bluuebunny/crossref_metadata_2025 huggingface dataset:
The National Shipbuilding Research Program Advanced Shipbuilding Enterprise: Five Years of Delivering Value, 1998 to 2003
Authors: Carney J. , Conroy T , Hite T , Knowles R , Mays J , Nix R
Published: January 2021

The National Shipbuilding Research Program (NSRP) Advanced Shipbuilding Enterprise (ASE) began formally in 1998, with a mission to manage and focus national shipbuilding research and development funding on technologies that will reduce the cost of warships to the US Navy and will establish international shipbuilding competitiveness. A key means for accomplishing this mission was to provide a collaborative forum for improving business, shipbuilding, and ship repair processes. In response to a Navy request, shipyard executives formed Articles of Collaboration, which enabled the execution of a Joint Funding Agreement (JFA) with Naval Sea Systems Command (NAVSEA). Successes from the Defense Advanced Research Projects Agency (DARPA) Maritime Technology (MARITECH) program and the National Shipbuilding Research Program (NSRP) were leveraged to initiate a framework that would enable collaboration and sharing. Leaders of the Ship Production Committee (SPC) panels of the Society of Naval Architects and Marine Engineers (SNAME) also joined the collaborative forum, and the NSRP ASE was formed. Through the new collaborative forum, the strategic investment plan (SIP) was created, outlining consensus priorities in six major initiative (MI) areas and setting a course toward more affordable ships.
A Hybrid-Agent-Based Approach for Block Break Definition Using Fuzzy Logic
Authors: Ferrie Kevin , Spicknall Mark H.
Published: January 2021

This paper presents a hybrid-agent-based methodology for defining block breaks using fuzzy logic mechanisms for agent preference representation and mediation. The concept of a hybrid agent is defined, and the fuzzy-logic-based mechanisms for defining the preferences of individual agents and then deriving joint preferences are described. Working examples are given for defining blocks and associated breaks in the hold area and engine room of the notional fast sealift ship PD-337. The agents jointly defining the block breaks in these examples are a structure manufacturing planner, a structure assembly planner, and an outfitting planner. Excel spreadsheets are used in these examples to execute the fuzzy-based operations. This methodology has proven to be straightforward, to provide useful results, and to have the potential to improve the efficiency and optimality of block definition. The methodology could be effectively integrated into the detail/production design process and could also be applied to the definition of other planning units, such as outfit units and on-board outfitting zones. Areas of further research include exploring within the hybrid agent and fuzzy-based context (1) the ability to define breaks in all three dimensions simultaneously rather than sequentially where simultaneous three-dimensional optimization is necessary, (2) dynamic break definition where a break location is dependent to some extent on the location of adjacent breaks, (3) the simultaneous consideration of preferences from lifting/weight and planning/work content agents that use block attributes other than location to determine if breaks are satisfactory, and (4) the development of an integrated and user-friendly tool for block break definition for use in the production planning or build strategy development process.
Improving Shipyard Manufacturing Processes Using STEP-NC
Authors: Hardwick Martin , Kassel Ben , Crump Barry , Garrett Steven
Published: January 2021

A recent study showed that a UK Navy depot can save $4 million by rapidly manufacturing machined parts from a feature-based product data description. However, the study also showed that only 2,000 of a potential 13,000 parts can be eliminated from the inventory if the data are given just a feature-based description because there is a limit to the complexity of the parts. Now a new product data protocol is becoming available that describes complete feature-based computerized numerical controller(CNC) manufacturing programs for parts that can have any degree of complexity. This paper describes a proof of concept demonstration of the new protocol for the US shipbuilding industry.
Computer-Controlled Robotic Marine Coatings Application System
Authors: Tolliver David , Morton Steve
Published: January 2021

This paper will examine the current methods used for the surface preparation and painting of a ship hull and contrast it with the advantages of automation through the use of computer-controlled robotic equipment. The evolution of marine coatings, equipment, and techniques will be discussed. Through the use of automation in the ship coating application process, shipyard productivity can be advanced. Material and labor costs can be reduced, worker safety is improved, impact to the environment over current methods can be minimized, and quality results become repeatable and predictable.
Propeller Geometric Parameter Extraction From Inspection Data Clouds
Authors: Allen David W. , Howell Ivan L. , McIntyre Charles J. , Reiser Jacob J. , Machin James D. , Hettema Charles D. , Madden Craig J.
Published: January 2021

Methods and conventions for propeller geometric parameter extraction from inspection data clouds are presented. Steps in the extraction process include constructing a representation of the inspected propeller from inspection data clouds, constructing sections through the representation, mapping the sections from three to two dimensions, and computing propeller parameters for the sections.
Reliability-Based Shipboard Facility Optimization
Authors: Hester Patrick , Thomas Larry , Mahadevan Sankaran
Published: January 2021

This paper develops a methodology for reliability-based facility optimization (RBFO), that is, finding an optimum and reliable solution for a facility layout problem given a set of operational and resource constraints. The RBFO problem examined in this paper involves the TAKE class of ships being designed for the US Navy. The primary goal of the TAKE ships is to provide efficient underway replenishment (UNREP, or delivery of cargo to a deployed ship) of goods and ammunition to ships in the Navy's fleet. As a supply ship delivering goods to deployed ships, the TAKE must complete its mission in minimum cycle time with maximum reliability. The reliability constraints are practical cycle time limits based on Navy contractual requirements developed from existing ships. The proposed methodology combines branch and boundbased optimization, cargo simulation, and probabilistic reliability and sensitivity analyses. The methodology is demonstrated for application to a practical shipboard layout with realistic requirements.
Productivity and Consumption Variation in Dry Abrasive Blasting With Coal Slag
Authors: Kambham Kalpalatha , Sangameswaran Sivaramakrishnan , Potana Sandhya , Kura Bhaskar
Published: January 2021

Coal slag, a by-product from coal-fired utility boilers, is a commonly used material in dry abrasive blasting. This paper presents the results of a research study to evaluate the variation of productivity and consumption with pressure, feed rate, and surface contamination for coal slag.
Study on Forced Convection Boundary Condition for Subcooled Water in the Simulation of Line-Heating Process
Authors: Ji Wang , Yujun Liu , Zhuoshang Ji , Yanping Deng , Jun Zhang
Published: January 2021

In the simulation of line-heating process, the convection boundary condition, especially the subcooled water forced convection, has great influence on the result. The calculation of the convection coefficient is a difficult problem in the simulation. This paper uses the theory of forced convection boiling to study subcooled water forced convection during the line-heating process. By solving the wall temperatures of originating nucleate boiling and critical heat flux for subcooled water and comparing the plate temperature with these two wall temperatures, the status of water can be determined, and then the corresponding convection coefficient is calculated. The simulation results show that the precision of the forced convection boiling boundary condition presented in this paper is much better than that of a boundary condition based on the pool boiling curve.
Low Heat Input Welding for Thin Steel Fabrication
Authors: Kelly S.M. , Martukanitz R.P. , Michaleris P. , Bugarewicz M. , Huang T. D. , Kvidahl L.
Published: January 2021

As thinner members are used in marine construction, the use of conventional joining techniques results in significant angular and buckling distortion due to the inherent high heat input with these processes. Several low heat input alternatives, including laser beam, gas metal arc, and hybrid laser arc welding, are explored. The paper focuses on process development, real time distortion measurements, and implementation of these processes.
Development of a STEP-based Production Information System for Block Assembly Process
Authors: Lee Chang-keun , Kim Hoon-joo
Published: January 2021

More effective production planning and scheduling in shipbuilding is needed to prepare the master data related to the products, the progress of work, and the production method. Therefore, it is most important to generate automatically the master data from a computer-aided design (CAD) model. However, production engineers manually read and analyze the assembly drawings with the detailed process of production, create, and input the master data. It is a time consuming job and also the data are neither clear nor accurate. In this study, we have developed a production information system using Standard for the Exchange of Product Model Data (STEP), which generates detailed production-oriented master data systematically and automatically from the CAD hull models considering work process. This production information includes many properties, such as assembly trees, working location, the working posture of setting and welding, material, detailed welding property, direction of stiffeners, plates and assemblies, specifications of parts and assemblies, curvature, turn-over, bevel of seams, slit and open, and throat thickness of welds. Secondly, three-dimensional geometric data (Virtual Reality Modeling Language, VRML) from subassemblies to grand assembly can be generated automatically according to the production process and method. We've tried to improve the quality of the production planning and scheduling with highly accurate detailed master data.
Looking-Forward Scheduling Approach Applied in Pre-erection Area of a Shipyard
Authors: Yoon Duck Young , Varghese Ranjan
Published: January 2021

The major problem arises at a shipyard because of scarcity of space for arranging the building blocks of a ship under construction. A standardized erection sequence diagram is generally available to provide the prioritized erection sequence, and it serves as the framework. In order to make a timely erection of the blocks, a post plan has to be developed so that the blocks lie in the nearest possible vicinity of the material-handling devices while keeping the priority of erection, and the blocks are arranged in the pre-erection area. The genetic algorithm based solution procedure is developed to produce the optimal spatial arrangement. An innovative algorithm nicknamed ISBAS (Intelligent Spatial Block Arrangement Scheduler) has been developed and implemented using genetic algorithm, and a workable computer program has been developed using VC++. The detailed genetic operation is performed to run to meet the objectives of the critically complicated problem. Also, hand-in-hand algorithms such as knapsack problem, traveling salesmen problem, and weight assignment algorithms are used to segregate the better options. An indigenously developed looking-forward algorithm is also in place.
Ship Pipe Routing Design Using the ACO with Iterative Pheromone Updating
Authors: Xiaoning Fan , Yan Lin , Zhuoshang Ji
Published: January 2021

Ship pipe routing design (SPRD) that belongs to non-deterministic polynomial (NP)-hard problem concerns minimizing the cost of pipe material while satisfying constraints and avoiding obstacles. Currently, this total solution mainly depends on human experts. The stochastic search algorithms suitable for computer technology provide the opportunity to automate and optimize it. The Ant Colony Optimization (ACO) is an effective metaheuristic and stochastic search technique to solve combinatorial optimization problems by using principle of pheromone information. Based on ACO, the method of ant colony algorithm with iterative pheromone updating is first proposed to solve ship pipeline routing in three-dimensional space. Simulation results show that the new updating approach of pheromone is feasible and effective. Mean-while, the performance and computer processing time of the proposed algorithm outperform the original ACO used to generate SPRD solutions.
Leading a Sea Change in Naval Ship Design: Toward Collaborative Product Development
Authors: Keane Robert G. , Fireman Howard , Billingsley Daniel W.
Published: January 2021

In October 1989, the Naval Sea Systems Command (NAVSEA) conducted the Ship Design for Producibility Workshop with broad participation from the Navy, shipbuilders, ship design agents, and academia. The Workshop was one of NAVSEA's first Total Quality Leadership (TQL) initiatives and was subsequently expanded by NAVSEA's Chief Engineer (CHENG) and the Deputy Assistant Secretary of the Navy (DASN) for Ships into the Ship Design, Acquisition, and Construction (DAC) Process Improvement Project. In addition, the National Shipbuilding Research Program (NSRP) initiated a number of thrusts in concurrent engineering and increased throughput. The authors describe one of these major process improvement initiatives, NAVSEA's 3-D "Product Model" Strategy to extend throughout the enterprise-wide process of warship development a primary focus on the bridge between ship design and shipbuilding. The Workshop and subsequent process improvement initiatives have had a profound impact on the naval ship design process. Yet, as reported to Congress in 2002 by the Secretary of the Navy, the unbudgeted cost growth and increased cycle times for detail design of new warships have "reached an untenable level." This necessitated the October 2004 ASN (RDA) policy memorandum on integrated digital data environment (IDDE). To realize transformational innovations in our ship designs, as well as transformational innovations in the entire warship development process, the National Naval Responsibility in Naval Engineering (NNRNE) was recently established by the Navy. To support NNR-NE the Office of Naval Research (ONR) and the Naval Sea Systems Command (NAVSEA) created the Center for Innovation in Ship Design (CISD). A summary of some recent CISD Innovation Cells and how CISD can contribute to breaking down the existing organizational cultures and institutionalizing a collaborative product development environment are also discussed. As we begin a new century, it is appropriate that our naval ship design and shipbuilding community review its progress, look at the crosscut principles of leading change, determine what it takes to bring about dramatic cultural transformation, and discuss the critical need for Navy, shipbuilder, design agent, and academia leadership to continue developing a new collaborative product development environment that fosters a sea change in the whole naval ship development process.
Engineering and Production Technology for Lightweight Ship Structures, Part II: Distortion Mitigation Technique and Implementation
Authors: Huang T. D. , Conrardy C. , Dong P. , Keene P. , Kvidahl L. , DeCan L.
Published: January 2021

Shipboard applications of lightweight structures have increased over recent years in both military and commercial vessels. Thin steel reduces topside weight, enhances mission capability, and improves performance and vessel stability, but the propensity of buckling distortion has increased significantly. At present, several US Navy construction programs are experiencing high rates of buckling distortion on thin steel structures. The standard shipyard practice of fabricating stiffened steel panels by arc welding is one of the major contributors to this distortion. Correcting the distortion is a necessary but time-consuming operation that adds no value and ultimately tends to degrade the quality of the ship structure. With a major initiative funded by the US Navy, Northrop Grumman Ship Systems (NGSS) has undertaken a comprehensive assessment of lightweight structure fabrication technology since 2002. Through collaborative research, significant progress has been achieved in the development of distortion-control techniques. Reverse arching, transient thermal tensioning (TTT), stiffener assembly sequencing, and other preferred manufacturing techniques were developed at NGSS to reduce distortion and eliminate the high rework costs associated with correcting that distortion. Complex lightweight panel structures, which are reinforced by long slender stiffeners along with numerous cutouts and inserts, pose a major challenge for distortion control. The geometric complexity yields a more complicated buckling behavior, which drives the need to develop a more fine-tuned finite element model to determine critical parameters and heating patterns for the TTT process. NGSS has recently teamed with Edison Welding Institute (EWI), Battelle Memorial Institute, and the University of New Orleans on a Navy project to further refine TTT procedures for complex lightweight ship structures. In this paper, functional requirements and the design of TTT process and production equipment are discussed. The refined TTT process will be benchmarked by the test panel observations, and a laser scanning device, LIDAR, will be used to analyze panel distortion topography.
Ship Design Educational Framework Using ShareFast: A Case Study of Teaching Ship Design With CAD Software
Authors: Hiekata Kazuo , Yamato Hiroyuki , Rojanakamolsan Piroon
Published: January 2021

This paper proposes a ship design educational framework using ShareFast, an open source, client/server application for a document-management system based on workflow. The association between design documents and workflow is described by metadata based on Semantic Web technology. The client software offers a workflow editor to create and edit workflow and then uploads the created workflow to the server. It also allows users to browse the workflow and associated documents. Additionally, the software offers a function for instructors to monitor student's behavior so that they can analyze it to improve class efficiency. The system has been used for an experimental investigation with university students. The result showed that learning ship design by workflow helped the students understand design process more easily, and the system can shorten the students' learning duration.
Application of STEP Technology to Ship Repair Data Management
Authors: Ventura Manuel , Soares C. Guedes
Published: January 2021

This paper describes some aspects of the application of STEP technology to the development of a data management system for a ship repair yard. The business process associated with ship repair activities implies a lot of data exchange between several companies, with different core businesses and organizations, using different software platforms and systems. In this activity, where the duration of the typical work is relatively small and the schedules are tight, the improvement of the communications between the actors involved is relevant. The system described here manages the information exchanged between ship owner and shipyard during the repair process, covering tendering, contract, production, and invoice phases. STEP technology was used not only for data exchange but also for the development of the persistent storage of data on an object-oriented database, driven by a formal EXPRESS-based schema.
Transient Thermal Tensioning and Numerical Modeling of Thin Steel Ship Panel Structures
Authors: Yang Y. , Dull R. , Conrardy C. , Porter N. , Dong P. , Huang T. D.
Published: January 2021

Finite element models were developed for transient thermal tensioning of complex thin steel panels for specific test panel designs and for representative production panels both composed of inserts, transition thicknesses, and penetrations.
Practical Aspects of Conducting Speed Trials in the Open Ocean
Authors: Ashcroft Frederick H. , Davidson Andrew
Published: January 2021

In September 2000, General Dynamics NASSCO entered into a contract with BP Shipping Ltd. for the design, construction, and delivery of four 185,000 deadweight ton crude tankers for the Trans-Atlantic Pipeline System (TAPS) trade. NASSCO was required to undertake progressive speed trials on all four vessels. In July 2004, the first vessel underwent trials in the Eastern Pacific, approximately 60 nautical miles due west of San Diego. The corrected results were not as expected, and the vessel appeared to not make design speed by a significant margin. In light of the lead ship experience, a number of changes were made to the trial procedures and practices. These changes resulted in the successful demonstration of design speed in the follow ships. This paper presents data, discusses various environmental influences, and data collection system issues experienced during the preparation of the vessel for trials, trial data collection, and data reduction for the three follow ships.
Application of Sandwich Panels in Design and Building of Dredging Ships
Authors: Kortenoeven Jeroen , Boon Bart , de Bruijn Arnold
Published: January 2021

The main objective of this paper is to assist shipyards and ship owners to actually decide to examine and implement sandwich panels in ship structures. The awareness that the application of sandwich panels may lead to substantial lower production costs, relatively shorter product delivery times, improved ship performance due to a lower structural weight, and improved fatigue and corrosion characteristics is increasing. As a builder and supplier of dredging ships and dredging equipment, IHC Dredgers(Member of the IHC Merwede Group) is continuously seeking ways to improve the performance of its complex and special ship designs to further reduce production costs and shorten delivery times. Sandwich panels have already been applied in commercial vessels, but on a rather modest scale. After some exploratory studies, IHC is convinced of the potential benefits for the shipyard and its customers, mainly dredging companies. However several factors affect the potential use of sandwich panels in the design and building processes including acceptance by clients, class societies, and the shipyard's own personnel.
Fatigue Crack Control in Structural Details Using Surface Peening
Authors: Ngiam Shi Song , Brennan Feargal P.
Published: January 2021

This paper presents an analytical and experimental study of crack shape evolution in steel plate specimens under cyclic loading. It is widely known that the introduction of compressive residual stresses by cold working the surface can be highly beneficial in improving the fatigue performance of structural components. Although it is recognized that relaxation of surface compressive residual stress can reduce the potential benefits, the effects of residual stress on crack shape evolution are often overlooked. Previous studies have shown that the intensity of the surface compressive residual stress has a pronounced effect on fatigue crack initiation. A recently developed technique termed controlled stitch cold working, which applies differing intensities of compressive residual stress at specific regions in a structure, is shown in the paper to influence fatigue crack propagation life considerably. The approach can be used to prevent crack growth in particular directions, for example, encouraging a controlled or fail-safe scenario. The paper describes fatigue crack growth tests on shot peened specimens tested under uniaxial tension. The specimens were peened to varying intensities and of differing coverage areas. Cracks were initiated from starter notches after peening, meaning the approach can be used for fatigue performance enhancement at the construction stage or later as part of a maintenance and repair strategy. Crack growth retardation is apparent in all tests, and this is attributed to the constrained crack shape. Further work will consider the use of laser and ultrasonic peening to contain cracks from rapidly propagating from stress concentrations. This approach used with careful design of stiffness can significantly extend the fatigue crack propagation resistance of ship and offshore structures.
Estimation of Welding Distortion Using Neural Network
Authors: Okumoto Yasuhisa
Published: January 2021

Recently, the prediction of welding distortion of steel structure has been carried out widely. Though the thermal elastic-plasticity finite element method (FEM) analysis is usually required to ensure the accuracy of the estimation, technical knowledge is required, and long computing time is necessary. In this study, simplification of the prediction was done using a neural network model, in which the calculation result of the FEM analysis was incorporated in teacher data, for the fillet welding of T-type buildup structure, etc. This program would be able to estimate the welding distortion of the joint with different dimensions and welding conditions in a simple manner.
Strength Analysis of Lifting Padeye Based on Curved Beam Theory
Authors: Bo Zhou , Yujun Liu , Zhuoshang Ji
Published: January 2021

The lifting padeyes are widely used in the construction of offshore structures and ships. Because of the lack of more accurate information, heavily conservative simplified approaches have to be applied to strength analysis and structure design. Therefore, the calculated stress results contain a lot of discrepancies with the actual stress. In the paper, the external loads on the padeyes are analyzed and a robust stress check formula is derived using curved beam theory. The results of finite element method (FEM) and the solutions of traditional check formula and new check formula are compared. It is shown that the new expressions account for a better representation of the real stress value and distribution. By applying the strength check formula presented in the paper, the safe reliability of structure design can be improved significantly.
A Computer Simulation Approach to Improving Tugboat Shipbuilding Design and Development Productivity
Authors: Das Biman , Tejpal Navin
Published: January 2021

Tugboat shipbuilding design drawings are currently prepared with insufficient and untimely information of material/equipment availability, resulting in drawing changes and errors, increased labor and material costs, and lengthening of ship completion time. It is proposed that the design drawings are only prepared after confirmation of material/equipment availability from vendors to deal with the problem. The concept of concurrent engineering is introduced by integrating design and vendor activities through adequate and timely vendor-furnished information (VFI) to deal with the problem. The PERT (program evaluation and review technique) computer simulation models were employed through the use of a simulation package AweSim to analyze the work activity networks of piping drawings. A cost savings of about $1,389,700 would be possible through a 10% reduction in total design and including piping drawings and development labor costs and construction labor and material costs. The completion time for preparing design drawings and ship construction can be reduced by about 186 days or 19.5% of the total throughput time for a tugboat shipbuilding process.
Ready to Design a Naval Ship? - Prove It!
Authors: Keane R. , Fireman H. , Hough J. , Helgerson D. , Whitcomb C.
Published: January 2021

Last year, the Naval Sea Systems Command (NAVSEA) sponsored the Navy’s Center for Innovation in Ship Design (CISD) to establish a framework for developing ship design capability readiness levels as part of a business case to provide incentives for the naval ship enterprise to invest in developing, sustaining, and improving mature naval ship design capabilities. The authors describe the accomplishments thus far and note that there is now enough documentation that new ship acquisition programs can specify design readiness requirements and have valid criteria for evaluating the design capabilities of contractors proposing to perform early stage naval ship design. They actually apply the framework to NAVSEA and assess NAVSEA's readiness to design a naval ship. Although significant progress is being made on developing Ship Design Capability Readiness Models (SDCRM), much work remains to be done!
Automatic Line-Heating Process for Forming the Double-Curved Shell Plates
Authors: Wang Ji , Liu Yujun , Ji Zhuoshang , Deng Yanping , Zhang Jun
Published: January 2021

An automatic line-heating process for the double-curved shell plates is introduced. This process contains four subprocesses: calculating the heating information based on shell development and analysis of primary technological parameters, which is named as prediction system of heating information; heating the plate by an automated line-heating machine according to the calculated heating information; measuring and inspecting the plate surface to determine whether it matches the designed surface; and calculating the reheating information for the deformed plate and reheating the plate automatically until the designed shape is achieved. Therefore, an iterative loop system of an automated line-heating process can be developed based on the integration of these four components.
Estimation of Man-Hours for Fabrication of Ships and Offshore Platforms
Authors: Westby Ola
Published: January 2021

This paper presents a procedure for estimating the man-hours (MH) required for building ships and offshore platforms. Information gained from building completely different types of products may be used. The procedure is suitable for the bidding phase. The procedure makes it possible to investigate changes in estimated MH caused by changes in the fabrication process or design or effectiveness in the workshop. Sensitivity analysis of estimated MH may be used for evaluation of investments or as a basis for reduction of MH in bidding. Part I of the paper is the theoretical basis of the procedure. Part II is an implementation in building of a hull. This method for estimation of MH is implemented for building of load-bearing structures. Estimation can take place quickly, and sensitivity to changes in fabrication methods, design, and effectiveness in the workshop is visible. Examples of graphical representation of fabrication data for five disciplines are presented.
A Concept and Framework for a Shipyard Layout Design Based on Simulation
Authors: Shin Jong Gye , Song Young Joo , Lee Dong Kun , Woo Jong Hun
Published: January 2021

Recently, global shipbuilding companies have been increasing their productivity or expanding their shipyards to accommodate a large amount of orders. However, few studies have been carried out on shipyard layout designs. This research presents a simulation-based shipyard layout design framework to resolve the problems of the shipyard layout design. The shipyard layout design framework was developed on the basis of the systems engineering method. The disciplined systems engineering technique was guided by ISO/IEC 15288 during the planning phase of the shipyard layout design framework development. This framework suggests how to achieve an efficient and effective shipyard layout design that can satisfy the stakeholder of the layout design process. Furthermore, a method is recommended for how the proposed shipyard layout should be verified and validated using a computer simulation. It is expected that the framework will contribute not only to the improvement of the existing shipyard layout design but also to the construction of the new shipyard or ship-yard advancement.
Optimization of Torch Movements of Welding and Cutting Using Ant Colony Method
Authors: Okumoto Yasuhisa
Published: January 2021

Though many methods are applied to solve the combinatorial optimization problem, there are many cases in which the solution cannot be solved in practical computation time, even if the computer becomes more advanced. Recently the "ant colony optimization method (ACO)" has been proposed as one of the meta-heuristic method. This research tried the ACO in ship production field. Firstly, the ACO was applied and verified for the traveling salesman problem (TSP) to obtain the shortest path in many cities, as a representative combinatorial optimization problem. Next, based on the result, the ACO was applied to the problem in search of the optimum torch movement of a welding robot for the assembly of ship hull structure, and of a NC plasma cutting machine of steel plate. As a result, it was confirmed that the ACO is effective to solve the optimum path of machines.
Study of Flexible Scheduling System of the Hull Job Shop Based on OOCPN
Authors: Wang Ji , Liu Yujun , Ji Zhuoshang , Deng Yanping , Zheng Yuanyuan
Published: January 2021

The hull job shop in a shipyard is a typical flexible manufacturing system (FMS), the flexibility and efficiency of which largely depends on the level of FMS scheduling. In this paper, the Object-Oriented Colored Petri Net (OOCPN) is used to build the FMS model for the hull job shop. A four-step modeling method of FMS has been developed to successfully simulate the scheduling of the hull job shop.
Experimental Investigations on ThermoMechanical Tensioning (TMT), comparison with Heat Sink, and Its Application to a Grillage Structure
Authors: Gadagi Amith , Mandal Nisith Ranjan , Sha Om Prakash , Kumar Sharat , Pujari Sanyappa , Pentakota Ravi Kumar , Podder Debabrata , Akurati Prabhakar
Published: January 2021

Thin plates, which are widely used in ship structures, undergo weld-induced buckling distortions because of their lower critical buckling strength. Thus, there is a need for an active in-process distortion control mechanism in the welding involving thin plates. In this regard, a ThermoMechanical Tensioning (TMT) method was developed and implemented successfully. In the current work, experimental investigation of the effect of TMT pull on the resulting welding distortions is studied and also the TMT process is compared with a heat sinking technique. The experimental results indicate that an increase in the TMT pull would reduce the extent of weld-induced buckling distortions. The results also suggest that a complicated heat sinking technique can be effectively replaced by a TMT process in reducing the welding out-of-plane distortions. The concept of TMT is further extended to the fabrication of grillage structures used in ship structures, which includes longitudinal and transverse welds.
Analysis on Hull Block Erection Process Considering Variability
Authors: Shen Huiqiang , Lee Yonggil , Jeong Yong-kuk , Woo Jong Hun
Published: January 2021

The hull block erection network process, which is performed during the master production planning stage of the shipyard, is frequently delayed because of limited resources, workspace, and block preparation ratio. In this study, a study to predict the delay with respect to the block erection schedule is conducted by considering the variability of the block preparation ratio based on the discrete event simulation algorithm. It is confirmed that the variation of the key event observance ratio is confirmed according to the variability caused by the block erection process, which has the minimum lead time in a limited resource environment, and the block preparation ratio. Furthermore, the optimal pitch value for the key event concordance is calculated based on simulation results.
Distortion Control and Prevention by Fabrication Techniques in Cold Bent Steel Frame with Perforated Web
Authors: Li Peiyong , Tang Zheng , Huang Yuwen , Wang Yunpeng , Wang Chong
Published: January 2021

Cutouts are widely used in ships and offshore structures. Cutouts of big size are used mainly for inspection, passing pipes, and weight reduction. Some cutouts of small size may be used for various purposes, such as water hole in the web of stiffeners. The stiffeners with perforated web are the most commonly adopted structure members in the shipbuilding industry, and they are mainly fabricated by cutting and bending the frame to meet the requirements of desired design configuration. In ship production, the manufacture of the curved stiffener with holes is desirable to perforate first and then to bend the frame. This fabrication procedure is adopted for efficient production because of the layout of the production line. However, structural distortion and damage may occur during cold bending of the frames with perforated web, such as necking, wrinkling, and even crack initiation. This problem should be solved in ship production. In this study, cold bending experiments and finite element simulations were performed to analyze the deformation characteristics of curved frames with cutouts. A fabrication method is proposed to control the deformation in the cutouts during the bending process. In this method, the block cut out during the first step is filled in the hole and afterward the frame is bent. The results show that this method can control well the deformation localized around the hole during the bending process. It offers an important guidance for cold bending steel frames in ship production.
Microstructure and Mechanical Properties of GTAW Welded Joint of Invar Alloy
Authors: Zhao DongSheng , Zhang TianFei , Wu LiangLiang , Kong LeLe , Liu YuJun
Published: January 2021

Experiment of automatic gas tungsten arc welding of liquefied natural gas carrier Invar alloy with a thickness of .7 mm was completed, and the welding parameters were optimized, as well as microstructure and mechanical properties of the welded joint were measured and analyzed. The grain size of the area near the weld centerline was small, mainly cellular dendrites, and the grain size on both sides of the weld centerline increased gradually, mainly dendrites, whereas the grain size near fusion line was larger, and there were more columnar crystals. The heat-affected zone was composed of coarse austenite grains. Transgranular cracks were the main cracks in the welding seam. When welding current was 40 A, frequency was 120 Hz, and welding speed was 350 mm/min, tensile strength of the welded joint was 446.9 MPa, which 88.1% of the base metal’s tensile strength and 10.3% of the fracture elongation. The fracture surface of tensile specimens showed typical plastic fracture characteristics, with no obvious crack characteristics, and no eutectic liquid films were observed.

Introduction

Invar alloy is a Fe–36%Ni alloy. Its thermal expansion coefficient at room temperature is less than 1.6X10-6/k, which is about one-tenth of that of low carbon steel, and changes little in a larger temperature range. Therefore, Invar alloy is widely used in making precision measuring instruments and low temperature-resistant materials (Corbacho et al. 1998; Park et al. 2011; Qiu et al. 2016; Yakout et al. 2018). In recent years, with the increasing demand for clean energy, liquefied natural gas (LNG) carriers are developing rapidly (Zhao et al. 2015; Oh et al. 2018). LNG liquefies at temperatures below -161.5°C. The volume of LNG is about 1/ 625 of the volume of gaseous natural gas of the same mass; thus, it can transport large quantities of natural gas over long distances.
Optimization of Module Arrangement in Ship Engine Room
Authors: Gunawan Gunawan , Utomo Allessandro Setyo Anggito , Hamada Kunihiro , Ouchi Kazetaro , Yamamoto Hiroyuki , Sueshige Yoichi
Published: January 2021

This article presents a new approach for engine room design based on the modularization concept including the part arrangement optimization. The characteristics of the proposed methods are as follows. First, attention was paid to piping systems of multiple bulk carrier series of different sizes. The cost and length of the piping system as well as the similarity and the commonness of the modules and arrangements were considered. Second, to define an effective module that could be commonly used in different ships, a design structure matrix was adopted. Third, in the arrangement design, an optimization system was developed using a genetic algorithm to obtain a similar pattern for module arrangement in multiple series ships with specific consideration toward cost and similarity. Some examples using the proposed method are shown at the end of article.
Washington State Ferries 2007–2009 Biodiesel Demonstration Project
Authors: Brodeur Paul H. , Renehan Lisa N. , Larsen David W.
Published: January 2021

Washington State Ferries (WSF) is potentially one of the largest consumers of biodie-sel fuel in the Pacific Northwest region. Puget Sound Clean Air Agency (PSCAA) managed a scientific study to determine appropriate fuel specifications and fuel-handling procedures for using biodiesel blended fuels in WSF operations. Study results will transfer directly to other marine applications, as well as to land-based end users. This paper focuses on the second phase of this study, implementation of the trials.
Application of Monte Carlo Method in the Marine Environment
Authors: Cunningham A. , Wang J. , Allanson D. , Wall A.
Published: January 2021

This paper gives a methodology for the application of Monte Carlo methods, specifically their application to onboard systems within the marine environment. The aim is to demonstrate the efficacy and worth of Monte Carlo methods as a tool and how their application can provide engineers with more information when making maintenance decisions. A case study of a marine cooling system is included using Monte Carlo Methods to examine its failure probability.
Dynamic Analysis and Injury Prediction for Small Craft Collisions
Authors: Salzar Robert S. , Ash Joseph , Lucas Scott R. , Planchak Christopher , Dalton Antony , Emond Bryan , Getz James E.
Published: January 2021

Six staged watercraft collisions were performed to assess the corresponding boat dynamics and boat operator kinematics. Each boat was operated remotely through a series of handheld radio transmitters capable of controlling steering, throttle, and a master kill switch. Triaxial accelerometers mounted to the deck of each boat provided sensor data that was measured and recorded using several MotionMaster EDR-6DOF recorders. Hybrid-II crash test dummies were placed in occupant positions, and their resulting kinematics recorded. The triaxial deck acceleration data was used as input to a lumped-mass human dynamics model (MADYMO) to understand occupant kinematics and potential for injury. Noted results include the presence of large vertical (z-axis) deck accelerations, and the low risk of head and neck injuries during the first phase of the collisions.
The Loss of Andrea Doria—A Marine Forensic Analysis
Authors: Garzke William H. , Simpson Pierette Domenica
Published: January 2021

The Andrea Doria shipwreck of 1956 is still of interest to naval architects and historians. It pertains to the most catastrophic and the most recent collision in history between two ocean liners. One of the most controversial aspects of the event involves the sinking of the Italian luxury liner (shown on her maiden voyage in Fig. 1). This report's main goal is to delve into the reasons for the sinking, which is surprisingly still controversial and debated. A New York Times article published only last year, called "From Death Ship to Cruise Ship"—referring to the Stockholm—attracted an editorial response from a Swedish coauthor of a book on the collision. Mr. Bruce Paulsen wrote: . . the ship never should have sunk; she did so because of a substantial design defect."After much research done by author-survivor Pierette Simpson, who was provided with substantial data from findings of marine experts in both Italy and the United States that included members of Panel SD-7, she conducted her own inquiry, along with dialogue with divers and crew members of the Andrea Doria. This paper presents definitive conclusions on the sinking based on information from Simpson and Italian naval architects familiar with the ship's design as well as insights on a marine forensics investigation by coauthor and Chairman of Panel SD-7 William Garzke.
Application of Grey Relational Analysis to Evaluate Port Safety in Keelung Harbor
Authors: Wang Hui-Chiao , Lee Hsuan Shih
Published: January 2021

The objective of this paper is to devise a port safety analysis in a harbor. In this paper, the Grey Relational Analysis (GRA) is applied to analyze and discuss the marine casualties occurring in Keelung Harbor. GRA is mainly applied to explore the relativity between marine casualties and accident sites. The paper concludes that the coastal and in-port areas are the main accident sites. Fire or explosion and damage to machinery are the main marine casualties. The results will assist in improving port safety in Keelung Harbor.
Technical Practices of Compressed Natural Gas Fueled Ship
Authors: Yang Xu-dong , Hu Ke-xin , Yang Xu-dong , Hu Ke-xin
Published: January 2021

On July 6, 2009, the world's first commercial single compressed natural gas (CNG) fueled ship, M.V. NP Jenjosh—the first of 12 contracted vessels built in Dajiang and Hongyu shipyards located in Wuhu city of Anhui Province, P.R. China and classed to China Classification Society (CCS)—was delivered to the owner, Jenjosh Group based in Thailand. This paper contains some technical discussions that took place during the class plan review of the subject vessels, including: hull technical practices, machinery, and electrical technical practices, and also discusses designing the similar CNG fueled ships and developing the international gas-fueled (IGF) ship code in future. Finally, this paper draws conclusions and looks forward to the future practice of the CNG fueled ship.
Transforming the Shipbuilding and Ship Repair Project Environment
Authors: Dlugokecki Victoria , Fanguy Dennis , Hepinstall Lisa , Tilstrom David
Published: January 2021

In April 2008, NSRP awarded the project entitled "Customization of Web-Based Planning and Production Engineering Technologies to Support Integrated Shipyard Work Flow," a collaborative research project that included Bollinger Shipyards and Atlantic Marine-Mobil. The purpose of the project was to develop and validate a project management approach to shipbuilding and ship maintenance through the delivery of a web-based production and engineering management tool tailored to the needs of this industry along with a reliable, exportable implementation process using planning and production engineering methodologies. This project was designed to enable shipyards to achieve reduction in project costs and cycle time through project standardization and the ability to perform rapid replanning while maintaining align-ment of all project stakeholders in real time. The project enabled the shipyards to bring forth quantifiable improvement opportunities that reflected the biggest impact on project delivery. This paper shares insight into the key findings derived through this transformational body of research, as well as provide an understanding of the robust process used to implement the shipyard-specific web-based project solutions in ship-building and ship repair project environments. The paper also provides a quantification and appreciation of the resulting cost benefits experienced by each of the participating shipyards. New construction programs in each of the shipyards enabled real-time metrics to be captured, illustrating the achievement of cost reduction opportunities resulting from this project.