• Title/Summary/Keyword: Robust design

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Initial Robust Design of Deadweight 150,000 ton Bulk Carrier (재화중량 150,000톤 산적화물선의 초기 로버스트 설계)

  • Koh, Chang-Doo;Kim, Soo-Young
    • Journal of Ocean Engineering and Technology
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    • v.13 no.4 s.35
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    • pp.182-189
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    • 1999
  • The robust design technology which can determine design variables getting best performance function with insensitivity to the environment noise, is an important method for improving the performance of products at low cost. Applying the robust design technology in ship design, Koh et al[10] introduced the planing hull design. This paper reports the application this technology to a 150K bulk carrier which has many design variables and shows that the robust design technology is superior to optimization technique in practical use.

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Robust Design of Crankshaft (크랭크샤프트 강건 설계)

  • Lee, Seungwoo;Yang, Chulho
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.3
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    • pp.279-284
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    • 2016
  • Finite element analysis along with DOE scheme has been performed to obtain robust design of crankshaft assembly. This study focused on obtaining optimized fillet radius of crankshaft mainly by statistical approach. 27 design cases using 3 factors with 3 levels are constructed by design of experiment. Changes of design factors and noise factor may influence the durability of crankshaft system. General two stages of robust design may enhance the durability of crankshaft model. Increasing crank arm thickness was adopted as a shrink step and change of fillet radius was used as a shift step. By combining these two steps, the stress concentration at the fillet area is reduced and adequate fillet radius is determined for the robust design of crankshaft.

A Robust Design Using Approximation Model and Probability of Success (근사모델 및 성공확률을 이용한 강건설계)

  • Song, Byoung-Cheol;Lee, Kwon-Hee
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.7 no.3
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    • pp.3-11
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    • 2008
  • Robust design pioneered by Dr. G. Taguchi has been applied to versatile engineering problems for improving quality. Since 1980s, the Taguchi method has been introduced to numerical optimization, complementing the deficiencies of deterministic optimization, which is often called the robust optimization. In this study, the robust optimization strategy is proposed by considering the robustness of objective and constraint functions. The statistics of responses in the functions are surrogated by kriging models. In addition, objective and/or constraint function is represented by the probability of success, thus facilitating robust optimization. The mathematical problem and the two-bar design problem are investigated to show the validity of the proposed method.

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A Study on the Design of the Robust Feedback Active Noise Controller (강인한 궤환 능동 소음 제어기의 설계에 관한 연구)

  • Ahn, Woo-Hyun;Chung, Tae-Jin;Yu, Chi-Hyung;Chung, Chan-Soo
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.1018-1020
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    • 1996
  • In this paper, when a robust active noise controller for a small cavity to control the noise induced in the cavity is designed, the Graphical method based on the robust stability and performance requirements is studied. The problem of designing controller that achieve these robust performance conditions is related to minimizing the $H_{\infty}$ norm of the mixed sensitivity function by using $H_{\infty}$ control theory. Also, For design the controller, the loopshaping method which control the weight functions to satisfy the design specification without loss of a robust performance can be used. Therefore, we determined the acceptable design specification with the system characteristics of the small cavity and obtained its robust controller with the robust performance specifications by stability margin.

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Probabilistic Structure Design of Automatic Salt Collector Using Reliability Based Robust Optimization (신뢰성 기반 강건 최적화를 이용한 자동채염기의 확률론적 구조설계)

  • Song, Chang Yong
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.5
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    • pp.799-807
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    • 2020
  • This paper deals with identification of probabilistic design using reliability based robust optimization in structure design of automatic salt collector. The thickness sizing variables of main structure member in the automatic salt collector were considered the random design variables including the uncertainty of corrosion that would be an inevitable hazardousness in the saltern work environment. The probabilistic constraint functions were selected from the strength performances of the automatic salt collector. The reliability based robust optimum design problem was formulated such that the random design variables were determined by minimizing the weight of the automatic salt collector subject to the probabilistic strength performance constraints evaluating from reliability analysis. Mean value reliability method and adaptive importance sampling method were applied to the reliability evaluation in the reliability based robust optimization. The three sigma level quality was considered robustness in side constraints. The probabilistic optimum design results according to the reliability analysis methods were compared to deterministic optimum design results. The reliability based robust optimization using the mean value reliability method showed the most rational results for the probabilistic optimum structure design of the automatic salt collector.

Optimization of Sheet Metal Forming Process Based on Two-Attribute Robust Design Methodology (2속성 강건 설계를 이용한 박판성형공정의 최적화)

  • Kim, Kyung-Mo;Yin, Jeong-Je;Park, Jong-Cheon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.2
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    • pp.55-63
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    • 2014
  • Fractures and wrinkles are two major defects frequently found in the sheet metal forming process. The process has several noise factors that cannot be ignored when determining the optimal process conditions. Therefore, without any countermeasures against noise, attempts to reduce defects through optimal design methods have often led to failure. In this study, a new and robust design methodology that can reduce the possibility of formation of fractures and wrinkles is presented using decision-making theory. A two-attribute value function is presented to form the design metric for the sheet metal forming process. A modified complex method is adopted to isolate the optimal robust design variables. One of the major limitations of the traditional robust design methodology, which is based on an orthogonal array experiment, is that the values of the optimal design variables have to coincide with one of the experimental levels. As this restriction is eliminated in the complex method, a better solution can be expected. The procedure of the proposed method is illustrated through a robust design of the sheet metal forming process of a side member of an automobile body.

Minimization of Warpage of Injection Molded Parts using Dynamic Robust Design (동특성 강건 설계를 이용한 사출품의 휨 최소화)

  • Kim, Kyung-Mo;Park, Jong-Cheon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.14 no.1
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    • pp.44-50
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    • 2015
  • This paper presents a heuristic process-optimization procedure for minimizing warpage in injection-molded parts based on the dynamic robust design methodology. The injection molding process is known to have intrinsic variations of its process conditions due to various factors, including incomplete process control facilities. The aim of the robust design methodology advocated by Taguchi is to determine the optimum design variables in a system which is robust to variations in uncontrollable factors. The proposed procedure can determine the optimal robust conditions of injection molding processes at a minimum cost through a trade-off strategy between the degree of warpage and the packing time.

Robust Design of a Driver-Side Airbag Using the Taguchi Method (다구찌법을 이용한 운전석 에어백의 강건설계)

  • 이권희;주원식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.2
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    • pp.131-138
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    • 2004
  • In the proto design stage of a new car, the performances of an occupant protection system can be evaluated by CAE even though the real test should be carried out. The number of the real test is reduced by the exact predictions followed by the appropriate design recommendation. However, the existing researches using CAE in predicting the performances do not consider the uncertainties of parameters. That often leads to inconsistency between test and CAE. In this research, the robust design of a protection system such as airbag and load limiter is suggested considering the frontal crash. The parameter design scheme of the Taguchi method is introduced to obtain the robust design of arbitrary airbag and load limiter. It is performed based on the frontal crash test condition of US-NCAP with an arbitrary passenger car. The variances of the performances such as HIC, chest acceleration and probability of combined injury are calculated by the outer array and the Taylor series expansion. Through the analysis of the Taguchi method, the robust optimum is determined.

Robust Optimization with Static Analysis Assisted Technique for Design of Electric Machine

  • Lee, Jae-Gil;Jung, Hyun-Kyo;Woo, Dong-Kyun
    • Journal of Electrical Engineering and Technology
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    • v.13 no.6
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    • pp.2262-2267
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    • 2018
  • In electric machine design, there is a large computation cost for finite element analyses (FEA) when analyzing nonlinear characteristics in the machine Therefore, for the optimal design of an electric machine, designers commonly use an optimization algorithm capable of excellent convergence performance. However, robustness consideration, as this factor can guarantee machine performances capabilities within design uncertainties such as the manufacturing tolerance or external perturbations, is essential during the machine design process. Moreover, additional FEA is required to search robust optimum. To address this issue, this paper proposes a computationally efficient robust optimization algorithm. To reduce the computational burden of the FEA, the proposed algorithm employs a useful technique which termed static analysis assisted technique (SAAT). The proposed method is verified via the effective robust optimal design of electric machine to reduce cogging torque at a reasonable computational cost.

A Global Robust Optimization Using the Kriging Based Approximation Model (크리깅 근사모델을 이용한 전역적 강건최적설계)

  • Park Gyung-Jin;Lee Kwon-Hee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.9 s.240
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    • pp.1243-1252
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    • 2005
  • A current trend of design methodologies is to make engineers objectify or automate the decision-making process. Numerical optimization is an example of such technologies. However, in numerical optimization, the uncertainties are uncontrollable to efficiently objectify or automate the process. To better manage these uncertainties, the Taguchi method, reliability-based optimization and robust optimization are being used. To obtain the target performance with the maximum robustness is the main functional requirement of a mechanical system. In this research, a design procedure for global robust optimization is developed based on the kriging and global optimization approaches. The DACE modeling, known as the one of Kriging interpolation, is introduced to obtain the surrogate approximation model of the function. Robustness is determined by the DACE model to reduce real function calculations. The simulated annealing algorithm of global optimization methods is adopted to determine the global robust design of a surrogated model. As the postprocess, the first order second-moment approximation method is applied to refine the robust optimum. The mathematical problems and the MEMS design problem are investigated to show the validity of the proposed method.