• 한국산업융합학회 논문집
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• 제23권5호
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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.

• 한국기계가공학회지
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• 제19권12호
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• pp.70-79
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• 2020

This paper describes a comparative study of characteristics of probabilistic design using various reliability analysis methods in the structure design of an automatic salt collector. The thickness sizing variables of the main structural member were considered to be random variables, including the uncertainty of corrosion, which would be an inevitable hazard in the work environment of the automatic salt collector. Probabilistic performance functions were selected from the strength performances of the automatic salt collector structure. First-order reliability method, second-order reliability method, mean value reliability method, and adaptive importance sampling method were applied during the reliability analyses. The probabilistic design performances such as reliability probability and numerical costs based on the reliability analysis methods were compared to the Monte Carlo simulation results. The adaptive importance sampling method showed the most rational results for the probabilistic structure design of the automatic salt collector.

• 한국해양공학회지
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• 제34권4호
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• pp.253-262
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• 2020

This study provides a comparative analysis of experiments-based enhancements and sensitivity evaluations for the structural design of an automatic ocean salt collector under various load conditions. The sizing variables of the structural members were considered as design factors. The strength and weight performances were selected as output responses. The design of experiments used in the comparative study consisted of the orthogonal array design, Box-Behnken design, and central composite design. The response surface model, one of the metamodels, was applied to the approximate model generation. The design enhancement performance metrics, including numerical costs and weight minimization, according to the design of experiments, were compared from the best design case results. The central composite design method showed the most enhanced design results for the structural design of the automatic ocean salt collector.

• 융합정보논문지
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• 제11권1호
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• pp.109-117
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• 2021

본 논문에서는 해양자동채염기의 구조중량 최소화를 위해 구조설계에 대한 메타모델 기반 근사최적화를 수행하였다. 구조해석은 해양자동채염기의 초기설계에 대한 강도성능을 평가하기 위해 유한요소법을 이용하여 수행하였다. 구조해석에서는 설계하중조건에 대한 강도성능을 평가하였다. 최적설계문제는 강도성능 제한조건을 만족하면서 중량을 최소화할 수 있는 구조두께의 설계변수를 결정하도록 정식화하였다. 근사최적화에는 반응표면법, 크리깅 모델 및 체비쇼프 직교 다항식의 메타모델을 사용하였다. 수치계산 특성을 검토하기 위해 근사최적화 결과는 비근사최적화 결과와 비교하였다. 근사최적화에 사용된 메타모델 중 체비쇼프 직교 다항식이 해양자동채염기의 구조설계에 가장 적합한 최적설계 결과를 나타내었다.

• 융합정보논문지
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• 제10권7호
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• pp.138-146
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• 2020

본 논문은 다양한 설계하중조건 상태에서 자동채염기 구조설계의 성능분석과 개선을 위해 실험계획법을 이용한 설계민감도 평가와 대리모델의 특성에 대한 비교연구를 수행하였다. 실험계획법은 수치해석 기반의 직교배열설계 방법을 이용하였다. 설계인자는 주요 구조부재의 두께치수 변수를 고려하였고, 응답치는 중량과 강도성능을 선정하였다. 직교배열실험을 통해 설계인자 별 응답치에 대한 정량적인 영향도를 분석하였다. 또한 최소의 중량증감으로 구조성능을 개선할 수 있는 최적의 설계조건을 탐색하였다. 직교배열실험 결과를 이용하여 반응표면모델, 크리깅모델, 그리고 체비쇼프 직교 다항식과 같은 다양한 대리모델을 생성하였다. 대리모델의 결과를 통해 직교배열실험 결과의 타당성을 검증하였다. 자동채염기 구조설계 공간 탐색에는 반응표면모델이 가장 적합한 대리모델로 평가되었다.

• 한국해양공학회지
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• 제34권5호
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• pp.316-324
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• 2020

This paper presents comparative studies of reliability analysis and meta-modeling using the sampling method of Monte Carlo simulation for the structure design of an automatic ocean salt collector (AOSC). The thickness sizing variables of structure members are considered as random variables. Probabilistic performance functions are selected from strength performances evaluated via the finite element analysis of an AOSC. The sampling methods used in the comparative studies are simple random sampling and Sobol sequences with varied numbers of sampling. Approximation methods such as the Kriging model is applied to the meta-model generation. Reliability performances such as the probability failure and distribution are compared based on the variation of the sampling method of Monte Carlo simulation. The meta-modeling accuracy is evaluated for the Kriging model generated from the Monte Carlo simulation and Sobol sequence results. It is discovered that the Sobol sequence method is applicable to not only to the reliability analysis for the structural design of marine equipment such as the AOSC, but also to Kriging meta-modeling owing to its high numerical efficiency.