• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 춘계학술대회 논문집
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• pp.96-103
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• 2000

This research is a new design method, which will be presented as a basic concept for a more efficient minimum weight design of grillages, as an attempt to describe true collapse mechanism in as overall search as possible. It serves as introduction to the numerical technique of Linear Programming(LP) and Automatic Modified Direct Plastic Frame Analysis(AMDPFA). Attention is directed to both analysis and design, and emphasis is placed on the physical significance of Systematic Searching Techniques(SST) involved. In weight minimum grillages design, the parameterisation study in optimum beam configuration which was carried out over the range of beam sections for a given plastic section modulus likely to occur in structures by suing an adaptive stochastic optimisation technique, Genetic Algorithms.

• 대한조선학회논문집
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• 제41권6호
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• pp.91-101
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• 2004

For the grillage which is common types of structures in marine and land-based structural system, the elastic response and design methods are usually applied. However, plastic analysis and design methods are considered Tn those structures to maintain the structural stability at the limit states. In grillage design, the central intersection point load may be used as a worst loading condition. However, a point load may often move around on the grid system. in such case, the worst load point would not necessarily be at the central point. To investigate the variation of plastic collapse load according to the location of moving load between intersections, the plastic collapse loads are obtained for the three types of grillages with simply-supported ends. From the result of each case, it is confirmed that the worst load point is located between intersections. General formulae related with plastic collapse loads for the three groups of grillages with simply-supported boundaries are derived. Those plastic collapse formulae for the grillages are applied to the design of pontoon deck, and optimum design procedure is illustrated. Consequently, general formulae for the plastic collapse of grillages derived from this study can be easily applied to the plastic analysis and optimum design of similar grillages.

• 대한토목학회논문집
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• 제6권3호
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• pp.21-30
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• 1986

강(鋼) 격자항(格子桁)의 탄소성(彈塑性) 해석(解析)을 수행(遂行)할 수 있는 수치해석(數値解析) 방법을 제시하였다. 격자항(格子桁)의 각(各) 구성부재(構成部材)가 이상적(理想的) 탄소성(彈塑性) 성질(性質)을 갖는다고 가정하였는데 이 문제를 각(各) 구성부재(構成部材)의 양단(兩端)에 휨스프링과 비틂스프링을 부착(附着)한 모델을 고안(考案)해 냄으로써 해결(解決)하였다. 이 개념에 의거하여 격자항(格子桁)이 탄성상태(彈性狀態)에서 소성붕괴(塑性崩壞)에 이르기 까지의 거동(擧動)을 해석(解析)할 수 있는 프로그램 EPAG(Elasto-Plastic Analysis of Grillages)를 개발(開發)하였다. 이 해석방법(解析方法)의 특성(特性)은 하중(荷重)을 한꺼번에 가(加)할 수 있고, 격자항(格子桁)을 이루는 부재(部材)들의 배치가 규칙적(規則的)이 아니라도 적용이 가능하다. 또한 제하(除荷)(unloading)를 고려할 수 있으며 소성활절(塑性滑節)이 1개씩 형성될 때마다 가해진 하중(荷重), 부재단력(部材端力) 및 변위(變位) 등(等)을 구할 수 있다는 장점(長點)을 지니고 있다. 또한 기존의 논문이나 단행본(單行本)에 있는 예제(例題)들을 본(本) 프로그램으로 해석(解析)한 후 그 결과가 본(本) 프로그램으로 해석한 결과와 잘 일치한다는 것으로써 본(本) 이론(理論)의 정당성(正當性)과 정확성(精確性)을 확인하였다.

• 대한조선학회논문집
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• 제33권2호
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• pp.56-64
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• 1996

균일 분포 횡하중이 작용하는 격자형 구조물의 극한 해석법의 개발에 대한 이전의 연구(참고문헌 1과 5)를 검증해 보았고, 붕괴 이론에 있어서 면내력의 영향을 고찰 하였다. 논문의 주된 내용은 최소 중량과 최소 비용을 갖는 격자형 구조물의 최적설계법을 개발하였고, Pareto 해석법을 적용하여 다목적 함수를 갖는 구조물에서 최적 절충해를 구하는 최적화 기법을 소개하였다.

• 대한조선학회지
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• 제13권3호
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• pp.11-19
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• 1976

Grillages are abundant in ship structures and in many other types of structures such as bridges and building floors. Clarkson has shown that plated grillages can be satisfactorily analyzed as gridworks if an appropriate effective breadth is taken into account. Also, it has previously been pointed out, by Nielsen, that grillage calculations could be simplified by use of the Laplace transformation. In this paper, it is assumed that the torsional rigidity of the members and axial load are negligible, also that girders have the same scantling and spacing each other and so stiffeners do. Then the grillages composed of both-end-fixed girders and both-end-hinged stiffeners, which are subjected only to uniform normal loads are investigated. The calculus of variation is used to set up the differential equations and the Laplace transformation is applied to solve the differential equations. The program has been tested by FACOM 28 and the results show good agreements with those by the STRESS, which was developed in M.I.T.. The amount of the data input and computing time are much less than those of the STRESS. But this program has so much restrictions that it is urgent to extend the program to the grillage problems of arbitrary loading and boundary conditions.

• Structural Engineering and Mechanics
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• 제5권1호
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• pp.33-49
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• 1997

A method of analysis is proposed for curved multicell box girder grillages. The method can be used to analyze box girder grillages comprising straight and/or curved segments. Each segment can be modelled by a number of beam elements. Each element has three nodes and the nodal degrees of freedom (DOF) consist of the six DOF for a conventional beam plus DOF to account for torsional warping, distortion, distortional warping, and shear lag. This element is an extension of a straight element that was developed earlier. For a more realistic analysis of the intersection regions of non-colinear box girder segments, the concept of a rigid connector is introduced, and the compatibility requirements between adjoining elements in those regions are discussed. The results of the analysis showed good agreement with the shell finite element results, but the proposed method of analysis needs a fraction of the time and effort compared to the shell finite element analysis.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.110-117
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• 2004

The aim of a benchmark study is carried out nine methods are employed for ULS analysis which implicitly predict the ultimate strength of aluminium stiffened panels under axial compression. For this purpose, DNV PULS, experimental and numerical data on the ultimate strength of panels were collected. Comparison of these experimental / numerical, DNV PULS / numerical, results with theoretical solutions by the candidate methods is performed. Also it's compared that ALPS/ULSAP program is based on closed-form formula for the ULS of plates and grillages under axial compression. It is considered that ALPS/ULSAP methodology provides quite accurate and reasonable ULS calculations by a comparison with more refined FEA. Comparison of these experimental data, numerical, computational software results with the simplified solutions obtained by the candidate methods is then performed. The model uncertainties associated with the candidate methods are studied in terms of mean bias and COV (i.e., coefficient of variation) against experiments and numerical solutions, and the relative performance of the various methods is discussed.

• 전산구조공학
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• 제2권2호
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• pp.101-112
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• 1989

직교 이방성으로 보강된 평판 구조물 해석을 위한 방법제시가 본 논문의 주요 내용이다. 이 방법에서는 변형된 정적 압축법을 이용하여 직교 이방성으로 보강된 평판 구조물과 동등한 강성을 가지는 2차원 그릴리지 구조물을 생성하여 해석에 응용하고 있다. 대표적인 구조물을 선택하여 이론을 적용시켜 해석을 한 결과 직교 이방성으로 보강된 평판 구조물 해석에는 본 논문의 방법이 매우 효과적임이 입증되었다.

• 대한조선학회논문집
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• 제47권6호
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• pp.792-802
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• 2010

A plastic analysis method is commonly used in ship and offshore structural system to utilize the ultimate strength. In this paper, the basic principle of plastic analysis method is applied to ship grillages such as transverse oil-tight bulkheads. The main emphasis is placed on the optimum arrangement of grillage system to give minimum weight. Additional parametric study is carried out to find the effect of various arrangement of grillage system. The above methods are applied to oil-tight bulkhead design, and results are compared with the existing one.