• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.279-286
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• 2002

This study is concerned wiか the practical optimum design of concrete framed structures considering serviceability - deflection, crack, fatigue. The optimizing problems of framed structure are formulated with the objective function and the constraints which take the section properties as the design variables. The objective functions are formulated as the total cost of the structures and the constraints are derived by using the criteria with respect to safety and serviceability based on the part of concrete bridge in the Korea standard code of road bridge. The SLP method is introduced to solve the formulated nonlinear programming problems in this study and tested out through the numerical examples. This developed optimizing algorithm is tested out and examined through the numerical examples for the practical use of design on the concrete framed structures. And their results are compared and analyzed to examine the possibility of optimization, the applicability and the convergency of this algorithm.

• Structural Engineering and Mechanics
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• v.17 no.5
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• pp.611-626
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• 2004

On the basis of a structural analysis of radial gate (i.e. Tainter gate), the current paper focuses on weight minimization according to the location of the arms on a radial gate. In spite of its economical significance, there are hardly any previous studies on the optimum design of radial gate. Accordingly, the present study identifies the optimum position of the support point for a radial gate that guarantees the minimum weight satisfying the strength constraint conditions. This study also identifies the optimum position for 2 or 3 radial arms with a convex cylindrical skin plate relative to a given radius of the skin plate curvature, pivot point, water depth, ice pressure, etc. These optimum designs are then compared with previously constructed radial gates. Local genetic and hybrid-type genetic algorithms are used as the optimum tools to reduce the computing time and enhance the accuracy. The results indicate that the weights of the optimized radial gates are appreciably lower than those of previously constructed gates.

• Journal of Ocean Engineering and Technology
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• v.33 no.2
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• pp.146-152
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• 2019

A design system was developed for the doubler plate of a ship structure simultaneously subjected to in-plane loads and lateral pressure based on general dimensions and those of a representative ship structure. An equivalent design equation that considers various structural design parameters was derived by introducing the equivalent plate thickness theory, and the design of the doubler plate reinforcement of the ship structure was developed. A hybrid structural design system was established for a doubler plate simultaneously subjected to in-plane loads and lateral pressure consisting of two modules: an optimized design module and a double plate strength & design review module. The practical application of this design system was illustrated to show its usability. It was found that the design safety of the doubler plate was ensured, and this system could be used as an initial design guide to review the double plate reinforcement for a dent or corrosion of the ship plate members. Using the developed design system would make it possible to obtain a more reasonable doubler plate structure that considers the rational reinforcement of plate members of ship structures. In addition, a more reliable structural analysis using a strength evaluation process can be performed to verify the efficiency of the optimum structural design for the doubler plate structure.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.4
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• pp.84-90
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• 1997

The paper is mainly concerned with the applications tn develop an optimum structural design procedure for hatchcoverless container ship. L.R rules are applied to determine the scantlings of the longitudinal members. As for an object function of midship section design, the total sectional area of all the longitudinal members for midship section is selected. The SUMT procedure combined with direct search method is applied to the solution of nonlinear optimum design problem to find a optimum midship section arrangement. The results of optimization study show that the weight of model ship may be saved about 8.0% per unit length.

• 연구논문집
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• s.22
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• pp.65-74
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• 1992

This paper aims at calculating optimum design dimensions to minimize the weight satisfied strain and stress intensity of the frame while loading maximum weight into a mechanical press in the static condition. Analysis of the frame was carried out by using the FEM, then the optimum condition was obtained by using these data. As modeling in the finite element analysis has great impact on the reliablity of analysis results, the analyzed object was selected a 150-ton mechanical press of J Company, the part little affected to structural rigidity was simplified, the load condition was considered in the only maximum load, the boundary condition was used by giving symmetric displacement due to symmetric boundary condition, the finite element was applied a linear membrane element. An intermediate processor program applied the normal ANSYS to analyze finite elements was developed, and the design sensitivity was calculated. This program was applied to the optimum design.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.187-194
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• 2004

The structural behavior of superstructure by ILM is strongly dependent on the process of launching nose according to the construction process. The ratios of length, weight, and flexural stiffness of launching nose to those of superstructure are taken as the analysis parameters in this study. The interaction behaviors are analyzed according to the variation of parameters. Design formulas to pursue the optimum values for length, weight, and stiffness of launching nose are suggested through the parametric study. As a result, the minimum stiffness ratio is analyzed as I₂/I=0.045 and I₁/I=0.02 for the optimum track of the sectional force while the elastics modulus ratio is 6.8359. Additionally, the design results of real projects are analyzed by the developed formulas to verify that they are designed well in structurally optimal point of view.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.133-138
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• 1999

3차원 트러스 구조물을 설계대상으로, 구조계와 제어계의 동시최적설계문제에 대하여 고찰하였다. 구조 설계에대한 최소중량설계와 제어 설계에대한 외란 억제문제를 설계목적으로 고려하였다. 그리고, 본연구의 유용성을 입증하기위한 수치 시뮬레이션의 결과를 기술하였다.

• Structural Engineering and Mechanics
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• v.29 no.4
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• pp.391-410
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• 2008

In this article, a harmony search algorithm is presented for optimum design of steel frame structures. Harmony search is a meta-heuristic search method which has been developed recently. It is based on the analogy between the performance process of natural music and searching for solutions of optimization problems. The design algorithms obtain minimum weight frames by selecting suitable sections from a standard set of steel sections such as American Institute of Steel Construction (AISC) wide-flange (W) shapes. Stress constraints of AISC Load and Resistance Factor Design (LRFD) and AISC Allowable Stress Design (ASD) specifications, maximum (lateral displacement) and interstorey drift constraints, and also size constraint for columns were imposed on frames. The results of harmony search algorithm were compared to those of the other optimization algorithms such as genetic algorithm, optimality criterion and simulated annealing for two planar and two space frame structures taken from the literature. The comparisons showed that the harmony search algorithm yielded lighter designs for the design examples presented.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.10a
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• pp.216-223
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• 1993

The safety factors of current standard code are considered to be not appropriate compared to design and construction practices, even this safety factors are not determined from probabilistic study but merely from experiences and practices. This study pripose the optimum safety indices based on expected total cost minimization using only three parameters, which are the level of the failure cost to the initial cost by improvement in safety, and the order of the initial cost function.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.100-106
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• 2013

This paper describes an integrated optimization design using multilevel decomposition technique on the base of the parametric distribution and independent axiom at the stages of lower level. Based on Pareto optimum solution, the detailed parameters at the lower level can be defined into the independent axiom. The suspension design is used as the simulation example.