, Chang-Seop
    • Proceedings of the KIEE Conference
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    • pp.70-72
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    • 2004
  • The ferromagnetic pole piece of permanent magnet assembly for magnetic resonance imaging(MRI) is optimally designed to get high homogenious magnetic field, taking into account the non-linearity of the magnetic materials. In the design, the pole face is kept smooth and axis-symmetric by using B-spline parameterization, and nonlinear design sensitivity analysis is used for search direction.

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Multi-objective optimal design of magneto-mechanical system using topology approach regarding magnetic reluctance force and magnetostriction (릴럭턴스 힘과 자기변형을 고려한 자계-기계계의 다목적 위상최적설계)

  • Shim, Ho-Kyung;Wang, Se-Myung
    • Proceedings of the KIEE Conference
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    • pp.651-652
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    • 2008
  • This research presents a multi-objective optimal design employing topological approach to maximize magnetic energy while minimizing structural deformation which is caused by magnetic reluctance force and magnetostriction. A design sensitivity formula is derived by employing the adjoint variable method (AVM) to avoid numerous sensitivity evaluations for a coupled magneto-mechanical analysis. The sensitivity analysis is verified using the finite difference method (FDM) in a C-shape actuator. A linear actuator used in a home appliance is examined for optimal design and demonstrates the strength of the proposed topology optimization approach.

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The Change of 'Attention Resources' and 'Space-Memory' by Lighting focusing on 'Selective Attention (선택적 주의 관점에서 본 조명에 의한 주의 자원과 공간 기억의 변화)

  • Seo, Ji-Eun
    • Korean Institute of Interior Design Journal
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    • v.25 no.2
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    • pp.41-49
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    • 2016
  • The purpose of this study is to analyze the change and to compare to the difference of 'selective elements' and 'space-memory' focusing on the theory, 'selective attention' through the survey results. In this study, In this study, the lighting is considered a important factor in the change of 'selective elements'. this survey is to find the selective elements of participants and to measure the spatial sensitivity of respondents through 'self- test'. The analysis in this study is conducted by descriptive statistics, t-test and one way ANOVA by SPSS program 22. The results of this study are as following; Firstly, 'attention-element' could be classified with 4 types, 'shape', 'material', 'contrast' and 'combination'. 'shape' could divide into 'structure' and' furniture and object'. In case of 'material', it could section with 'pattern' and 'color'. Secondly, through the results of study, 'attention-element' is different each space during the day in detail. But we could know that 'shape' is the important element of the 'attention-elements' during the day through comparison of this result. That means users consider this as a important factor when they evaluate the space. Therefore, it is effective way designers to consider 'shape' as the first element when they want to conduct the special sensitivity of users in the space through planning. On the other hand, what selective elements of users are different by the lighting situation should be acknowledged by designers. And they should think the kinds of selective elements are more various when lighting turns on than turns off.. Thirdly, through the results such as the meaningful difference of space-memory of users according to the change of 'attention-elements', designers should judge about which kind of feeling of users to the space do you want lead in the design process. For the effective feedback between spaces and users to induce the same emotion of users, designers need to consider the unified design and the individual design both. Also, we will regard the differences in the users' emotion to the space according to the lighting situation when we design the space.

A Study on Shape Design of the Passenger Airbag for Efficiency Improvement (조수석 에어백 성능 개선을 위한 형상 설계연구)

  • Yang, Sunghoon;Yim, Jonghyun;Kim, Seungki;Chae, Soo-Won
    • Transactions of the Korean Society of Automotive Engineers
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    • v.25 no.2
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    • pp.242-249
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    • 2017
  • In this study, the relationship between the shape of a passenger airbag and the possibility of injury is analyzed using the Taguchi method. The optimal shape combination is proposed for a design guideline that can reduce the possibility of injury to the dummy. The airbag FE model for analysis is obtained using a CAD system that can change the shape through several independent variables. The widths of the left / right, top / bottom, and back / forth direction of the airbag shape are set as the design factors, and the effect of the combination injury probability according to the shape is analyzed. The minimum geometric combinations are obtained using the orthogonal array method. The signal to noise ratio is calculated and the optimal shape combination is obtained through sensitivity analysis. The obtained optimal shape combination is compared with the possibility of injury of the initial airbag shape to confirm improved airbag performance.

Shape Sensitivity Analysis for the Optimal Design of Air Bearing Sliders of Optical Disk Drives (광디스크 드라이브 공기베어링 슬라이더의 최적설계를 위한 형상민감도 해석)

  • Kim, Hyun-Ki;Jang, Hyuk;Kim, Kwang-Sun;Lim, Kyong-Hwa;Jeong, Tae-Gun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.742-747
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    • 2000
  • The optical storage device has recently experienced significant improvements, especially for the aspects of high capacity and fast transfer rate. However, it is the fact that the optical storage device has the lower access time for the randomly scattered data compared to the hard disk drives. It is, therefore, necessary to develop a new type of optical storage system. In this study, we investigate the air bearing characteristics for the optical disk drives which have the swing arm actuator similarly to the hard disk drives. Considering the requirements of the optical disk drives, we parametrize the shape of the air bearing surface and investigate its sensitivity to the flying characteristics for further optimized design outputs.

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