• Computers and Concrete
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• v.14 no.3
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• pp.233-245
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• 2014

In this paper, a rule based Mamdani type fuzzy logic model for prediction of slippage at maximum tensile strength and slippage at rupture of structural lightweight concretes were discussed. In the model steel rebar diameters and development lengths were used as inputs. The FL model and experimental results, the coefficient of determination R2, the Root Mean Square Error were used as evaluation criteria for comparison. It was concluded that FL was practical method for predicting slippage at maximum tensile strength and slippage at rupture of structural lightweight concretes.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1988.10a
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• pp.36-42
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• 1988

In this study, a formulation of the idealized plate element based upon the idealized structural unit method(ISUM) firstly proposed by Ueda et．al is made in an attempt to analyze the geometric nonlinear behaviour up to the buckling strength of thin-walled long structures like box-column structure including the coupling effect between local and global buckling. An application to the example box-column is also performed and it is found that the present method gives reliable results with consuming very short computing times and therefore is very useful for evaluation of the buckling strength of thin-walled long structures.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.372-377
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• 2008

Camber with positive deflection is one of the very important design parameters in the manufacture of railway coach. Positive camber is defined as concave shape such as an arch and it increases the strength of structure remarkably. But during the operation of a structure, the positive camber turns into negative camber and it loses the strength of structure. Therefore we should consider the camber effect when we evaluate the fatigue strength of negative cambered structure. For this purpose, we made a model of negative cambered locomotive car body and performed structural analysis and also we measured the dynamic loads at critical points during commercial line operation. Fatigue strength of locomotive was calculated by applying Miner's damage accumulation rule. Fatigue strength of the two locomotives which have different camber were compared to find out the effect of camber on dynamic load amplitude. We found that the more negative camber a locomotive had, the shorter fatigue strength obtained.

• Computational Structural Engineering
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• v.20 no.1 s.75
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• pp.59-64
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• 2007

• Computational Structural Engineering
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• v.18 no.3 s.69
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• pp.50-55
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• 2005

• Special Issue of the Society of Naval Architects of Korea
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• 2017.10a
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• pp.32-37
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• 2017

Due to the nature of semi-submergible drilling rig, various equipments are arranged in a limited space, and therefore the many types of outfitting holes passing through the hull structure are densely arranged and that is required the detailed structural strength evaluation in terms of ULS and FLS by class or client. Particularly, semi-submergible drilling rig has a variety of global load which affects the structure strength around holes compared to general commercial ship, and its response of stress is also complicated, so it is difficult to carry out the prediction design of structural strength evaluation and reinforcement. In this regard, this paper presents a case study on the evaluation of structural strength for the various holes and large openings of semi-submergible drilling rig conducted by our company, as well as an established hole verification procedure.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.1
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• pp.59-68
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• 1997

Recently, the cases of using bonded dissimiliar materials which have each of the different components tend to increase for the purpose of developing new materials and using the special objects in the field of industry. Among the cases the strength evaluation of the joining materials of vehicle engine and the structural materials with ceramic/metal bonded joints becomes more important. But the residual stress occurs, because the joining of ceramics and metals is performed in extremely high temperature. It becomes a dominant cause to reduce the strength of the ceramic/metal bonded joints. In this paper, strength evaluation method of ceramic/metal bonded joints considering stress singularity was investigated by boundary element method and 4-point bending test. An advanced method of quantitative strength evaluation for ceramin/metal bonded joints is to be suggested.

• Journal of Welding and Joining
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• v.11 no.4
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• pp.112-124
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• 1993

It has been reported that fatigue damage sometimes occurred at the stress concentrated and dynamic loaded structural members of bulk carrier. In this paper, studies on fatigue strength of hull structures are reviewed, and the program for evaluating fatigue strength is developed. And the fatigue crack initiation and propagation on the end part of cargo hold frame of bulk carrier were calculated by FEM stress analysis and the fatigue strength evaluation program. These method can be applied not only to the crack initiation life but also to crack propagation life for the hull structural members at the hull design stage and be effective as the guideline to prevent the crack initiation or to estimate the fatigue strength for repairing of the fatigue damaged structures of real ships.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.162-169
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• 2001

Tubular joints are usually reinforced using thicker can section or ring stiffeners to increase the load carrying capacity. In this paper, a numerical study has been performed for evaluation of axial strength for X-joints with internal ring stiffener, The finite element analysis software was used for nonlinear strength analysis. According to variation of ring geometries, the effect of ring stiffener for X-joints are investigated. Internal ring stiffener is found to be efficient improving ultimate strength of tubular joints. Relations of thickness of ring and axial strength are observed considering geometric parameters of ring stiffeners.

• Journal of Ocean Engineering and Technology
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• v.22 no.2
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• pp.91-98
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• 2008

In order to establish a design guide for the bottom plate structure of a 4.3 ton aluminum planning boat, the feasibilities of bottom plate scantling of the ship are investigated based on the results of structural strength analysis and a simple equation and evaluation system are developed for initial structural design purposes. This study consists of 5 steps: First, the background, necessity, and purpose of this study are explained briefly, Second, the principal dimensions of this ship, the position of the considered bottom plate members and material characteristics are introduced. Third, the equivalent design pressure concept is introduced and evaluated based on experience and experimental data. Fourth, the strength of bottom plate members are examined using elasto-plastic nonlinear structural analysis, and response levels and several boundary conditions are reviewed based on the analysis results. Finally, in order to suggest design guides in respect to the ship's structural design, a simple design equation and evaluation system for bottom plate members are suggested for boats in the 4.3 ton aluminumboat range through the introduction of safety factorsbased on the ultimate design pressure concept.