ABSTRACT DSME has recently developed a new membrane type cargo containment system, SOLIDUS, and launched it to the LNG market. The system has double metallic membrane barriers to increase safety and adopted a newly developed reinforced polyurethane foam as insulation material. The integrity of the system in terms of ultimate strength has been proved by comparing the calculated minimum safety factors with the required values while the obtained minimum fatigue life of primary and secondary membranes has shown that the system has enough fatigue strength. The system's sloshing resistance has also been verified by the obtained utilization factors smaller than the requirement. INTRODUCTION With the effort during the past few years together with its experience and technology in LNG industry, DSME recently has developed its new membrane type cargo containment system (CCS), SOLIDUS, and officially launched the new system into the LNG market claiming to a safe and economic membrane type CCS. SOLIDUS is a market driven product following the demand of less cost and less boil off gas but higher safety. Those requests have been fulfilled by lowering the product loyalty, by employing the newly developed reinforced poly-urethane foam (R-PUF) of high performance and by utilizing the double independent metallic barriers, respectively. In this paper, it is focused on the technical excellence of SOLIDUS by explaining the engineering works involved in the development of the system leaving behind the symbolical value it has brought into the LNG market. SYSTEM OVERVIEW OF SOLIDUS SOLIDUS is a next-generation membrane type cargo containment system which consists of two layers of insulation panels (sandwich type made of plywood, R-PUF and plywood) and has double metallic barriers satisfying the International Gas Carrier (IGC) code. The primary membrane is 1.2 mm of SUS 304L and the secondary membrane is 0.7 mm of invar. Both membranes have corrugations to alleviate burdens from the thermal contraction due to cryogenic cargo. The insulation panels with primary of 100 mm and secondary of 300 mm thickness are installed to meet the market need for low Boil-Off Rate (BOR). An eco-friendly and high-performance insulation material, R-PUF, that has been developed in cooperation with the German chemical company, BASF, is utilized to lower BOR and satisfy strength requirements. The system is designed to be secured to inner hull via mastic bonding on the bottom of the secondary panel and a mechanical securing module is devised for securing of the primary panel with the secondary panel. The basic characteristics of the SOLIDUS system are shown in Fig. 1.

ABSTRACT: The majority of Arctic class rules have been revised continuously based on collision experiences of small or medium size vessels operating in arctic area. IACS (International Association of Classification Societies) Polar Class Rules was also developed based on collision data for those small vessels with level ice and ultimate hull strength calculated from non-linear FE analysis. During the design of 107k DWT arctic tanker, which is much larger than the vessels utilized in rule development, several collision scenarios were provided through co-work between ABS, BMT Fleet and DSME to consider possible ice loads which IACS Polar Class does not cover. Three different collision scenarios were suggested for bow structure strength assessment. They are based on actual ice characteristics in Barents Sea. Besides level ice, ice floe and semi-ramming, which are not considered in IACS Polar Class, were also considered in collision scenarios. For each collision scenario, ice loads were directly calculated. Direct strength assessment through non-linear FE analysis was followed to verify bow structure design of 107k DWT arctic tanker. INTRODUCTION Vast reserves of oil and gas are expected to be exploited in the Russian Arctic including the Barents Sea, the Pechora Sea and the Kara Sea. To transport crude oil, large crude oil tankers, which should be prepared for ice collision, are required. In structural point of view, ice loads as well as wave and current loads should be considered in hull design. However, ice loads are not familiar with ship designers since market demands were not so strong yet. With the increase of market requirement, lots of joint research works are under progress to consider the ice loads in design stage. So, we have researched the features of the Barents Sea and then we have developed ice load models based on these data.

ABSTRACT: The goal of this report focuses on the development of an assessing method for ultimate strength of ship hull plate with corrosion damnification. It is confirmed that corrosion damnification on ship hull plate generally appears as pits with different shape, size and distributing density. According to a long term inspected results for pitting on ship hull plates, all the kinds of pits appearing on the hull plate would be equivalent to semi-spherical shape, conical shape and cylindrical shape. Pitting corrosion results in a quantity loss of the plate material as well as a significant degradation of the ultimate strength of the hull plate due to reducing of the effective thickness of the plate. Accordingly, the model for describing the correlations between the ultimate strength and the corroded volume loss of a corroded plate is firstly proposed based on relative theory. Such model was then completed through numerical experiment by nonlinear finite element analyses for series of corroded plate models. INTRODUCTION People have paid increasing attention to the corrosion-caused structural damage in recent half century. Corrosion-caused thickness loss makes the ultimate strength of typical thin-walled ship structural plates degraded significantly. For general corrosion, it is thought that the thickness is uniformly reduced over the entire plate, so the ultimate strength of the corroded plate can be assessed based on the thickness. However, for pitting corrosion, the corrosion form is complicated and the thickness of the whole plate is not uniform. Until now, there is still no acknowledged method to assess the ultimate strength of the plate with pitting corrosion damnification. The method of ultimate strength assessment for the pitted plate has been developed from the effective thickness method to the method in which many factors have been considered to represent the characteristics of pitting corrosion.