Ship Parts Research Articles

Finding Scepter: assessing European influences in early Swedish shipbuilding and evaluating new excavation techniques

In 2017 the Swedish National Maritime and Transport Museums were commissioned to monitor the excavation at the old shipyard at Skeppsholmen’s quay in Stockholm in case remains were revealed. The shipyard was the biggest workplace in the 17th century. During the excavation a careening dock that was used for the maintenance and repair of large naval ships was first found. It was made of a large number of huge piles. The piles were pulled up and massive ship parts appeared beneath. It turned out to be a large shipwreck in oak. Due to the short time available we tried a new technique. We used a powerful suction digger so as not to damage the roots of trees during excavations. The suction digger helped us to remove the fill material very smoothly and quickly. With this method we managed to uncover large parts of the starboard side. A great number of dendro-samples were taken and it was also possible to conduct detailed archaeological documentation.The identification of the Scepter was made with the support of archaeological observations and dendrochronological samples, confirmed by archival documents. With these results we could see that this ship was indeed the first flagship of King Gustav II Adolf. The ship had a long and exciting history that now could be revealed.This is a fine example of how salvage archaeology together with new techniques can give us new information and great history that was once forgotten.

Study influence factors of the spraying process on the properties of electric arc spraying coatings

The paper considers possibilities to increase the wear resistance, corrosion resistance, and service life for parts machines and mechanisms via their hardening and renovating using electric arc coatings characterized by high density, adhesion strength, and micro hardness thanks to activation of the spraying process. Also, the possibility of controlling the properties of restored surfaces owing to choice of the related equipment with required structure and characteristics in order to prolong the service life of machinery parts is shown. The right choice of equipment for spraying makes it possible to increase the speed and temperature of the spraying gas and particles, reduce the droplet diameter, increase the density and reduce the oxidation of coatings. The influence of spray factors such as the flow rate and pressure of working gases, composition of combustion mixture, spraying distance, dispersion of the spray, properties of wire material, etc. on the properties of the coatings obtained has been investigated. The possibility of controlling the properties of surfaces owing to choice with required characteristics electric arc coatings is shown. The influence of spray factors such as the flow rate and pressure of working gases, composition of combustion mixture, spraying distance, dispersion of the spray, properties of wire material, etc. on the properties of the coatings obtained has been investigated. The use of coatings makes it possible to increase the wear and corrosion resistance of working surfaces of machine parts and mechanisms, in particular ship parts, and so to reduce the costs of alloyed steels and alloys. The coatings application is associated with implementation of a fundamentally new approach, according to which the strength and carrying capacity of a part is provided by its basic material, whereas the resistance to corrosion, wear, and other factors may be increased via using hardening protective coatings. There are many alternative methods for producing coatings, from which it is advisable to choose an optimal, easy to implement, and inexpensive one. Of the variety of methods for hardening coating deposition, the most common technologies used to restore and improve the performance properties of parts are gas-thermal spraying techniques, among which the cheapest and simplest method is electric arc spraying (EAS), whose current improvement is aimed at modifying and activating the spraying process. Such combined technologies do not require additional expensive equipment and operations, which predetermines a reduction in the cost of hardening processes.

Wreckage recycled. Salvage auctions and their economic impact in eighteenth century Sweden

ABSTRACT In 1729, the privately owned Diving and Salvage Company gained a national monopoly for sea salvage in the Swedish Realm, a position it held until 1803. The Company sold all salvaged ships and goods in public auctions, creating a lively salvage market in Swedish and Finnish port towns. In this article, I examine these auctions and their economic impact in two towns, Visby and Helsinki. Via effective organisation and skilful advertising, the Company was able to sell large quantities of salvaged ships, ship parts, and cargo to a large pool of buyers. The auctions had large economic impact and were an especially important factor in the late eighteenth century rise of shipping and shipbuilding in both Helsinki and Visby. The local merchants controlled the auctions and bought all ship material in bulk, recycling it to the new-built ships in their dockyards.

A review on navy ship parts by advanced composite material

Composite materials are now used throughout the marine industry but their susceptibility to impact events is still an unresolved problem. There is a huge body of work in the area, succinctly summarised here, but the great majority concerns impact events and composite materials more relevant to the marine industry. A discussion of the complexity of the problem in terms of damage and dependence on the many material and impact event parameters shows why there is a need for a review of work specifically considering ‘impact on marine composites’ due to the distinctive impact events and materials of marine applications. Marine impact scenarios are discussed and comparisons between composite and other construction methods made. Together with parts II and III, this paper gives a comprehensive review of ‘marine impact on marine composites’, providing a valuable resource for the marine industry and research fields. The review paper is an attempt of popular navy ship and the major parts of navy ship overview of composite materials.

Underwater radiated noise model of marine object

The paper is devoted to the developing a comprehensive model for underwater radiated noise of marine object in order to model and simulate sonar systems. Many works present underwater radiated noise models, but as a rule, they consider either one of the noise components in order to develop algorithms for the corresponding sonar operation mode, or one of the noise sources in order to design ship parts and assemblies. This paper combines several noise models of marine objects considering additional factors that were not taken into account in these models. The obtained comprehensive model is under verification phase, but its application will significantly expand the possibilities for developing and synthesizing classification and tracking algorithms of sonar system

Designators, descriptions, and artifact persistence

Hobbes' (1672/1913) famous puzzle of the Ship of Theseus – in which a wooden ship's parts are replaced plank by plank, and the old planks are subsequently reassembled to create a second ship – has been the source of debate about the criteria that underlie human judgments of individual artifact persistence. This puzzle has led some philosophers to the paradoxical conclusion that an artifact observed at one time is the same persisting individual as two artifacts seen at a later time. We argue that prior discussions of the puzzle have conflated property persistence (judged in conjunction with a description, like “Theseus' ship”) with individual persistence (judged in conjunction with a designator, like “X”). In three studies, we manipulated the linguistic expression (description, designator) used to label the original object in the puzzle. When participants solved the puzzle in conjunction with a description, they gave systematically high ratings to any object (either or both) that could be inferred to match the description. Yet when participants solved the same puzzle in conjunction with a designator, they gave significantly higher ratings to one post-change object (the object made of the reassembled old parts) than to the other post-change object (the object made of replacement parts). The results suggest that individual persistence judgments concerning the puzzle (i.e., those made in conjunction with a designating expression) are not paradoxical but rather are based on the continuity of the object's parts/material.

Celebrating 45 years of ACS Public Policy Fellows

Legend has it that generations of foresters employed by the University of Oxford tended forests of oak trees so that a supply of suitable lumber would be available when New College’s dining hall, built in 1379, needed to replace its 14 m ceiling beams centuries later. Sixteenth-century Basque shipbuilders pruned trees in northern Spain so that the branches would grow into the proper angles required for ship parts that would be cut 150 years later. Today, such long-term planning seems, well, the stuff of legends. But a similar spirit of foresight and commitment to the future must have been present in 1974, when the American Chemical Society Board of Directors started an effort to provide scientific expertise and advice to government policy makers by supporting ACS members to work in Congress. More than 4 decades later, the ACS Public Policy Fellowship Programs have proved to be an especially long-sighted effort

Vendor-managed inventory as data interchange strategy in the networked collaboration of a Vietnam ship parts supplier and its customers

ABSTRACTThis research paper explores through a single case study the networked data interchange strategy in supply chain collaboration of an anonymized company in a developing region, hereafter called Ship Parts (SP) Vietnam, a pipes and valves supplier for the shipbuilding industry. Our research applies descriptive analysis approach to examine the question: what are the strategic and technological considerations for information exchange in the various customer collaboration practices in management of the supply chain as networked collaborative relationships? We discuss the role of Electronic Data Interchange exhibited as the practice of Vendor-Managed Inventory (VMI) in the case relationships. The names of all key stakeholders in this study are anonymized. We investigate the effects of the IT strategy of SP Vietnam on the social and economic business relationship developed with its customers. An important finding of this case study of networked customer relationships is that they vary in relation to how they practice the logistics of customer supplies. VMI is revealed as enabled by maturing relationships. Achieving quality collaboration is likewise dependent on learning through the customer relationship.

天然树木和竹子纤维材料的力学性能及仿生研究进展

Natural bio-fiber composites have the characteristics of simple elements and sophisticated structure, superior mechanical properties of high strength, high toughness and low coefficient of friction, and are the inspirational sources for the design of new materials. Biomimetic fiber composites have been widely used in modern industry. At present, studies of learning from the natural biological material structure-functional characteristics to manufacturing biomimetic structure—Functional integration material have originated lots of results, such as imitating wood porous ceramic material, imitating shell multi-layer composite materials and imitating bone porous scaffolds, etc. However, a lot of problems still exist, such as fiber is brittle and easy to be pulled out, the size selection of the whisker is difficult, the choice of ceramic matrix composite toughening methods is difficult, etc. To guide advanced biomimetic materials designs, it is important to reveal the relationships between the distribution, angle and density of cellulose, structure and binding mode of interface and the mechanical and frictional properties of the biological fiber composites. Wood and bamboo are the most common natural biological fiber composites which have excellent mechanical properties. They have been widely used in a variety of traditional architectural and ship parts. In this manuscript, recent researches on the mechanical properties of the wood and bamboo as the typical representatives of the natural biological fiber composites have been reviewed. The biomimetic composites of natural fiber materials have been briefly summarized. This tentative review might provide a reference for the design and preparation of biomimetic high strength, wear-resistant fiber composites. Trees and bamboo with excellent tribological properties relies not only on its internal structure, but also on its biological activity. If purely from a mechanical point of view to achieve the purpose of the bionic, it is difficult to obtain satisfactory results. Modern fiber composites in the rapid development process, often there is a big fiber brittle, difficult to interface design, easy to pull the fibers lead to enhanced failure whisker size selection difficult to choose the difficulty of ceramic matrix composites toughened approach the problem. Therefore, the application of bionic fiber reinforced composites toughened functional design principle, simulate biological fiber composite materials and structures excellent interface characteristics, is expected to further address the interface of chemical and physical properties of stability and strength of fiber composites tough problem, has important academic significance and application value.

수치 실험을 통한 조선 강판 전용 Nesting Algorithm의 적합도 함수의 결정

In this paper, a research on the composition of the nesting algorithm fitness function is carried out by performing various numerical experiments to inspect how it affects the scrap efficiency, allocation characteristics, and time consumption, targeting the nesting results of ship parts. This paper specifically concentrates on a method to minimize the scrap ratio and efficiently use the well-defined remnants of a raw plate after the nesting process for the remnant nesting. Therefore, experiments for various ship parts are carried out with the weighting factor method, one of the multi-objective optimum design methods. Using various weighting factor sets, the nesting results are evaluated in accordance with the above purposes and compared with each set for each ship part groups. Consequently, it is suggested that the nesting algorithm fitness function should be constructed differently depending on the characteristics of the parts and the needs of the users.

Research on Ship Part Nesting System Based on Energy Principle and Intelligent Optimization

A nesting system based on minimum potential energy principle and intelligent optimization for ship part nesting problem was proposed. Discussing polygon judgment and separation, intersection test and collision problems of ship parts, a kind of polygon overlap detection method was put forward, and contacting process was analyzed by use of envelope rectangle intersection test algorithm; During analyzing ship part nesting process based on minimum potential energy principle and genetic algorithm fusion, basic physical meaning of nesting problem was explained from mechanics. Throng intelligent ship part nesting system verification, the algorithm is feasible, physical meaning is clear; it can realize ship part nesting.

An efficient nesting algorithm recognizing the placing area

Automatic nesting acting as a CAM system in the shipbuilding industry has more constraints any other field nesting such as automobile, clothes and shoes. The nesting software has a large influence on the productivity of the shipbuilding industry while it is equipped with useful functions: automated operation system, user friendly interface, generation of stable cutting data and draft, and synchronization with ERP system. Many algorithms have been developed to decrease the scrap ratio and to increase the utilization of metal sheet plate. However, the satisfaction respecting to the minimization of computational time and scrap is not fulfilled yet. This study presents an attractive nesting algorithm to identify the scrap by defining the attributes while the ship parts are arranged by two-step method: the bitmap-based arrangement squeezes the part to the leftbottom side of the plate. Secondly, the re-arrangement step is carried out to further decrease the scrap while an overlap between parts is allowed and released by moving the previously placed parts. To increase the computational efficiency in the second step, the attributes of sub areas are used. The proposed method is validated using actual ship parts.

Ship part nesting by pattern recognition and group arrangement

The automatic nesting for a computer-aided manufacturing (CAM) system in shipbuilding industry requires more constraints than in other fields such as automobile, clothes and shoes. The nesting software has more influence on the productivity of shipbuilding industry, being equipped with such functions as automated operation, user-friendly interface, generation of stable cutting data and draft, and synchronization with enterprise resource planning (ERP). Many algorithms have been developed to increase the utilization rates of sheet metal plates and decrease scrap ratios. However, the minimization of the computational time and scrap ratio has not been fulfilled yet because of inherent constraints in nesting processes. To increase the efficiency of the part nesting in shipbuilding industry, this study presents pattern recognition and group arrangement method. The form features of ship parts are recognized and classified into pre-defined patterns by using the ray projection method. Then, the parts are grouped based on grouping rules. The proposed method has been validated with actual ship parts.

Research on Ship Parts Nesting with Immune Ant Colony Algorithm

A kind of method with immune ant colony algorithm (IACA) was applied for ship parts nesting problems. Graphics coding and pretreatment method of ship parts were proposed. A method of combination and filling transformed ship parts nesting problem into orthogonal rectangular nesting problem. An automatic nesting system was realized by use of remaining rectangular matching method and orthogonal approach grafting algorithm. A specific example was given according to the proposed algorithm, the nesting results prove that it is feasible for ship parts optimization nesting problem with IACA.

Application of a photogrammetry-based system to measure and re-engineer ship hulls and ship parts: An industrial practices-based report

In this paper, an industrial application of CAD is presented, which concerns the measurement and re-engineering of the shape of a complete ship hull and of ship’s parts, which is a frequently recurring task in the shipbuilding and ship repair sector. In order to choose the most appropriate measurement method, several typical aspects of our object of measurement, such as its size, possible obstructions and poor accessibility, have to be taken into consideration, and we concluded that photogrammetry would be the most flexible method. One of the considerations in this respect was that with photogrammetry not only the 3D geometry can be measured, but that also topological properties will implicitly be taken into account, thanks to the fact that a human is interpreting and processing the photos. So a re-engineering system was developed, which consists of two major parts: the shape processing software and the photogrammetric measurement, which are tightly coupled. This system has proved to work fine for large-scale 3D objects, however, additionally, from the ship repair practice the question arose for the measurement of flat construction elements. For this purpose, an alternative and much simpler system was developed, strictly aimed at the measurement and further processing of flat steel parts. For both methods, the practical applications and best practices are presented and discussed, and a tentative economical evaluation has been composed which shows that the proposed method is cost-effective. Finally, the general conclusion is drawn that the proposed photogrammetry-based system is quite versatile and applicable, although there are also points of concern or attention, such as the required space around the object, the aspect of sufficient light and visibility, camera calibration and the required skills of the users. The proposed method could benefit from further research in areas such as the optimal placement of a minimum number of landmarks and integration of laser-sensing and photogrammetry.

A code-based approach for labeling in complex irregular regions

Labeling information in a complex irregular region is a useful procedure occurring frequently in sheet metal and the furniture industry which will be beneficial in parts management. A fast code-based labeler (FCBL) is proposed to accomplish this objective in this paper. The region is first discretized, and then encoded by the Freeman encoding technique for providing the 2D regional information by 1D codes with redundancies omitted. We enhance the encoding scheme to make it more suitable for our complex problem. Based on the codes, searching algorithms are designed and can be extended with customized constraints. In addition, by introducing a smart optimal direction estimation, the labeling speed and accuracy of FCBL are significantly improved. Experiments with a large range of real data gained from industrial factories demonstrate the stability and millisecond-level speed of FCBL. The proposed method has been integrated into a shipbuilding CAD system, and plays a very important role in ship parts labeling process.

Review of test methods for zero PPM performance

PurposeMarket demands, especially within the automotive sector, are pushing towards increased product complexity and performance with zero ship parts per million (PPM) requirements. To achieve both quality and performance goals very stringent requirements are being placed on the test manufacturing solution. These requirements lead to conflicts between cost, performance and quality. The purpose of this paper is twofold: first, to investigate the conflicts that exist between quality, performance, and cost, and second, to review current practices and techniques being used in tests to minimise ship PPM.Design/methodology/approachIn the paper a test process development flow chart is presented, along with a review of current methods being used for both defect screening and performance testing. The relationship between test coverage and ship PPM is investigated using established yield models. The cost in terms of gross margin degradation of yield loss at final test to extensive screening and aggressive limits is modelled.FindingsThe paper finds that to maintain ship PPM very high levels of test coverage are required – typically test coverage needs to be > 98 per cent. The cost of yield loss to this testing typically matches on a percentage point basis gross margin degradation. Reviewing current test methods shows the need both for extensive defect‐screening techniques for the defective portion of the population, and for optimised guardbanding techniques for performance testing. Weaknesses that exist are the absence of a model to predict outgoing PPM, and the conservative nature of existing guardband techniques for performance testing.Originality/valueThis is a review paper and it serves to highlight both the weaknesses in current practices, and areas where improved models are required.

Connecting the Dots Parametrically: An Alternative to Cubic Splines

Click to increase image sizeClick to decrease image size Additional informationNotes on contributorsWilbur J. HildebrandW. J. Hildebrand received his B.S. degree from Shippensburg University, his master's degree from Indiana University, and his D.Ed. in mathematics from Penn State University. He is presently a professor of mathematics and computer science at the Germantown, Maryland campus of Montgomery College. Prior to joining the Montgomery College faculty, he served on the mathematics faculties of Penn State University and the U.S. Naval Academy. He has also worked as a mathematician for the Computing Laboratory at Aberdeen Proving Ground, Maryland; the Electronic Data Processing Division of the Ship's Parts Control Center at Mechanicsburg, Pennsylvania; and IIT Research Institute's Electromagnetic Compatibility Analysis Center at Annapolis, Maryland.

The Nesting and Marking of Ship Parts Cut from Steel Plate

The methods presently used by U.S. shipbuilders for preparing, nesting and marking plate parts are discussed. The use of existing computer technology is explored as a means for improving these operations by conserving plate and reducing operating costs. Appendices are included which list the advantages and disadvantages of both the oxy-flame and plasma cutting processes, the use of special sized plate in hull construction, and the basic features of a computerized parts nesting system.