• Title, Summary, Keyword: Optimal design

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Sensitivita Analysis and Optimal desing of plane Vehicle Frame Structures (평면 차체프레임구조물의 민감도해석 및 최적설계)

  • 이종선
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.5 no.4
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    • pp.74-81
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    • 1996
  • This paper is to estimate sizing design sensitivity of linear and nonlinear vehicle frame structure using structural ananlysis result from ANSYS. Using design sensitivity results, optimal design of plane vehicle frame structure with buckling constraint is carried out the gradient projection method. Optimal design results are compares gradient projection method resrult with SUMT result.

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Analysis and Design of Surface Plasmon Waveguide

  • Kim, Min-Wook;Jung, Jae-Hoon
    • Journal of the Semiconductor & Display Technology
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    • v.8 no.3
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    • pp.7-11
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    • 2009
  • In this paper, we developed and presented a design result for optimizing the geometry of Ag circular SPP waveguide for subwavelength waveguide applications. We investigated the effect of the design parameters on the light propagation and find the optimum design for small modal size, high coupling coefficient, and low sensitivity. The results show that the globally optimal design locates optimal waveguide geometries more efficiently than individual optimal points for multivalued objective function.

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Optimal Design of Slim TV Wall Mount Arm with Cantilever Structure (외팔보 구조의 슬림형 TV 월마운트암의 최적설계)

  • Jang, Woon-Geun
    • Journal of the Korean Society of Industry Convergence
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    • v.14 no.4
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    • pp.167-172
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    • 2011
  • This paper investigated optimal design for slim wall mount arm for flat TV. Recently the number of flat TV sets in use went on increasing in TV market. As the flat TV sets are getting common, consumers came to need another requirements like aesthetic factor besides display performances. As the new TV sets tend to be slimmer due to aesthetic design, Wall mount also requires to be slimmer for aesthetic balance. Slim structures, however, are vulnerable to structural rigidity. In this study, slim wall mount arm has been designed by 3D CAD and DOE (Design of Experiments) and finite element analysis for optimal structural design were carried out to determine the design variables for minimize working stress of wall mount arm. Finally two optimal design conditions were selected through DOE and FEM and one of those was chosen under constraint of minimizing blanking developed length.

Optimal Design of Composite Rotor Blade Cross-Section using Discrete Design variable (이산설계변수를 고려한 복합재 로터블레이드 단면 최적설계)

  • Won, You-Jin;Lee, Soo-Yong
    • Journal of Aerospace System Engineering
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    • v.8 no.1
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    • pp.12-17
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    • 2014
  • In this paper, optimal design of composite rotor blade cross-section to consider manufacturability was performed. Skin thickness, torsion box thickness and skin lay-up angle were adopted as discrete design variables and The position and width of a torsion box were considered as continuous variables. An object function of optimal design is to minimize the mass of a rotor blade, and various constraints such as failure index, center mass, shear center, natural frequency and blade minimum mass per unit length were adopted. Finally, design variables such as the thickness and lay-up angles of a skin, and the thickness, position and width of a torsion box were determined by using an in-house program developed for the optimal design of rotor blade cross-section.

Parameter Study for Optimal Design of Smart TMD (스마트 TMD의 최적설계를 위한 파라메터 연구)

  • Kim, Hyun-Su;Kang, Joo-Won
    • Journal of the Korean Association for Spatial Structures
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    • v.17 no.4
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    • pp.123-132
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    • 2017
  • A smart tuned mass damper (TMD) was developed to provide better control performance than a passive TMD for reduction of earthquake induced-responses. Because a passive TMD was developed decades ago, optimal design methods for structural parameters of a TMD, such as damping constant and stiffness, have been developed already. However, studies of optimal design method for structural parameters of a smart TMD were little performed to date. Therefore, parameter studies of structural properties of a smart TMD were conducted in this paper to develop optimal design method of a smart TMD under seismic excitation. A retractable-roof spatial structure was used as an example structure. Because dynamic characteristics of a retractable-roof spatial structure is changed based on opened or closed roof condition, control performance of smart TMD under off-tuning was investigated. Because mass ratio of TMD and smart TMD mainly affect control performance, variation of control performance due to mass ratio was investigated. Parameter studies of structural properties of a smart TMD was performed to find optimal damping constant and stiffness and it was compared with the results of optimal passive TMD design method. The design process developed in this study is expected to be used for preliminary design of a smart TMD for a retractable-roof spatial structure.

Optimal Safety Valuation of High-Speed Railway Bridges Based on Reliability Assessment and Life-Cycle Cost Concept

  • Han, Sung-Ho
    • International journal of steel structures
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    • v.17 no.1
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    • pp.339-349
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    • 2017
  • This study was intended to evaluate the dynamic performance high-speed railway bridges (HSR bridges) of composite box girder type so as to propose the rational safety level and optimal design method using reliability assessment (RA) and expected life-cycle cost (LCC) concpet. To that end, a various design alternatives were created considering the variation of member section based on a standard design section (current Korean code) of HSR bridges and then the static analysis, natural frequency analysis and time history analysis using time series of traffic load were implemented on each design alternative. Based on finite element analysis (FEA) results, the dynamic amplification factor (DAF) of the standard design section was evaluated in a way of comparing with related alternatives. RA depending on design strength limit state function was carried out considering the effect of external uncertainty contained in FEA results by each design alternative. Furthermore, the expected LCC of HSR bridges was evaluated using RA results and the optimal design method was determined through the calculated minimum LCC. To review the effect of internal uncertainty included in the safety index, failure probability and minimum LCC of selected optimal design method, sensitivity assessment was implemented and, consequently, a frequency-histogram (cumulative-percentage) was illustrated. The outcomes of research, along with the dynamic performance assessment of HSR bridges, will be expected to provide the basic information in determining the structural safety and optimal design method.

Kinematic Analysis and Optimal Design of 3-PPR Planar Parallel Manipulator

  • Park, Kee-Bong
    • Journal of Mechanical Science and Technology
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    • v.17 no.4
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    • pp.528-537
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    • 2003
  • This paper proposes a 3-PPR planar parallel manipulator, which consists of three active prismatic Joints, three passive prismatic joints, and three passive rotational joints. The analysis of the kinematics and the optimal design of the manipulator are also discussed. The proposed manipulator has the advantages of the closed type of direct kinematics and a void-free workspace with a convex type of borderline. For the kinematic analysis of the proposed manipulator, the direct kinematics, the inverse kinematics, and the inverse Jacobian of the manipulator are derived. After the rotational limits and the workspaces of the manipulator are investigated, the workspace of the manipulator is simulated. In addition, for the optimal design of the manipulator, the performance indices of the manipulator are investigated, and then an optimal design procedure Is carried out using Min-Max theory. Finally. one example using the optimal design is presented.

A New Reliability-Based Optimal Design Algorithm of Electromagnetic Problems with Uncertain Variables: Multi-objective Approach

  • Ren, Ziyan;Peng, Baoyang;Liu, Yang;Zhao, Guoxin;Koh, Chang-Seop
    • Journal of Electrical Engineering and Technology
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    • v.13 no.2
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    • pp.704-710
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    • 2018
  • For the optimal design of electromagnetic device involving uncertainties in design variables, this paper proposes a new reliability-based optimal design algorithm for multiple constraints problems. Through optimizing the nominal objective function and maximizing the minimum reliability, a set of global optimal reliable solutions representing different reliability levels are obtained by the multi-objective particle swarm optimization algorithm. Applying the sensitivity-assisted Monte Carlo simulation method, the numerical efficiency of optimization procedure is guaranteed. The proposed reliability-based algorithm supplying multi-reliable solutions is investigated through applications to analytic examples and the optimal design of two electromagnetic problems.

An optimal design of the Kopp Ball Variator continuously variable transmission (Kopp Ball Variator 무단변속기의 최적설계)

  • 임경호;김두만
    • Journal of the korean Society of Automotive Engineers
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    • v.14 no.1
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    • pp.38-46
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    • 1992
  • An optimal design technique for minimum power loss in Kopp Ball Variator Continuously Variable Transmission is developed. Kinematic analysis of traction drive contact is performed to find spin for Kopp Ball Variator, and traction force and torque are calculated from mathem atical model of traction drive contact. The objective function for optimal design is total power loss including contact loss and bearing losses. The design contraints are derived from energy balance for input and output power. The formulated optimal design problem is implemented to a non-linear programming algorithm to find minimum power loss. The performance of optimal ly designed Kopp Ball Variator shows that efficiency is increased about 5-10% compare to a commercial unit.

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Stochastic Optimal Control and Network Co-Design for Networked Control Systems

  • Ji, Kun;Kim, Won-Jong
    • International Journal of Control, Automation, and Systems
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    • v.5 no.5
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    • pp.515-525
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    • 2007
  • In this paper, we develop a co-design methodology of stochastic optimal controllers and network parameters that optimizes the overall quality of control (QoC) in networked control systems (NCSs). A new dynamic model for NCSs is provided. The relationship between the system stability and performance and the sampling frequency is investigated, and the analysis of co-design of control and network parameters is presented to determine the working range of the sampling frequency in an NCS. This optimal sampling frequency range is derived based on the system dynamics and the network characteristics such as data rate, time-delay upper bound, data-packet size, and device processing time. With the optimal sampling frequency, stochastic optimal controllers are designed to improve the overall QoC in an NCS. This co-design methodology is a useful rule of thumb to choose the network and control parameters for NCS implementation. The feasibility and effectiveness of this co-design methodology is verified experimentally by our NCS test bed, a ball magnetic-levitation (maglev) system.