• International Journal of Aeronautical and Space Sciences
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• 제17권1호
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• pp.29-36
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• 2016

Tensairity girder is a light weight inflatable fabric structural concept which can be used in road emergency transportation. It uses low pressure air to stabilize compression elements against buckling. With the purpose of obtaining the comprehensive target of minimum deflection and weight under ultimate load, the cross-section and the inner pressure of tensairity girder was optimized in this paper. The Variable Complexity Modeling (VCM) method was used in this paper combining the Kriging approximate method with the Finite Element Analysis (FEA) method, which was implemented by ABAQUS. In the Kriging method, the sample points of the surrogate model were outlined by Design of Experiment (DOE) technique based on Optimal Latin Hypercube. The optimization framework was constructed in iSIGHT with a global optimization method, Multi-Island Genetic Algorithm (MIGA), followed by a local optimization method, Sequential Quadratic Program (SQP). The result of the optimization gives a prominent conceptual design of the tensairity girder, which approves the solution architecture of VCM is feasible and efficient. Furthermore, a useful trend of sensitivity between optimization variables and responses was performed to guide future design. It was proved that the inner pressure is the key parameter to balance the maximum Von Mises stress and deflection on tensairity girder, and the parameters of cross section impact the mass of tensairity girder obviously.

• 한국항공우주학회지
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• 제49권1호
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• pp.75-84
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• 2021

저자는 이전 두 편의 논문[1,2]을 통하여 미국과 유럽의 헬리콥터/회전익 개발에 대한 현황을 발표하였다. 그러나, 최근 세계적으로 진행되고 있는 차세대 회전익의 개발은, 이제까지 전통적으로 사용되었던 헬리콥터의 단점을 보완하는 새로운 형상(틸트 로터, 동축반전, 복합형)의 회전익 수직 이착륙기들이 나타나고 있다. 이러한 새로운 형상의 회전익 개발을 위해서는, 이제까지 전통적인 헬리콥터 개발에 사용되었던 기본개념설계/통합해석 프로그램을 한 단계 업그레이드한 새로운 설계/해석 프로그램이 필요하다. 미국과 유럽에서는 이미 반세기 이상 자체 축적되었던 기술 및 데이터 베이스를 이용하여 새로운 개발 프로그램들이 만들어지고 있다. 국내에서도 지난 20여 년간 헬리콥터와 다양한 형상의 회전익 개발이 이루어지면서 국내 연구진들에 의해 요소기술(공력, 구조해석 및 동역학, 비행역학, 소음해석 등 분야)들이 개발되었고 여전히 진행 중이다. 이들 개발된 요소기술들의 성숙도는 해외 선진국에 상응하는 정도이다. 본 논문에서는 미국/유럽에서 사용되고 있는 차세대 회전익 개발에 사용되는 기본개념설계/통합해석 프로그램들에 대한 장/단점들을 요약해 보고, 또한 앞에서 언급한 국내 연구진들에 의해 축적된 기술들에 대한 평가와, 이들을 통합하여 우리자체의 기본개념설계/통합해석 프로그램을 개발하는 가능성과 문제점들을 조사해 보았다.

• 자동차안전학회지
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• 제14권4호
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• pp.27-34
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• 2022

In the development of automated driving, interest in the interior parts of vehicle is to become more significant in terms of the occupant safety and comfort. This study proposed an optimal design of front seat according to the design requirements for frame stiffness and seat comfort. For the seat comfort, the appropriate foam thickness was obtained using the structural analysis under reclined occupant loadings. While the strength and stiffness analyses were performed to evaluate the seat frame structure. Topology optimization was carried out based on the simulation results and the derived optimal model and baseline seat design was updated. The conceptual seat design for the autonomous vehicle in this study showed that the model development process is appropriate for the design parameters in both frame stiffness and seat comfort.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.627-631
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• 2003

사용후연료 저장과 관련된 규정 중 구조에 대한 예상운전사고 및 설계기준사고의 구조 안전성이 보장되도록 설계하여야 한다. 이러한 구조 평가항목으로서 낙하, 전복, 폭풍, 홍수 및 지진으로 인한 사고에 대하여 하중조건과 구조적 개념평가 방법을 제시하고, 콘크리트 저장시스템에 대한 예비 구조안전성 해석을 수행하였다.

• 복식
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• 제58권4호
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• pp.58-71
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• 2008

The demand for personalized products and service of apparel product has increased dramatically. In order to acquire a personalized apparel product, consumers may have to sacrifice more expense or time. The purpose of this study was to investigate various personalization strategies in apparel business and to identify antecedents that influence the process. Clothing involvement and two price related variables (clothing expense and willingness to pay more) were included in the study as antecedents. Four personalization strategies were included in the study: design selection, size customization, in-store service and promotion personalization. For an empirical study, a conceptual model was designed and research questionnaire was developed. A measure of personalization of apparel shopping was developed based on existing scale items of prior research and a pilot study. Data from 766 men and women in their twenties to forties were used for statistical analysis. Structural Equation Modeling was used for the data analysis. Results indicated that the conceptual model was a good fit to data. Structural paths indicated that there was significant influence of clothing involvement on design selection and sales promotion personalization strategies. Involved consumers spent more on chothing products and were likely to pay more on personalized products and services. Monthly clothing expense influenced size customization significantly. It also had negative influence on service related personalization strategies. Consumers were willing to pay more when it comes to product related personalization strategies such as design and size but not necessarily to service related strategies. This study was an attempt to provide an in-depth and synthesized approach on consumer attitudes toward personalization of apparel products.

• Structural Engineering and Mechanics
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• 제12권6호
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• pp.573-594
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• 2001

A two-level displacement-based design procedure is developed. To obtain the displacement demands, elastic spectra for occasional earthquakes and inelastic spectra for rare earthquakes are used. Minimum global stiffness and strength to be supplied to the structure are based on specified maximum permissible drift limits and on the condition that the structure responds within the elastic range for occasional earthquakes. The performance of the structure may be assessed by an inelastic push-over analysis to the required displacement and the evaluation of damage indices. The approach is applied to the design of a five-story reinforced concrete coupled wall structure located in the most hazardous seismic region of Argentina. The inelastic dynamic response of the structure subjected to real and artificially generated acceleration time histories is also analyzed. Finally, advantages and limitations of the proposed procedure from the conceptual point of view and practical application are discussed.

• 한국의류학회지
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• 제40권1호
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• pp.131-147
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• 2016

This study investigated the relationship between fashion behavior, impression management behavior, and career success. A conceptual model and hypotheses were established based on theoretical linkages between the constructs. Thereafter, empirical data were collected using a set of questionnaires. For this reason, the sample was taken from 720 office workers' who worked at 14's Korea Enterprise, 697 of which was used for an empirical analysis (sample: men over 30 years of age and more than three years continuous service). This study conducted an exploratory factor analysis and confirmatory factor analysis for the validity test. Cronbach's alpha test is used for the reliability test. Moreover, PLS structural equation modeling (SEM) was employed to test hypothesized relationships in the conceptual model (SPSS 20.0 window/Smart PLS 3.0). This study shows that the proposed model is reasonably fit to the actual data. The following results were obtained from the analyses. First, fashion behavior and impression management behavior is positively related to career success. The result shows that economics of the fashion behaviors sub-types were statistically more significant to influence career success. The self-focused of the impression management behavior sub-types were more than statistically significant to influence career success. This finding has great implications to understand self-management behavior and the career success of male office workers.

• 국제강구조저널
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• 제18권4호
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• pp.1191-1199
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• 2018

Concepts of submerged floating tunnels (SFTs) for land connection have been continuously suggested and developed by several researchers and institutes. To maintain their predefined positions under various dynamic environmental loading conditions, the submerged floating tunnels should be effectively moored by reasonable mooring systems. With rational mooring systems, the design of SFTs should be confirmed to satisfy the structural safety, fatigue, and operability design criteria related to tunnel motion, internal forces, structural stresses, and the fatigue life of the main structural members. This paper presents a feasibility study of a submerged floating tunnel moored by an inclined tendon system. The basic structural concept was developed based on the concept of conventional cable-stayed bridges to minimize the seabed excavation, penetration, and anchoring work by applying tower-inclined tendon systems instead of conventional tendons with individual seabed anchors. To evaluate the structural performance of the new type of SFT, a hydrodynamic analysis was performed in the time domain using the commercial nonlinear finite element code ABAQUS-AQUA. For the main dynamic environmental loading condition, an irregular wave load was examined. A JONSWAP wave spectrum was used to generate a time-series wave-induced hydrodynamic load considering the specific significant wave height and peak period for predetermined wave conditions. By performing a time-domain hydrodynamic analysis on the submerged floating structure under irregular waves, the motional characteristics, structural stresses, and fatigue damage of the floating tunnel and mooring members were analyzed to evaluate the structural safety and fatigue performance. According to the analytical study, the suggested conceptual model for SFTs shows very good hydrodynamic structural performance. It can be concluded that the concept can be considered as a reasonable structural type of SFT.

• 한국정밀공학회지
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• 제13권7호
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• pp.66-77
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• 1996

Optimal topology design is to search the optimal configuration of a structure which can be used as a shape at the conceptual design stage. Our objective is to maximize the stiffness of the structures and ribs under a material usage constraintl. The density of each finite element is the design variable and its relationship with Young's modulus is expressed by quadratic form. The configuration is represented by the entire density distribution, the structural analysis is performed by finite element method and the optimiza- tion is performed by Feasible Direction Method. Feasible Direction Method can handle various problems simultaneously, that is, mult-objectives and multi-constraints. Total computation time can be reduced by the quadratic relationship between the density and the material property and fewer design variables than Homogenization Method. Toplogy optimization technique developed in this research is applied to design the shapes of the ribs.

• 한국건설관리학회논문집
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• 제19권5호
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• pp.70-80
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• 2018

최근 건설업계에서는 거푸집 공사의 작업 생산성 및 안전성을 향상시키기 위해 시스템 폼의 활용을 적극적으로 검토하고 있으며, 보 테이블 폼이 그 중 하나이다. 그러나 현재 보 테이블 폼은 층별로 보 규격이 일정한 건축물 시공에만 제한적으로 활용되고 있는 실정이다. 층별 용도에 따라 보 규격이 상이하게 설계된 건축물에서도 보 테이블 폼이 적용될 수 있도록 하기 위해서는 보 테이블 폼의 구성요소 중 하나인 보 브라켓이 간단한 조작만으로도 보 거푸집의 규격을 유연하게 조절시킬 수 있어야만 하는 것으로 분석되었다. 본 연구의 목적은 간단한 조작만으로도 보 거푸집의 규격 조절이 가능하며 현장 적용성 또한 우수한 보 테이블 폼 전용 가변형 보 브라켓의 개념 디자인을 제시하는 것이다. 본 연구의 보 테이블 폼 전용 가변형 보 브라켓 개념 디자인이 실물로 제작될 경우 층별 용도에 따라 보 규격이 상이하게 설계된 건축물에서도 보 테이블 폼의 적용이 가능하게 될 것이며, 이는 거푸집 공사의 작업 생산성 및 안전성 향상에 기여할 것으로 기대된다.