• Journal of the Society of Naval Architects of Korea
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• v.42 no.3
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• pp.284-289
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• 2005

A structural design system is developed for the optimum design of double hull tankers based on the multi-objective function method. As a multi-objective function method, Pareto optimal based random search method is adopted to find the minimum structural weight and fabrication cost. The fabrication cost model is developed by considering the welding technique, welding poses and assembly stages to manage the fabrication man-hour and process. In this study, a new structural design is investigated due to the rapidly increased material cost. Several optimum structural designs on the basis of high material cost are carried out based on the Pareto optimal set obtained by the random search method. The design results are compared with existing ship, which is designed under low material cost.

• Journal of Power System Engineering
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• v.15 no.3
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• pp.65-69
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• 2011

This paper introduces the multi-coil eddy current sensor and its characteristic in magnetic material gas turbine rotor. In the past, magnetic particle inspection method was used for qualitative defect evaluation in magnetic material gas turbine rotor. And the ultrasonic inspection method was used for quantitative defect evaluation. Nowadays, eddy current method is used in magnetic gas turbine rotor inspection due to advanced sensor design technology. We developed multi-coil eddy current sensor for the rotor dovetail inspection. At first, rotor stress is analyzed for the determination of sensor position and number. The sensor coils are designed to cover the stress concentration area of rotor dovetail. We select optimum frequency according to material standard penetration data and experiment results. The rotor mock-up and artificial defects were made for the signal detection and resolution analysis of multi-coil eddy current sensor. The results show that signal detection and resolution capabilities are enhanced in comparison to the commercialized sensor enough for the gas turbine rotor inspection. So, this developed multi-coil eddy current sensor substituted for commercialized one and it applied in real gas turbine rotor inspection.

• Journal of the Korea Institute of Military Science and Technology
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• v.3 no.2
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• pp.179-188
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• 2000

Multi-disciplinary optimization design concept can provide a solution to many engineering problems. In the field of structural analysis, much development of size or topology optimization has been achieved in the application of research. This paper demonstrates an optimum design of a multi-layer cylindrical tube which behaves thermoelastically. A multi-layer cylindrical tube that has several different material properties at each layer is optimized within allowable stress and temperature range when mechanical and thermal loads are applied simultaneously. When thermal loads are applied to a multi-layer tube, stress phenomena become complicated due to each layer's thermal expansion and the layer thicknesses. Factors like temperature; stress; and material thermal thicknesses of each tube layer are very difficult undertaking. To analyze these problems using an efficient and precise method, the optimization theories are adopted to perform thermoelastic finite element analysis.

• Journal of Fashion Business
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• v.13 no.2
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• pp.123-135
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• 2009

To cope with the threats posed by climate change actively, this study tries to examine multi-functional fashion design with the moral awareness of environment, which could be a direct cause of climate change. Literature and patents on multi-functional fashion design following climate change at home and abroad are examined to find the trend of multi-functional fashion designs. And fashion design that can protect human body to cope with climate change is analyzed. This study found that first, it is necessary to recognize the environment problems in the design process so that material is used to the minimum to minimize pollution and enable welfare and continuation of human society; second, environmentally friendly production and rational consumption such as manual production without waste of energy and material need to be favored to minimize the destruction of environment; third, to cope with environment and climate changes, design that allows an item to have diverse functions is needed so that it can have varied lengths, widths, and thicknesses, and it can be put on and taken off.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.2
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• pp.65-71
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• 2022

Recently, multi-material structural topology optimization is more critical because it provides reasonable solution to weight reduction challenges and can as well provide effective conceptual design. For conventional multi-material topology optimization (MMTO), the number of design variable increases when the number of candidate materials increases, and accordingly, a significant increase in computational time occurs. Therefore, MMTO with a single design variable, such as the phase section method (PSM) was proposed. This research is focused on improving the PSM, considering three major limitations: the composition ratio does not represent the area or volume ratio, design variables are not sufficiently concentrated to target values, and certain materials are created less than they are required. To address such limitations, the redefined composition ratio and adjusted parameters for better convergence are proposed. The validation of proposed modifications is verified via two- and three-dimensional numerical examples.

• Steel and Composite Structures
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• v.27 no.2
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• pp.177-184
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• 2018

This study contributes to evaluate multiphase topology optimization design of plate-like structures on elastic foundations by using classic plate theory. Multi-material optimal topology and shape are produced as an alternative to provide reasonable material assignments based on stress distributions. Multi-material topology optimization problem is solved through an alternative active-phase algorithm with Gauss-Seidel version as an optimization model of optimality criteria. Stiffness and adjoint sensitivity formulations linked to thin plate potential strain energy are derived in terms of multiphase design variables and Winkler-Pasternak parameters considering elastic foundation to apply to the current topology optimization. Numerical examples verify efficiency and diversity of the present topology optimization method of elastic thin plates depending on multiple materials and Winkler-Pasternak parameters with the same amount of volume fraction and total structural volume.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.560-561
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• 2005

For the insulation design of a HTS cable, the withstand voltage of three kinds were proposed. One of them is the AC design withstand voltage, another is the impulse design withstand voltage, and the other is the partial discharge inception stress. However, the multi-layered effect was not considered on insulation design of a HTS cable at existent design process. Therefore in this paper, the electrical breakdown characteristics by multi-layered effect of LPP insulation paper were investigated. Based on these results, the insulation thickness of 22.9 kV class HTS cable was designed, and compared with existent design process.

• Korean Institute of Interior Design Journal
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• v.22 no.5
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• pp.216-224
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• 2013

There are the relevant provisions that apply to building regulations about the Building codes, Fire Protection laws, and more Multi-using interior finish materials businesses etc. The differences between these regulations are as follows: The Building codes is defined the main use of the building according to facilities to used to set the scale by the use of the floor space, On the other hand, Fire Protection laws are the basic purpose and the act of using the architectural space(or sales) by separating object by fire. And Multiple-using Businesses Facilities consist of two regulations engaged in the kind of law and the size of the floor area. One building can not be based on operating facilities and together in Multiple use businesses Law. As such, the Buildings are applied to the Building codes, Fire Protection laws, such as Multi-using Businesses Facilities interior construction industry due to the structural differences in the position of the designer feeling a lot of difficulties and confusion. The Multi-use businesses Facilities engage in the kind of law, the size of the floor area and seating capacity. These can not be based on operating facilities, and consists of two regulations together in one building. This study is purposed to help improving the finish of the interior architecture that is related to the Building code regulations, Fire Protection laws, Multi-using Facilities interior finishing material relevant with the provisions from the law through analyze the case of developed countries, and the current Multiple use Businesses Facilities research range from the law of multiple-using facilities, interior finishing, interior architecture for supervision reasonably and compensation for the interior design. So, Result is as follows: First, interior decorations can be separated the fixed material and the moveable things. second, It should be included multi-using Business though small size business space at the basement floor. third, It should be established statute law that design and construction responsibility. forth, re-testing fire resist performance after some period. and finally, it need to mitigate regulation where be installed sprinkler.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.387-388
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• 2008

This paper presents the design approach and test results of the Q-band precision subminiature coaxial adaptor based on transmission line theory using multi-step impedance and air-holes to increase its cutoff frequency. In order to increase the frequency performance, the adaptor is designed with hooked structure, fixing step, multi-air-holes, and outer conductor. The return loss increments due to the hooked structure and multi air-holes are minimized to 2 dB and 1.5 dB, respectively. A VSWR(Voltage Standing Wave Ratio) of <1.2 is obtained from DC to 40 GHz, while guaranteeing the durability of the adaptor from room-temperature$(25^{\circ}C)$ to $120^{\circ}C$.

• Journal of Information Technology Applications and Management
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• v.19 no.3
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• pp.19-30
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• 2012

Material selection is a complex problem in the design and development of products for diverse engineering applications. This paper is aimed to present a fuzzy decision making approach to deal with the material selection in engineering design problems. A fuzzy multi criteria decision-making model is proposed for solving the material selection problem. The proposed model makes use of fuzzy TOPSIS (Technique for Order reference by Similarity to Ideal Solution) with trapezoidal numbers for evaluating the criteria and ranking the alternatives. And result is compared with fuzzy VIKOR (VlseKriterijumska Optimizacija I Kompromisno Resenje in Serbian, means Multi criteria Optimisation and Compromise Solution) which is proposed by Jeya Girubha and Vinodh [2012]. The present paper is aimed to also improve literature of fuzzy decision making for material selection problem.