• Journal of Navigation and Port Research
• /
• v.33 no.8
• /
• pp.589-594
• /
• 2009

The Major inspection is a ship inspection which is executed voluntarily for tankers by Major oil companies(hereinafter it is called "Major"). To take the Major's cargo tanker should pass Major inspection. Thus, even though Major inspection is executed voluntarily, it is more important one than any other inspection for ship's crews and owner because it is closely related to the business profit of shipping company. In this study, authors suggested the improving measures after checking the problems concerned with Major inspection through status analysis. For the status analysis, authors carried out a questionary survey and interview with the interested parties, such as tanker crews, persons in charge of shipping company and inspectors, as well as studied the related literature and statistics data.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.9 no.1
• /
• pp.7-14
• /
• 1972

Recently, the matrix method has become almost universal tool to solve various engineering problems in conjunction with the rapid development of high speed electronic computers. The method also has been introduced to ship structure analysis in past few years. This paper treats a method to obtain an approximate solution for stress distribution in a web frame of oil tankers. The method is designed to use relatively small computer. The procedure consists of two steps. In the first step, the web frame is idealized to a plane frame of slender members as shown in Fig. 2. Then, the plane frame is analyzed with a matrix method to determine forces and moments in each members. In the second step, the original shape of the web frame is restored and any portion of the frame, in which the stress distribution is desired, is isolated as shown in Fig. 3. Then, again, a finite element method is used to determine the stress distribution in the isolated portion. In this work, IBM 1130 computer in the computation center, SUN has been used. A numerical example with scantlings of an actual ship is worked out to prove the validity of this method.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.13 no.8
• /
• pp.591-597
• /
• 2003

The oscillation of the fluid caused by external motions is called sloshing, which occurs in moving vehicles with contained fluid masses, such as the oil tankers, railroad cars, aircraft and rockets. Natural frequencies of fluid are much lower than that of solid structures, and the deformation caused by the excitation that is less than 1st natural frequency of fluid is very large. For the reason of that, sloshing characteristics under the ekcitation that is less than the 1st natural frequency must be studied prior to the consideration of natural frequencies of fluid. The experimental devices are constructed to simulate the translation motion. The rectangular tanks are made to study the sloshing characteristics under external excitation. The changes of water height are measured using an analogue camcorder and MPEG board, and those are compared to each other through a standard deviation. From the results of experiments, the sloshing is greatly influenced by the length of the rectangular tank than the width of that under the periodic translational motion in the length direction. The rapid amplification of sloshing by resonance is also confirmed experimentally.

• Journal of the Society of Naval Architects of Korea
• /
• v.33 no.2
• /
• pp.65-74
• /
• 1996

For the structural analysis of ship structures finite element method is generally used but it requires lots of working and computing time from the design viewpoint. Therefore, it is desirable to adopt a new analysis method which gives little computing time and high accuracy instead of finite element method to carry out various alternative design and optimum design. In this study, from the analysis viewpoint, structural analysis of oil tankers is carried out to verify the effectiveness of the generalized slope deflection method and the new equivalent curved beam theory which were formulated by the authors and their superiority is verified by comparison of the computing time and the results of accuracy with existing methods.

• Journal of the Society of Naval Architects of Korea
• /
• v.51 no.4
• /
• pp.321-327
• /
• 2014

A wide scope of numerical simulations was performed to predict model-ship resistances by using STAR-CCM+ and OpenFOAM. The numerical results were compared with experimental measurements in towing tank to analyze statistical reliability of the present simulations. Based on the normal distribution of resistance errors in 113 cases of container carriers, tankers and very large crude-oil carriers, the confidence intervals of numerical error were estimated as [-2.64%,+2.32%] and [-1.82%, +1.87%] with 95% confidence in STAR-CCM+ and OpenFOAM, respectively. The resistance errors of liquefied natural gas carriers with single- and twin-skeg were confident in the ranges of [-2.51%,+2.64%] and [-2.29%, +1.46%], respectively. The grid uncertainty of resistance coefficients for KCS was also quantitatively analyzed by using a grid verification procedure. The grid uncertainty of OpenFOAM (5.1%) was larger than 4.4% uncertainty of STAR-CCM+ although OpenFOAM provided statistically more confident results than those of STAR-CCM+. It means that a grid system verified under a specific condition does not automatically lead to statistical reliability in general cases.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.3
• /
• pp.191-197
• /
• 2016

The shaft system of a vessel becomes stiffer because of larger engine power, whereas the hull structure becomes more flexible because of scantling optimization conducted by using high-tensile thick steel plates. The draught-dependent deformation of the hull affects each bearing offset and reaction force comprising the subsequent shaft system. This is the reason that more sophisticated shaft alignments are required. In this study, an FE analysis performed under the expected operating conditions of two (2) vessels, as maximum draught change and to analyze the shaft alignment using the relative bearing offset change, which was derived from an FE analysis of the 50,000 DWT oil/chemical tanker, which has become an eco-friendly vessel in recent years. Based on this, the influence of the hull deflection on the bearing offset was reviewed against results for shaft alignment conditions.

• Journal of the Society of Naval Architects of Korea
• /
• v.53 no.4
• /
• pp.336-342
• /
• 2016

H-CSR(Harmonized Common Structural Rules) integrating CSR-BC(Common Structural Rules for Bulk Carriers) and CSR-OT(Common Structural Rules for Double Hull Oil Tankers) came into effect in July of 2015, so that bulk carrier and double hull oil tanker should comply with this rules. So far, several studies for trend analysis of requirements of structure scantling based on H-CSR have been carried out briskly. However, those studies are rare to apply H-CSR in actual structural design of ships, especially bulk carriers. In this study, an automated system for compartment arrangement is used to search the design case that minimizes still water bending moment(S.W.B.M) in 38k bulk carrier designed by Far East Ship Design & Engineering Co. Ltd. Also, various structural design cases are considered by changing arrangement of structural members to reduce ship weight. The SeaTrust-Hullscan software developed by Korean Register is used to perform structural design of ships based on mother ship and proper design cases are selected by user. The DSA(Direct Strength Analysis) is performed to evaluate structural safety for the yielding and buckling analysis by using MSC Nastran software. The effect of weight reduction is verified by comparison of ship weight between mother ship and the selected design cases.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2011.09a
• /
• pp.117-126
• /
• 2011

The buckling assessment of plate panels described in common structural rules (CSR) is to be determined according to the buckling utilization factor with hull girder stresses calculated on net hull girder sectional properties. As the thickness requirement for the buckling assessment of plate panels is not explicitly given in CSR, a lot of time is spent to find the proper thickness of plate panels until reaching to an allowable buckling utilization factor. In this study, in order to reduce time and cost, the thickness requirement of plate panels satisfying buckling assessment was derived. The structural design system included with the thickness requirement for buckling assessment was developed. The system is called as Oil-tanker Automated Structural Investigation System (OASIS). The design result of longitudinal strength members using OASIS was verified by Nauticus Hull which is the rule scantling software of DNV. Finally, optimum design of a double hull tanker for the minimum weight using OASIS was presented.

• Structural Engineering and Mechanics
• /
• v.52 no.3
• /
• pp.613-632
• /
• 2014

In the early design stage of ships, the two most important structural analyses are performed to identify the structural capacity and safety. The first step is called global strength analysis (longitudinal strength analysis or hull girder strength analysis) and the second step is local buckling analysis (stiffened panel strength analysis). This paper deals with the ultimate strength performance of Arctic Sea Route-going commercial ships considering the effect of low temperature. In this study, two types of structural analyses are performed in Arctic sea conditions. Three types of ship namely oil tanker, bulk carrier and container ship with four different sizes (in total 12 vessels) are tested in four low temperatures (-20, -40, -60 and $-800^{\circ}C$), which are based on the Arctic environment and room temperature ($20^{\circ}C$). The ultimate strength performance is analysed with ALPS/HULL progressive hull collapse analysis code for ship hulls, then ALPS/ULSAP supersize finite element method for stiffened panels. The obtained results are summarised in terms of temperature, vessel type, vessel size, loading type and other effects. The important insights and outcomes are documented.

• Proceedings of KOSOMES biannual meeting
• /
• 2007.05a
• /
• pp.187-194
• /
• 2007

In order to control and manage oil-tanker scrapped materials and wastes properly, the actual conditions and global trends of the treatment and the management of ship scrapped wastes were surveyed and some amendments to marine pollution prevention law of Korea were proposed. Global annual volume of scrapped ships was estimated to be about 22 million DWT and most of them were scrapped in 4 major ship scrap countries such as Bangladesh, China. India and Pakistan and in minor ship scrap countries such as Turkey, the Philippines, Indonesia and Vietnam. The industry of ship scrap has been mainly developed in developing countries or undeveloped countries rather than in advanced countries. Most of scrapped ships were found to be small or medium size below 1,000 GRT In Jellanam-Do and Jeju-Do of Korea. Most of ship scrap enterprise and all enterprises of collection, transfer, treatment and disposal for ship scrapped materials and wastes were shown to be small sized in Korea. The regulations and/or rules which shall prohibit or limit trans-boundary movement of overage oil-tankers for scrap from Korea to developing or undeveloped countries, and vice versa should be Included in marine pollution prevention law of Korea. the criteria of manpower and facilities for enterprise of ship scrap, and for enterprises of collection, transfer, treatment and disposal of ship scrapped materials and wastes should be stipulated in marine pollution prevention law of Korea. It is desirable to introduce the system or concept of recycle or reuse of ship scrapped materials and wastes on producer's responsibility into marine pollution prevention law of Korea.