Test and estimation of ballistic armor performance for recent naval ship structural materials

Shin, Yun-ho,Chung, Jung-hoon,Kim, Jong-Hwan The Society of Naval Architects of Korea 2018 International Journal of Naval Architecture and Oc Vol.10 No.6

This paper presents the ballistic armor performance examination and thickness estimation for the latest naval ship structure materials in the Republic of Korea. Up to date, research regarding methods of ballistic experiments establishing database on the latest hull structure materials as well as a precise method of estimating required thickness of armor against specific projectiles have been rarely researched. In order to build a database and estimate proper thicknesses of structure materials, this study used four structure materials that have been widely applied in naval ships such as AH36 steel, AL5083, AL5086, and Fiber Reinforced Plastics (FRP). A $7.62{\times}39mm$ mild steel core bullet normally fired by AK-47 gun was considered as a threat due to its representativeness. Tate and Alekseevskii's penetration algorithm was also used to calculate a correction factor (${\alpha}$) and then estimate the armor thickness of naval ship hull structure materials with a given impact velocity. Through live fire experiments, the proposed method performance difference was measured to be 0.6% in AH36, 0.4% in AL5083, 0.0% in AL5086, and 8.0% in FRP compared with the experiment results.

Development of performance measures based on visibility for effective placement of aids to navigation

Fang, Tae Hyun,Kim, Yeon-Gyu,Gong, In-Young,Park, Sekil,Kim, Ah-Young The Society of Naval Architects of Korea 2015 International Journal of Naval Architecture and Oc Vol.7 No.3

In order to develop the challenging process of placing Aids to Navigation (AtoN), we propose performance measures which quantifies the effect of such placement. The best placement of AtoNs is that from which the navigator can best recognize the information provided by an AtoN. The visibility of AtoNs depends mostly on light sources, the weather condition and the position of the navigator. Visual recognition is enabled by achieving adequate contrast between the AtoN light source and background light. Therefore, the performance measures can be formulated through the amount of differences between these two lights. For simplification, this approach is based on the values of the human factor suggested by International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA). Performance measures for AtoN placement can be evaluated through AtoN Simulator, which has been being developed by KIOST/KRISO in Korea and has been launched by Korea National Research Program. Simulations for evaluation are carried out at waterway in Busan port in Korea.

Undergraduate courses for enhancing design ability in naval architecture

Lee, Kyu-Yeul,Ku, Namkug,Cha, Ju-Hwan The Society of Naval Architects of Korea 2013 International Journal of Naval Architecture and Oc Vol.5 No.3

Contemporary lectures in undergraduate engineering courses typically focus on teaching major technical knowledge-based theories in a limited time. Therefore, most lectures do not allow the students to gain understanding of how the theories are applied, especially in Naval Architecture and Ocean Engineering departments. Shipyards require students to acquire practical ship design skills in undergraduate courses. To meet this requirement, two lectures are organized by the authors; namely, "Planning Procedure of Naval Architecture & Ocean Engineering" (PNAOE) and "Innovative Ship Design" (ISD). The concept of project-based and collaborative learning is applied in these two lectures. In the PNAOE lecture, sophomores receive instruction in the designing and building of model ships, and the students' work is evaluated in a model ship contest. This curriculum enables students to understand the concepts of ship design and production. In the ISD lecture, seniors learn how to develop their creative ideas about ship design and communicate with members of group. They are encouraged to cooperate with others and understand the ship design process. In the capstone design course, students receive guidance to facilitate understanding of how the knowledge from their sophomore or junior classes, such as fluid mechanics, statics, and dynamics, can be applied to practical ship design. Students are also encouraged to compete in the ship design contest organized by the Society of Naval Architects of Korea. Moreover, the effectiveness of project-based and collaborative learning for enhancing interest in the shipbuilding Industry and understanding the ship design process is demonstrated by citing the PNAOE and ISD lectures as examples.

A New Concept of Energy Absorbing System for the Double Hull Tanker

Lee, J. W.,Petershagen, H.,Rorup, J.,Kim, J. Y.,Yoon, J. H. The Society of Naval Architects of Korea 1999 Journal of ship and ocean technology Vol.3 No.1

A new concept of collision energy absorbing system for ;he New Oil-tankers with Advanced Double Hull Structure(NOAHS and NOAHS II) are presented through the joint-research pro-gran between Inha and Hamburg-Harburg University. A comparative study on col vision resistance of these proposed side structures with standard double hull structure of 310K DWT class VLCC, is carried out. The fatigue investigation of structural detail parts is also included. It contains a comparative fatigue study based on pertinent regulations of Classification Societies.

A study on the development of the OMS/MP based on the Fundamentals of Systems Engineering

Jeong, Yeonhwan The Society of Naval Architects of Korea 2018 International Journal of Naval Architecture and Oc Vol.10 No.4

The Systems Engineering method is increasingly recognized as a central in the Acquisition of Weapon Systems in South Korea. Because of these trends, issues concerned with improving weapon system design are increasingly raised. This paper presents a development of Operational Mode Summary/Mission Profile (OMS/MP) in terms of Weapon Systems Acquisition for application to Systems Engineering method. For a systematic approach, a precise concept of OMS/MP is derived by analyzing the concept of conventional OMS/MP. This paper reviews the results of a series of previously reported examples aiming to develop the OMS/MP of a weapon system. Based on this, the limitations of the conventional OSM/MP applications are investigated. And these limitations can be resolved by the Fundamentals of Systems Engineering. Finally, the OMS/MP framework based on the Fundamentals of Systems Engineering has been proposed and is successfully implemented for the Harbor Underwater Surveillance System.

Corrigendum to "[Maneuvering simulation of an X-plane submarine using computational fluid dynamics]" [Int. J. Nav. Architect. Ocean Eng. (2020) 843-855]

Cho, Yong Jae,Seok, Woochan,Cheon, Ki-Hyeon,Rhee, Shin Hyung The Society of Naval Architects of Korea 2021 International Journal of Naval Architecture and Oc Vol.13 No.1

Fatigue Strength Assessment of A Longitudinal Hatch Coaming in a 3800 TEU Containership by ABS Dynamic Approach

Cui, Weicheng,Yang, Chunwen,Hu, Jiajun The Society of Naval Architects of Korea 1999 Journal of ship and ocean technology Vol.3 No.4

Fatigue strength assessment procedures have been implemented in the ship design rules by many classification societies. However, a large variation tin the details of the different approaches exists in practically all aspects influding load history assessment, stress evaluation and fatigue strength assessment. In order to assess the influences of thesd variations on the prediction of fatigue lives. a comparative study is organized by the ISSC Committee III.2 Fatigue and Fracture. A pad detail on the top of longitudinal hatch coaming of a panamax container vessel is selected for fatigue calculation. The work described in this paper is one set of results of this comparative study in which the ABS dynamics approach is applied. Through this analysis the following conclusions can be drawn. (1) With the original ABS approach, the fatigue life of this pad detail is very low, only 2.398 years. (2) The treatment of the stillwater bending moment in the ABS approach might be a source of conservatism. If the influence of stillwater bending moment is ignored, then the fatigue life for this pad detail is 7.036 years. (3) The difference between the nominal stress approach and the hot spot stress approach for this pad detail is about 26%.

A Fusion Positioning System of Long Baseline and Pressure Sensor for Ship and Harbor Inspection ROV

Seo, Dong-Cheol,Lee, Yong-Hee,Jo, Gyung-Nam,Choi, Hang-Shoon The Society of Naval Architects of Korea 2007 Journal of ship and ocean technology Vol.11 No.1

The maintenance of a ship is essential for safe navigation and hence regular surveys are prescribed according to the rule of classification societies. A hull inspection is generally performed by professional divers, but it takes a long time and the efficiency is low in terms of time and cost. In this research, a ROV(Remotely Operated Vehicle) named as SNU-ROV(Seoul National University-ROV) is developed to replace the conventional inspection method. In this system, the ROV is intended to be used for inspecting ship and harbor because harbor inspection is merging as a safety measure against any possible terror actions. In order to increase the efficiency of inspection, the ROV must be able to measure the exact position of damages. SNU-ROV has a positioning system based on LBL(Long Base Line). In shallow water such as harbor, however, LBL has bad DOP(Dilution of Precision) in the depth direction due to the limited depth. Thus LBL only can not locate the exact depth position. To solve the DOP problem, a pressure sensor is introduced to LBL and a complementary filter is attached by using indirect feedback Kalman filter. Thus developed positioning system is verified by simulation and experiment in towing tank.

Development of Korea-China Train Ferry System An Example of Short Sea Shipping in Northeast Asia

Lee, Jae-Wook,Lee, Seung-Hee,Kang, Young-Jin The Society of Naval Architects of Korea 2006 Journal of ship and ocean technology Vol.10 No.3

The train ferry, accommodating trains roll on and off, is often called as 'Railway on the Sea' or 'Blue High-way' since she can connect the railways or roads segregated by the sea and improve the accessibility and continuity of land transport systems. The ferry is especially appropriate to the intermodal transport routes mostly passing through the land but have relatively short sea segment. As the train ferry can considerably reduce the cost and time for cargo handling and modal shift and unnecessitates excessive initial investment on infrastructures such as large harbor cranes or vast container yards, introduction of train Ro-Ro ferries lessen the total transport cost for door-to-door transportation with full exploitation of the existing railway system. All the ports placed in Shandong, Liaoning and Jiangsu provinces of China are connected to the hinterlands via well developed railway and road systems. Therefore, realization of the Incheon-Yantai train ferry system will link Korea railways to TCR and the 4,131-kilometer-long Longhai-Lanxin Railway, along the famous Eurasian Continental Bridge. In the present paper, the Incheon-Yantai train ferry will be introduced as a good example of an efficient multimodal short sea shipping system for Northeast Asia.

Ultimate Compressive Strength-Based Safely and Reliability Assessment of the Double Skin Upper Deck Structure

백점기,Jeom-K. Paik The Society of Naval Architects of Korea 1991 大韓造船學會 論文集 Vol.28 No.1

본 연구에서는 압축최종강도(壓縮最終强度)를 기준으로 한 이중갑판구조(二重甲板構造)의 실용적인 안전성(安全性) 및 신뢰성(信賴性) 평가법을 제안한다. 이를 위하여 선체상갑판(船體上甲板)에 작용하는 압축응력(壓縮應力)을 기존의 선급규정에 의해 근사적으로 추정하며, 압축최종강도(壓縮最終强度)는 이상화구조요소법(理想化構造要素法)을 적용하여 해석한다. 초기(初期)처짐 및 잔류응력(殘留應力)의 영향과 국부좌굴(局部挫屈) 및 전체좌굴(全體挫屈)의 상관효과(相關效果)를 고려한 이상화판요소(理想化板要素)를 정식화한다. 이상화판요소(理想化板要素)의 정도(精度)와 유용성(有用性)은 단위(單位) 판부재(板部材) 및 상자형 용접구조물(熔接構造物)에 대한 기존의 실험결과(實驗結果) 또는 유한요소해석결과(有限要素解析結果)와 비교하여 확인한다. 본 제안법을 이중선각구조설계(二重船殼構造設計)개념하에서 설계된 정유운반선(精油運搬船)의 갑판구조(甲板構造)의 안전성(安全性) 및 신뢰성평가(信賴性評價)에 적용하고, 초기처짐, 잔류응력(殘留應力)등의 영향과 고장력강(高張力鋼)을 사용한 경우의 효과등에 대해 고찰한다. A practical procedure for the ultimate compressive strength-based safety and reliability assessment of the double skin upper deck structure is described. The external compressive stress acting on the upper deck structure which is due to the still water and wave-induced sagging moment is approximately estimated by using the existing rule of classification society. The ultimate compressive stress of double skin structure under the action of sagging moment is analyzed by using idealized structural unit method. Here an idealized plate element subjected to uniaxial load is formulated by idealizing the nonlinear behaviour of the actual element taking account of the initial imperfections in the form of initial deflection and welding residual stress. The interaction effect between the local and global failure in the structure is also taken into consideration. The accuracy of the present method is verified comparing with the present solution and the existing numerical and experimental results for unit member and welded box columns. The safety of the structure is evaluated using the concept of conventional central safety factor and the reliability assessment is made by using Cornel's MVFOSM method. The present procedure is then applied to upper deck structure of double skin product oil carrier. The influence of the initial imperfections and the yield stress of the material on the safety and reliability of the structure is investigated.