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Chun H.H.,Pusan National University | Kim M.C.,Pusan National University | Lee I.,Pusan National University | Kim K.,Korea University | And 2 more authors.
International Journal of Naval Architecture and Ocean Engineering

The stern boat deployment system was investigated to evaluate the capability of launching and recovering rigid hull inflatable boat (RHIB) via the stern ramp. The main parameters to launch and recover RHIB were tested at the design stage. The combined hydrodynamic effect of the stern wake and the water jet flow made it difficult to maintain the maneuvering and sea-keeping ability of RHIB approaching to the stern ramp. The safe recovery course was proposed to maintain the directional control of RHIB and to reduce the combined hydrodynamic effect in the transom zone. To evaluate the feasibility of RHIB recovery, the stern sill depth was measured in various conditions and the ramp availability time was obtained. Also, the experimental percent time operability (PTO) test was performed by the number of successive launching and recovering operations. © SNAK, 2012. Source

Heo H.-S.,Pusan National University | Lee C.-S.,Pusan National University | Lee T.-K.,Gyeongsang National University | Yang C.-H.,Sungdong Shipbuilding and Marine Engineering Co. | And 5 more authors.
11th International Symposium on Practical Design of Ships and Other Floating Structures, PRADS 2010

The primary aim of the present study is to propose new design formulae that can be used to evaluate the structural performance of breakwaters installed on container carriers under green water impact loads. A series of numerical analyses for green water impact loads inducing post-buckling and breakwater collapse have been carried out. The well-known fluidstructure interaction analysis technique has been adopted realistically to consider the phenomenon of green water impact loads. The structural behavior of these breakwaters under green water impact loads has also been carried out simultaneously throughout the transient analysis. A verification study of the numerical results was performed using the actual collapse incidents of breakwaters on container carriers. It would be expected that the proposed design formulae, based on the obtained insights, could be used as practical guidelines for the design of breakwaters on container carriers. © 2010 COPPE/UFRJ. Source

Lee J.S.,Hanjin Heavy Industries and Construction Co. | Jeong S.H.,Hanjin Heavy Industries and Construction Co. | Lim D.Y.,Hanjin Heavy Industries and Construction Co. | Yun J.O.,Hanjin Heavy Industries and Construction Co. | Kim M.H.,Pusan National University
Metals and Materials International

This paper is concerned with the effects of welding heat (current x voltage = W) and travel speed (v) on the impact property and microstructure of FC (flux cored) welds. Two sets of plate were welded under different welding conditions such as higher W, v and lower W, v, while maintaining identical heat input. We evaluated the effects of each factor by Charpy impact test and observation of the microstructure, and then compared these data with the results of the numerical temperature analysis. The size of the re-heated zone was increased as the v value decreased, and the results of numerical analysis also revealed the same tendency. Cooling rate of welds (both of as-welded and re-heated zones) decreased as the W value increased. Despite identical heat input conditions, the use of lower W and v made the microstructure finer and increased the volume fraction of AF, thereby leading to a substantial improvement of the impact property. © KIM and Springer. Source

Ha S.,Seoul National University | Seo S.-H.,Hanjin Heavy Industries and Construction Co. | Roh M.-I.,Seoul National University | Shin H.,University of Ulsan
Ships and Offshore Structures

The weight information of an FPSO plant, especially of the FPSO (floating, production, storage, and off-loading), is one of the important data needed to estimate the amount of production material (e.g. plates) and to determine the suitable production method for its construction. In addition, the weight information is a key factor that affects the building cost and the production period of the FPSO plant. Although the importance of the weight has long been recognised, the weight, especially of the topside, has been roughly estimated using the existing design and production data as well as the designer's experience. To improve this task, a nonlinear simplified model for the weight estimation of the FPSO plant topside using the statistical method was developed in this study. To do this, various past records on the estimation of the weight of the FPSO plant were collected through literature survey, and then correlation analysis and multiple regression analysis were performed to develop a nonlinear simplified model for weight estimation. Finally, to evaluate the applicability of the developed model, it was applied to an example of the weight estimation of the FPSO plant topside. The results showed that the developed model can be applied to the weight estimation process of the FPSO plant at the early design stage. © 2015 Taylor & Francis Source

Park S.,Hanjin Heavy Industries and Construction Co. | Yu B.,Hanjin Heavy Industries and Construction Co. | Yu Y.,Hanjin Heavy Industries and Construction Co. | Lee P.,Hanjin Heavy Industries and Construction Co.
11th International Symposium on Practical Design of Ships and Other Floating Structures, PRADS 2010

The wire-frame method for hull form design has been widely applied more than the surface based method because it is convenient for the hull form design including hull form definition, variation, fairing, hydrostatics calculation and grid generation for CFD analysis. On the other hand, the wire-frame method also has weakness to apply to complex geometry such as a hull form with twin skegs due to the difficulty of defining hull form. In that case, it is very complicated to generate the various curves such as section lines, waterlines and buttock lines from existing curves due to sorting problem of nodal points. In this paper, the polygon tracing method is introduced to solve the problem with keeping the convenience of the wire-frame method. It is a kind of method to generate the curve using a set of points and shared edge of two connected polygons. The developed method from present study has been applied to several hull forms having a special stern shape. Also, it has been proven that the developed method was effective and convenient for definitions of hull form at hull form design point of view. © 2010 COPPE/UFRJ. Source

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