bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrating the Collaborative Environment in Shipbuilding: An Implementation Strategy
Authors: Tann Wei , Shaw Heiu-Jou , Bronsart Robert
Published: January 2021

Coordination procedures in commercial ship design, production, and procurement are widely predominantly analyzed fields. While deadlines become shorter and shorter, the complexity of modern commercial vessels increases steadily, so that these information systems are more and more indispensable for integration in maritime industry. Based on a detailed evaluation of integrating the upstream and downstream data flows, this paper describes the current implementation states under the collaborative environment concept and establishes the future integration network for shipbuilding.
Interoperability Framework
Authors: Briggs Ted L. , Baum Stephen J. , Thomas Tammi M.
Published: January 2021

One of the biggest problems today for ships and shipbuilding programs is the proliferation of data and the rising number of disparate data systems that do not communicate and certainly do not interoperate. The traditional approaches to solving these problems have been costly point-to-point integrations or system-specific integrations. Today, there is another alternative. The Interoperability Framework (Intergraph Corporation, Huntsville, AL) is a flexible, extensible, nonintrusive, and open platform that provides the end user with integrated data from multiple interoperating systems. Although this approach does require the development of an adapter for each data source, the adapter, once written, allows the data to plug and play within the Interoperability Framework, thereby eliminating further interface development to or from that system. Hence, today one can choose between developing one adapter for the Interoperability Framework versus developing many interfaces to a multitude of other legacy and new systems. The latter is a costly and never-ending endeavor. Because the Interoperability Framework is based on XML and Web technology, it complements other emerging technologies. Further, the Interoperability Framework provides an application interface based on the Integrated Shipbuilding Environment (ISE) XML product data management (PDM) schema, potentially allowing direct use by other shipyard applications. While it is true that improved technology is producing newer, better software systems for data development, presentation, and management, the Interoperability Framework is the technology that will ensure interoperability of these systems.
Product Data Exchange to Support Modeling and Simulation
Authors: Briggs T. , Gischner B. , Lazo P. , Lazo P. , Royal A. , Wood R.
Published: January 2021

Successful and efficient exchange of product model data has been a major challenge in the shipbuilding industry for the past two decades. The Standard for the Exchange of Product Model Data (STEP) has been developed to enable this capability. Four STEP application protocols (APs) to facilitate the exchange of structural and distributed systems models in shipbuilding were completed in 2003 and were adopted by the International Organization for Standardization (ISO) by mid-2004. In August 2003, ISO 10303–216: Ship Moulded Forms (AP216) became the first shipbuilding STEP AP to be published as an international standard. Participants involved in these efforts represent several major US shipyards, the Navy, and their computer-aided design/ engineering (CAD/CAE) vendors. The thrust of shipbuilding data exchange efforts has now shifted from development to implementation. This paper will report on efforts to develop and use translators for this AP to exchange hull form product data in the ship modeling and simulation arena. In addition, process simulation is becoming common in the design of new ships to validate that the design meets the customer's specifications. Current technology requires that the ship be modeled both in the computer-aided design (CAD) environment and then repeated in the simulation workbench. Not only is this effort inefficient, but it is inherently error prone. Through the National Shipbuilding Research Program (NSRP)-sponsored Integrated Shipbuilding Environment (ISE) projects, we have developed tool sets that use AP227: Plant Spatial Configuration to permit the design to flow smoothly from the CAD workbench to the simulation workbench. This paper summarizes the efforts to develop and use a suite of tools that enables US shipyards to become more productive. It details the specific successes in using AP216 and AP227 for modeling and simulation, as well as efforts to exchange design data electronically between CAD systems. The report also outlines efforts that are underway to use other APs to successfully exchange data describing ship electrical; heating, ventilation, and air-conditioning (HVAC); and controls systems.
Factors Affecting Ship Design and Construction Lead Time and Cost
Authors: Moyst Howard , Das Biman
Published: January 2021

This paper reviews a ship design and construction case study in the context of the published literature on the design process and its impact on construction. The objective was to explore the factors that impact design and construction lead time and cost. Design and construction managers constantly experience pressure to accelerate the construction start time in an environment characteristic of frequent design changes and rework. Often the construction of the first ships of a series will aggressively overlap the design phase. This investigation assessed a case study that illustrated that as the degree of overlap between design and construction increases, design changes increased ship construction costs and duration. This negates the advantage of trying to reduce lead time by overlapping phases. Before strategies of overlapping are utilized, shipbuilders need to better understand the details of the design process and its integration with other functions to improve design quality and reduce the impact of design changes on manufacturing and construction. It is recommended that when overlapping strategies are considered, design changes and their impact on construction be factored into the decision. A better strategy would be to eliminate design quality issues and design and construction rework.
Dimensional Management in Shipbuilding: A Case Study From the Northrup Grumman Ship Systems Lightweight Structures Project
Authors: Spicknall Mark H. , Kumar Ramesh , Huang T. D.
Published: January 2021

This paper gives an overview of some of the activities at Northrop Grumman Ship Systems (NGSS) related to improving dimensional management procedures in support of the production of lightweight steel ship structures. Specifically, this paper discusses a survey on overall dimensional management practices at NGSS, a general examination of residual stress relief methods for steel plates prior to part cutting, and simulation of the impact of different plate part fabrication processes on unit/block critical dimensions. All of these efforts are contributing to the improvement of lightweight structures production and general quality practices at NGSS.
Design Support Tool for Prediction of Welding Distortion in Multiply Stiffened Plate Structures: Experimental and Computational Investigation
Authors: Camilleri Duncan , Comlekci Tugrul , Gray Thomas G. F.
Published: January 2021

Many industries, such as shipbuilding, concerned with the fabrication of fusionwelded plate structures, face increasing challenges to produce lightweight structures. This design requirement is commonly met by using thin-plate, multiply stiffened, welded structures, but severe difficulties and high rectification costs are frequently incurred, related to the evolution of out-of-plane deformations. The overall scope of this study is to improve the applicability of computational prediction of distortion by providing simple and adaptable methodologies, which can be readily validated through experience of application in the industrial context. These methods are designed to be computationally economic and robust, and they are also generic with respect to material properties, welding processes, and thickness. The aim is to provide design engineers with the tools to explore alternative structural and process parameters and hence to find out if the outcomes will be acceptable, prior to embarking on manufacturing operations typical of large-scale welded structures. The validity of the simulations was investigated via full-scale tests where several filletwelded 100 mm × 6 mmstiffeners were attached to 4 m × 1.5 m × 5 mmthick plates, according to different sequences. The computational models were used to optimize the welding scheme with respect to minimum out-of-plane deformation and welding sequence.
Applying XML Data Exchange Technology to the Supply Chain Management System of the Yacht Industry
Authors: Chien Wen-Yen , Shaw Heiu-Jou , Wang Shen-Ming
Published: January 2021

In this article, Taiwan Ship Net is proposed to be a portal Web site of the Taiwan yachtindustry. By using Microsoft Distributed interNet Application (DNA) and Active ServicePage (ASP), the supply chain management system, consisting of three sections, shipyards, suppliers, and administrator, exchanges and transfers the information ofenterprise's system. Through applying XML to conduct the information exchange, weintegrate the formats of orders for several yacht manufacturers and suppliers, develop the system of placing orders online, and edit XML documents to exchange the information in the system. E-catalogs that are easy to preserve and update will replace the traditional paper catalogs hereafter. The various demands of accessories will result in an increase in the costs of production and logistics. Through this system, yacht manufacturers can search the material of E-catalogs and purchase online directly. Meanwhile, it will allow the suppliers to update the E-catalogs regularly to be more competitive in the market. Taiwan Ship Net can provide the newest information to foreign customers and communicate with all yacht companies, equipment suppliers, and manufacturers in Taiwan.
Portable Automated Plate Straightener
Authors: Turner Garth E. , Jones Jerry E. , Rhoades Valerie L. , Clem Timothy E. , Sarnow Pierre L. , Madden Stephen K. , Cuneo Adam , McMahon J.
Published: January 2021

Welding thin plates and fitting together ship modules, using heavy weights and hoists, causes distortion of the decks. This distortion drives decks out of compliance with specifications for fairness. The Portable Automated Plate Straightener (N.A. Tech, Golden, CO) is an application of flexible automation. It is able to straighten the deckplates without operator intervention.
Accuracy and Distortion Control Challenges in Lightweight Structural Unit Assembly at Northrop Grumman Ship Systems
Authors: Spicknall M. , Hodges E. , Huang T. D.
Published: January 2021

Shipboard applications of lightweight structures have increased over the past decade in both military and commercial vessels. Severe distortions have emerged as a major obstacle to the cost-effective fabrication of such lightweight structures. With a recent major initiative funded by the US Navy Office of Naval Research, Northrop Grumman Ship Systems (NGSS) has undertaken a comprehensive assessment of lightweight structure technology. This program includes a comprehensive investigation of the fabrication and assembly processes for thin steel structures and their contributions to the final dimensional accuracy and distortion. As part of this effort, substantial work was done to characterize current dimensional quality performance in partial subunit (PSU) and combined partial subunit (CPSU) assemblies, and to identify contributing factors to dimensional inaccuracy and distortion in unit assembly stages. This information will be used by NGSS as a basis for improvements in fitting and welding processes, jigging and fixturing methods, dimensioning and tolerancing, and accuracy control processes. This paper summarizes the current dimensional quality performance in PSU and CPSU at NGSS, and the factors contributing to current performance.
Simulation-Based Ship Production Using Three-Dimensional CAD
Authors: Okumoto Yasuhisa , Hiyoku Kentaro , Uesugi Noritaka
Published: January 2021

The application of three-dimensional computer-aided design (CAD) is becoming more popular for design and production in many industrial fields, and digital manufacturing is spreading. With preconstruction simulation of the production process using a three-dimensional digital model, which is a core of a computer-integrated manufacturing (CIM) system, the efficiency and safety of production can be improved at each stage of work and optimization of manufacturing can be achieved. This paper first describes the concept of simulation-based production in shipbuilding and digital manufacturing. The three-dimensional CAD system is indispensable for effective simulation because the ship structure is three-dimensionally complex, and threedimensional viewer software enables workers to examine structures on a computer display. With simulation, computer-optimized manufacturing is possible. Simulation is most effective for jobs in which many parties must cooperate to handle structures or equipment of complex shape. Two-dimensional drawings are inadequate for imaging whole figures in such cases. Some examples of the successful applications in IHI Marine United, Inc., are shown: erection of a complex hull block, scaffolding planning, and installation of a rudder.
Enhancing Interoperability Throughout the Design and Manufacturing Process
Authors: Gischner B. , Lazo P. , Richard K. , Wood R.
Published: January 2021

As part of the National Shipbuilding Research Program (NSRP) program, various tools and standards have been developed to enable the efficient exchange of product models during the design process. In particular, the Integrated Shipbuilding Environment (ISE) Project has developed and demonstrated the capability for successful transfer of structural, piping, and heating, ventilation, and air-conditioning (HVAC) product models that could be used in detail design. During 2005, NSRP awarded a project for ISE Interoperability Modules (known as ISE4). This project will expand the testing and implementation of ISE tools to support both early-stage design and manufacturing efforts. An international standard (ISO 10303-215: Application Protocol— Ship Arrangement) will be used to exchange product model information during early-stage design. Another task in this project, entitled Steel Processing, will focus on using ISE tools and the Standard for the Exchange of Product Model Data (STEP) Standard to define a shipbuilding product model format that will support the requirements of multiple, disparate manufacturing processes. The ISE4 Project also includes tasks to enhance interoperability by providing exchange capabilities for engineering analysis and electrical data. This paper and presentation will show how these new ISE tools will facilitate the exchange of ship product models to support interoperability from early-stage design (using ship arrangements) through manufacture.
Efficient Algorithms for Inspection and Reforming of Double-Curved Plates in Line-Heating Process
Authors: Liu Yujun , Ji Zhuoshang , Deng Yanping , Zhang Jun , Wang Ji
Published: January 2021

Line heating is an effective and economical method for forming metal plates into three-dimensional shaped plates for ships, trains, and airplanes. When a curved plate subject to deformation is formed in line-heating process, the deformed shape is repeatedly inspected and reformed to reach the designed shape. Efficient automatic inspection and reforming processes are essential to enhance productivity in the whole manufacturing process. In this paper, efficient algorithms for inspection and reforming of double-curved plates are introduced. These algorithms have been developed to automatically inspect the transverse and longitudinal shape of plate surfaces and provide technical parameters to reform the unformed plates. The longitudinal shape of the plate surface is examined based on a shell plate development with plastic deformation during the plate formation, and the transverse shape is inspected through error analyses of transverse curvature radiuses. How to use the inspection results to reform unformed plates is discussed. In the end, experiments are performed with comparison to the current industrial plate manufacture, and results show a prospective application of our algorithms to the practical manufacturing of doublecurved plates. The methods presented in this study may play a role in realizing the automation of the entire curved-plate manufacturing process.
Design Guidelines for Doubler Plate Repairs of Ship Structures
Authors: Sensharma Pradeep K. , Willis Malcolm , Dinovitzer Aaron , Nappi Nat
Published: January 2021

The use of doubler plates or "doublers" has become routine for temporary ship repairs. It is the preferred method for ship structural repairs for plate corrosion due to its relative ease and low cost of installation over the more costly permanent welded plate insert repair. A lack of performance data and engineering design guidance are the reasons that repairs with doublers are currently considered only temporary. The objective of this study was to develop a set of guidelines for designing and applying doubler plate repairs to ship structures. The guidelines were established using the following criteria: various stress analyses, buckling strength, corrosion types and rates, weld types, and doubler plate fatigue and fracture assessment. Studying and understanding doubler plate repair performance by comparison to welded plate insert repair performance in the primary hull allows critical operational decisions to be made with greater ease and confidence. However, the ultimate goal of this study was to establish the design and limitations on the applications of doubler plate repairs for surface ships.
Abstracting Data With A Decision Support System Based on Data Warehouses for the Evaluation of Ship Form Alternatives
Authors: Sang Song , Li Hua-jun
Published: January 2021

A new aided decision support system (DSS) based on data warehouses is discussed. It is composed of data warehouses, on-line analysis processing, and data mining, which is new in the field of DSS. The essential principle, the setting up of the model, the development environment, the main system interface, and a sketch of the theory framework of the new DSS architecture are also described. The decision support system was applied to data abstraction for evaluating ship form scenarios. Tests have shown it to be practical and dependable in complex systems, such as in the demonstration of ship forms.
A Genetic Algorithm for Erection Scheduling at a Dock
Authors: Xu Ai-min , Jin Ye
Published: January 2021

This study presents a genetic algorithm for the scheduling of erection at a dock. First, the model is formulated, which includes the constraints of crane capacity and erection network, and the objective function that concerns the shortest make span at the dock and the earliest time of shafting optical alignment. Then, a genetic algorithm is proposed to optimize the erection sequence, and a novel crossover operator is employed to ensure that each individual in new population is feasible. Finally, the erection sequence of a 74,500 dead weight ton (DWT) bulk carrier is optimized, and the result shows that this approach is effective.
Welding of Thicker Steel Joints of Container Ships
Authors: Baba Osamu , Okumoto Yasuhisa , Abe Akinori
Published: January 2021

Recently, many container ships have been built worldwide, and the size of them is skyrocketing to 10, 000 TEU (Twenty Equivalent Unit) capacity. As a result, the plate thickness in the area of upper deck torsion box becomes thicker and thicker with higher-strength steel, up to 60 mm, to keep longitudinal strength, and then the welding work becomes more difficult and severe. For such joints of super thick plates IHI Marine United Inc. Kure shipyard has established high-quality and high-efficient welding methods:Development of new steel plates. In order to weld the thicker plates by high heat input such as 450 KJ/cm, new steel plates were applied in cooperation with a steel maker in Japan.Automation of butt welding. Electro-gas arc welding was applied for skin plates, and CO2 welding robot system was also introduced for longitudinals around the torsion box.Establishment of high quality welding practice.

Welding without defects became possible by establishing adequate groove shape and welding procedure, as a result of many welding tests and inspections. This paper describes the improved methods and the test results in detail.
Surface Engineering for Adhesively Bonded Metal-Composite Joints
Authors: Smith Mark , Hutapea Parsaoran
Published: January 2021

Recently, many nations along with private shipbuilders have begun developing large maritime vessels using composite materials structurally. Concurrently, the US Navy has a need for research on bonded metal-composite joints. For these reasons, a literature review was conducted to establish a fundamental knowledge base of adhesive bonding and failure theories along with surface cleaning and engineering processes that would be valuable for metal-composite joint designs. It is believed that by understanding bonding and failure fundamentals, optimal surface characteristics can be targeted. Furthermore, by knowing the available cleaning and surface engineering processes, in conjunction with understanding their resulting surface topographies and compositions, creative and novel joints can be designed. This report provides the results of the literature review performed, which serves as a platform for future research aimed at optimizing bonded joints for use in naval applications.
Thin Plate Distortion—The Ongoing Problem in Shipbuilding
Authors: McPherson N. A.
Published: January 2021

Distortion induced in thin plate continues to create adverse performance effects in the shipbuilding industry. A number of issues have been reviewed, along with potential tools to reduce distortion, practically and theoretically. Many of the factors described are management-control issues as the technology is now well established. This probably encompasses about 80% of the solution. The remaining 20% is significantly more complex to resolve and as a result will take disproportionately longer to achieve. Two key issues have been highlighted. The first is the role of designers in reducing distortion. If tackled at the source, then this will start to reduce the remaining 20% of the problem. The second is the role of residual stresses in materials being used in the building process. This has been established as a largely unresearched area with significant complexities in achieving potential solutions. The latter item, when solved, will also increase the significance of finite element model outputs.
Portable Weld Inspection Management System
Authors: Ludwig Michael J. , Conrardy Chris
Published: January 2021

Manual visual inspection is by far the most widely used weld inspection method. A given weld may be visually examined multiple times as parts are joined and made into assemblies. Because visual inspection is somewhat subjective, and prone to error (a typical inspector only identifies about 85% of the visible defects); welds that pass one inspection may fail subsequent inspections, resulting in multiple inspection and repair cycles. This paper discusses a project that tested the benefits and limitations of a semiautomated weld inspection system. The goal of this semiautomated inspection approach is to provide quantitative, nonsubjective quality measurements of welded structures in order to: eliminate redundant inspections, reduce unnecessary multiple repair cycles, avoid repair of welds that meet minimum size requirements, and enable recording of weld size so that overwelding can be identified and reduced. The technology would also allow tracking of weld quality and statistical analysis of welding process capability to support lean/six-sigma continuous improvement initiatives. A prototype system was assembled and field tested by inspecting actual ship structures. The equipment evaluated has potential, but needs both hardware and software modifications before it can be used as a tool on a regular basis in a shipbuilding environment. As is, it will be useful as an audit tool to gauge the health of the visual inspection process and to further document the inherent variability of the visual inspection process. Recommendations were made for improvements to refine the prototype tool prior to broader deployment.
Friction Stir Welding (FSW) of Littoral Combat Ship Deckhouse Structure
Authors: Halverson Bruce , Hinrichs John F.
Published: January 2021

The US Navy's Littoral Combat Ship (LCS) represents a new direction in military capabilities and ship design. The LCS's aluminum superstructure and deckhouse reduces weight and lowers the center of gravity of the ship. Arc welding aluminum is subject to distortion requiring no value straightening activities to be used. Friction stir welding (FSW), a welding process invented in 1991 at TWI in the United Kingdom, is a solid-state welding process that has considerably less weld distortion. It results in more affordable fabrication and inspection of the butt joint weld root. Details of the FSW process development, certification, and fabrication of the LCS superstructure and deck house are described. Experience with FSW on the LCS has resulted in a number of new fabrication ideas and concepts to improve affordability of future LCS and other aluminum ship structures.
Measuring the Performance of Today’s Antifouling Coatings
Authors: Swain Geoffrey W. , Kovach Brett , Touzot Arthur , Casse Franck , Kavanagh Christopher J.
Published: January 2021

The transfer from the self-polishing organotin to tin-free antifouling coatings has created a new learning curve for the shipping industry. This study investigated the hydrodynamic performance of four commercially available antifouling coatings that were subjected to both static and dynamic seawater immersion. The results showed that each coating type developed its own characteristic fouling community and that there were significant differences in drag properties that were further modified by the static or dynamic immersion conditions.
Real-Time Semiautomatic 3D Pipe Routing
Authors: Rourke Patrick , Merritt Lyn
Published: January 2021

The routing of pipe, ducts, and other services in 3D through congested areas is difficult, even with the best available 3D CAD systems. This paper describes a new approach in which a real-time automatic 2D router is combined with a simple user interface to create a 3D sketching environment in which a designer can rapidly create optimal 3D routes for piping, ductwork, and cableways.
Shipyard Space Allocation and Scheduling
Authors: Finke Daniel A. , Ligetti Christopher B. , Traband Mark T. , Roy Allan
Published: January 2021

In this paper we describe the development of a tool that allows shipyard planners to efficiently and effectively plan space within valuable areas of a shipyard. Traditionally, space is considered a resource; however, it is difficult to accurately account for and plan its consumption with the current planning software tools available. The spatial scheduling tool described in this paper can be used by planners and construction management teams to manually or semiautomatically reserve space within the shipyard for construction of large units over the entire ship erection period. The result is the ability to efficiently generate and compare multiple space allocation plans with the ultimate goal of maintaining the critical ship erection schedule. This work has been developed with Northrop Grumman Newport News (NGNN) under a project funded by an Office of Naval Research (ONR) Manufacturing Technology (ManTech) program.
Transient Thermal Tensioning and Prototype System Testing of Thin Steel Ship Panel Structures
Authors: Huang T. D. , Dull R. , Porter N. , DeCan L. , Evans N. , Kvidahl L. , Keene P.
Published: January 2021

At Northrop Grumman Shipbuilding, a prototype transient thermal tensioning system was installed and successfully demonstrated on a complex test panel design from the Shipboard Applications of Lightweight Structures program.
Welding Distortion Simulation of Large Stiffened Plate Panels
Authors: Biswas Pankaj , Mandal N. R.
Published: January 2021

Fusion welding leads to heat-induced distortion. These deformations may adversely affect the structural integrity and subsequent alignment of the adjacent panels. The extent of distortion depends on several parameters such as welding speed, plate thickness, welding current, voltage, restraints applied to the job while welding, as well as sequence of welding. Welding being a transient phenomenon, finite element analysis of large stiffened panels is virtually not possible. In the present work, an analysis methodology based on the quasi-stationary nature of welding and the resulting symmetric behavior of the stiffened panels has been developed for studying the distortion pattern of orthogonally stiffened large plate panels. The effect of filler metal deposition has been taken into account by implementing element birth and death technique. The numerical model yielded results comparing well with the ex- perimental results.
Design Optimization of Steel Sandwich Hoistable Car Decks Applying Homogenized Plate Theory
Authors: Romanoff Jani , Klanac Alan
Published: January 2021

This paper describes an approach for concept design of laser-welded web-core steel sandwich panels. The method uses a newly developed theory for the bending response of laser-welded web-core sandwich plates. Structural optimization is carried out using enumeration and newly developed vectorization-based genetic algorithm. To demonstrate these concepts, a case study in design of a hoistable car deck is considered. Finally, the optimization is conducted considering the objectives of deck weight.
Six Sigma Methodology Used To Improve Ship Welding
Authors: Noruk J. , Boillot J. P.
Published: January 2021

Nowhere in manufacturing is the old axiom of "Do the job right the first time" more true than in the welding operations in a shipyard. The welding process needs to be optimized to achieve high productivity while maintaining quality levels required by stringent welding standards. However, even with the most fine-tuned process, the welder or welding machine operator can be "done in" by upstream operations where the material is prepared for welding. This paper discusses how new welding automation equipment can be used before, during, and after the weld is made to reduce overall variability in the process. Reduced variability results in higher levels of productivity and quality. Intelligent sensors have been combined with different levels of automation including mechanized, machine, and robots to facilitate flexible and portable automation capable of multitasking processing.
Development of Product Model Management System for Naval Shipbuilding
Authors: Oh Dae Kyun , Jeong Yeon Hwan , Kim Yong Gyun , Shin Jong Gye , Yeo Yong Hwan , Ryu Cheolho
Published: January 2021

Since the concept of integrated product development environment (IPDE) was introduced from the US Department of Defense, the Korean navy has made efforts to apply the concept to its naval design and production. Recently, the Korean navy has supported a project for naval shipbuilding to achieve the advanced defense acquisition program. This project focuses on the integration of naval shipbuilding information. The Product Model Management System (PMMS) for Korean naval acquisition was a partial result of the project. The architecture of PMMS and the product structure of a naval ship are proposed in this paper. Also, the data acquisition process among acquisition program administration offices and contractors is defined for the construction of three-dimensional naval ship product models in PMMS. By constructing the product model on previous Korean naval ships, the PMMS was confirmed to a suitable innovative acquisition strategy. PMMS is on the leading edge of new product and process innovations in the Korean naval shipbuilding.
An Alternate Approach to the Exchange of Ship Product Model Data
Authors: Kassel Ben , Briggs Ted
Published: January 2021

This paper considers an alternate approach to the exchange of ship product model data based on general-purpose STEP application protocols. The vision is to provide the functionality defined in the shipbuilding application protocols using a combination of STEP AP239, AP214, and reference data libraries. It is expected that AP239 translators will soon be available, thus enabling the exchange of significant portions of ship product model data.
Reduction of Manufacturing Distortion in Arc Welded Ship Panels Using Thermal Tensioning
Authors: Sanderson Ruth , Lucas Bill , Pocock Roy
Published: January 2021

Large sheet or thin plate steel structures invariably suffer from distortion especially when fabricated using an arc welding process. The cost of reworking in shipbuilding is high. Low-stress no-distortion (LSND) welding has been demonstrated to effectively prevent distortion. The technique has been show to work well by rapidly cooling the weld with atomized water or liquid CO2 immediately after solidification. However, this can be expensive and difficult to apply in the fabrication of large structures. In this work, only a thermal tensioning technique is presented. The technique controls distortion by applying thermal stresses in front of the weld pool to counteract the stresses induced in the structure by welding. A combination of finite element modeling and experimentation has been used to find a thermal tensioning arrangement that reduces distortion by 50% in 4 mm butt welded steel plates using arc welding.
Performance of Major US Shipyards in 20th/21st Century
Authors: Gray William O.
Published: January 2021

Since WW II, major US shipbuilders have been unable to compete in price with shipyards in other parts of the world, and often the quality from US yards has been inferior to world standards. Furthermore, the mistaken US government assumption that shipyards and ship owners have a common interest has led to laws to protect American yards from competition. It has also caused commercial shipping to lose out to alternative forms of transportation such as trains, trucks, pipelines, and tug/barge rigs from more efficient smaller yards and crews. The "US built" requirement of the 1920 Jones Act for domestic cargo has been a prime reason for this modal shift. Tragically for coastal shipping, most large US shipyards have failed to adopt the efficient manufacturing lessons of pioneers such as Admiral "Jerry" Land and Henry Kaiser that led to the "WW II shipbuilding miracle," that built nearly 6,000 merchant ships in 5 years, a feat that Winston Churchill said "saved Europe." After WW II, while foreign yards adopted these efficiency measures, that did not happen here, and our yards suffered from few repeat orders because of their high prices. Drawing heavily on SNAME's Journal of Ship Production pioneered by Professors Bunch, Storch, and Lamb, this paper describes not only the history and "secrets" of many successful yards abroad, but also many of the failures in US shipyards during the same Post WW II period. As a result of their failures, and despite "US Friendly" laws, big US yards seldom got multiple repeat orders which they rightly believe might solve their problems. The paper concludes that because of the very serious congestion now occurring on our near-coastal highways, together with major environmental and economic incentives to take cargo "off the roads and rails" should give US shipbuilders a new golden opportunity. Efficient yards should be able to get major repeat orders for a new fleet of fast roll-on/roll-offs (Ro/Ros) and feeder container ships, however, only if they will finally after nearly 60 years adopt the "lean production" principles pioneered in WW II and then exported to Asia and Europe.
Numerical and Experimental Investigations on Temperature and Stress Distribution in Oxygen Cutting
Authors: Bo Zhou , Yujun Liu , Zhuoshang Ji
Published: January 2021

Oxygen cutting is a reliable and efficient process in shipbuilding. This study applies thermal elastoplastic analysis, using finite element techniques, to analyze the thermomechanical behavior and evaluate the residual stresses in oxygen cutting. A model for the temperature distribution during cutting and stress distribution in the workpiece are presented. The presented finite element model is capable of predicting the interface temperature and stress distribution during cutting and their influences in the workpiece. A noncontact temperature method—infrared radiation (IR) was used for surface temperature measurement. The residual stresses at the surface of the workpiece were measured by impact-indentation measurement. The results of finite element analysis were compared with experimental results to confirm the accuracy of the method. The numerical results are in good agreement with the experimental ones.
A Capacity and Variance Model to Investigate Yard Layouts
Authors: Pruyn Jeroen F. J. , Hekkenberg Robert G. , Ebbelaar Jeroen A. C.
Published: January 2021

In this paper, models to support the decision-making process for the design of a new shipyard are presented. The first model provides a way of globally assessing the effects various product mixes have on the effectiveness of a yard layout. The second, more detailed model is used to verify the rough results and analyze the effects of fluctuations in the product mix.
A Goal Programming Model for Vessel Dry Docking
Authors: San Cristóbal  Jose´ Ramon
Published: January 2021

Vessel dry docking takes place on a large number of occasions during a ship's life. During dry docking, vessels may be repaired or inspected, either in relation to specific rule (statutory) requirements or in order to gain an overall view of the condition of the vessel. Dry docking can represent a considerable amount of time as they involve the inspection, overhaul, and, where necessary, the modification of existing equipment. Time and cost are two factors that, generally, play a significant role in the planning and controlling of dry docking. Faster completion will, probably, generate additional costs, but can also create additional revenues as ships can enter markets early. In this paper, the Goal Programming (GP) formulation is applied to the drydocking survey carried out on the vessel "Campeo´ n." With the aim to balance time and cost, we establish three objectives, that is, to limit: the crashing costs, the time to undertake the dry docking, and the daily costs incurred by the vessel during the dry docking.
A Web-Based Decision Support System for the Planning of Vessel Dismantling Processes
Authors: Pylarinou Charalambia , Karacapilidis Nikos , Adamides Emmanuel D.
Published: January 2021

Aiming to augment the quality of decision making in vessel dismantling, this paper presents an innovative decision support system that takes into account the diversity of the associated constraints to aid stakeholders handle issues such as the appropriateness of a disposal methodology or the level of safety in a dismantling yard. Being seamlessly integrated with an advanced simulation environment, the system also facilitates the collaborative design of dismantling processes.
An Estimate of the Market Potential for Corrosion Protection, Prevention, and Monitoring Systems in Ships
Authors: Dhiman Saurav , Datta Biplab
Published: January 2021

There was a sudden increase in the number of ship accidents in the early 1990s. The primary reason for these accidents was a combination of local corrosion, fatigue cracking, and operational damage. This paper establishes the need for corrosion protection and monitoring systems for marine vessels. An attempt has been made to estimate the market potential for such systems in the near future.
Optimum Configuration of the Secondary Artillery of the F-110 Spanish Frigates
Authors: Echevarría Gerardo González-Cela , Campo Cabana Marco Antonio , Torres Javier Martínez , Carreño Morales Rafael María , Rivera Roberto Bellas , Touza Ramón , Arto Angeles Dena
Published: January 2021

The design process of the F-110 frigate for the Spanish Navy is still underway. This work aims to support the decision of the Navy, on the configuration of secondary artillery of the new F-110 frigate. To do this, in this case study, we use and develop a methodology based on an analytical decision maker built ad hoc. This decision-making methodology allows reducing the present subjectivity based on an analytic hierarchy process algorithm. Using objective tools such as numerical simulation and statistical techniques, we are able to evaluate objectively the contributions of the alternatives to different criteria.
A Three-Dimensional Model for Strength Assessment of Type-C Independent Cargo Tank Structures
Authors: Song Ming , Qin Bin , Zhou Li , Ren Zhengru
Published: January 2021

For the analysis of the arrangement and strength of Type-C independent cargo tank structures, the linear spring or rod elements are usually used to model supporting woods, in which one-dimensional and linear contact behaviors are assumed. This study aimed at developing a three-dimensional model for achieving more accurate strength assessment. In the model, solid elements are modeled to simulate the supporting woods. The nonlinear contact between the cargo tanks and the supporting woods is taken into account through LS-DYNA software. Numerical simulations of a 22,000-m3 liquefied petroleum gas carrier are carried out using both one-dimensional and three-dimensional models. Three load cases including one static and two dynamic cases are considered to assess the strength of the tank structures and supporting woods. The results obtained by the proposed model are compared with the results on the basis of spring elements. It is found that this new model can provide more reasonable strength predictions of the tank structures and the supporting woods. The method based on spring elements underestimates the wood stress, which indicates that it may be not conservative. Some discussions and suggestions are presented.
Residual Ultimate Strength of Steel Plates with Longitudinal Crack and Pitting Corrosion under Axial compression: Nonlinear Finite Element Method Investigations
Authors: Ahmadi Farzaneh , Ranji Ahmad Rahbar
Published: January 2021

The main aim of present study was to determine the ultimate strength of cracked and corroded plates under uniform in-plane compression. Corrosion is considered as pitting-type corrosion at one side of the plate with a central longitudinal crack. Nonlinear finite element analysis using commercial computer code, ANSYS, is used to determine the ultimate strength of deteriorated plates. Different geometrical parameters, including the aspect ratio (AR) and thickness of the plate, number of pits, pit depth-to-thickness ratio, and crack length, are considered. It is found that the AR of plates have great influence on the ultimate strength of cracked-pitted plates. Because of the position and orientation of the crack, the length of central longitudinal crack has no influence on ultimate strength reduction of cracked and cracked-pitted plates. The results show that regardless of the number of pits and crack length, in thin plates where buckling controls failure modes at ultimate strength, the number of pits has less influence on reduction of the ultimate strength than thick plates where yielding controls failure mode. Also it is concluded that in rectangular plates, arrangements of pits has more effect on reduction of the ultimate strength of cracked-pitted plates than the number of pits.
Modularity: Facilitator for Commercial Shipyards in Naval Shipbuilding
Authors: Daidola John C.
Published: January 2021

Modularity in the design and construction of naval vessels is considered wherein functional naval system-module installations that provide basic ship structure and ship interfaces are permanently integrated in an otherwise conventional ship envelope during construction. Consideration is given to a paradigm shift consisting of a ship envelope constructed by a primarily commercial shipbuilder, which is then transferred to a naval shipyard integrator for completion, including insertion of those modules which are purely naval mission-oriented. In the context of such consideration, the competitive practices of international commercial shipbuilders, particularly related to large passenger ships, suggest a potential application to naval vessels.
Optimizing Tack Welding Fabrication Procedures Using Numerical Finite Element Models
Authors: Camilleri D. , Gray T.G.F. , McPherson N.
Published: January 2021

The aim of this study was to investigate the influence of different tack welding fabrication procedures on the final deformations of seam welded plate structures. In this study the length of the tacks, number of tacks, and position of tacks with respect to the final seam weld are altered, and their sensitivity with respect to out-of-plane deformation is established. A parametric study of these three different procedural variations is performed via finite element models to identify which fabrication procedures would lead to minimal out-of-plane distortion.
Application of an Artificial Neural Network to the Selection of a Maximum Efficiency Ship Screw Propeller
Authors: Matulja Dunja , Dejhalla Roko , Bukovac Ozren
Published: January 2021

The idea of the present study is to apply the advantages of neural networks to the choice of an optimum ship screw propeller as an introduction to more complex ship design problems. The neural network was created and trained to provide the characteristics of the maximum efficiency propeller. To train the network, data regarding the blade number, advance speed, delivered power, rate of revolution, diameter, pitch ratio, and expanded area ratio as well as thrust and efficiency were set as inputs and outputs. The testing of the network proved its efficiency, which makes it a reliable tool for the preliminary screw propeller selection.
Resistance of a Compartmented Surface-Effect Ship
Authors: Day Alexander H. , Clelland David , Doctors Lawrence J. , Beveridge Philip
Published: January 2021

A series of carefully controlled experiments on the resistance of a model of a compartmented surface-effect ship has been conducted in a towing tank. Configurations of the model included cases encompassing one subcushion and two subcushions, as well as differing values of the pressures in the subcushions. It was shown that a reduced total resistance in the appropriate range of Froude number could be achieved in this manner. Furthermore, the previously developed theory for the resistance of a surface-effect ship was verified for the model for a Froude number greater than 0.40.