• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2011.04a
• /
• pp.689-692
• /
• 2011

본 논문에서는 해양작업 상태의 하중조건을 고려한 부유식 원유생산 저장 하역 장치에 설치된 라이져 보강구조의 강도설계에 관련하여 다양한 근사화 기법 기반 설계 최적화 및 그 성능을 비교하고자 한다. 설계 최적화 문제는 하중조건별 구조강도의 제한조건 하에서 중량을 최소화하여 설계변수인 구조 부재치수가 결정되도록 정식화 된다. 비교 연구를 위해 사용된 근사화 기법은 반응표면법 기반 순차적 근사최적화(RBSAO), 크리깅 기반 순차적 근사최적화(KBSAO), 그리고 개선된 이동최소자승법(MLSM) 기반 근사최적화 기법인 CF-MLSM와 Post-MLSM이다. 본 연구에 적용한 MLSM 기반 근사최적화 기법들은 제한조건의 가용성을 보장할 수 있도록 새롭게 개발되었다. 다양한 근사화 모델 기반 설계 최적화 기법에 의한 결과는 설계 해의 개선 및 수렴속도 등의 수치적 성능을 기준으로 실제 비근사 설계최적화 결과와 비교검토 하였다.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.5 no.4
• /
• pp.74-81
• /
• 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.

• Journal of the Society of Naval Architects of Korea
• /
• v.37 no.1
• /
• pp.118-126
• /
• 2000

An optimum structural design system for double hull oil tankers is developed based on the generalized slope deflection method which was previously proposed by the authors. For the optimization technique, the Hooke & Jeeves direct search method is applied to the minimum weight design problems with discrete design variables. A minimum weight design program is developed for the longitudinal members by the classification rules and for the transverse frames and the bulkhead members by the generalized slope deflection method. By this program, a minimum hull weight design of double hull oil tankers considering tank arrangement is performed and the design results are compared with existing ship. It is possible to find optimum tank arrangement and efficient types of hull structures for the minimum weight design of double hull oil tankers.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.13 no.2
• /
• pp.121-133
• /
• 1993

Presented is a study on the establishment of a method of advanced reliability analysis for the realistic analysis and design of reinforced concrete(RC) structures. Considerable variabilities exist in concrete structures due to random nature of concrete materials and member dimensions. The present study analyzes first the uncertainties in concrete, reinforcements and member dimensions and then a method is proposed to determine the probability uncertainties of basic variables. The limit state equations are also proposed for the RC members with axial compression and bending and RC footings. The advanced invariant second-moment method is applied to analyze those structures. The present study provides an important base for realistic reliability analysis of RC structures.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.9
• /
• pp.1099-1107
• /
• 2013

This study proposes a weight reduction design for urban transit, specifically, a Korean EMU carbody made of aluminum extrusion profiles, according to size optimization and useful material changes. First, the thickness of the under-frame, side-panels, and end-panels were optimized by the size optimization process, and then, the weight of the Korean EMU carbody could be reduced to approximately 14.8%. Second, the under-frame of the optimized carbody was substituted with a frame-type structure made of SMA 570, and then, the weight of the hybrid-type carbody was 3.8% lighter than that of the initial K-EMU. Finally, the under-frame and the roof-panel were substituted with a composite material sandwich to obtain an ultralight hybrid-type carbody. The weight of the ultralight hybrid-type carbody was 30% lighter than that of the initial K-EMU. All the resulting carbody models satisfied the design regulations of the domestic Performance Test Standard for Electrical Multiple Unit.

• Journal of Conservation Science
• /
• v.19
• /
• pp.73-84
• /
• 2006

The conservation methods for the charred-woods excavated under the Daewoongjeon Hall of Youngguksa Temple, Youngdong, Chungbuk, Korea were investigated. The tests revealed that PEG#400 10% for four days followed by gradual application of PEG#4000 10% to 40% showed the most stable and robust results, showing no cracks in macroscopic examination. This treatment method was applied to the two charred elements, which appeared to be the capitals at the excavated site. After the treatment, the consolidated capitals were transported to the laboratory, where they were retreated with PEG#4000 80% at $85^{\circ}$.... Charred capitals showed also an excellent level of stability.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.10 no.2 s.21
• /
• pp.41-47
• /
• 2004

Plate has cutout inner bottom and girder and Door etc. in hull construction absence is used much, and this is strength in case must be situated, but establish in region that high stress interacts sometimes fatally in region that there is no big problem usually by purpose of weight reduction, a person and freight movement, piping etc.. Because cutout‘s existence is positioning in this place, and, elastic bucking strength by load causes large effect in ultimate strength. Therefore, perforated plate elastic bucking strength and ultimate strength is one of important design criteria to decide structural elements size at early structure design step of a ship. Therefore, we need reasonable & reliable design formula for elastic bucking strength of the perforated plate. The author computed numerically ultimate strength change about several aspect ratios, cutout dimension, and plate thickness by using ANSYS Finite element analysis code based on finite element method in this paper.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.29 no.1
• /
• pp.55-60
• /
• 2005

Plate that have cutout inner bottom and girder and floor etc. in hull construction absence is used much, and this is strength in case must be situated, but establish in region that high stress interacts sometimes fatally in region that there is no big problem usually by purpose of weight reduction, a person and change of freight, piping etc.. Because cutout's existence gnaws in this place, and, elastic buckling strength by load causes large effect in ultimate strength. Therefore, perforated plate elastic buckling strength and ultimate strength is one of important design criteria which must examine when decide structural elements size at early structure design step of ship. Therefore, and, reasonable elastic buckling strength about perforated plate need design ultimate strength. Calculated ultimated strength change several aspect ratioes and cutout's dimension, and thickness in this investigation. Used program applied ANSYS F.E.A code based on finite element method.

• Proceedings of KOSOMES biannual meeting
• /
• 2004.11a
• /
• pp.129-135
• /
• 2004

Plate has cutout inner bottom and girder and floor etc in hull construction absence is used much, and this is strength in case must be situated, but establish in region that high stress interacts sometimes fatally in region that there is no big problem usually by purpose of weight reduction, a person and change of freight, piping etc. Because cutout's existence gnaws in this place, and, elastic budding strength by load rouses large effect in ultimate strength. Therefore, perforated plate elastic budding strength and ultimate strength is one of important design criteria which must examine when decide structural elements size at early structure design step if ship. Therefore, and, reasonable elastic budding strength about perforated plate need design ultimate strength. Calculated ultimate strength change several aspect ratioes and cutout's dimension, and thickness in this investigation. Used program applied ANSYS F.E.M code based on finite element method

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.20 no.4
• /
• pp.463-468
• /
• 2007

Some network equipments made in Korea were exposed to severe earthquake in Japan several years ago. More than a hundred slim base transfer network stations had been seized with the severe earthquake at Nigata and it was reported that less than fifteen sets showed blackout by interruption of electricity, not by the structural failure. The purpose of this paper is to check the structural safety of the network equipments by performing table test, and the static and dynamic finite element analysis. For the dynamic test, the station weighing 200 kg was subjected to the Zone 3 earthquake loading of GR-63-CORE on the shaking table to obtain the dynamic responses to compare with the analysis results. It is shown that the FE analysis results are a little bit larger than that of the experimental values. And the sensitivity analysis and optimization for the natural frequency is performed and it is found that the first natural frequency is sensitive to small design change as shown in the results. And the dynamic response of optimized design is less than the original design.