• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.933-939
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• 2001

A Satellite shipping container must afford the satellite a relatively benign thermal, vibration, and particle environment that is oblivious to the extreme temperatures, sand, dust, vibrations and shocks that can accompany the transportation. In this study, we have designed a vibration isolation system of a spacecraft container that will be used to transport a satellite called KOMPSAT (KOrea Multi-Purpose SATellite) -2 from KARI (Korea Aerospace Research Institute) Taejon to its launch site. To identify the dynamic characteristics of the system, a 1/3-scaled mockup of the container was developed. A large electro-magnetic shaker (Max. 240 KN) was used to excite the mockup, and vibration signals from 20 points were collected for modal tests. Numerical simulations through CATIA 3D Modeling were performed to identify the behavior of isolation springs. The results showed that a simplified model predicts the behavior in a reasonable accuracy. Moreover, the model guides us how to design a full-scaled satellite-shipping container.

• Bulletin of the Society of Naval Architects of Korea
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• v.24 no.2
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• pp.36-46
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• 1987

This paper presents the results of seakeeping tests in a container ship model in irregular head waves. A time domain signal generating procedure is devised so that the wave maker behaves in accordance with the specified wave spectrum. The surface elevation of generated waves is measured and analysed to render the recorded wave spectrum for comparison with the specified one. Correction is made to the time domain signal until the differences between the two spectra become negligible. The motion responses and vertical acceleration of the self-propelled ship model are measured and analysed by both the spectral and the double amplitude methods. The two methods give nearly same statistical values. Finally the recorded spectra are compared with those calculated from the frequency domain motion analysis to show the credibility of the experimental results.

• Bulletin of the Society of Naval Architects of Korea
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• v.31 no.4
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• pp.10-13
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• 1994

최근 선박의 대형화, 고속화로 인하여 추진기의 부하가 증가되고 있으며, 특히 최근 등장한 1,000TEU급 콘테이너선의 경우 추진기가 흡수해야되는 축마력이 70,000HP 이상인 경우도 잇다. 커다란 축마력을 흡수하여 선박을 빠른 속도로 추진시켜야 되는 최근의 추진기는 작동 원리상 캐비테이션 발생을 피할 수 없으며 캐비테이션 발생량의 허용범위 및 캐비테이션 거동의 특성을 고려하여 추진기를 설계하여야 된다. 캐비테이션의 여유가 없이 추진기 설계가 수행되기 때문에 추진기 캐비테이션의 성능해석은 엄밀한 정밀도가 요구된다. 캐비테이션이란 일정한 온도에서 유체동력학 작용에 의해서 유체주위의 압력이 일정한 압력(예 : 증기압) 이하로 낮아질 때 물이 기화하여 수증기로 변하면서 빈 공간을 형성하는 현상을 말한다. 이렇게 발생된 캐비티는 주위 압력환경에 따라 생성, 성장, 수축, 붕괴의 과정을 거치게 된다. 특히 붕괴의 과정은 짧은 시간 내에 급격히 진행되기 때문에 진동 및 소음의 원인이 되고, 심할 경우 추진기 혹은 주위 물체 표면에 침식작용의 원인이 되기도 한다. 본 고에서는 캐비테이션의 물리적 특성 및 분류방법을 간단히 소개하고, 캐비테이션에 의한 선박추진기의 성능저하 특성 및 모형시험 기법을 이용한 캐비테이션 성능해석법을 소개하였다.

• Journal of Korean Port Research
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• v.5 no.1
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• pp.3-22
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• 1991

In recent years the hatchcoverless(or open-top) containerships have been evolving as a promising new concept for enhanced containership operations. The design concept of the hatchcoverless containership is innovative and appears to be worthwhile. especially from an operational viewpoint. The hatchcover and container lashing system have been eliminated and the containers are stacked in open hold fitted with cell guides. Thus this design concept can provide a more efficient and economically viable fleet due to the reduced time and cost of loading and unloading operations. Therefore turnaround time in port is also greatly reduced. This examination provides. brief background, advantages, brief review of new building containership, highlights of the pertinent areas requiring special consideration and recommendations of possible analyses herein.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.30-39
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• 1993

The study is concerned with the thermo-viscoplastic finite element analysis of nonisothermal hot container extrusion through conical dies. The problem is treated as a non-steady state incorporating the nonisothermal heat transfer analysis. The analysis of temperature distribution includes heat transfer though the boundary surface including conduction, convection and radiation. The analysis of heat transfer is decoupled with the analysis of deformation and the material interaction is considered through iteration procedure. The effect of important process parameters including die angle and extrusion ratio in the process is investigated. Due to the geometric feature for the container extrusion through conical dies, automatic remeshing is mandatory. Automatic remeshing is achieved by introducing the modular remeshing technique.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.204-207
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• 2001

The bending process for the circular curved tube and rectangular curved tube with fins can be developed by the hot metal extrusion machine with the multiple punches moving in the different velocity. The bending phenomenon can be controlled by the two variables. The one of them is the difference of velocity at the die exit section by the different velocity of billets through the multi-hole container. The other is the one by the different hole diameter. The results of the experiment show that the circular curved tube with fins and rectangular curved tube with pins can be formed by the extrusion process and that the curveture of the product can be controlled by the velocity of punch and diameter of container hole and that the defects such as the distortion of section and the thickness change of the wall of tube the folding and wrinkling of thin tube and fins did not happen after the bending processing by the extrusion bending machine.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.212-215
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• 2001

The bending process for the rectangular curved tube can be developed by the hot metal extrusion machine with the multiple punches moving in the different velocity. The bending phenomenon can be controlled by the two variables, the one of them is the difference of velocity at the die exit section by the different velocity of billets through the multi-hole container. The other is the difference by the different hole diameter. The results of the experiment show that the rectangular curved tube can be formed by the extrusion process and that the curvature of the curved product can be controlled by the velocity of punch and the diameter of container hole and that the defects such as the distortion of section and the thickness change of the wall of tube and the folding and wrinkling of thin tube did not happen after the bending processing by the extrusion bending machine.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1991.04a
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• pp.127-132
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• 1991

충격에 민감한 용기나 기계들은 운반이나 보관중에 받을 수 있는 진동충격 을 완화시키기 위해 충격 마운트를 이용하게 되며, 충격마운트는 용기나 기 계들이 허용하는 최대가속도와 이들이 취급되는 환경에 의해 적절히 선정되 어야 한다. 그러므로 내충격 설계는 최대 허용 가속도나 취급환경에 대한 사 양과 이 사양에 의한 충격 마운트의 선정, 그리고 선정된 내충격 시스템의 충격시험에 의한 오일 탬퍼의 결합용이 사용되기도 하지만 구조가 복잡하고 가격이 비싸서 대용량이 경우에만 국한되어 사용되고 있으며, 가장 경제적인 것은 방진고무를 사용한 것이다. 내충격 시스템은 일반적으로 큰 변형량을 요구하고 있으며, 방진고무의 경우 큰 변형에서는 hardening 스프링의 비선 형성을 가지고, 형상계수와 고무배합율에 따라 정적 스프링상수와 동적 스프 링상수가 큰 차이를 보이는 등, 설계상의 여러 제한이 있다. 그러나 방진고 무는 형상변화가 자유로우며 제작이 용이하기 때문에 이러한 장점을 이용하 면 저렴하고 다양한 용도의 충격마운트 제작에 효과적으로 사용될 수 있다. 본 논문에서는 원통형 콘테이너의 내충격 설계를 위해 충격사양에 의한 충 격마운트의 설계, 설계된 내충격 시스템의 충격시험에 의한 검증을 순차적으 로 실시하여, 방진고무를 이용한 충격마운트 설계기술을 제시함으로써, 이후 방진고무제품의 설계를 위한 자료 및 과정의 제정에 도움을 주고자 한다.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.2
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• pp.119-126
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• 1996

A hydraulic type active control system has been developed for the purpose of vibration suppression of ship superstructrures. The active mass of the developed system weighs about three tons and is designed to have ${\pm}5mm$ stroke below 10Hz. Thus maximum control force of the system is about 60kN. Performance test of the developed system has been carried out on a 4,400TEU contrainer carrier built in Samsung Heavy Industry Co., LTD. Through the exciter tests, it has been confirmed that the vibration levels of the superstructure can be reduced to about 20% of the uncontrolled levels near resonant frequency.

• Journal of Ocean Engineering and Technology
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• v.24 no.2
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• pp.62-66
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• 2010

The goal of this work is to establish the reliability of FCA welded joints for high strength EH36-TMCP ultra thick plate. For this, heat conduction and thermo elasto-plastic analyses have been conducted on a multi-pass, X-groove, butt-joint model to clarify the thermal and mechanical behavior (residual stresses, magnitude of the stresses, and their production and distribution mechanisms) of the weld joint. In addition, the results of the welding residual stress obtained from thermo elasto-plastic analysis was verified and compared with results obtained by XRD analysis.