Seung-Soo Na

Optimum Structural Design of D/H Tankers by using Pareto Optimal based Multi-objective Function Method

A structural design system is developed for the optimum design of double hull tankers based on the multi-objective function method. As a multi-objective function method, Pareto optimal based random search method is adopted to find the minimum structural weight and fabrication cost. The fabrication cost model is developed by considering the welding technique, welding poses and assembly stages to manage the fabrication man-hour and process. In this study, a new structural design is investigated due to the rapidly increased material cost. Several optimum structural designs on the basis of high material cost are carried out based on the Pareto optimal set obtained by the random search method. The design results are compared with existing ship, which is designed under low material cost.⨀႘ꐂ

Development of a Multi-objective function Method Based on Pareto Optimal Point

It is necessary to develop an efficient optimization technique to optimize the engineering structures which have given design spaces, discrete design values and several design goals. As optimization techniques, direct search method and stochastic search method are widely used in designing of engineering structures. The merit of the direct search method is to search the optimum points rapidly by considering the search direction, step size and convergence limit. And the merit of the stochastic search method is to obtain the global optimum points by spreading point randomly entire the design spaces. In this paper, a Pareto optimal based multi-objective function method (PMOFM) is developed by considering the search direction based on Pareto optimal points, step size, convergence limit and random search generation . The PMOFM can also apply to the single objective function problems, and can consider the discrete design variables such as discrete plate thickness and discrete stiffener spaces. The design results are compared with existing Evolutionary Strategies (ES) method by performing the design of double bottom structures which have discrete plate thickness and discrete stiffener spaces.

The Structural Design of a Large Oil Tanker based on the CSR by Considering the Web Arrangement and Material Property

The structural design of oil tankers and bulk carriers should be performed based on the Common Structural Rules(CSR) which were recently established by the International Association Classification Societies(IACS). At first, in the structural design viewpoint, the scantling and hullweight based on the CSR should be compared with those of existing rules, and then a minimum weight/cost design should be performed by considering the variation of the number of web and the material property. In this study, the optimum web space and material property will be proposed by performing a minimum weight/cost design of a large oil tanker, and the results will be compared with those of existing ship. The longitudinal members are determined by SeaTrust-Holdan developed by the Korean Register of Shipping(KR), and the transverse members are determined by NASTRAN and PULS.

Optimum Structural Design of Mid-ship Section of D/H Tankers Based on Common Structural Rules

Abstract It is necessary to perform the research works on the general structural designs and optimum structural designs of double hull tankers and bulk carriers due to the newly built Common Structural Rules(CSR). In this study, an optimum structural design of a mid-ship part of double hull oil tanker was carried out by using the CSR. An optimum structural design program was developed by using the Pareto optimal based multi-objective function method. The hull weight and fabrication cost obtained by the single and multi-objective function methods were compared with existing ship by the consideration o f CSR and material cost which is recently increasing. ※Keywords: Common structural rules(통합구조규정), Multi-objective function method (다목적함수기법), Pareto optimal (Pareto 최적점), Optimum structural design(최적구조설계) 1. 서 언 지난 몇 십년 전부터, 각 조선소에서는 인건비의 상승으로 인해 선체 중량 및 건조비를 최소로 하는 경제적인 설계를 수행하는데 전력을 다하고 접수일 : 2007년 11월 27일, 승인일: 2008년 3월 6일 g교신저자: ssna@mokpo.ac.kr, 061-450-2761 있다. 최근에 들어 원자재비의 급상승으로 인해 선체 구조의 새로운 설계 방안을 모색할 필요성이 대두되고 있다. 다목적함수기법에 의한 최적 설계 연구는 1896년에 발표된 Pareto에 의한 다목적함수 최적화기법(Pareto 1896)을 이용하여 그 동안 다수의 연구(Shin 2000)가 이루어지고 있으나 실제 설계에 적용하기는 아직 어려운 점이 많이 있다.

A Study on the Weight Reduction of Mid-sized Bulk Carrier based on the Harmonized Common Structural Rules

지속적인 조선경기의 침체를 극복하기 위해서는 제조원가를 줄이는 것뿐 아니라 연료절감형 선형을 개발하는 것은 매우 중요 한 일이다. 이를 위해서는 설계 및 생산 전 분야에 걸쳐 부단한 노력을 해야 하며, 그 중에서도 최적설계를 통한 선체 중량을 줄 이는 것은 매우 효과적인 방법이라 사료된다. 최적설계를 수행하 기 위해서는 해당 선박의 관련 규정에 대한 분석과 실제 설계에 대한 적용단계의 연구가 선행되어야 한다. 2015년 7월부터 기존의 CSR-BC (International Association of Classification Societies (IACS), 2012)와 CSR-OT가 통합되 어 통합공통구조규칙(H-CSR Harmonized CSR)이 발효되었다 (IACS, 2015). 따라서 향후 계약되는 모든 유조선과 산적화물선 은 이 새로운 규칙에 기반을 두어 설계를 수행하여야 하는데, 운 항되는 상선 중 절반 이상이 유조선과 산적화물선임을 고려한다 면 통합공통구조규칙의 발효는 향후 상선 시장에서 매우 중요한 안건이 될 것이다. 그동안 통합공통구조규칙에 대한 경향분석과 직접 요구치에 통합공통구조규칙 기반 중형 살물선의 중량 절감에

Development of an Automated Design Algorithm for the Longitudinal Members of Oil Tankers based on H-CSR

국제해사기구(IMO)는 국제사회의 온실가스 저감 노력에 부응 하여 선박의 탄소가스 규제를 논의하고 있다. 이는 지구환경변화 를 막기 위한 온실가스 규제에서 비롯되었으나 해운산업에 있어 서는 고연비화 경쟁을 촉발하는 원인이 되고 있다. 고연비 선박의 개발을 위해 저항성능이 좋은 선형, 효율이 좋 은 엔진뿐만 아니라 최적구획배치 및 구조설계를 통한 구조 경량 화 연계의 필요성이 점증되고 있다. 기존의 선체 구조 설계에 이용될 수 있는 최적 설계 기법에 대 한 연구 (Na, 2005; Shin, et al., 2006; Jo, 2010)는 꾸준히 진 행되어왔으며, 전통적인 구조해석법을 기반으로 한 중앙 횡단면 의 최소 중량 설계 및 건조비 설계 등을 기본 설계에 응용해 왔 다. 이러한 최적 구조설계 기법은 설계의 흐름상 확정된 구획배 H-CSR 기반 유조선 종강도 부재의 설계 자동화 알고리즘 개발 박찬임 .정솔1,† .송하철2 .나승수2 .박민철1 .신상훈3 .이정렬4 국립목포대학교 대학원 조선해양공학과 국립목포대학교 조선해양공학과 현대중공업 선박연구소 (사)한국선급 IT융합연구팀

On the Standardization of FRP Ships for the Cooperative Production System

The cooperative production system was proposed as an efficient production system to reduce the ship construction cost and to enhance the competitiveness for small/medium sized shipbuilder in the previous paper. In viewpoint of cooperative production system, the specialization of the FRP ship sizes has already been accomplished to reduce the number of the hull molds by FRP shipbuilders of the Sapjin industrial complex located in Mokpo area in 2003. There also exist lots of effective methods, as a cooperative production system, to cut down the construction cost. In this study, an effective production system in connection with the super structure and outfitting members is proposed such as the standardization of those items and specialized company which intensively produces the super structure and outfitting members at the collectivization area for cooperative work.