• Journal of the Society of Naval Architects of Korea
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• v.33 no.4
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• pp.97-105
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• 1996

For the minimum weight design of ship structures it is desirable that tank arrangement is predetermined to obtain the minimum weight and then structural arrangement and scanting of each murder is determined to obtain the minimum weight within the given tank arrangement. To carry out the tank arrangement to give minimum weight a minimum weight design program which covers whole ship structures is developed by the combination of minimum weight design program of longitudinal members by classification rules and minimum weight design program of transverse members by generalized slope deflection method which were developed by the authors. The hullweight is estimated by summation of the weight of cargo hold part and the weight except cargo hold part which can be estimated by the empirical formula. In this study, the variation of hullweight is shown with the number of tank, the number of web and the location of longitudinal bulkhead. For the application of actual design alternative designs of tank arrangement which satisfy MARPOL regulation are determined. And several minimum weight designs of whole ship structures are carried out to obtain the tank arrangement which gives minimum weight and then the hullweight is compared with that of existing ship.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.2
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• pp.131-135
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• 2013

In this study, to develop a light weight duo type aluminum LPG tank in stead of a conventional steel tank optimization technology is used. Two types of optimization method are carried out for internal compression test simulation of a LPG tank. The first is the thickness only optimization of LPG tank components. The second is the thickness and shape optimization. For the case of the thickness only optimization the weight reduction rate of an optimized tank compare to that of the initial design is 42%. Also 48% weight reduction was achieved for the case of the thickness and shape optimization.

• Textile Coloration and Finishing
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• v.10 no.2
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• pp.1-7
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• 1998

In this study, PET fabric was hydrolyzed with NaOH using the Tank m/c and Liquor-flow m/c to determine the alkali hydrolysis properties of PET fabrics. The results were as follows ： The weft density and tensile strength of PET fabrics hydrolyzed with Liquor-flow m/c were higher than those hydrolyzed with Tank m/c in case of less than 10％ of weight loss. However, above 10％ of weight loss, reverse phenomenon was showed. K/S value of hydrolyzed PET with Liquor-flow m/c was higher than that with Tank m/c above 10％ of weight loss. It was observed that the micropores of PET surface were collapsed due to physical force(abrasion and collision) during hydrolysis. Bending rigidity of hydrolyzed PET fabric was about 32％ and 40％ of bending rigidity of warp and weft direction of untreated fabric at 7％ of weight loss, respectively. Above 7％ of weight loss, decrease rate was decreased.

• Textile Coloration and Finishing
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• v.12 no.2
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• pp.121-128
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• 2000

This study discussed the mechanical properties such as bending and shear of polyester fabric treated with a several weight reduction machine. With the increase in the rate of weight loss, the bending rigidity of the warp and weft of treated fabric decreased regardless of the weight reduction machine. At 6.5% weight loss, the bending rigidity of warp and weft yarn decreased to $0.035\;gfcm^2/cm$ and $0.017\;gfcm^2/cm$, respectively, and these values show 54% and 94% of their untreated warp and weft. At same rate of the weight loss, the bending rigidity of polyester fabric treated with C.D.R slightly higher than that of the tank type or liquor-flow type. On the other hand, below 6.5% weight loss, the shear rigidity of the warp and weft of the treated fabric rapidly decreased. But with the increase in the above 6.5% rate of weight loss, the decreasing tendency of the shear rigidity declined. At same rate of the weight loss, the shear rigidity of fabric treated with tank type nearly equal to the that of the liquor flow type. But at same rate of the weight loss, the shear rigidity of the fabric treated with C.D.R type higher than that of the tank or liquor-flow type.

• Textile Coloration and Finishing
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• v.10 no.4
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• pp.37-44
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• 1998

The purpose of this study was to elucidate the effect of weight loss of polyethylene terephthalate(PET) fabrics on the mechanical properties such as bending and shear. In order to compare the effect of treatment machine on the mechanical properies of treated PET fabrics, PET fabrics were hydrolyzed with NaOH aqueous solution using Tank machine and Liquor flow machine, respectively. The results were as follows ： 1. The bending rigidity and shear stiffness of hydrolyzed PET fabric decreased markedly up to about 10％ weight loss regardless of treatment machines. At the above 10％ weight loss, the variation of these properties is nearly unchanged. In addition, the bending hysteresis and shear hysteresis also showed similar trend. 2. Weft density change of PET fabrics treated with Liquor flow machine decreased by 1pick/inch. It is assumed that this is attributed to the tension during the treatment of Liquor flow machine. On the other hand, the weft density change of PET fabrics treated with Tank machine is scarcely influeneced by the weight loss. While warp density of PET fabrics treated with Liquor flow machine had no change with weight loss, warp density of PET fabrics treated with Tank machine decreased by 6pick/inch due to the tension. 3. The bending rigidity and shear stiffness of PET fabrics hydrolyzed with liquor flow machine slightly higher than with Tank m/c at the above 10％ weight loss. It is assumed that this is caused by the increasement of the crossing pressure of warp and weft yarn and contact points of filaments in the yarns. Also, the bending and shear hysteresis of PET fabrics treated with Tank machine were higher than that of liquor flow machine.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.6
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• pp.12-19
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• 2003

Corrugated bulkheads for a bulk carrier are divided into watertight bulkheads and deep tank bulkheads. Design of the watertight bulkheads is principally determined by the permissible limit of Classification and IACS requirements. But, the verification of strength through finite element analysis is indispensable for design of the deep tank bulkheads. A stage for stress evaluation of corrugated part is required for optimum structural design of the deep tank bulkheads. Since the finite element analysis for real model requires excessive amount of calculation time, in this study one corrugated structure is replaced with beam element and is idealized as 2 dimensional frame structure connected to upper and lower stool Minimum weight design of the deep tank bulkheads is performed through generalized sloped deflection method(GSDM) as direct calculation method. The purpose of this study is the development of design system for the minimization of steel weight of deep tank bulkheads as well as watertight bulkheads. Discrete variables are used as design variables for the practical design. Evolution strategies(ES) is used as an optimization technique.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.38-60
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• 1999

The main objective of this study is systemization of the technique of ROC quantification and optimization of baseline design by applying CE principle to the acquisition process of a weapon system. QFD and TOA techniques can be employed to a good working example of the conceptual design of a future main battle tank. In this paper, Product Planning Phase, the first phase of four QFD phases, is deployed in terms of eight steps including customer requirements and final product control characteristics. TOA is carried out considering only combat weight. In order to perform combat weight analysis and performance TOA, Preliminary Configuration Synthesis Methodology is used. Preliminary Configuration Synthesis Methodology employs the method of least squares and described linear equations of weight interrelation equation for each component of tank. As a result of QFD based upon the ROC, it was cleared that armor piercing power, main armament, type of ammunition, cruising range, combat weight, armor protection, power loading, threat detection and cost are primary factors influencing design and that combat weight is the most dominant one. The results of TOA based on the combat weight constraint show that 5100 lb reduction was required to satisfy the ROC. The baseline design of a future main battle tank is illustrated with assumption that all phases of QFD are employed to development and production process of subsystems, components, and parts of main battle tank. TOA is applied in iterative process between initial baseline design and ROC. The detailed design of each component is illustrated for a future main battle tank.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.1
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• pp.118-126
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• 2000

An optimum structural design system for double hull oil tankers is developed based on the generalized slope deflection method which was previously proposed by the authors. For the optimization technique, the Hooke & Jeeves direct search method is applied to the minimum weight design problems with discrete design variables. A minimum weight design program is developed for the longitudinal members by the classification rules and for the transverse frames and the bulkhead members by the generalized slope deflection method. By this program, a minimum hull weight design of double hull oil tankers considering tank arrangement is performed and the design results are compared with existing ship. It is possible to find optimum tank arrangement and efficient types of hull structures for the minimum weight design of double hull oil tankers.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.1
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• pp.153-160
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• 2018

A pressure vessel consists of an inner tank and the outer tank; the material of the inner tank is austenite stainless steel, and the outer tank is general carbon steel. As the storage amount increase, the size of the inner tank for LNG also increases, which eventually increases the weight of the LNG storage tank. The Cold Stretch method can transport and store the LNG in a larger amount than the conventional pressure container, and the weight of the pressure vessel can also be reduced at 50 70% due to the reduction of the thickness, which is excellent from an economic and energy consumption perspective. Although the Cold Stretch method has these advantages, the domestic situation has not developed any related legislation. In this study, the actual production of pressure vessels using the Cold Stretch method will be processed and the volume expansion after the Cold Stretch will be checked and compared with the mechanical properties.

• Journal of the Korean Institute of Gas
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• v.18 no.2
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• pp.81-86
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• 2014

The analysis of the cost optimization and the total demand weight of 9% Ni-steel plates for installing shell stiffeners in the side wall of the large capacity LNG storage tank are carried out in order to reduce the costs of the plates for stiffeners. This study can be possible for developing the calculation program which evaluates the bill-of-material for stiffeners to reduce the manual calculation time of tank designer, and to enable the estimation of weight and cost for various plate width. The results show that the demand weight and cost are reduced as the plate width is wider. Nevertheless, both the weight and the cost with plate width for stiffeners should be compared and evaluated to obtain the optimum cost time to time because of various cost incremental factors of plates such as transportation and handling cost, etc.