STX Offshore and Shipbuilding Co.

Chinhae, South Korea

STX Offshore and Shipbuilding Co.

Chinhae, South Korea
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Shin K.-H.,STX Offshore and Shipbuilding Ltd. | Jo J.-W.,STX Offshore and Shipbuilding Ltd. | Hirdaris S.E.,Lloyd's Register | Jeong S.-G.,Lloyd's Register | And 4 more authors.
Ships and Offshore Structures | Year: 2015

In recent years, the increase in world trade has resulted in a large expansion of sea traffic. As a result, market demands are leading to the development of Ultra Large Container Ships (ULCSs), with lengths of up to 400 m and increased flexibility of operational requirements. The multicellular open-decked thin-walled structural design of these ships means that flexible hull girder dynamics become important for the prediction of wave loads. This paper investigates the importance of various hydroelastic modelling approaches on the global symmetric and anti-symmetric response of a 16,000 twenty-foot equivalent unit (TEU) ULCS design. Two- and three-dimensional linear and weakly non-linear flexible fluid–structure interaction models that respectively combine Vlasov beam and three-dimensional finite element analysis (FEA) structural dynamics with a B-spline Rankine panel and Green's function hydrodynamics are assessed and compared. Comparisons between rigid body and hydroelastic predictions demonstrate the importance of considering the effects of hull flexibility on the dynamic response and the suitability of different idealisations at preliminary or detailed design stages. © 2015 Taylor & Francis.

Lee D.H.,STX Offshore and Shipbuilding Co. | Kim H.K.,STX Offshore and Shipbuilding Co.
IEEE International Conference on Automation Science and Engineering | Year: 2012

Painting works in double hull blocks are very difficult and dangerous because working space is isolated and narrow. The structure in double blocks is too complex to apply automatic painting equipments. For these reasons, every shipyard still applied manual painting process which causes delay in ship construction and low quality. Therefore, the purpose of this study is to develop the semi-automatic painting system that is able to painting inside longitudinal stiffener of double hull blocks. It is divided into two groups. One is the semi-automatic painting machine and the others are the supplement devices. By applying the developed automatic system, productivity and painting quality can be increased and workmen's accident and injuries can be reduced. © 2012 IEEE.

Park J.-K.,STX Offshore and Shipbuilding CO | Jo Y.-C.,STX Offshore and Shipbuilding CO | Lee C.-H.,STX Offshore and Shipbuilding CO
Proceedings of the 10th (2012) ISOPE Pacific/Asia Offshore Mechanics Symposium, PACOMS 2012 | Year: 2012

Green ship using LNG for fuel has emerged as new trend recently due to increasing environmental regulations in the world. This is the reason for continuous active research of LNG Tank. IMO type 'B' independent LNG cargo tank has received attention in order to get over limitation of membrane type LNG cargo tank. In this paper, global FE analysis was carried out in order to find out structural considerations of IMO type 'B' LNG cargo tank. © 2012 by International Society of Offshore and Polar Engineers.

Lee S.E.,Pusan National University | Kim B.J.,Pusan National University | Seo J.K.,Pusan National University | Ha Y.C.,Pusan National University | And 4 more authors.
Ships and Offshore Structures | Year: 2015

This is a sequel to a previous paper by the same authors, which proposed a probabilistic approach to determine the nominal values of tank sloshing loads in the structural hull design of liquefied natural gas, floating production, storage and offloading units (LNG FPSO or FLNG). This study presents a procedure for the numerical computation of nonlinear impact responses in FLNG cargo tank structures under sloshing loads. The computations are performed using ANSYS/LS-DYNA nonlinear finite element software. Applied examples using a hypothetical FLNG are presented. The insights and conclusions obtained from the study are documented. © 2015 Taylor & Francis.

Jeong H.,STX Offshore and Shipbuilding Co. | Hwang J.,Korea Aerospace University | Kwon S.J.,Korea Aerospace University
Journal of Institute of Control, Robotics and Systems | Year: 2010

In the flat panel display and semiconductor industries, the visual alignment system is considered as a core technology which determines the productivity of a manufacturing line. It consists of the vision system to extract the centroids of alignment marks and the stage control system to compensate the alignment error. In this paper, we develop a Kalman filter algorithm to estimate the alignment mark postures and propose a coarse-fine alignment control method which utilizes both original fine images and reduced coarse ones in the visual feedback. The error compensation trajectory for the distributed joint servos of the alignment stage is generated in terms of the inverse kinematic solution for the misalignment in task space. In constructing the estimation algorithm, the equation of motion for the alignment marks is given by using the forward kinematics of alignment stage. Secondly, the measurements for the alignment mark centroids are obtained from the reduced images by applying the geometric template matching. As a result, the proposed Kalman filter based coarse-fine alignment control method enables a considerable reduction of alignment time. © ICROS 2010.

Paik J.K.,Pusan National University | Lee S.E.,Pusan National University | Kim B.J.,Pusan National University | Seo J.K.,Pusan National University | And 3 more authors.
Journal of Offshore Mechanics and Arctic Engineering | Year: 2015

The aim of this study is to develop a new probabilistic approach to determine nominal values for tank sloshing loads in structural design of in LNG FPSO (liquefied natural gas, floating production, storage, and offloading units). Details of the proposed procedure are presented in a flow chart showing the key subtasks. The applicability of the method is demonstrated using an example of a hypothetical LNG FPSO operating in a natural gas site off a hypothetical oceanic region. It is noted that the proposed method is still under development for determining reliable estimates of extreme sloshing induced impact loads. It is concluded that the developed method is useful for determining the sloshing design loads in ship-shaped offshore LNG installations in combination with virtual metocean data and operational conditions. © 2015 by ASME.

Bang J.-K.,STX Offshore and ShipBuilding Co. | Heo J.-H.,STX Offshore and ShipBuilding Co. | Jeong T.-S.,STX Offshore and ShipBuilding Co. | Lee C.-H.,STX Offshore and ShipBuilding Co. | And 2 more authors.
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2013

Recently because of structural problems of LNG carrier, LNG FPSO and other LNG unit, study on IMO Type "B" LNG cargo tank (independent cargo tank) has been studied very actively in progress. IMO Type "B" LNG cargo tank is known to have structural safety for sloshing pressure and external impact compare with NO96 and Mark III LNG cargo tank. This IMO Type "B" LNG cargo tank independently consists of cargo tank, hull structure and support structure. Especially, support structures of cargo tank could experience various loading conditions related to LNG shipping. And Local reaction force of high level has influences on structural safety of cargo tank and support structures. In this study, we introduce support structures and evaluate structural safety of support structures throughout local fine mesh analysis method for independent LNG cargo Tank (IMO Type "B" LNG cargo tank of STX Offshore & Shipbuilding Co., Ltd). Copyright © 2013 by the International Society of Offshore and Polar Engineers (ISOPE).

Park T.G.,Changwon National University | Kim J.M.,Changwon National University | Yoon H.Y.,Changwon National University | Lee J.H.,Changwon National University | And 2 more authors.
Journal of Korean Institute of Metals and Materials | Year: 2010

The charpy impact property was lower at the surface and middle regions than that at the root region in metal welded by Tandem EGW of 82 mm thick EH40-TM steel plates. Temperature distribution in the weld sample and the heating/cooling temperature throughout the various regions in the weld metal were estimated by the commercial weld simulation program SYSWELD. The microstructure of the weld metal consisted of acicular ferrite and grain boundary ferrite. Grain boundary ferrite in the acicular ferrite matrix was found more in the surface and middle regions than in the root region, and the acicular ferrite was also coarser in the surface and middle regions where the impact toughness was lower and the input temperature was higher. Our results indicated that the impact toughness property was related to the microstructure morphology, the distribution of grain boundary ferrite, and the acicular ferrite.

Kwon S.-H.,Catholic University of Korea | Kim T.-W.,Seoul National University | Choi H.I.,Seoul National University | Moon H.P.,Dongguk University | And 3 more authors.
CAD Computer Aided Design | Year: 2011

We present a blind watermarking scheme for rational Bézier and B-spline curves and surfaces which is shape-preserving and robust against the affine transformations and Mbius reparameterization that are commonly used in geometric modeling operations in CAD systems. We construct a watermark polynomial with real coefficients of degree four which has the watermark as the cross-ratio of its complex roots. We then multiply the numerator and denominator of the original curve or surface by this polynomial, increasing its degree by four but preserving its shape. Subsequent affine transformations and Mbius reparameterization leave the cross-ratio of these roots unchanged. The watermark can be extracted by finding all the roots of the numerator and denominator of the curve or surface: the cross-ratio of the four common roots will be the watermark. Experimental results confirm both the shape-preserving property and its robustness against attacks by affine transformations and Mbius reparameterization. © 2011 Elsevier Ltd. All rights reserved.

Nam J.-H.,Korea University | Kim D.-H.,STX Offshore and Shipbuilding Co.
Journal of Ship Production | Year: 2010

Ships use the ballast system to maintain stability. The ballast system greatly influences loading capacity and navigation of a ship as well as the ocean environment. Therefore, it is necessary to select an adequate ballast system not only to increase the efficiency of ship operation but also to protect the ocean from undesirable results of current ballasting process. The ship ballast system can be optimized by performance during the period of ship design and production. Until now most shipbuilders have implemented a ballast system based on similar data from previously built ships or experts' knowledge. If previous ballast data is unavailable, however, it is necessary to determine the most appropriate ballast system by trial-and-error. To have an efficient ship design and production process, this time-consuming and expensive bottleneck should be avoided. In this paper, a ballast simulation system that predicts the ballasting and deballasting processes using a computer model is introduced. The amount of fluid flowing through a ballast system is analyzed considering friction losses in the pipe's inner walls, junctions, and valves. The developed system uses the graphic user interface approach for convenient interaction between the user and the system. The results of real-time simulation will help the user to foretell the ballasting process with efficiency and accuracy.

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