bluuebunny/crossref_metadata_2025 huggingface dataset:
Producibility in the Naval Ship Design Process: A Progress Report
Authors: Keane Robert G. , Fireman Howard
Published: January 2021

In October 1989, A Ship Design for Producibility Workshop was held by the Naval Sea Systems Command (NAVSEA) at the David Taylor Research Center (DTRC). The purpose of the workshop was "To develop the framework of a plan to integrate producibility concepts and processes into the NAVSEA Ship Design Process." The major recommendations of the workshop included initiatives related to increased training of NAVSEA design engineers in modern ship production concepts, development of producibility design tools and practices for use by NAVSEA design engineers, improved cost models, implementation of producibility strategies for ship design process improvements, modification to existing acquisition practices, and improved three-dimensional (3-D) digital data transfer. The workshop was one of NAVSEA's first Total Quality Leadership (TQL) initiatives and was subsequently expanded into the Ship Design, Acquisition and Construction (DAC) Process Improvement Project. This paper reports on the major findings and recommendations of the workshop, the near term accomplishments since the workshop, and the long range strategic plan for continuously improving producibility in the Naval Ship Design Process.
Defining the Shipyard’s Engineering Requirements
Authors: Kraine Gilbert L. , Wilkins James R.
Published: January 2021

It is customary for a shipyard to subcontract with one or more design agents for at least some portion of the detail design of a ship to be constructed by the shipyard. Experience with this process has demonstrated that it has the potential to be the source of inefficiencies, wasted efforts and deteriorated relations between the shipyard and design agent. The Society of Naval Architects and Marine Engineers Ship Production Committee Panel, (SP-4), Design/Production Integration, sponsored a project to improve this process. This effort developed a list of the information which should flow from a shipyard to a design agent in order for the design agent to generate the calculations, drawings, and other deliverables in a timely fashion and usable format to support the construction effort. This paper describes the methodology used to develop the required information and reviews the details of the list
Computer-Aided Materials Management and Control for a Shipbuilding Yard
Authors: Kar A.R. , Sha O. P.
Published: January 2021

This paper deals with the development of a computerized information system for materials management and control for shipbuilding yards. It begins by critically examining the manual and semi-manual data processing methods used in medium and small-sized shipyards and highlighting their drawbacks. Based on this and with the knowledge of the ready availability of desktop computers in small/medium-sized shipyards, a computerized materials management and control system is proposed. The schema of the proposed database system is then presented by the help of block diagrams. A number of application programs have been developed to manage, control, and update the various database files under the "Network," "Purchase," "Inventory," and "Drawing" modules. The system has been tested in a simulated production environment by entering the production, planning, materials, and drawing information of two different vessels during construction. The range of information that can be obtained and the results from the proposed system are shown briefly. It is felt that a computerized information-based materials management system has a major role to play in the smooth and profitable running of a shipyard. It is very effective in a quick appraisal of complex queries relating to materials procurement, production and drawing status, and the cause of delays.
Computerized Angle Measurement for Inclining Experiments
Authors: Chen Victor Y. , Weinrich Peter K.
Published: January 2021

This paper examines the application of the latest in precision electronic angle measurement instrumentation combined with portable computer technology to measure the angles of inclination during inclining experiments. The Computerized Angle Measurement System (CAMS) is described as to its configuration and function including the methods used in data acquisition to enhance both its ease of use and accuracy of results. The software for data acquisition is also discussed. CAMS is compared with traditional pendulums and mechanical tangent inclinometers in the areas of accuracy, cost, and ease of use. CAMS is shown to be a very accurate, cost-effective, and easy to use tool for angle measurement during inclining experiments.
NIDDESC—Enabling Product Data Exchange for Marine Industry
Authors: Murphy James
Published: January 2021

The use of computer-aided design (CAD) technology in the U.S. Navy and marine industry has evolved from a drafting-based design tool to a three-dimensional (3D) product-oriented information base, used for design, production and service life support. One of the most significant enhancements to current CAD technology has been the incorporation or integration of non-graphic attribute information with traditional graphics data. This expanded information base or product model has enabled the marine industry to expand CAD use to include such activities as engineering analysis, production control, and logistics support. While significant savings can be achieved through the exchange of digital product model data between different agents, current graphics-based CAD data exchange standards do not support this expanded information content. The Navy/Industry Digital Data Exchange Standards Committee (NIDDESC) was formed as a cooperative effort of the Naval Sea Systems Command (NAVSEA) and the National Shipbuilding Research Program to develop an industry consensus on product data and to ensure these industry requirements are incorporated into national and international data exchange standards. The NIDDESC effort has resulted in the development of a suite of product model specifications or application protocols (APs) defining marine industry product model data. These APs have been submitted for inclusion into the next generation of data exchange standards.
Building on the Success in Standardization of the U.S. Navy
Authors: Marcus Henry S. , Zografakis Nikolaos E. , Tedesco Matthew P.
Published: January 2021

Standardization of hull, mechanical, and electrical (HM&E) components in U.S. naval ships can take the form of identical components on one ship, on one class of ships, or on the entire Navy fleet. The Navy has shown through a variety of successes that it has the potential to do even more challenging tasks in this area. This paper describes the database and tools used by the Navy and some of the Navy's success. A vision and course of action for the future are discussed that might include commercial as well as naval ships.
Computer-Integrated Manufacturing: A Perspective
Authors: Latorre Robert , Zeidner Lawrence
Published: January 2021

The introduction of computer-integrated manufacturing in ship production will involve more than linkage of separate automated ship production processes. It will create major changes from design through delivery. This paper presents the results from a three-part project:a manufacturing literature survey of computer-integrated manufacturing (CIM) and supporting technologies,a National Science Foundation (NSF)-sponsored workshop on CIM in ship production, andresearch and development recommendations to facilitate CIM in ship production.
The Effect of Learning When Building Ships
Authors: Erichsen Stian
Published: January 2021

Learning—the ability to do the same tasks faster and better as experience is gained—has the effect of reducing time and money spent on repetitive building of the same type of ship. Reports from (East) German and Norwegian yards indicate a pronounced effect of learning. However, it varies with external circumstances, types of ships, and the degree of complication. The effect may be modeled mathematically to describe a general cost development. Recordings of man-hours per ton of steel and per 1000 ft3 bale of reefer capacity at Norwegian yards indicate clearly that factors that tend to disturb the learning reduce its effect greatly. Much can be saved by avoiding accidental changes in the production systems and other interferences with established procedures.
Training Initiatives for Classification Society Personnel
Authors: Blanding Howard C.
Published: January 2021

The ship classification society is an institution unique to the commercial maritime industry. For a single vessel the classification society may act on behalf of a number of client organizations: owner, shipyard, underwriters, furnishers of capital, flag state, port state, etc. The interests of these various groups require a professional staff totally familiar with the uses and practices of the industry, codes and laws of vessels trading nationally and internationally, flag and port state regulations and, of course, the engineering disciplines and practical skills associated with the design, construction, maintenance and operation of vessels. In the not too distant past it was possible to acquire experienced professional staff requiring little additional training. With the shrinking U.S. flag fleet, this pool of professionals has largely disappeared in this country. Today's professional staff of engineers and field surveyors is drawn largely from recent graduates of the maritime academies and colleges of engineering. Although well prepared, these personnel do require extensive on-the-job and classroom training to meet the objectives of the American Bureau of Shipping. In addition to our internal objectives, the quality assurance constraints of the European Community and others place a special emphasis on documented training. This paper discusses some of the problems encountered in delivering training for a multinational, multicultural, and multilingual organization, and the initiatives being undertaken to provide the necessary skills and to ensure reasonable and consistent interpretation and application of codes and standards and professional execution of assigned tasks. In order to realize these objectives, a training program must be aggressive and pro-active and look into the future to anticipate the requirements of developing technologies and it must do this within severely defined budgetary and manpower constraints.
Network Scheduling Development in an MRP II Environment
Authors: Neumann Richard J.
Published: January 2021

Large manufacturing industries have been able to successfully reduce cost and cycle time through the use of Manufacturing Resource Planning (MRP II) systems and principles to control material flow and the production process. Ship construction cannot be neatly classified as a manufacturing process. The complex relationships involved with the installation and activation of ship's systems more closely resembles a construction operation. Work of this type has traditionally been controlled through an activity based network scheduling system. However, MRP II principles offer numerous benefits for the shipbuilding industry. This paper discusses an approach to planning, scheduling, and management of ship construction which takes advantage of benefits from both approaches. By using both network scheduling and MRP II in an integrated scheduling system, a shipyard will be better able to plan and execute the ship construction process.
The Department of the Navy Approach to TQM
Authors: Dockstader Steven L.
Published: January 2021

The Department of the Navy (DON) has adopted total quality management (TQM) as the principal leadership and management system to achieve mission effectiveness. Adapted for practice by DON personnel, the approach has been called Total Quality Leadership (TQL) in order to emphasize the pivotal role played by leaders. The purpose of this paper is to describe TQL and the approach used for implementation. The central thesis of the paper is that the change to TQL is transformational in nature. Transformational changes require a planning approach that is sensitive to the systemic effects of organizational changes. Strategic change management (SCM) is described as the methodology for achieving this change in the DON. The rationale for SCM is described and the resulting implementation approach is evaluated.
New System to Control Magnetic Arc Blow in Welding
Authors: Jones R. Brian
Published: January 2021

Welding of magnetized steels has long been a problem in the welding industry. When welding is attempted in the presence of a magnetic field, the welding arc becomes deflected. This phenomenon is known as arc blow. Arc blow can cause significant weld defects, it can reduce productivity, and it is frustrating to the welder. Sometimes weld joint magnetism is so great that control methods must be used to produce a satisfactory weld. In 1991, Newport News Shipbuilding (NNS) developed and built six magnetic field negators (patent applied for) for their welding department. Each unit consists of a small hand-carried electromagnet and power supply that operates off any standard 110/120 volt ac power source. The lightweight system is designed to counteract magnetic fields up to 200 milli-tesla (mT) (2000 gauss) across a 13 mm (0.5 in.) weld joint in 25-mm-thick (1 in.) steel. Through laboratory and production testing, the magnetic field negator has demonstrated the ability to neutralize local areas of high residual magnetism, resulting in a considerable reduction of magnetism-related weld quality problems.
Shell Development Computer Aided Lofting—Is There a Problem or Not?
Authors: Lamb Thomas
Published: January 2021

Some shipyards are not satisfied with the computer aided shell development systems that they use. This is because of fit-up problems and the need for excess material to allow corrections to be made at erection. Most shipbuilders desire a "cut to neat size" approach. Most computer aided lofting (CAL) developers recommend that excess material be used. They claim that this is to take care of limitations in the plater's skill and the forming machinery, not in the CAL system. The paper reports on a study that was undertaken to determine the correct perspective for the shell plate development problem, and if the shipbuilder's goal of cutting all shell plates neat is reasonable.
Implementation of HSLA-100 Steel in Aircraft Carrier Construction—CVN 74
Authors: Christein J. P. , Warren J. L.
Published: January 2021

High strength low alloy (HSLA)-100 steel was developed to be less sensitive to hydrogen embrittlement than high yield (HY)-100 steel. The primary benefits sought through the use of this new steel were savings in energy, labor, and scheduling that would result from reduced preheat for welding. This paper reviews the overall efforts required to implement the use of HSLA-100 steel during CVN 74 aircraft carrier construction. It discusses the engineering and design effort required to incorporate a new material on a vessel midway through construction. Also included is a discussion of the development of an implementation plan which ensures successful welding procedure qualification, production welding, and inspection of HSLA-100 welds. Results confirm that HSLA-100 steel can be successfully substituted for HV-100 steel in a shipyard environment, and that significant benefits can be realized from reduced welding preheat. Also, key elements of future applications of HSLA-100 are presented.
A Look Back on 1942 Combatant Production: An Example of Successful Employee Empowerment at Higgins Industries
Authors: Haddock Graham , Latorre Robert
Published: January 2021

World-class ship production in the United States will be achieved by shipyards using production planning based on the strengths of their workforce and technology base. While a large portion of technical literature deals with ship production technology, there is a growing awareness that the employee empowerment can realize substantial savings in labor hours and material usage. In 1942 the demands for military landing craft resulted in Higgins Industries opening two new boat building plants in New Orleans. By the cessation of hostilities in 1945, over two thousand 50–56 ft LCM landing craft and one hundred 180 ft FS cargo ships were delivered. The LCM and FS ship production were maintained in the face of wartime shortages in propulsion engines, steel, and a skilled workforce. This paper describes Higgins Industries' production planning and how what is now termed employee empowerment was utilized to achieve reduction in manhours and material usage. This ship production achievement 50 years ago provides many lessons in utilizing the workforce intelligence with a positive corporate culture to achieve world-class shipbuilding in the United States
Past and Present Concepts of Learning: Implications for U.S. Shipbuilders
Authors: Spicknall Mark H.
Published: January 2021

The experience curve has been used as the model of learning within manufacturing for nearly a century, and has been used as a basis for predicting future performance and for setting performance targets. First, a summary of the experience curve and its underlying premises is given Then deficiencies in experience-based model of learning are presented. The case is made that an organization that attempts to compete on the basis of incremental improvements on past experience, as represented by past competence and number of units produced, will not be able to compete with the most competent competitors that are using market-driven performance targets and conscious learning and problem-solving methods to drive innovation. Two actual examples of learning outside the paradigm of the experience curve are discussed. One method of measuring present learning rates for individual processes is presented. It is concluded that U.S. shipbuilders need to look outside the experience-based model of learning, and the associated idea of series production of standard ships, toward conscious methods of learning and problem solving in order to become competitive in the commercial shipbuilding market.
Intelligent Selection of Main Engine at the Preliminary Design Stage of Ships
Authors: Lee Dongkon , Lee Kyung-Ho , Han Soon-Hung
Published: January 2021

The propulsion system is one of the most complicated systems in a ship and its performance greatly depends on the selection of the main engine. Also, the propulsion system occupies a large portion of the total shipbuilding cost, as well as a large portion of the annual operating cost in fuel consumption. Selecting the right propulsion system is an important factor consideration for shipowners and designers. In the preliminary stage of ship design, the main engine is selected by a design expert and this usually is a difficult task for a novice designer. With the help of a design support system, efficiency in selecting the right engine can be increased. In this study, a knowledge-based system for engine selection which can be used in the preliminary design stage for a merchant ship has been developed. The knowledge base is constructed using heuristic knowledge acquired from design experts. Two databases of engine catalogs and of existing ships are also constructed. Various performance prediction modules of the domain of naval architecture are integrated with the knowledge bases and databases. To enhance the user interface, a graphical user interface (GUI) built upon the Motif widgets is adapted.
3-D Computerized Measuring Systems for Increased Accuracy and Productivity in Shipbuilding and Repair
Authors: Holmes Michael D.
Published: January 2021

Conventional measurement and alignment methods for shipbuilding and repair are no longer compatible with today's technology. Measurements made with plumb bobs, taught wires, transits, optical-mechanical theodolites, levels and wooden templates, while adequate in many applications, are labor intensive and leave some redundancy with regard to accuracy. With the increased popularity and use of the personal computer during the 1980's, several laser, electronic theodolite and photogrammetry based measurement technologies emerged. These methods require highly skilled workers, and although they increased the reliability of measurements, they are costly and again are labor intensive [1].2 This report describes two computer-based measurement systems. Each system requires only a single operator to generate three-dimensional coordinates rapidly and accurately. Each system measures in the spherical coordinate system of the instrument. The supporting software programs allow for the transformation of the measured data to the blueprint values or object coordinate system. Data can be imported from computer-aided design or lofting software for measuring or locating specific points of interest, or can be exported for comparison of as-built coordinates with design values. The choice of measurement system employed will depend on the task at hand, accuracy required, environment and budget of the user. Actual shipyard applications stating increased accuracy and/or productivity are cited for each measurement system.
The Use of Fuzzy Logic in Shipping and Shipbuilding Market Modeling, Analysis, and Forecasting
Authors: Li Jun , Parsons Michael G.
Published: January 2021

Fuzzy logic is a technique that attempts to systematically and mathematically emulate human reasoning. This paper investigates the feasibility of applying fuzzy logic to transportation and shipbuilding market modeling, analysis and forecasting. Fuzzy systems called fuzzy decision modelers (FDMs) are developed based on fuzzy logic techniques to model the crude oil tanker freight rate market, the tanker new order market and the tanker scrapping market. Our results show that the FDMs are able to model and forecast these economic systems very well. In addition, the FDMs also provide valuable insights into market mechanisms and market participants' decision-making patterns. The FDMs are mathematical model-free, nonlinear systems capable of capturing complicated relationships among economic variables. The FDMs are easy to develop and easy to interpret. These advantages of fuzzy systems suggest that fuzzy logic techniques are a promising alternative in shipping and shipbuilding market modeling, analysis and forecasting.
Analysis of Ship End Launching Without Fore Poppet
Authors: Shen Wei Qin
Published: January 2021

A new technology on the end launching of a ship without fore poppet is presented. A theoretical analysis of the new technology is carried out based on the actual measurements which were recorded during the launching. By means of the Ritz method, the reactive forces from launching ways, the deflection curves and the longitudinal bending moments of ship hull beams are calculated for two ships under three assumptions. The theoretical results are in good agreement with the measured data. The strength of ships in the launching process is examined. A computer program for an optimum arrangement of the blocks is proposed.
Build Strategy Development
Authors: Clark John , Lamb Thomas
Published: January 2021

The 1985 NSRP Design for Production Manual describes the use of a Build Strategy as a basis for improved shipbuilding performance through front-end involvement of all departments and better communication. A number of U.S. shipbuilders are known to have used the approach. However, the extent of its use and the experience of the users was unknown. To remedy this situation the SP-4 Panel conceived a project to determine:how widely "the Build Strategy approach" was known and used by U.S. shipbuilders, anda suitable Build Strategy framework with examples of its use for two typical ship types.

This paper summarizes the performance of the project and briefly describes the findings of the U.S. and foreign shipyard surveys and visits, the required prerequisites for use of a Build Strategy and benefits from its use. It also includes the contents list for the proposed Build Strategy framework.
Preconstruction Primers for Improved Shipyard Efficiency
Authors: Kelly John
Published: January 2021

Significantly improved productivity, efficiency, quality and reduced costs for shipbuilders worldwide are achievable by making the correct choice of preconstruction primer technology. Use of super heat-resistant, weldable, zinc silicate shop primers offers shipbuilders unrivaled performance, unique solutions and significantly reduced costs. Such products, which were jointly developed with the Shipbuilders' Association of Japan (SAJ), have already been extensively tested and fully proven in Japan, the most demanding newbuilding market, and are now being used successfully in the Western Hemisphere. Whatever the size and technical capabilities of a shipyard, this type of technology offers shipbuilders "world class" standards with the best overall balance of properties, enabling overall shipyard production requirements to be met or exceeded.
Development of STEP Ship Model Database and Translators for Data Exchange Between Shipyards
Authors: Wyman Jeff , Wooley Dan , Gischner Burt , Howell Joyce
Published: January 2021

Effective data exchange of product model data is essential for future competition in the global marketplace. Many efforts have been undertaken in recent years to establish a transfer mechanism for product model data in the Shipbuilding industry. These include the development of the STEP Standard, creation of the NIDDESC Application Protocols, and efforts of the European NEUTRABAS and MARITIME Projects. The ARPA/MARITECH Project for "Development of STEP Ship Product Model Database and Translators for Data Exchange Between Shipyards" provides a unique opportunity to attempt to implement the still developing Standards for Product Model Exchange and to enable their use for data exchange between the major US Shipyards. The project will create and populate a prototype product model database, develop translators for exchange of product model data between Shipyards, and facilitate adoption of the Shipbuilding Application Protocols as part of the emerging International Standard (STEP). These ambitious goals are being undertaken by a consortium of US Shipbuilders, their CAD vendors, and STEP experts. The participants will help develop a product model data exchange capability for the entire Shipbuilding industry, while they enhance their own ability to compete in the global marketplace.
A Model of Environmental Management System Introduced in the Shipyards of “Astilleros Españoles” Group
Authors: Rodriguez Jesus Casus
Published: January 2021

In the last few decades, the risks of environmental impact using new technology have increased rapidly and, as a consequence, the number, magnitude, and frequency of manmade ecological disasters are continuing to increase. Some of these disasters have had irrevocable effects on the environment. Today, industrial processes are the main polluting agents, and for this reason are a priority where important measures should be taken (actually some have been taken) to reduce the impact on the environment and natural resources. This process of change in industrial practices must be supported by the enactment of appropriate legislation, which must regulate the new industrial behavior for achieving sustainable development. Shipbuilding cannot be left out of this process, not only because of its industrial activity, but also because of the traditional environmental awareness of the shipyards, which have an old and close relationship with the sea. It follows that the shipyards must take action on environmental problems which their industrial processes could produce. That is, shipyards must introduce in their organizations an appropriate environmental management system.
Control of Distortion in Thin Ship Panels
Authors: Conrardy Chris , Dull Randy
Published: January 2021

The increased use of thin section (i.e., less than 10-mm (3/8-in.) thick) steel in ship panel construction has aggravated distortion problems, adding to the costs for fitting and flame straightening. This paper describes the results of a study to evaluate techniques for control of distortion in thin panels used in ship construction. The objective of this project is to identify cost effective techniques for controlling distortion. Buckling is usually the dominant mode of distortion in thin panels, followed by angular distortion. Means of reducing both forms of distortion are discussed. During the design phase relatively small adjustments to the design, such as changing plate thickness or stiffener spacing, can significantly reduce distortion. Improving manufacturing techniques, including reducing weld size, implementing intermittent welding, and restraining the panel during welding, can also make a major impact on reducing distortion. New techniques such as egg-crate construction, laser welding, thermal tensioning, back-side line heating, back-bending, and weld quenching also show promise.
State-of-the-Art Procedures for Ensuring Optimum Coating Longevity in Navy Tank Coating Operations
Authors: Kuljian Gordon G. , Kaznoff Alexis , Parks A. Richard
Published: January 2021

Annual corrosion control costs have led the Navy maintenance community to institutionalize state-of-the-art surface preparation, coating, and inspection procedures for seawater ballast, potable water, and other critical internal tank and void areas. This new direction will double or triple the current service life of the tank corrosion control systems.
Standardization -A Competitive Tool
Authors: Hengst Sjoerd
Published: January 2021

The paper deals with aspects of standardization in relation to international developments. In the E. U. the role of the organization for standardization, CEN, is changing. This is the result of the tie of standards with the directives issued by the E.C. and affects the National Standards. For shipping and shipbuilding, IMO will be the reference. ISO is the international organization to develop the standards. In Europe, standardization for the maritime industry, the international (ISO) developments and the role of CEN in relation to Council Directives of the E.C. are the concern of the administrators in Brussels. CEN TC 300, the CEN Technical Committee for Shipbuilding, is responsible for the liaison between ISO, IMO, and the national standard organizations. A review is given of the constraints, advantages and disadvantages of international standards for the shipbuilding industry.
Simultaneous Three-Edge Pre-Weld Cleaning
Authors: Blomquist Paul A.
Published: January 2021

Equipment and technologies which could be used to clean three adjacent surfaces of shipbuilding steels simultaneously in a single pass prior to welding operations have been surveyed. Seven methods were evaluated: closed-circuit grit blasting, laser beam stripping, high-pressure water blasting, high velocity oxy-fuel flame stripping, multiple-head wire brushing, vacuum-shrouded needle-gunning, and carbon dioxide bead blasting. A commercially available vacuum-recovery recirculating grit-blast unit was evaluated in a shipyard trial. Results of the survey are presented in a comparison table and discussed in detail. For each method, production speed, approximate acquisition cost, consumables used, and environmental effects are considered. Surfaces produced by various cleaning methods were evaluated by visual examination and Scanning Electron Microscopy.
Shipyard Technology Development Strategies
Authors: Birmingham Richard , Hall Sue , Kattan Raouf
Published: January 2021

Effective development strategies for shipyards need to recognize the different economic and technological environments in which individual organizations operate. The benefits of implementing a given technology will vary according to the different cost structure, labor market and technological development of the individual shipyard. Specifically, capital investments in expensive hardware, can lead to a deterioration of the overall performance of the business, whereas improvement in the organization and practices of the business may produce improved performance from the existing hardware and facilities. Development strategies must be targeted towards quantifiable improvements against the needs of the market or competition and must recognize the impact of different technologies on the performance of the particular yard. This paper looks at the issues involved and appraisal techniques to support effective investment in hard and soft technological developments.
Making the Jump to Product Model Technology
Authors: Ross Jonathan M. , Garcia Luis
Published: January 2021

Without doubt, product model technology represents the state-of-the-art in world-class ship design and production tools. It is driven by sophisticated CAD/CAM software, and it features one-stop access to all design and production data for each ongoing ship project. This technology provides an elegant and compelling alternative to traditional design and production methods. Or does it? Some yards are unconvinced of the value of such technology, which they view as overly complex and not effective in the nitty-gritty real world of shipbuilding. For example, while the product model is touted as providing a basis for ordering material, the time to construct the product model seems impractically long. This paper summarizes today's product model state-of-the-art and goes on to examine practical applications of the technology. One application is a new building project in a small shipyard. Another application is a conversion project in a large yard. The applications show how design firms and shipyards are successfully using product model technology to increase their competitive edge in the world market.
IPPD -The Concurrent Approach to Integrating Ship Design, Construction and Operation
Authors: Cote Mark , DeVries Richard , Duneclift Lee , Perrin Watson , Prince Kevin , Ribeiro Jorge
Published: January 2021

The concept of "concurrent engineering" is philosophically widely accepted as the correct approach to considering all disciplines in the course of a design. The methods that are used to solicit and incorporate the input are not so widely accepted. Integrated Product and Process Development (IPPD) is a technique that has been successfully applied to the Engine Room Arrangement Modeling (ERAM) project. The paper addresses the experience of the (ERAM) team, which is an element of the US Navy's Mid-Term Sealift Ship Technology Development Program and will focus on issues that may be experienced in a U.S. shipyard environment when applying IPPD. The IPPD process will be discussed from two perspectives. First the team formation, training and operation will be addressed. The team issues include such elements as team formation, requirements for collocation, project pre-planning, team training, team member development, integration of new team members, maintaining team work including peer review, establishment of norms and consensus building. In general, issues differing from current practices will be addressed. Next, the application of the approach to ship design while considering ‘cradle to grave’ costs will be addressed from a technical standpoint. The technical approach will provide a general outline of the steps followed in developing the engine room arrangement models, using the IPPD approach. This outline reflects both the initial development and the evolution over several engine room designs. The conclusion of the paper will define what steps the ERAM team recommends U.S. shipbuilders should implement in adopting the IPPD process.
Low Cost Digital Image Photogrammetry
Authors: Mugnier Clifford J.
Published: January 2021

A problem in modular shipbuilding is the lack of a reliable, low-cost method of obtaining and utilizing dimensional control in 3D. Photogrammetry has been successfully used as a tool for this application, but because of the large number of systematic errors associated with film-based cameras, only very large shipyards are using it. Recently, developments in Charge Coupled Device (CCD) imaging arrays for cameras have allowed some success in applying photogrammetric techniques dimensional control Mainstream photogrammetric software and hardware configurations have been expensive and complicated. Digital camera systems and computers were purchased and programmed to tie existing inexpensive software packages with Geometric Dilution of Control (GDOP) error propagation analysis, originally designed for topographic mapping, into a tool for production shipyard fabrication dimensional control.
A Numerical Thermoplastic Analysis of Line Heating Processes for Saddle-type Shells with the Application of an Artificial Neural Network
Authors: Shin Jong Gye , Lee Jang Hyun , Park Sung Kun
Published: January 2021

Line heating (LH) is a process for forming compound-curved shells of a ship's hull, and is carried out by skilled workers. The accuracy of final shape and the production time are based solely on the experience and intuition of the workers. Many attempts have been tried to analyze the LH mechanism theoretically and experimentally, in order to achieve productivity. The nature of the LH process involves a three-dimensional transient thermal conduction phenomenon, followed by temperature-induced permanent plastic deformation. Due to the complexity of the physical problem, a theoretical analysis is not presently available. Previous studies have been limited to simplified models or two-dimensional analyses, which are inadequate for applications in current shipyard practices. In addition, a final manufactured shape is dependent on many factors involved in the process, such as torch speed and position, type of heat, cooling method (air or water), as well as plate dimensions. The effect of each factor on a final deformed shape con not be obtained using simplified modeling. With a practical application in mind, a numerical approach was employed, to simulate the LH process. Based on the mechanics of LH, temperature and stress fields are uncoupled, and each field is solved using a general finite element program. Heat flux for the heating torch and convection condition for the cooling hose are modeled for temperature analysis. The plate to be fabricated is descretized using three-dimensional solid elements. In order to verify the validity of the present model, a temperature distribution is obtained for a flat plate problem and compared with published data. The results are in good agreement with the published data. A numerical simulation is then carried out for forming saddle-type shells according to current shipyard practices. Currently, the line heating is applied to a cylindrically curved shell to produce a doubly curved shape, that is saddle-type shell. Thus, singly curved shells are modeled to simulate the forming process of saddle-type shells and temperature distribution, permanent plastic deformation, and residual stress are calculated for the obtained final shells. Parametric studies are given and discussed relative to the effects of forming parameters, such as torch speed, cooling method, and plate dimensions. It should be noted that each piece of shell of a ship's hull is not identical. In addition, each ship is different. This means that every single piece of flat plate is fabricated using different combination of forming parameters. Thus, it is necessary to generate new parameters from the calculated results for the automation of the LH process. An artificial neural network (ANN) algorithm is applied to generate new parameters, and is verified with several actual examples.
A Study on the Prediction of Deformations of Welded Ship Structures
Authors: Seo Seung II , Jang Chang Doo
Published: January 2021

Welding deformations injure the beauty of appearance of a structure and decrease its buckling strength. In addition, welding deformations cause errors during the assembly of the structure and prevent increase of productivity. Welding deformations of real structures are complicated and the accurate prediction of welding deformations has been a difficult problem. This study presents a method to predict welding deformations of large structures accurately and practically based on the accumulated research results. The presented method uses the finite element method combining the inherent strain theory and the experimental results for accurate and efficient analysis. The weld joint is assumed to be divided into 3 regions: inherent strain region, material softening region and base metal region. The simplified elasto-plastic analysis method is introduced and representative material values during the thermal elasto-plastic process are used in this method. It is revealed from the analysis results for the simple welded model that the inherent strains are changed by joint restraint as well as heat input and elastic modulus of the inherent strain region, and the material softening region must be different from that of the base metal region. These results have been supported by the experimental data. The method proposed in this study can be combined with the commercial finite element analysis software to predict reasonably an efficiently the welding deformations of large structures.
On-Demand Education to Meet Marine Industry Professional Development Needs
Authors: Bongiorni Bruce , Spicknall Mark , Horsmon Albert , Cohen Pamela
Published: January 2021

There is both the need and opportunity to create an environment to share knowledge that will help the maritime industry grow and compete. Technology helps break away from traditional education, which is both synchronous and location-dependent. The freedom to be asynchronous and location-independent lets the instructor and the students plan and control their participation and use of resources to suit their own schedules and preferences. In this learning model, the instructor still determines what is to be learned, but instead of simply presenting information, he or she creates a learning environment that encourages the student to be more self-directed; in fact, the learning experience itself becomes student-centered. In addition to gaining formal, degree-related education, current technologies also provide the possibility of just-in-time education in which a student learns what is needed at the moment to do his or her job. This paper describes the underlying concepts of education on demand, provides some examples of some online programs available today, both generic and marine-industry specific, and presents the authors' views of the future of online education for marine-related organizations and businesses.
A Study on the Application of Large Aluminum Hollow Extrusion Profiles to Ship Structures
Authors: Seo Seung II , Son Kon Ho , Park Jae Hong
Published: January 2021

Aluminum is much useful material for high speed light crafts due to high strength and light weight. Large aluminum hollow extrusion profiles have another merits such as easy production of complicated shapes, reduction of welding and cutting lines, easy fabrication, high quality and labor cost-down. In this paper, a design method for aluminum hollow extrusion profiles was developed. Detailed finite element analysis was carried out to comprehend the structural behaviors of the hollow extrusion profiles subjected to normal pressure and compression. Simple formulas were proposed to analyze structural characteristics of the hollow extrusion profiles based on orthotropic plate theory and plate buckling theory. By comparison with the detailed analysis results, it was shown that simple formulas have good accuracy and efficiency. For practical application of the proposed simple formulas, optimization for reduction of weight under strength and production constraints was carried out and useful results were obtained.
A Study on the Prediction of Ship Plate Distortion Topology by Neural Networks
Authors: Yuliadi M. Z. , Shahab A. , Bruce G.
Published: January 2021

Ship plate distortion results in a decrease in strength and aesthetics, has a detrimental effect on the fabrication process, as well as an increase in production cost due to the need for correction. Welding heat has been regarded as a major contributor to distortion. Assessing the distortion problem, without making assumptions, is extremely difficult due to the complexity of the variables involved, e.g., welding procedures, materials, design, and geometry. This paper develops a neural network model to predict the topology of ship plate distortion. The developed model presents good agreement with actual distortion data that have been obtained. In terms of variable sensitivity, chemical composition should be taken into account.
Collision Avoidance Schemes for Orthogonal Pipe Routing
Authors: Kuo C. C. , Wu J. K. , Shaw H. J.
Published: January 2021

This paper describes collision detecting and avoidance schemes to automatically lay out piping routes. The overlapping between the boundary boxes of equipment and pipelines is the basis for determining two types of collision: vertex-interference and edge-interference. Three collision-avoidance routing schemes have been developed using the modified adjacency and distance matrices and the line-surface intersection method. This collision avoidance scheme is for orthogonal pipe routing and forms the basis for extension to other routing principles.
Object-Oriented Analysis of an Information Model for Hull Piece Fabrication
Authors: Shin Jong Gye , Kim Won Don
Published: January 2021

The production procedure of ship's hull plates includes hull modeling, lofting, cutting, and forming in sequence. Each process is isolated from the point of view of information flow and current practices in forming hull pieces are experience-dependent. This, in turn, reduces productivity and prevents the development of automation. To satisfy shipyards' demand for improved accuracy and enhanced productivity with mechanization or automation, it is necessary to collect production information, and to structure and maintain it in a well-organized manner. The objective of this paper is to propose an information model for ship's hull piece forming in a systematic manner. First, current shipyardsi practices and information flow relative to hull production process are described. From the point of view of information integration, the necessity of an information model is clarified. An information model for ship's hull piece forming is then proposed. For the information model, product model and concurrent engineering concepts are introduced. Since the construction of the information model with the two concepts requires an object-oriented approach, a new mixed-type, called here ‘hybrid’, object-oriented methodology for hull piece information model is defined. Based on the proposed methodology, the object association and operation analyses are carried out for the information modeling of hull piece forming. Through the analysis, the object-relation diagram shows that kinematics data is indispensable to construct the information model for hull piece forming.