Modern Shipbuilding Research Articles

서해안 해양 출수 유물 조사에 따른 고대 선박 닻돌 형태 분석 : 인천 옹진군 영흥도선 인근 유물을 중심으로

An anchor used to hold a ship fast to the seabed and in specified areas of territorial sea is one of the most important and necessary ship accessories. According to relevant literature, especially, there was a very long history of anchoring, which used an anchor stone hung up on the anchor cable put down on the ocean floor, before development in modern shipbuilding technology, but there is a shortage of related studies. Therefore, this study analyzed the shapes and sizes of four relics, which are preserved relatively well, among nine anchor stones that were recently discovered within 1.3kilometers of the Yeongheung-do Shipwreck near Yeongheung-do in Incheon. The analysis result showed that the top and bottom of the center of the anchor stone had clearly processed grooves for tying the anchor cable that have an average length, height and thickness of 133.6cm, 42.8cm and 17.4cm respectively.

Air-Independent Power Plants for Marine Vehicles

In this paper, we review modern developments of air-independent power plants (AIPPs) for the world submarine fleet. Equipping nonnuclear submarines with such plants is shown to be the main trend in modern shipbuilding. It can be predicted that submarines with AIPPs will almost completely occupy this niche of world shipbuilding by 2030. The most widespread at present are AIPPs based on fuel cells and Stirling engines. In the near future, electrochemical generators with better energy efficiency (power, efficiency) and stealth indicators (noise, thermal fields, and other unmasking factors) will remain the main types of AIPPs. The level of technology that has been achieved allows the creation of promising power plants based on solid-oxide fuel cells that will have significant advantages over diesel generators, which opens up prospects for their use in surface and submarine shipbuilding, in civil shipbuilding, and in other types of vehicles.

Методика определения гидродинамических изгибающих моментов, действующих на судовой валопровод

The paper considers the problem of engineering systems design in modern shipbuilding, which is based on using the computer-aided design systems. In today’s environment, not all engineering calculations can be implemented in the form of an algorithm for a specific design procedure. One of these calculations is determining the resonant frequency of transverse vibrations of a ship shaft line. Analyzing the parameters of such a dynamic system is a serious task even at the stage of preliminary design. The urgent task in the design and strength calculations of the shaft line is to calculate the hydrodynamic bending moments resulting from the operation of the propeller in an uneven velocity field. There has been presented a software implementation of the semi-empirical methodology for determining the hydrodynamic bending moments acting on ship shaft lines. The main principles of the methodology, the initial data on the vessel hull, and the quantities characterizing the operating mode of the propeller are described. There is proposed a sequence and software implementation of the method for determining hydrodynamic bending moments in the environment of Maple computer algebra. The problem of representing empirical data in the form of bilinear interpolation and interpolation polynomial is solved. The results of a numerical experiment to determine the constant and amplitude values of the hydrodynamic bending moments for shaft shafts of full-scale vessels are presented. The software implementation of the technique proposed made it possible to automate the process of determining external forces in the calculations of the cyclic strength of the propeller shaft at the early stages of the design of the vessel. The research results are in addition to existing automation tools.

On Rough Set-Based Modeling and with Application to Process Decision for Forming Plate by Line Heating

In shipbuilding, forming plate by line heating is atypical complex manufacturing process involving many uncertain factors, so it is difficult to establish an accurate mathematical model. How to establish a knowledge model that can reflect technological laws is the key to the development of an intelligent decision system for forming plate by line heating. In this article, rough set (RS) theory is applied to the modeling of the line heating process. By defining variable-inclusion RSs, an algorithm of knowledge reduction is proposed, which enhances the noise immunity and fault tolerance of the model, and improves the efficiency of knowledge acquisition. Through introducing fuzzy logic, a method of modeling the line heating process based on RSs and fuzzy logic is proposed, which effectively extracts the technological rules of plate formation. Finally, rapid decision-making for process parameters is implemented by fuzzy inference technology. 1. Introduction For some complex manufacturing technologies in modern shipbuilding, such as line heating and welding processes, it is difficult to establish an exact mathematical model because of high nonlinearity, multivariable coupling, and uncertainties of the system. With the development of computer technology and artificial intelligence, soft computing methods such as artificial neural networks, genetic algorithms, fuzzy logic, and rough set (RS) theory have been applied successively in ship manufacturing process modeling, which shows good prospects for intelligent technology in shipbuilding. Shin et al. (1999) at Seoul National University used a single-curvature plate model to simulate the formation of saddle-type shells and deduce the technological parameters of line heating by an artificial neural network. They also proposed a comprehensive algorithm for automatically curving plate by line heating, and further developed an application system that can simulate the deformation of double-curved plates (Shin et al. 2004a, 2004b). Liu et al. (2006) applied a hierarchical genetic algorithm to optimize the technological parameters of an automatic line heating process. In the field of ship welding, fuzzy logic technology has been used to establish a fuzzy model of the relationship between welding variables and weld forming-parameters (Su 2009). Feng (2012) set up a knowledge base of a ship-welding process by a RS method and then implemented ship-welding production design through uncertainty reasoning. Based on RS theory, Chen and Lv (2013) developed a data-driven knowledge base for quality control of ship hull welding.

ОБОСНОВАНИЕ ПРИМЕНЕНИЯ МНОГОСЛОЙНЫХ КОМПОЗИТНЫХ МАТЕРИАЛОВ В СУДОСТРОЕНИИ

The development of modern shipbuilding requires using new structural materials, superior to traditional ones. Polymeric composite materials are among the most promising. The article studies the mechanical properties of multilayer polymer composite materials made of glass fabrics under tension and the effect of the number of layers of glass mat on the tensile strength of the material. The technology of manufacturing samples from polymer composites reinforced with fiberglass plastic is being considered. The size and shape of the samples, the technological parameters of the manufacturing process, which depend on standard requirements, and the technological features of the testing machine are substantiated. It has been stated that fiberglass is the cheapest and most common type of composite materials, which does not require special maintenance, the cost of maintenance of fiberglass structures being significantly lower than that of steel structures. The method of testing the tensile strength of the samples has been studied. For conducting experiments, samples of glass mat brand EMC-600-1250-E were used. According to the study results, the mathematical dependence of tensile strength on the number of layers was established, and the most important stages of statistical processing of test results were laid out using the Minitab 18.1 software package. A graph of the relationship between the number of layers and tensile strength is presented. For all the examined samples the ultimate strength will depend on the number of layers. The results of mechanical properties can be used in solving problems associated with the application of polymer composite materials in shipbuilding, for example, in manufacturing superstructures of dry cargo vessels.

Analytical Solution of the serial Bernoulli production line steady-state performance and its application in the shipbuilding process

The modern shipbuilding industry is faced with numerous challenges urging abiding improvement of the shipbuilding process and its management. Such a demanding problem is usually approached using complex production management models involving large data basis handling. The same problem can be solved using simpler, intuitive and mathematically transparent models developed within production system engineering. For these purposes, the analytical solution of the serial Bernoulli production line steady-state performance involving an arbitrary number of machines and buffers of arbitrary occupancy is developed based on Markov chain approach and eigenvalue problem including formulation of the generalised transition matrix as a key novelty. Performance measures in case of general serial Bernoulli production line are developed and the theory is validated using serial Bernoulli lines composed of two, three, four and five machines. The obtained results are compared to those determined using a semi-analytical approach. In order to further demonstrate the applicability of the developed theory, performance measure analysis is performed in cases of longer lines composed of 6, 7, 8, 9 and 10 machines with non-equal buffer capacities. Application of the developed procedure in the analysis of the shipbuilding process is illustrated in a case of the plate prefabrication line usually placed in each shipyard.

日本造船業の黎明期における上田寅吉 : 日本のものづくりの源流を探って(第397回例会報告)

日本造船業の黎明期における上田寅吉 : 日本のものづくりの源流を探って(第397回例会報告)

A METHODOLOGY FOR IMPROVING PRODUCTIVITY OF THE EXISTING SHIPBUILDING PROCESS USING MODERN PRODUCTION CONCEPTs AND THE AHP METHOD

In recent years, shipyards have been facing difficulties in controlling operational costs. To maintain continual operation of all of the facilities, a shipyard must analyze ways of utilizing present production systems for assembling interim vessel products as well as other types of industrial constructions. In the past, new machines continuously improved shipbuilding processes, including software and organizational restructuring, but management continued to search for a modern technological concept that will provide higher productivity, greater profit and overall reduction in costs. In the article the authors suggest implementing Design for Production, Design for Maintainability and Group Technology principles using the Analytical Hierarchy Process (AHP) to apply to multi criteria decision making methods as an efficient tool for maintaining international competitiveness in the modern shipbuilding industry. This novel methodology is implemented through four phases. In the first phase, the present situation analysis is suggested for a real shipyard by establishing closest relations among production lines. The second phase presents a constraint analysis that must be evaluated when developing the design solution. The third phase involves generating a typical number of selected alternatives of the Design for Production, Design for Maintainability and Group Technology principles. In the fourth phase, the optimal design solution is selected using the Analytical Hierarchy Process (AHP) method. The solution incorporating this modern methodology will improve productivity, profit and lead to decreasing operational costs.

Foreign Direct Investment and the Shipbuilding Industry: A Bangladesh Perspective

Traditionally, Bangladesh has been a shipbuilding country. Bangladesh had exported ships even in the seventeenth and eighteenth century. The modern shipbuilding industry started since the period in Bangladesh in mid 1950s, and has made some progress since then and also attracted foreign buyers. It took a number of years before the country could register its name as an ocean-going shipbuilder. The Bangladesh Shipbuilding Industry got a spurt in 2008 when a 2,900 DWT ocean-going ship was exported from Bangladesh. Bangladesh created a new history for the export sectors of the nation. Almost exclusively, the Ready Made Garment (RMG) has been the largest export sector in Bangladesh. There is both a necessity and opportunity for expansion to other sectors and to widen the export base. Shipbuilding is an opportunity, which can grow into a billion-dollar industry in a single decade. Analyzing the micro economic factors, present study describes the segment of the market where Bangladesh enjoys the highest advantage and to draw out a strategy for exploitation of the potential. The present study also identifies that attracting Foreign Direct Investment (FDI) is a necessity for exposure to market, infusing management as well as technology and much needed finance.

What Really Happened in the Beginning of Korean Modern Shipbuilding Industry in 1971?

What Really Happened in the Beginning of Korean Modern Shipbuilding Industry in 1971?

Modernization of ships for launching ultra-precision weapons in the conditions of modern warfare

The most modern shipbuilding issues concerning stealth technology in navy ships are focused on wake and acoustic signature reduction, reduction of visibility of ships and submarines as well as of their displacement. Special materials and alloys are used in shipbuilding for such purposes. In solving a wide range of such issues, a special emphasis has been placed on equipping vessels with up-to-date missile and artillery systems, antiaircraft defence systems and electronic warfare and radar systems. The multifunctionality of Navy vessels becomes the main criterion for their combat deployment.

Numerical and Experimental Study on Plate Forming Using the Technique of Line Heating

Nowadays manual and experiential technique patterns of line heating process could not meet the requirement of modern shipbuilding. Therefore, the automatic forming method is being an active research topic in manufacturing. An accurate and practical predicting method is an essential part of the automatic plate forming system. In the present work a numerical elasto-plastic thermo-mechanical model has been developed for predicting the thermal history and resulting deformation and residual stress field of line heating process. A moving Gaussian distributed heat source was used in the modelling to create a realistic simulation of the process. The transient temperature distributions were predicted using temperature-dependent material properties. The deformation and residual stress field were predicted based on the transient temperature distributions of line heating. Experiments were conducted to prove the validity of the numerical thermo-mechanical model. The final numerical results of temperature, deformation and residual stresses are in good agreement with experiment results. The proposed method presents a valuable reference for the study of similar thermal process.

Study on Plate Forming Using the Line Heating Process of Multiple-torch

With increasingly competition in the world shipbuilding market, manual and experiential technique patterns of line heating process could not meet the requirements of modern shipbuilding in product speed and quality. In recent years, the improvement of productivity for line-heating process is one of the goals in the shipbuilding industry, which means an accurate prediction model is very important. In this study, a finite element analysis (FEA) model for the line-heating process was established and experiments were conducted to prove the validity of the model. The final numerical results are in good agreement with experiment results. Based on the FEA model, the feasibility of the multiple-torch process is verified. The multiple-torch process could greatly save processing time, which is entirely feasible in the specific automation implementation. Finally, the effect of heat line spacing is analyzed, which could provide important information for the line-heating process design. The proposed method presents a valuable reference for the study of the similar thermal process.

Health profile of workers in a ship building and repair industry.

Background:The modern ship building industry, which encompasses the ship yards and marine equipment manufacturing, is an important and strategic industry. The various activities in modern ship building, maintenance, and repair have to be carried out at heights, or in closed confined spaces along with the added risk of exposure to chemicals and metal fumes. These activities expose the workers to various health hazards.Aims:This study was carried out with an aim to assess the health profile of workers in the ship building industry and to assess the occupational health issues related to ship building.Settings and Design:It was a cross-sectional study carried out on 100 randomly selected workers in a ship building yard in Mumbai, and their health profile was studied.Materials and Methods:The workers were enquired for history of co-morbidities, addictions and personal protective equipment use, health-related complaints, and were examined systemically as well as for bedside tests for hearing and detailed systemic examination as per the history or co-morbidity.Results:The important observations were those of prevalence of addictions (69%), irregular use of personal protective equipments (PPEs) among 50% of paint workers, presence of hypertension (20%), overweight (53%), osteoarthritis (10%), hearing loss (25%), and poor self-care.Conclusions:Health education to the workers regarding occupational hazards and lifestyle diseases along with more emphasis on the use of PPEs with regular health examination needs reinforcement.

Study on Plate Forming Using the Line Heating Process of Multiple-torch

With increasing competition in the world shipbuilding market, manual and experiential technique patterns of line heating process could not meet the requirements of modern shipbuilding in product speed and quality. In recent years, the improvement of productivity for line-heating process is one of the goals in the shipbuilding industry, which means an accurate prediction model is very important. In this study, a finite element analysis (FEA) model for the line-heating process was established and experiments were conducted to prove the validity of the model. The final numerical results are in good agreement with experiment results. Based on the FEA model, the feasibility of the multiple-torch process is verified. The multiple-torch process could greatly save processing time, which is entirely feasible in the specific automation implementation. Finally, the effect of heat line spacing is analyzed, which could provide important information for the line-heating process design. The proposed method presents a valuable reference for the study of the similar thermal process.

Shipbuilding-Oriented Welding Technology Based on NX

The requirement of the welding technology is very rigid in modern shipbuilding industry. This paper firstly analyzed the different forms of welding joints and grooves in detail, then described the function of NX-based welding technology. The difference of the features of Fillet Weld and that of Welding Joint were compared in the paper. Finally, a case was employed to explain the process of feature creation.

RESEARCH ON SHIP MANUFACTURABILITY AND EVALUATION METHOD

Ship manufacturability is one of the most important works for modern shipbuilding industry. The basic concept of ship manufacturability and its evaluation system are discussed first. Then the characteristics of ship manufacturability are analyzed. One kind of ship manufacturability evaluation (SME) strategy is put forward. Two evaluation methods of ship manufacturability (knowledge-based manufacturability evaluation and simulation-based manufacturability evaluation) are proposed too. With the proposed methods, the ship manufacturability can be evaluated reasonably.

Evaluation of the performance of contemporary shipbuilding industries in Bangladesh

In this paper, an effort has been made to evaluate the present shipbuilding industries in Bangladesh. To do this, at first an overall picture of this industries have been depicted by identifying the actual shipbuilding practice in both public and private sector. Relevant data have been explored through extensive review of literature, field visits, interacting with shipyard and Ship owners, shipyard managers, Government regulatory and monitoring bodies using structured, unstructured and open ended questionnaires. Existing and upcoming yards have been identified and yards have been categorized by describing the shipyard in terms of modern shipbuilding requirements. The labor cost, labor hour, relative labor rate, productivity etc. have been quantified and compared with other nations. An investigation of cost breakdown of a sample exportable quality ship has been assessed to find out percentage of local components of total cost structure. The potentiality, capability and problems of the shipbuilding sector of Bangladesh have been identified & some recommendations have been made in line with this study.DOI: 10.3329/jname.v7i2.5407

No-Excess Block Construction in Oil Drilling Platform Sevan Driller

The technique of hull block accuracy control is the main concern for modern shipbuilding. The method of no-excess block construction is introduced in Sevan Driller, the world’s first cylindrical ultra-deep offshore drilling platform. According to the structural characteristics of the drilling platform and production capacity, the partition and construction programs of the hull blocks are proposed. Modeling and drawing for platform in the design stage is analyzed. In the manufacturing stage, the factors affecting the block accuracy include plate-cutting, plate alignment, marking, assembling and welding. Additionally, the range of accuracy controlling aspect and compensation values are confirmed. The application of no-excess block construction in this drilling platform results in the improved quality of the drilling platform, reduced shipbuilding costs and the shortened shipbuilding cycle.

I K Brunel's Ships — First Among Equals?

A attempt is made to reveal Brunel's true position in the world of shipbuilding, and to show what he and his more experienced contemporaries had so far achieved and what was left to be done before the iron steamship (but not yet its engines) could be regarded as mature, by the 1850s. Brunel's ships are much admired, and he is regarded by the general public as having virtually invented the iron steamship. This is not a true account of the man's work in this sphere, but is a distortion caused primarily by his son's hagiographic biography of him, which enthusiasts are ready to accept as entirely true. Brunel himself was not given to making false claims. The story that he originated the idea of transatlantic steamship travel is demonstrably false, and there are other tall tales that the primary documentation discounts. In fact Brunel depended to a high degree on the work of others, and he would have been foolish to ignore what had already been learned. A chronology of the evolution of the steamship, and in particular the iron steamship, demonstrates what happened in the development of the transatlantic ferry and on other steamship routes, granting Brunel his correct place. Brunel's ships did employ a few new ideas, some of which may have been employed because of Brunel's limited production facilities and others were clearly intended to avoid problems that had already been defined by others. Brunel introduced the longitudinal framed double bottom in SS Great Britain, and was the first to use double riveted lap joints throughout in her plating. His other innovations were relatively unimportant; it was these two ideas that gained wide acceptance in the industry and were a distinct step forward in iron shipbuilding. In the longitudinally framed double bottom Brunel started a development that was brought to fruition by William Fairbairn, whose definitive study on the strength of ships confirmed the longitudinal frame as superior to the traditional transverse frame and extended the idea to the deck. This concept is essential for modern shipbuilding. Fairbairn also confirmed that Brunel's riveting techniques, while they were different to those so far used by the best shipbuilders, were valid and were easier to apply.