• Journal of Ship and Ocean Technology
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• 제12권1호
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• pp.45-56
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• 2008

Recently, International Association Classification Societies (IACS) has adopted the Common Structural Rules (CSR) for Bulk Carriers and Tankers, which specifies the requirement associated with the ultimate strength of hull girder structure. The theoretical background and the results of verification study are neither well summarized nor released. Furthermore, the requirement is not a form of deterministic formula but a form of program in which source code is not disclosed. The reliability of the non-linear structural analysis program is verified through the comparison with the results of the analysis and the model test. Then, the reliability of the ultimate strength requirement in CSR is checked by comparing with the results of rigorous non-linear analysis.

• 대한조선학회 특별논문집
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• 대한조선학회 2011년도 특별논문집
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• pp.117-126
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• 2011

The buckling assessment of plate panels described in common structural rules (CSR) is to be determined according to the buckling utilization factor with hull girder stresses calculated on net hull girder sectional properties. As the thickness requirement for the buckling assessment of plate panels is not explicitly given in CSR, a lot of time is spent to find the proper thickness of plate panels until reaching to an allowable buckling utilization factor. In this study, in order to reduce time and cost, the thickness requirement of plate panels satisfying buckling assessment was derived. The structural design system included with the thickness requirement for buckling assessment was developed. The system is called as Oil-tanker Automated Structural Investigation System (OASIS). The design result of longitudinal strength members using OASIS was verified by Nauticus Hull which is the rule scantling software of DNV. Finally, optimum design of a double hull tanker for the minimum weight using OASIS was presented.

• 항공우주시스템공학회지
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• 제12권4호
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• pp.26-34
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• 2018

이륙 중량 25 kg급 멀티콥터용으로 개발된 프로펠러에 대해 정적 구조 시험 및 성능 시험을 통해 설계 요구도 충족 여부를 판별하기 위한 시험 평가를 수행하였다. 정적 구조 시험에서는 극한 하중 및 요구도 하중 부가 후 시편 파손이 발생하지 않음으로써 프로펠러 구조 강도에 대한 안전 여유 3 이상을 갖는 것으로 나타났다. 성능 시험에서는 설계 요구도의 제자리 비행 추력 및 최대 추력을 발생시키고, 운용 추력 영역에서 제자리 비행 성능 효율은 0.73 이상을 나타내었다. 기준 프로펠러와 비교할 때, 성능 효율 최대값은 3% 이상 증가되고, 소비 전력은 운용 영역에서 4% 이상 저감되는 것으로 나타났다. 구조 강도 요구도 및 성능 요구도를 충족시킴으로써 프로펠러는 성공적으로 개발된 것으로 평가되었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.70-71
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• 2014

The structural work is the main process of building construction which influence on the time, cost, safety and quality. The form work is one of the main process which has from 20 to 30 percentage of structural work. Especially the form work for beams is complex and need more manpower compared with form work for column or slab. When the existing forms such as plywood form, steel framed wooden form and aluminum form, is used for form work of beam, it would result in the cost overrun caused by needs of lots of manpower and resources. Therefore, the aim of this study is analysis of the requirement for development of SMART beam form. The result of this study shall be used for the development of SMART form work system.

• Structural Engineering and Mechanics
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• 제34권6호
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• pp.739-753
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• 2010

Pointing to the design requirement of prestressed space grid structure being the target cable force, the pretension scheme decision analysis method is studied when there's great difference between structural actual state and the analytical model. Based on recursive formulation of cable forces, the simulative recursive system for pretension process is established from the systematic viewpoint, including four kinds of parameters, i.e., system initial value (structural initial state), system input value (tensioning control force scheme), system state parameters (influence matrix of cable forces), system output value (pretension accomplishment). The system controllability depends on the system state parameters. Based on cable force observation values, the influence matrix for system state parameters can be calculated, making the system controllable. Next, the pretension scheme decision method based on cable force observation values can be formed on the basis of iterative calculation for recursive system. In this way, the tensioning control force scheme that can meet the design requirement when next cyclic supplemental tension finished is obtained. Engineering example analysis results show that the proposed method in this paper can reduce a lot of cyclic tensioning work and meanwhile the design requirement can be met.

• 한국군사과학기술학회지
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• 제17권2호
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• pp.275-281
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• 2014

Although self-propelled artilleries are mobile equipment, they need their own covered-positions for survival against preemptive strikes. The most important military requirement is enough protective capacity against blast pressure caused by explosion. This paper aims to assess the protective capacity of the newly-placed concrete box-type artillery positions using accurate structural geometric models as well as soil-structure interaction analysis. The commercial program is used to model the structural geometry of the positions. In order to describe the correct wave propagation in the backfill along with soil-structure interaction, used parameters in shock equation of state are selected based on the related studies as well as theories and then their final results are verified with the ones calculated with empirical equations in the US Unified Facility Criteria. In sum, it could be concluded that the protective capacity of the newly-built positions satisfies the protective structural requirement.

• 한국전산구조공학회논문집
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• 제23권5호
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• pp.543-550
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• 2010

내진설계는 타 설계의 요구사항, 즉 각 구조부재의 설계강도가 소요강도 이상이어야 한다는 것을 만족해야 하는 동시에 지진발생시 구조물의 항복과정을 규명하여 제시하여야 한다. 이러한 요구사항이 추가되는 이유는 타 하중과는 차별되는 지진하중의 불확실성이다. 이 연구에서는 일반교량을 해석대상교량으로 선정하고 연결부분의 설계를 수행하여 연성파괴메카니즘을 확보하는 과정을 제시하였다. 이와 같은 과정으로부터 구조부재의 강도 증가 또는 지진저감장치 도입 등의 비용증가 없이 타 설계에서 요구되는 구조부재의 강도 이내에서 내진성능을 확보할 수 있다는 것을 확인하였다.

• 한국산학기술학회논문지
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• 제16권9호
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• pp.5763-5768
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• 2015

압력방출밸브는 높은 압력을 조절하여 안정성을 유지하는 기계적 요소로, 압력용기, 증발기, 파이프라인 등 사용되고 있다. 높은 압력이 발생되면 스프링의 탄성력을 사용하여 압력방출밸브의 출구로 유체를 흘려보냄으로써 압력을 낮추게 되고, 정상적인 압력으로 돌아오게 되면 압력방출밸브는 초기상태로 돌아가게 된다. 압력방출밸브는 순조롭게 작동되어지기 위하여 요구되는 구조적 안정성을 만족하도록 설계되어져야한다. 본 연구에서는 상업용 소프트웨어 ANSYS/WORKBENCH를 사용하여 압력방출밸브의 유동해석과 구조해석을 수행한 결과 구조적 문제를 발생시킨다는 것을 알 수 있었다. 따라서 구조적 안전성을 만족하는 설계를 수행하고, 설계변수에 따른 구조적 안전성을 예측해보고자 한다.

• The Journal of Asian Finance, Economics and Business
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• 제8권10호
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• pp.259-267
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• 2021

Both structural transformation and education are the predominant subjects in the literature of development economics. This study examines the relationship between education before the tertiary level and the structural transformation of provinces by using Vietnam as a case study. In this study, education before the tertiary level would be disaggregated into three groups: primary, lower secondary, and upper secondary, then analyzed simultaneously on three-panel data models. Research data is taken from the statistical yearbook of provinces in Vietnam for 2015-2018. Research results show that education before the tertiary level plays a vital role in structural transformation. The enrolment rate of various education levels has a different influence on economic structure, and the lower secondary level has more significant effects than the upper secondary level. This reflects that participating in lower secondary is a fundamental requirement for taking some jobs in the non-agriculture sector, while upper secondary helps to upgrade the learner's abilities to respond to higher requirement jobs. The high rate of repeaters in upper secondary education will slow down the structural shift towards non-agriculture, and changing the traditional attitude about repeaters plays an essential role in improving this rate.

• 한국산업경영시스템학회:학술대회논문집
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• 한국산업경영시스템학회 2002년도 춘계학술대회
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• pp.139-149
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• 2002

This paper presents an approach to derive probability models for use in structural reliability studies. Two main points are made. First, that it is possible to translate engineering and physics knowledge into a requirement on the form of a probability model. And second, that making assumptions about a probability model for structural failure implies either explicit or hidden assumptions about material and structural properties. The work is foundational in nature, but is developed with explicit examples taken from planar and general stress problems, the von Mises failure criterion, and a modified Weibull distribution.