bluuebunny/crossref_metadata_2025 huggingface dataset:
Flexible Robotics for Shipbuilding
Authors: Reeve Ronald , Rongo Robert , Blomquist Paul
Published: January 2021

A twelve-member team is developing a new paradigm in shipbuilding robotics. The consortium, led by CYBO Robots in conjunction with the Technology Reinvestment Project (TRP), includes shipyards, hightech companies, technical institutes, universities, and federal agencies. The objective is to create and implement robotic technology that allows shipyards to move confidently into automated production of both commercial and combatant vessels, while making maximum use of existing facilities and personnel. Keys to the effort are reliable, easy-to-run robots driven by open-architecture controllers which develop robot path programs directly from the CAD model of the ship. Examples of applications for these robots are shown in Fig. 1. Differing from previous approaches, this project attacks the problems which traditionally have kept robots out of U.S. shipyards, and provides flexible solutions to organizations with limited financial resources and automation experience. This paper describes how the program is developing new approaches to the issues of component fit-up, part dimensional tolerances, and robot programming, as well as portability, usability, and acquisition costs. Also presented is the strategy for interconnecting these advanced technologies using a readily available PC-based environment that conforms to emerging open architecture standards. Fig. 1 Flexible robotics for shipbuilding
Development of a Welding Protocol for Automated Shipyard Manufacturing Systems
Authors: Milano Joel , Kassel Ben , Mauk Douglas
Published: January 2021

Robotic manufacturing systems have provided improvements in productivity and quality in the automotive and semiconductor industries. Shipbuilding, however, is a one-of-a-kind manufacturing process and as such embodies a completely different set of problems than the mass production environment. The planning for robotics applications in shipbuilding must be done for each unique component and, therefore, must be done efficiently to achieve the benefits of automation. This will require a close relationship between computer-aided design (CAD), computer-aided manufacturing (CAM), computer-integrated manufacturing (CIM), and the manufacturing systems used on the waterfront. One of the major efforts to be performed is the integration of these processes through the timely presentation of information. One of the tools that can be used to integrate these processes is the Standard for the Exchange of Product Model Data (STEP). This paper will identify the relevant components of a STEP applications protocol (AP) for welding which can be applied to shipbuilding and outline the efforts required to bring it into existence.
Reengineering of Small and Medium-Sized Ship Production Facilities: An Example for Turkish Shipbuilding Industry
Authors: Obadasi A. Yucel , Alkaner Selim , Olcer Aykut , Sukas Nedium
Published: January 2021

This paper represents a summary of the studies conducted for the development, design and evaluation of several Turkish shipyards' expansion programs. In each case, depending on the availability of usable area, existing equipment, machinery and investment limits, different considerations and scenarios needed to be generated. During the study, definition of the scope of work and the terms of preference, perceived ship construction logic and capacity requirements are presented and discussed, leading to the selection of the overall layout amongst various alternatives. During the plant design and evaluation of selected equipment within the pre-set production targets, various industrial engineering techniques have been extensively used. Among the most important of these are the specific studies for line balancing of block production, and simulation of new steel fabrication plant. The semi-automated flow type module construction plant was developed for maximizing the throughput and work efficiency in a controlled environment. This study indicates that, under proper operation conditions, it is possible to convert an existing shipyard into a third-generation shipyard by a careful application of modern computational tools and through the adoption of an innovative approach.
Advanced Welding Robot System to Ship Hull Assembly
Authors: Okumoto Yasuhisa
Published: January 2021

Robotics automation has increasingly been used in Japanese shipbuilding companies in accordance with the change of the circumstances i.e. a decreasing of labor force and wage hikes, especially for arc welding at hull block assembly stage. In order to get good cost performance for the investment, the hull production system should be reviewed as suitable to the robot system, and it is necessary to modify and add some functions to the standard model of welding robots. Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI) has developed a new production system "Unit panel and slit process", which is suitable for production automation, and has developed a fully automated robot welding system at the assembly stage. The system includes an automatic material transfer system, robot positioning system and NC (off-line) teaching system. The system has been successfully applied at IHI shipyard.
The Future of Navy Ship Maintenance — One Point-of-View
Authors: Blanton Gerald B.
Published: January 2021

In the next five years, Navy ship maintenance requirements will challenge both public and private ship repair organizations to provide quality upkeeps within costs and schedule constraints. This paper examines key forcing functions impacting ship maintenance decisions, discusses ongoing Navy maintenance initiatives, and speculates on maintenance philosophical changes. Finally, the paper addresses some implications of these forcing functions, initiatives, and philosophy changes on the ship repair industry.
On the End Launching of Vessels from Floating Platforms
Authors: Žiha Kalman
Published: January 2021

A quasi-steady iterative procedure is developed in order to investigate the end launching of buoyant vessels from freely floating platforms. A static analysis is used to find the relative positions and contact forces between the vessel and the platform. A dynamic analysis is used to find the distances of travel, the velocities and the accelerations in the horizontal direction of both the vessel and the platform. The presented procedure is applied to feasibility study of end launching ship-shaped vessels from a trimmable barge.
Comparison of Japanese and U.S. Environmental Regulations Impacting Shipbuilding
Authors: Kura Bhaskar , Knecht Albert , McManis Kenneth , Lea W. Reid
Published: January 2021

Environmental standards of Japan are reviewed and compared with United States' standards. Ambient air quality standards for criteria pollutants, water quality (stream quality) standards, and the effluent standards for wastewater discharges are compared. From this study, it is understood that some standards are more stringent in Japan while others are more stringent in the U.S. Comparisons are made for several water quality and air quality parameters which provide some understanding of the level of environmental compliance that may be required of a typical Japanese shipyard.
Improving Performance in the Navy’s Acquisition Process Through the Improved Use of Teams
Authors: Lemoine J. Paul , Marcus Henry S. , Curcio Joseph A.
Published: January 2021

The use of teams is a critical part of Total Quality Leadership/Management, and is a proven method for improving project performance in both civilian and Department of Defense applications. This paper considers whether the Navy should focus more attention on the application of team-based project administration in the ship acquisition process. A series of case studies written at MIT is analyzed to describe how teams have functioned in recent ship acquisition projects. Successful aspects of team performance are discussed. The lessons learned from these case studies are compared with the theory on the value and implementation of teams. The use of ship acquisition teams is analyzed in relationship to desired performance. Documented improvements in performance over previous contracts are presented. The paper concludes by assessing that the three cases examined were successful team efforts. Based on these projects, it is stated that the obstacles unique to the Navy ship acquisition process are surmountable by partnering approaches, and that such approaches should be considered for other yards and projects.
Concurrent Engineering in Ship Design
Authors: Elvekrok Dag Runar
Published: January 2021

Concurrent engineering is a systematic approach for integration and concurrent design of products. The systematic approach intends to consider all elements influencing the products and their related processes during the product life-cycle, such as manufacturing, support, costs, quality, user requirements etc. Especially the engineering design phase should be considered for improvements. This paper presents some of the major and most acknowledged concepts, ideas and principles of concurrent engineering. They are among others:trends and demands to product development time and product life-timeintroduction of a concurrent engineering environment, including the forces, dimensions, mechanisms and targets of concurrent engineeringthe design process, including considerations regarding to the quality and extent of iteration loops and construction of improved design processesquality function deployment, a method for identifying and managing requirements which is based on interfunctionality and interdisciplinary project-teams.

The paper also discusses concurrent engineering in proportion to traditional design theories. The human and organization aspects in concurrent engineering are treated superficially. Finally, some applied concepts, principles and methods are briefly presented. This paper gives an overview and introduction to concurrent engineering.
Shipyard Modernization – A Shipbuilder’s Experience
Authors: McAlear Ron
Published: January 2021

With the decline in Naval new building activities, U. S. Shipyards must once again reenter the commercial shipbuilding arena to provide a stabilized workload, and to maintain an industrial shipbuilding base that is vitally important for our national security. This paper will address the steps taken by one major U. S. Shipyard to become competitive in the commercial market, will explain the experiences that were encountered in their defense conversion, and will specifically address the shipyard modernization that has resulted from this new focus.
Risk Analysis of the TRI Emissions from the Shipbuilding, Repair, and Maintenance Industry
Authors: Kura Bhaskar , Lea W. Reid , Knecht Al , McManis Kenneth
Published: January 2021

The toxics release inventory (TRI) was mandated as a result of the enactment of the Emergency Planning, Community Right-to-Know Act (EPCRA) of 1986. Conceived largely in response to the Bhopal, India disaster in 1984, EPCRA was designed to compel state and local government to plan for unanticipated environmental excursions of hazardous chemicals. The TRI has evolved into a significant tool for regulatory agencies and public interest groups to use in assessing toxic chemical releases to the environment and, by inference, for use as a local indicator of environmental quality. An analysis of the TRI is limited almost exclusively to comparison of the annual discharge of pollutants to different media from year to year. The validity of this type of analysis has been seriously questioned as it fails to address even superficially the toxicity, persistence, and exposure factors arising from the reported releases. This paper explores the use of an adaptive method of scoring the chemical releases taking into consideration human and environmental toxicity and the potential for exposure. The relative risk of typical TRI emissions from the ship building, repair, and maintenance industry are scored and compared to other sources of TRI emissions. A software program for use by the industry to do self-scoring was developed by the Environmental Resources and Information Center (ERIC) at the University of New Orleans
A Parametric Approach to Machinery Unitization in Shipbuilding
Authors: Jaquith Peter E. , Burns Richard M. , Duneclift Lee A. , Gaskari Massood , Green Thomas , Silveira John L. , Walsh Anthony
Published: January 2021

During the past ten years, both U.S. and foreign shipyards have developed advanced unitization concepts that include multi-level assemblies representing large vertical segments of ship machinery spaces. This paper describes a parametrically derived family of large, fully integrated standard machinery units that are applicable over a range of ship types and installed horsepower. The results include a hierarchy of standard units, the selection of standard unit sizes and interfaces, the development of parametric standards for system design, engine room arrangement and structural design, and machinery unit structural and outfitting design. Benchmarking is reported with respect to Japanese and European shipbuilding practices, and with respect to U.S. land based industrial plant design and construction practices. The proposed unitization concept is demonstrated in a ship-specific engine room arrangement design effort. A business assessment for this unitization concept is presented which addresses its potential shipbuilding cost and schedule impacts as evaluated by three U.S. shipyards.
Design and Production of ANZAC Frigates for the RAN and RNZN: Progress Towards International Competitiveness
Authors: Beck Douglas , Lord John
Published: January 2021

ANZAC, the acronym of the Australian and New Zealand Army Corps, is the name given to a new class often frigates under construction for the Royal Australian and Royal New Zealand Navies. The prime contract was awarded in November 1989, and a separate design sub-contract was awarded concurrently. HMAS ANZAC, the first of eight ships for the Royal Australian Navy (RAN), was delivered in March 1996. HMNZS Te Kaha, the first of two ships for the Royal New Zealand Navy (RNZN), was delivered in May 1997. The paper describes the collaborative process, involving the Australian Department of Defence, the New Zealand Ministry of Defence, and Defence Industry in Australia, New Zealand and overseas, for the design and production of the ships. The need to maximise the level of Australian and New Zealand industrial involvement, led to a process of international competition between prospective suppliers, and significant configuration changes from the contract design baseline. Delivery of the first ship was extended to accommodate the revised approach, and in the event only five months additional time proved necessary. Although formal acceptance of HMAS ANZAC is not due until the completion of operational test and evaluation, the contractor's sea trials have successfully demonstrated the performance exceeding the requirements and the expectations of the RAN. The paper also describes the growing maturity of Australia's naval shipbuilding industry. It suggests some lessons learned from the project, and identifies issues important for the further development and sustainability of the industry. It advocates the need for agreed methodologies to evaluate the productivity of the various elements of the shipbuilding process, and to help ensure the establishment and maintenance of world competitive costs and quality.
A View to Flexible Automation in the Grillage Assembly of Ship Hull Blocks
Authors: Zaplatic Tomislav , Sladoljev Želimir
Published: January 2021

The paper presents some basic concepts and definitions of flexible automation and specific features of the shipbuilding production process most important for application of flexible automation in shipbuilding technology. Definitions and characteristics of prismatic hull blocks are given along with an analysis of grillages as typical parts of prismatic hull blocks. A model for marking the block parts and a diagram showing the flexible self-acting positioning of grillage elements during assembly are presented. The kinetic demands with necessary information for positioning of longitudinal and transverse girders are analyzed. Finally, the paper describes some advantages of flexible automation in the necessary shortening of a shipyard's building cycle in order to make the yard more competitive.
Modular Outfitting
Authors: Baade Ralf , Klinge Friedrich , Lynaugh Kevin , Woronkowicz Frank , Seidler Klaus-Michael
Published: January 2021

The concept of modular construction is not new in the manufacturing, construction, automotive, aeronautical or marine industries. This concept is presented from the initial stages of design, and production, through shipbuilder's trials and operations. Through careful thought, engineering, and communications with all involved, from design, construction, and operation, a quality product with schedule reduction is ensured using modular outfitting. Each phase of modular outfitting is discussed to explain how it has affected organizational issues, design issues, financial issues, production issues and life-cycle or operational issues.
An Integrated Steel Workshop for Shipbuilding: A Real Application of Automation
Authors: Di Filippo Giustiniano , Manzon Luciano , Maschio Paolo
Published: January 2021

The paper describes the layout of an innovative automated steel workshop for the manufacturing of ship blocks, recently set up at Fincantieri's Monfalcone Shipyard. The system implements the results of a European EUREKA! research program called FASP -Flexible Automation in Ship Prefabrication. The various working areas of the shop are described; for each of the new technologies being applied, the level of automation and integration with the other areas is discussed; the advantages obtained are compared with the best typical standards of a traditional production workshop. Inside a fully automated workshop, the information support must have a high integration and flexibility level. The two main issues relevant to information technology are described, i.e., :the modular and integrated systems for the design, part program generation and transmission; andthe production programming, management and control system.
An Algorithm to Determine Heating Lines for Plate Forming by Line Heating Method
Authors: Jang Chang Doo , Moon Sung Choon
Published: January 2021

The line heating method is a popular technique in shipyards to form ship hulls. This paper presents a new algorithm to determine heating lines for the simulation of a line heating process. The important feature of this algorithm is that it calculates the principal curvatures of the deflection difference surface that represents the shape difference between a target surface and a surface in fabrication, and uses a convergence index. Several trials of typical surface types show its usefulness and good practical applicability.
A Design Expert System for Auto-Routing of Ship Pipes
Authors: Kang Sang-Seob , Myung Sehyun , Han Soon-Hung
Published: January 2021

Finding the optimum route of ship pipes is a complicated and time-consuming process. Experience of designers is the main tool in this process. To reduce design man-hours and human errors an expert system shell and a geometric modeling kernel are integrated to automate the design process. Existing algorithms for routing problems have been analyzed -most of them are to solve 2-D circuit routing problems. Design of the ship piping system, especially within the engine room, is a complicated, large-scale 3-D routing problem. Methods of expert systems have been implemented to find the routes of ship pipes on the main deck of a bulk carrier. A framework of the intelligent CAD system for pipe auto-routing is suggested. The CADDS 5 of Computer vision is used as the overall CAD environment, the Nexpert Object of Neuron Data is used as the expert system shell, and the CADDS 5 ISSM is used to build user interface through which geometric models" of pipes are created and modified.
Implementation of Variation Merging Equations for Production Data Collections in Accuracy Control: A Case Study
Authors: Storch Richard Lee , Anutarasoti Sethipong , Sukapanpotharam Smith
Published: January 2021

Implementation of accuracy control in U. S. shipyards has encountered a number of impediments. These include the short run nature of shipbuilding, the difficulty in understanding the specifics of data collection, and the difficulty in prioritizing data collection efforts. As a part of its return to new construction, with the building of three new Jumbo Mark H Ferries for the State of Washington, Todd Pacific Shipyards was hoping to implement accuracy control. This paper reports on an approach outcome of applying variation merging equations as a means of prioritizing production data collections. The research, performed by University of Washington researchers in conjunction with Todd personnel, was successful in helping prioritize efforts to improve implementation of accuracy control.
An Assessment of Brazilian Shipbuilding Competitive Potential
Authors: Pires Floriano C. M.
Published: January 2021

This paper presents a brief description of the Brazilian shipbuilding industry's evolution since its implementation at the end of the 1950s. The aspects related to the protection and incentive policies are highlighted. Some elements are presented to characterize the production capacity of the main shipyards, and the structure of their global production. They are estimated and analyzed, and some indicators of labor productivity, building times, production costs and prices are given. The Brazilian industry offers low productivity levels in comparison with the main world producers, and the conditions of the shipyards at present are extremely difficult. However, the results obtained in the recent past and the low labor costs seem to indicate that Brazilian shipbuilding has some competitive potential. This potential could be activated by restructuring the companies and by an appropriate technological development policy.
Piping Assembly Vital Point Determination Using Variation Merging Equations
Authors: Storch Richard Lee , Sukapanpotharam Smith
Published: January 2021

The objective of this paper is to determine vital points for monitoring accuracy of joining piping assemblies. Variation merging equations are used to identify the vital points. Piping is one of the major outfitting categories in shipbuilding. Easy assembly of piping outfit units is a critical part of productivity improvement. A set of variation merging equations is proposed and demonstrates a method to find pipe piece vital points and critical dimensions.
Development and Implementation of Modern Work Breakdown Structures in Naval Construction: A Case Study
Authors: Koenig Philip C. , Christensen Walter L.
Published: January 2021

U.S. Navy ship acquisitions are currently managed using the Ship Work Breakdown Structure, or SWBS, which decomposes ships by operational (functional) systems. SWBS was an effective tool in an era when the entire ship procurement program was physically accomplished using a ship system orientation. However as this is no longer the case, the right type of design and management information is not being collected and analyzed under SWBS. This paper describes a cooperative effort on the part of shipyards, the academic community, and the U.S. Navy to develop a generic production-oriented work breakdown structure for ship design and construction. Progress towards implementation of this new approach at a large U.S. shipyard is reviewed. Some implications of the new system and problems encountered as well as projected benefits are discussed from both government and industry perspectives.
Evaluation of Software Tools Used to Analyze the Impact of Dimensional Variation on Complex Assembled Products and to Optimize Tolerances During Product Design
Authors: Spicknall Mark H. , Kumar Ramesh
Published: January 2021

The dimensional-variation problem for complex assembled products is described. A developmental history of methods and technologies for analyzing dimensional variation is provided. Commercially available dimensional-variation-analysis tools are evaluated against a number of criteria within a shipbuilding context. An outline for implementing such a tool on a pilot-project basis within a shipyard is provided.
Basic Studies on the Production Technology for Application of Large Extrusion Profiles of Aluminum A6005A Alloy to Ship Structures
Authors: Seo Seung Il , Lee Chan Suk , Lee Sang Rok
Published: January 2021

Aluminum is the preferred metal fabric for high speed vessels due to its light weight and high strength. Among various aluminum alloys, A6005A alloy has enough strength and good extrudibility, so large hollow extrusion profiles of A6005A alloy may be applied to high speed vessels for cost effective design. In this paper, for application of large extrusion profiles of aluminum A6005A alloy to ship structures, production technology required in constructing the ship structure is studied, and the usefulness of the material is described. A structural design process, welding and a production method for hollow extrusion profiles of A6005A alloy have been proposed. To investigate fatigue strength of the weld joint with latent defects, tensile and bending fatigue tests have been performed. Possible painting schedules for the surface of the extrusion profiles have also been proposed and the quality of the painted surface has been proven by test. From this study it can be concluded that the large aluminum extrusion profile of A6005A alloy is a useful structural material for high speed vessels.
MAAST Pilot: A Prototype of Collaborative Environments
Authors: Filling Carey , Diggs Greg , Helgerson David
Published: January 2021

During the spring of 1998, the authors were part of a unique six-week ship design experiment called the MAAST Pilot. The authors led a virtual enterprise, composed of 15 organizations geographically distributed around the world, whose purpose was to create a ship design twice as quickly as previously possible. The virtual enterprise communicated through a collaborative secure extranet, designed using 3D CAE tools from day one, and applied a product work breakdown structure as the information model of the ship. In this paper, the experiences of the authors are recounted in some detail, as a factual record of the results of the experiment. Results and conclusions are documented in the form of lessons learned. This experiment is believed to be one of the earliest examples of ship design carried out over the Internet by a virtual enterprise. Though the technology was simple, the lessons learned about business, culture and process should serve as a model for current and future work.
Design for Production: Principles and Implementation
Authors: Storch Richard Lee , Sukapanpotharam Smith , Hills Bill , Bruce George , Bell Malcolm
Published: January 2021

The principles of design for production have recently been updated to apply to commercially competitive shipyards, as published in the updated Design For Production Manual. Among the key areas that have been updated are the use of computers, automation, and quality technologies. An overall approach to the culture change required to instill design for production in a shipyard is a key ingredient in this application. An initial implementation has begun at NASSCO. This paper reports on the application of the updated principles and describes their use at NASSCO.
Optimization of a Working Route Using the Genetic Algorithm
Authors: Okumoto Yasuhisa
Published: January 2021

Since the working situation of the Japanese shipbuilding industry is changing due to the decrease of skilled workers, the production management system should be improved as suitable for skill-independent production. Under such conditions, it is important to indicate working details to non-skilled workers, which contain so-called 4W1H - Who, When, Where, What, How - including the working procedure. In this report, a working route simulation to achieve a minimum working period is carried out using the genetic algorithm (GA) for assembly welding or block painting work on a ship hull as an example. This defines the job sequence of each worker in a block. A personal computer based program (C++) was developed and applied. The calculation result of the sample data showed a good result to get optimum working route to have minimum working period.
Advanced Line-Heating Process for Hull-Steel Assembly
Authors: Ishiyama Morinobu , Tango Yoshihiko
Published: January 2021

Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI) has successfully employed the logic of the Finite Element Method on the principle of Thermal Forming or Line Heating, which facilitates use of computer aided, fully automated line heating machines for forming any curvature precisely and efficiently on a hull steel plate in the shipbuilding process. It is undesirable for the future in line heating that only an experienced technician is able to be skilled in the use of existing line heating f1 or steel plate forming. Accuracy of shape formed by existing line heating is not necessarily well controlled and work at succeeding stages is adversely affected by inaccurate interim products, though it is a very useful method informing steel plates and all apparatus required for line heating is just light tools. The IHI-Advanced Line-heating Process for Hull-steel Assembly (IHI-ALPHA) has succeeded in solving these problems.
Ship Block Assembly Modeling Based on the Graph Theory
Authors: Lee Kyu-Yeul , Jo Hag-Jong
Published: January 2021

In many industries, the balance of the production-cycle-t ne of an assembly can be controlled according to the assembly sequence. This is undesirable as an unbalanced production-cycle-time results in low productivity. To generate an assembly sequence, a large amount of data such as the"geometry", the"joint relation " and the"assembly method" must be prepared. This study is concerned with an example of automatic assembly modeling that is achieved using a prototype system based on graph theory and its algorithms. Four sub-levels of a ship block assembly model are proposed. These are the"geometry model", the"relational model", the"sequential model" and the"hierarchical model". The purpose of the hierarchical model in this study is to define an assembly tree and to calculate the Bill of Materials (BOM).
A Study on the Simplified Method to Calculate the Compressive Strength of Welded Structures
Authors: Seo Seung
Published: January 2021

Residual stresses and deformations due to welding have effects on the strength of structures. In this paper, for design of reliable structures, the effects of the residual stresses and the initial deformations on the compressive strength of beams, plates and cylindrical panels are investigated. Theoretical analyses for the basic structures are carried out and simplified methods to calculate the compressive strength are proposed for more efficient and accurate analysis. The proposed methods yield simple formulas to calculate the compressive strength of the structures, of which results are much useful and reliable. The accuracy of the proposed methods is revealed by comparison with regulations and experimental results.
Development and Implementation of Computer Simulation Models for the Manufacturing of Outfitting Components
Authors: Lilley Dexter , Degraw Kevin , Wallen Rex
Published: January 2021

The utilization of computer simulation in the shipbuilding industry is not a new concept and many shipyards in the U.S. and around the world are using simulation tools in a wide variety of ways and with various levels of success. In many industries, computer simulation of production processes has proven itself as a powerful tool for reducing nonvalue added activities and promises to become much more prominent in its use as a resource management tool. Its use in the manufacturing of Outfitting components in U.S. shipyards has had limited success due mainly to the inherent nature of ship construction, especially those yards primarily engaged in military ship construction. The focus of this paper is directed towards the implementation aspects of a computer simulation tool for the manufacture of Outfitting components in a naval shipbuilding context.
Prediction of Deformation to Thin Ship Panels for Different Heat Sources
Authors: Kuo H.C. , Wu L.J.
Published: January 2021

The increasing use of thin steel plates in manufacturing and the shipbuilding industry has given rise to several issues: massive deformation problems, the need for many skilled workers, and the expense of costs for straightening in on-line processes. This study explains the results of experiments and predicts techniques for the control of deformation in thin panels. The objective of this paper is to explain the use of the G(1,1) Grey method to predict deformation. Bending and buckling are usually the dominant modes of deformation in heat working. It follows angular deformation. De- formation due to different heat sources is discussed. In this paper, laser and torch are used in different constraints, for example, free-free beam and cantilever beam. Many important factors include tiny adjustments during the heat forming process, such as changing the moment speed, intensity of input heating, plate thickness and heating path, to improve manufacture techniques and to predict deformation by data series. For the prediction of deformation, a method to estimate input heating of laser and torch is introduced. The proposed prediction method can be used during the forming process simply and efficiently.
Marine Propeller Geometric Models for NC Machining Efficiency and Accuracy
Authors: Kuo Hsing-Chia , Dzan Wei-Yuan
Published: January 2021

Via the theories of computational geometry and differential geometry, the equation of the pressure side of a propeller blade with a constant pitch is presented. The model for defining maximal admissible ball-end cutter radius used in the NC machining of propeller blade surface is deduced. The odels for numerical analysis and for calculation of step lengths and path intervals are also provided. Besides, the related geometric model for calculating the actual maximal error by using the envelope surface of the cutter is presented. Finally, the feasibility and reliability of the proposed models and methods are verified by an example. It is also verified that the proposed method provides improved machining efficiency and accuracy relative to many other common contemporary methods.
Information Technology Challenge to the Chinese Shipbuilding Industry: A State-of-the-Art Survey
Authors: Jingyun Cheng , Bei Lu , Shengkun Zhang
Published: January 2021

The development of global information, communication technology and advanced manufacturing technology brings challenge and opportunity for the shipbuilding industry. China, as one of the major shipbuilding countries in the world, pays much attention to strengthening its competence in this area. The paper presents a state- of-the-art survey of related key technologies and their research and application in the shipbuilding industry. A ship product data model and STEP standard are developed, and production planning and scheduling in the industry as well as agile manufacturing are described. Finally, a research project China is carrying out is introduced and suggestions to the Chinese shipbuilding industry are proposed.
Least-Cost Structural Optimization Oriented Preliminary Design
Authors: Rigo Philippe
Published: January 2021

A computer design package is presented that provides optimum midship scantlings(plating, longitudinal members and frames). Basic characteristics such as L,B,T,Cb, the global structure layout, and applied loads are the requested data. It is not necessary to provide a feasible initial scantling. Within about one hour of computation time with a usual PC or laptop the LBR-5software automatically provides a rational optimum design. This software is an optimization tool dedicated to preliminary design. Its main advantages, in the early stage of design, are ease of structural modeling, rapid 3-D rational analysis of a ship's hold, and scantling optimization. Preliminary design is the most relevant and the least expensive time to modify design scantling and to compare different alternatives. Unfortunately, it is often too early for efficient use of many commercial software systems, such as FEM. This paper explains how it is now possible to perform optimization at the early design stage, including a 3-D numerical structural analysis. LBR-5 is based on the Module Oriented Approach. Design variables are the dimensions of the longitudinal and transversal members, plate thickness and spacing between members. The software contains three major modules. First, the Cost Module to assess the construction cost which is the objective function (least construction cost). So, unit material costs (Euro/kg or $/kg), welding, cutting, fairing, productivity (man-hours/m) and basic labor costs(Euro/man-hour) have to be specified by the user to define an explicit objective function. Then, there is the Constraint Module to perform a rational analysis of the global structure. This structure is modeled using stiffened plate and stiffened cylindrical shell elements. Finally, the Opti Module which contains a mathematical programming code (CONLIN) to solve constrained nonlinear optimization problems with a reduced number of re-analyses. Usually less than 15 analyses are required even with hundreds of design variables and hundreds of constraints. Optimum analysis of a FSO unit (Floating Storage Offloading) is presented as an example of the performance of the LBR-5 tool.
Technical and Economic Breakdown of Value Added in Shipbuilding
Authors: Koenig Philip C.
Published: January 2021

For shipbuilding and other heavy industries, the standard value chain breakdown by stage of production or functional activity provides an incomplete picture, in which some key strategic factors are absent. However, if each stage of production could be further decomposed to reveal factors of production, sourcing strategies, and production scenarios, then essential business strategic characteristics may be captured. This goal was realized by developing a new, more complex type of techno-economic breakdown, which was then implemented at a shipyard in Western Europe. Data from this trial implementation are used to show how the new method can be used in strategic management research in shipbuilding and in other heavy industries.
Optimization of Block Erection Using a Genetic Algorithm
Authors: Okumoto Yasuhisa
Published: January 2021

Block erection is a very important and demanding skill in shipbuilding quality control as well as in productivity improvement. Though this work at the present time depends on skilled workers in the yards, these workers eventually become old and retire, and then the training of their successors, or other countermeasures, will be required. Recently, CAD and CIM systems have been applied widely, and also efficient measurement technology has been developed in the shipyard; thus it has become possible to apply positional control at the erection stage by computer simulation. This paper presents a computer simulation method to place a block, which has dimensional errors, in a suitable position as designed using a genetic algorithm (GA). A pilot program using a personal computer has been developed and applied to a typical hexahedron block. The simulation results showed good agreement in achieving the optimum position.
A Shipbuilding Productivity Predictor
Authors: Lamb Thomas , Hellesoy Aasmund
Published: January 2021

The first author has been working on the development of a Shipbuilding Productivity Predictor for many years. His first attempt was presented as a SNAME Section paper in 1998. It used only two parameters, namely, size and Technology Level of the shipyard. However, it was clear that other parameters, such as throughput, vertical integration, range of ship types, and the ratio of production workers versus nonproduction workers also affected productivity, and since that time he has been working to determine what parameters should be included and to develop an equation including all the significant parameters. This paper describes the research performed by the authors and the resulting Shipbuilding Productivity Predictor Equation. It is not the intent that the Productivity Predictor presented should be used by any shipyard to predict a "Target Productivity" based on its values of the parameters, but rather to show an approach how it could be done, and validate it. If the approach was supported by shipyards around the world it would become more acceptable. Shipyards could then benchmark their actual productivity against the target productivity.
Object-Oriented Development of an Integrated System for Manufacturing Information of Roll Bending Process
Authors: Shin Jong Gye , Won Sun il , Ryu Cheol Ho , Yim Hyunjune , Lee Jang Hyun
Published: January 2021

An integrated software system was developed for the manufacturing information of the roll bending process for ship hull pieces. To this end, the information flow in the process was studied and designed using the object-oriented method. Separate program modules, obtained by introducing new approaches or modifying existing methods, were integrated to yield a software system that can provide all the manufacturing information required for the roll bending of hull pieces of general shape. The information includes roll orientations, roll lines, roll region, and the center roller movement. Two examples are presented to demonstrate the performance of the developed software. The software developed in this work is expected to provide a solid basis for the automated and efficient fabrication of hull pieces. Also, the object-oriented models developed here will be of great use for further study of ship production.
Prediction of Butt Welding Deformation of Curved Shell Plates by Inherent Strain Method
Authors: Takeda Yu
Published: January 2021

In order to achieve high productivity of assembly blocks of hull structure, it is important to predict welding deformations accurately and to apply these data to the production planning. For this purpose the transient thermal-elastic-plastic analysis by FEM (finite-element method) may be utilized. However, this method is not a practical approach to analyze the deformation of large and complex structures, such as ship hull structures, in view of time and cost. Whereas the inherent strain method deals the residual strain near the weld line as the inherent strain, therefore the residual deformation can be simply calculated by elastic analysis. This method is much more practical and efficient than the transient thermal-elastic-plastic analysis. Thus, in this paper, the inherent strain method is used to predict the welding deformation of hull structures. Past research activities of the inherent strain method have been focused on the prediction of the welding deformation of small size specimens and simple shape specimens; however, very few of them treat the problem of large and complex structures. Hence, in this paper, prediction of welding deformation of curved shell plate, of which size is approximately full scale, is conducted by the inherent strain method. In applying elastic analysis to predict the welding deformation of actual hull blocks, contact condition between the plate and the positioning jig should be adequately realized in the analysis. Therefore, a practical solution is proposed to con- sider the contact condition between the plate and the jig by judging reaction forces of the jig at calculation steps. Furthermore, since the welded plates may slip on the positioning jig due to the welding deformation, rigid body motion of plates is caused. Hence this motion should be taken into account of the estimation of calculated results of FEM. In addition to the rigid body motion, coordinate system of the measured data is usually different from the calculated data, therefore, the deviation of the coordinate system must be involved. These calibrations to assess the calculated deformation by FEM are also discussed. The above prediction method is confirmed to be successful by comparing the calculated deformations and the measured ones of large size specimen of curved shell plates due to butt welding.
The Rapid Improvement Workshop as a Tool for Change
Authors: Boyer Michael D.
Published: January 2021

Rapid Improvement Workshops (RIW) have been employed by many industries in many countries as a means of generating improvements. Applications in the shipbuilding industry (or any industry beginning on the road to lean) have shown that RIWs can also be an important tool for change, not only in terms of incremental improvements, but also in terms of changing the culture of an organization. This paper describes the process of conducting RIWs, discusses the tools employed, and gives case studies of their use in shipyards.
Applying Lean Above the Factory Floor
Authors: Drogosz John D.
Published: January 2021

Modern Kaizen events have been based on the principles of the Toyota Production System (TPS). However, TPS is a system used in repetitive manufacturing and not typically associated with business processes. The goal of TPS is to eliminate waste in order to improve quality, shorten lead times and reduce costs. Clearly this same philosophy applies as much above the shop floor as it does in the factory. This paper first discusses how to adapt the lean philosophy and Kaizen methodology to business processes above the shop floor. It will also present some case examples from lean workshops conducted in the shipbuilding industry.
Productional, Operational, and Theoretical Sensitivities of Fatigue Damage Assessment in Shipbuilding
Authors: Blagojevic Branko , Domazet Želko , Žiha Kalman
Published: January 2021

First, this paper summarizes some of the theoretical and practical aspects of fatigue assessments in shipbuilding. The basics of the spectral fatigue analysis procedure for ship structures are mentioned. The simplified procedures are presented in more detail, due to their practical merit. The paper is concerned primarily with the fatigue design procedures used by classification societies, as well as with possible standardizations under the auspices of IACS. Second, an example of fatigue damage assessment for a chemical tanker recently built in Croatian shipyards is provided in order to illustrate and compare the capabilities and differences of available procedures currently used by major classification societies. Finally, parametric studies are performed in order to investigate the effects of productional structural elements misalignment, constructional and fabricational tolerances, of corrosion during operations at sea, shape parameters of theoretical distributions, of selections of the S-Ncurves, and of the combinations of local and global loads. The sensitivity analysis presented here provides suggestions for improving design and production of the critical parts of the ship hull construction with respect to fatigue damage.
Biomechanical Study of Shipyard Access Activities
Authors: Okumoto Yasuhisa , Taruoka Masaki
Published: January 2021

Studies of industrial accidents in Japanese shipyards concluded that falling and tumbling from high places were frequent occurrences, and consideration of access in the workplace was very important to prevent such accidents. In this paper, a biomechanical analysis using a digital human model has been carried out for climbing up a ladder, passing an access opening, and walking on a scaffolding, because these are thought to be problems in industrial safety, and the most suitable condition in view of body load has been studied using response surface methodology: the optimum climbing position on an inclined ladder, the preferable position and size of access openings, and a suitable walking posture on scaffoldings.