• 대한조선학회 특별논문집
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• 대한조선학회 2013년도 특별논문집
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• pp.13-20
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• 2013

In this paper, a collision accident of a container/Ro-Ro ship was numerically analyzed. A container trailer collided with a longitudinal bulkhead of the ship in the accident, which constituted a longitudinal wall of a heavy fuel oil tank. Due to the accident, the bulkhead plate was ruptured and the heavy fuel oil spilled out of the tank. The detailed information regarding the collision velocity and the mass of the trailer was not provided. Therefore, several collision accident scenarios were constructed based upon the arrangement of the ramp way. Each collision accident scenario was analyzed to predict the extents of damage using a commercial numerical package, ABAQUS. Based on the analysis results it is proposed how to minimize the extents of damage. Through the investigations performed in this study it was found that the understandings of various damages due to collision accidents and the developments of structural design guidance against collision are necessary for the betterment of Container/RO-RO ships' performance.

• 자동차안전학회지
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• 제14권4호
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• pp.113-119
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• 2022

The structural safety of hydrogen buses is being evaluated for the successful introduction of hydrogen buses. The crash test methodology, for example, side impact test procedure is being discussed for hydrogen bus structure safety with a compressed hydrogen storage system located under the bus floor. Thus this study describes a new experiment method for side impact test with compressed hydrogen storage system independently based on finite element analysis instead of side impact test using full hydrogen bus. A side crash procedure of conceptual compressed hydrogen storage structure was investigated and impact simulations were performed. The finite element models of hydrogen bus, simplified structures, fuel tank system and side impact moving barrier were set up and simulation results reported model performance and result comparison of three different simplified models. Computational results and research discussion proposed the fundamental test framework for safety assessment of the compressed hydrogen storage system.

• 한국수소및신에너지학회논문집
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• 제34권5호
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• pp.431-438
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• 2023

Recently, study on hydrogen is being conducted due to environmental pollution and fossil fuel depletion. High-pressure gas hydrogen commonly used is applied to vehicle and tube trailers. In particular, high-pressure hydrogen storage tank for vehicles must comply with the guidelines stipulated in SAE J2601. There is a charging temperature limitation condition for the safety of the storage tank material. In this study, numerical analysis method were verified based on previous studies and the nozzle angle was changed for thermal management to analyze the increase in forced convection effect and energy uniformity due to the promotion of circulation flow. The previously applied high-pressure hydrogen storage tank has a length/diameter ratio of about 2.4 and was analyzed by comparing the length/diameter ratio with 8. As a result, the circulation flow of hydrogen flowing into the high-pressure hydrogen storage tank is promoted at a nozzle angle of 30° than the straight nozzle and accordingly, the effect of suppressing temperature rise by energy uniformity and forced convection was confirmed.

• 비파괴검사학회지
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• 제32권1호
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• pp.1-6
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• 2012

본 연구에서는 광대역(100 kHz - 1 MHz) 탐촉자를 사용하여 자동차용 CNG연료탱크의 파열시험시 발생하는 음향방출신호의 분석을 통해 압력용기의 손상정도를 평가하였다. 압력이 420 bar까지 올라가기 전의 각 단계에서는 Kaiser 효과가 나타나고 creep 효과가 거의 나타나지 않으나, 420 bar 이상 상승시 creep 효과가 현저히 나타남으로써 용기가 손상을 입었다는 것을 알 수 있었으며, 480 bar 압력 상승 단계에서는 Kaiser 효과가 없어졌다. 540 bar의 압력 단계에서 공진형 탐촉자의 경우에서는 480 bar의 압력단계에 비하여 energy나 count 같은 activity가 감소하였으나 광대역 탐촉자의 경우 계속적으로 증가하였다. 또한 rise time이나 주파수 분석을 통해서 복합재료 압력용기의 손상 메카니즘을 관찰하기 위해서는 일반적으로 금속압력용기에서 많이 사용되는 공진형 탐촉자(150 kHz)보다 광대역 탐촉자가 효과적임을 알 수 있었다.

• 한국기계가공학회지
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• 제19권7호
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• pp.89-97
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• 2020

Container vessels continue to grow in size, led by global shipowner. Large ships can be loaded more cargo at a time, reducing the cost of transportation per teu. this eventually leads to economies of sale, in which the production cost per unit decreases with increasing output. in accordance with the 70th Convention of the Marine Environment Protection Committee of the International Maritime Organization, as of January 1, 2020, MARPOL Annex VI Regulation 14.1.3 will be effective. All vessels must be meet these criteria to reduce Sox emissions and reduce NOx emissions by reducing the content of manned sulfur oxides from 3.5% to less than 0.5%, otherwise IACS Member States Entry to the port is denied. in order to do that need to LNG storage tank. in this study characteristic of the material after line heating (600℃,700℃,800℃,900℃) of 9% Ni steel used in the manufacture of LNG fuel tank of ship were verified using by mechanical test. In the heating method by line heating. The initial properties of steel are changed by variables such as temperature, time, speed. The experimental data of line heating presented in this paper confirmed that the initial change of 9% Ni steel could be minimized.

• 한국산학기술학회논문지
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• 제16권6호
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• pp.3736-3741
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• 2015

연료탱크 충돌충격시험은 연료탱크의 내충격 성능을 검증하는 시험으로, 충돌충격시험을 통과한 연료탱크는 생존가능 충돌환경에서 화재가 발생하지 않아 승무원의 생존성이 대폭 향상될 수 있음을 의미한다. 그러나, 충돌충격시험은 높은 충격하중 때문에 실패 위험성이 큰 시험이다. 만약, 충돌충격시험을 실패할 경우에는 설계보완 및 시편 재제작 등으로 재시험 준비 기간이 상당히 소요되어 항공기 개발일정에 상당한 지장을 초래하게 된다. 따라서, 연료탱크 설계 초기에 충돌충격시험에 대한 수치해석을 수행함으로써 실물시험에서의 실패 가능성을 최소화하는 노력이 필요하다. 본 연구에서는 충돌모사 프로그램인 LS-DYNA에서 지원하는 입자법을 사용하여 Phase I 인증시험의 연료탱크 충돌충격시험 수치모사를 수행하였다. 수치해석 조건으로 미군사규격(MIL-DTL-27422)에서 요구하는 시험조건을 반영하였고, 실물 연료탱크 소재의 시편시험을 통해 확보한 물성 데이타를 수치 해석에 적용하였다. 그 결과로 연료탱크 소재와 중첩부위, 피팅 부위에 작용하는 충격하중을 분석함으로써, 연료탱크 설계시 접착강도와 중첩범위 결정을 위한 설계하중 획득 가능성을 타진하였다.

• 전기학회논문지P
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• 제59권1호
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• pp.129-133
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• 2010

A hybrid system which is combined several complementary new and renewable power sources, such as photovoltaic, fuel-cell, and wind generator, etc., has been presented in various approaches. For instance, a photovoltaic cannot always generate stable output power with ever-changing weather condition, so it might be co-generated with a wind generator, diesel generator, and some other sources. In this paper, a residential PV-FC hybrid system is suggested as a distribution power source, and its operation is optimized by HOMER$^{(R)}$. As a result, it is the most economic that 5[kW] PV, 1[kW] FC, 4 batteries, 2[kW] electrolyzer, 0.5[kg] $H_2$ tank, 3[kW] converter are applied to the hybrid system.

• Structural Engineering and Mechanics
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• 제13권6호
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• pp.653-670
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• 2002

In order to ensure the structural dynamic stability of moving liquid-storage containers, the flow motion of interior liquid should be appropriately suppressed by means of mechanical devices such as the disc-type elastic baffle. In practice, the design of a suitable baffle requires a priori the parametric dynamic characteristics of storage containers, with respect to the design parameters of baffle, such as the installation location and inner-hole size, the baffle number, and so on. In this paper, we intend to investigate the parametric effect of the baffle parameters on the transient dynamic behavior of a cylindrical fuel-storage tank in an abrupt vertical acceleration motion. For this goal, we employ the ALE (arbitrary Lagrangian-Eulerian) kinematic description method incorporated with the finite element method.

• 한국수소및신에너지학회논문집
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• 제23권2호
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• pp.156-161
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• 2012

In case of commercializing of the hydrogen fuel cell vehicle, the suitable emergency response guide is necessary to prepare an accident. In order to suggest the suitable guide for the domestic affairs, the existing external guide about GM, Ford, Honda, and Hyundai was reviewed. The emergency response guides in CAFCP and main FC vehicle makers were included in the analysis. As the results, it was found that the design and make of vehicle for the domestic user are demanded in the emergency response and the guide is made with the shut-down manual picked out for the rescuer and repair man as well as user.

• Journal of Mechanical Science and Technology
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• 제16권4호
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• pp.557-563
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• 2002

In this paper, the characteristics of flow and spray motions affected by from piston head configurations were investigated numerically. Calculations were carried out from intake process to the end of compression. GTT (Generalized Tank and Tube method) code, which includes a third order upwind Chakravarthy-Osher TVD scheme and k-$\varepsilon$ turbulence model with fuel spray analysis was used for the calculations. As a results, piston heads with smaller radii of curvature were found to give stronger reverse tumble than those with larger radii of curvature. Similar results are shown in the convection and diffusion of fuel sprays.