Steady ship motion in calm water is a classical problem in ship hydrodynamics. Potential flow modelling is a common method to predict the wave resistance of ships. In its conventional form the flow is assumed to be free from damping due to the inviscid assumption of potential flow. It has been argued by the founding fathers of ship resistance predictions that damping plays an important role in determining the wave resistance. Despite this viscosity is often omitted from present wave resistance prediction methods. It is known that damping plays an important role in the formation of the wave pattern and it is therefore of interest to determine the effect on the resistance prediction by including a damping factor in a previously undampened model. In this study, the problem is modelled using Kelvin sources with a translating speed. The fluid flow is modelled using a linearised free surface condition but an exact body condition on the hull. Rayleigh damping is introduced in the model to emulate viscous damping. To calculate the source influences, a new dissipative 3D Green function is derived. The image source part of Green function is separated into the near field and far field disturbance to achieve fast convergence of the integrals. The method is evaluated using thin ship theory to determine the wave pattern behind and the wave profile along a Wigley hull. A panel method is used to determine the wave and residual resistance for submerged ellipsoids and spheres. The results are validated and compared to existing numerical and experimental data from other sources. The results show that it may be possible to capture the residual resistance by including damping in a potential flow model but that more evaluations are needed.

Polymer composite materials are becoming increasingly popular in many engineering structures in the civil, aerospace, marine and automotive industries. The increased strength and stiffness to weight ratios which are possible with certain types of composites make them particularly attractive to many high performance applications such as military aircraft, offshore lifeboats and formula one racing cars. One aspect of composite materials which is preventing more widespread use is the perceived poor performance in fire. The perception is due to the fact that organic compounds used in polymer composites are combustible. The loss of the Norwegian Navy’s composite mine hunter vessel Orkla in 2002 to a fire did much to prevent further widespread use of such materials. The work presented here describes the research that has been conducted into assessing and predicting the performance of single skin and sandwich composite materials subjected to fire and mechanical load. The materials that were investigated were representative of the materials used in the construction of Royal National Lifeboat Institution (RNLI) lifeboats. A new method has been developed to assess the response both thermally and mechanically of single skin and sandwich panels subjected to combined fire and mechanical load. This has been done by the construction of a small scale fire and load testing apparatus. An empirical relationship was developed to predict the stiffness of single skin and sandwich panels during a fire and load test. Numerical models have also been generated to predict the thermo-mechanical response of single skin and sandwich panels to fire and load. Testing of single skin and sandwich panels on the newly developed apparatus has been conducted to verify the numerical models. The numerical models and the empirical relationship were used to predict the response of a full scale composite sandwich panel, representative of a lifeboat deck, to a standard cellulosic fire and mechanical load.

Superhydrophobic surfaces appear frequently in the natural world, for example allowing insects to respire underwater and plants, such as the lotus leaf, to have self-cleaning properties. Attempts to mimic these superhydrophobic surfaces have been successful on nano- and micro-scales, with increased effciency of water flowing through micro-channels when the walls are superhydrophobic. This thesis is focused on the proposed use of superhydrophobic surfaces to reduce drag on a much larger scale, applicable to small water craft such as canoes and yachts. The potential for drag reduction using superhydrophobic surfaces arises from the ability of such surfaces to retain an air-layer or plastron on the surface. The presence of a plastron results in slip and reduced shear at the surface, producing a drag reduction. This potential drag reduction is explored through numerical simulations and experimental testing. Computational Fluid Dynamics is used to explore the effect of slip on flow separation and viscous drag, allowing the potential drag reduction mechanisms to be explored. A range of superhydrophobic surfaces have been developed and characterised based on their roughness, contact angle and ability to retain a plastron. Confocal microscopy is used to generate the first high resolution 3D images of the air-water interface on a superhydrophobic surface over a large area. These images confirm the presence of a plastron on the surfaces and help contribute to the understanding of optimal design of superhydrophobic surfaces. These surfaces are explored experimentally in a towing tank with a repeatability of better than 1%. Refinement of the surface design leads to the presence of a plastron producing a relative drag reduction of up to 3% for hydrophobic sand, up to 10% for hydrophobic ridges and up to 15% for a hydrophobic mesh. Overall, superhydrophobic surfaces are shown to be capable of producing a relative drag reduction when a plastron is retained on the surface, although with the penalty of increased roughness-induced drag component. The drag reduction is shown to be linked to both the structure of the surface, and the quality and thickness of the plastron. It is demonstrated that it is difficult to retain a plastron over long immersion periods and manufacturing constraints currently limit applicability.

Do ponto de vista econômico, entende-se que ao mesmo tempo em que a sociedade cria as instituições, baseado no comportamento dos indivíduos, as instituições também podem ser impostas a partir das necessidades da sociedade. As instituições desempenham um papel fundamental em permitir a realização do potencial dinâmico das economias nacionais. No entanto, este é o desafio que existe por traz da estruturação de setores re-emergentes, onde os decisores políticos e as empresas têm se esforçado para criar as condições institucionais para que a indústria possa prosperar, evoluir e inovar. As instituições são capazes de ajudar a impulsionar esses esforços a partir de políticas adequadas baseadas em ciência e tecnologia e ações de mercado. Este trabalho utiliza os conceitos da teoria econômica institucional e de inovação com o objetivo de analisar os principais traços da intervenção institucional capazes de estimular a inovação. Por instituições, entende-se um conjunto de restrições, construídas pelos indivíduos, para estruturar as interações sociais (econômicas e políticas), enquanto que por inovação, entende-se uma nova combinação de fatores para atingir resultados superiores. Assim, a inovação é um constructo social, por refletir as necessidades da sociedade, e de concepção institucional por ser aceito, reconhecido e adquirido pelo mercado. Entretanto, no momento em que a inovação não surgir de forma espontânea em determinado quadro institucional faz-se necessário à criação de métodos intervencionistas para estimulá-la. A não espontaneidade da indústria pode levar a distorções, entraves e custos não previstos, por isso, a necessidade de intervenções. A recente história da re-emergente indústria naval e offshore brasileira é ilustrativa para este caso, onde se percebe uma distorção do quadro institucional a partir da criação de regras e leis que servem como filtro para o desenvolvimento do setor. A presença de um quadro institucional formalizado em demasia e a grande presença de intervenções institucionais que estimulam as ações de mercado em detrimento da ciência e tecnologia é resultado de uma desconformidade entre as normas e regras institucionalizadas. Em outras palavras, essa indústria sofre as ações do institutional stuck. / From the economic perspective, it is understood that while the society creates institutions spontaneously, based on the behavior of individuals, institutions can also be imposed by society’s needs. Institutions play a key role in enabling the realization of the dynamic potential of national economies. However, that is the challenge behind the re-emerging structuring where policy makers and firms have been struggling to create the institutional conditions to allow the industry to flourish, evolve and innovate. Institutions are able to help boost such endeavors whenever the right policies are based on science and technology and market actions. The present study uses the concepts of institutional economics theory and innovation to analyze the main features of institutional intervention capable of stimulating innovation. Institutions mean a set of constraints, built by individuals to structure social interactions (economic and political), while innovation is understood as a new combination of factors to achieve economic results. Thus, innovation is a social construct, because it reflects the needs of society, as well as an institutional concept for it has to be accepted, recognized and purchased by the market. However, when the innovation does not arise spontaneously in certain institutional board it is necessary to create interventional methods to stimulate it. The lack of spontaneity of industry can lead to distortions, barriers and unanticipated costs, so the need for interventions. The recent history of re-emerging shipbuilding and offshore in Brazil illustrates that case, where we can recognize a distortion of the institutional framework from the creation of rules and laws that serve as a filter for the industry development. The presence of an institutional board formalized in excess and the big presence of the institutional interventions that stimulate the actions of the market in detriment of the science and technology is the result of a variance between institutionalized standards and rules. In other words, this industry suffer the actions of the institutional stuck.

O progresso tecnológico e a inovação são geralmente aceitos como propulsores do desenvolvimento econômico das nações. No entanto, a compreensão quanto aos mecanismos subjacentes ao desenvolvimento ainda parece ser um desafio tanto para pesquisa quanto para a formulação de políticas públicas. Isso requer uma avaliação empírica na forma como a atividade econômica é criada e absorvida pelos diferentes agentes econômicos dando a forma e escopo da organização industrial em uma região ou setor. Tendo com base a teoria evolucionária da mudança técnica e na teoria dos custos de transação, organização industrial é definida como relações econômicas de complementaridades tecnológicas onde as firmas estabelecem interfaces tecnológicas com outras em função dos seus próprios limites. A forma com que firmas lidam com os seus próprios limites, irá determinar o potencial dinâmico da organização industrial. Está pesquisa visa responder a seguinte pergunta: o que determina a forma e o escopo da indústria e sua dinâmica subjacente? Para responder essa questão, este estudo irá analisar os recentes desenvolvimentos da Indústria da construção naval brasileira e offshore Brasileira onde, nos últimos anos, houve uma grande mobilização institucional para viabilizar o catch-up de tecnologia e competitividade no setor. O cenário recente de construção e ampliação de capacidades das empresas em uma indústria complexa permite observar a dinâmica da organização industrial por meio da análise das interfaces tecnológicas. A pesquisa traz uma revisão da dinâmica e evolução da indústria naval nos principais polos produtores do mundo e, posteriormente, parte para a análise detalhada do desenvolvimento de da indústria no Brasil através da descrição do conjunto de interfaces tecnológicas e relações industriais inerentes ao arranjo de um grande estaleiro. Os resultados mostram que, apesar da elaboração de políticas que visam favorecer o desenvolvimento do setor, a indústria depende da capacidade dos diversos agentes econômicos absorverem os conhecimentos necessários e dar coesão às interfaces tecnológicas. Paradoxalmente, precede à geração de uma dinâmica industrial, buscar dar estabilidade às interfaces tecnológicas com o intuito de acelerar o processo de aprendizagem. Isso depende da integração dos diferentes atores envolvidos. Embora o estaleiro analisado detenha os ativos específicos que denotam um potencial competitivo, o mesmo busca superar os limites de conhecimento por meio da intensificação de transferência de tecnologia que lhe permita utilizar as tecnologias e, principalmente, dar fluxos e rotinas necessárias para operar de forma mais eficiente. Apesar do ambiente institucional favorável que deu origem ao ressurgimento do setor, a janela de oportunidade criada pelas instituições é limitada. Portanto, o setor precisa encontrar maneiras de aprender mais rápido, porém é preciso escolher mecanismos que economizem nos custos de construção de capacidades. Dado os limites das capacidades das empresas brasileiras, mecanismos de transferência de tecnologia parecem ser uma das principais estratégias para reduzir esses custos. / Technological progress and Innovation are generally accepted as the fundamental phenomenon of economic development of nations. However, understanding the underlying mechanisms behind 'development' still seems to be a challenge. This requires an empirical assessment into the way economic activity is created and distributed across firms and markets giving the shape and scope of industrial organization. Drawing on evolutionary and transaction costs, industrial organization is defined as economic relations of technological complementarities where bounded capabilities connect through technological interfaces. The way firms and markets deal with their capability boundedness will determine the dynamic potential that can be generated in the economic system. This research begins by asking what determines shape and scope of industries and its underlying dynamics? In order to address this question, this thesis will analyze the recent developments of the Brazilian Shipbuilding and Offshore Industry where government has put in place an entire institutional arrangement to boost industrial/market competitiveness and technological catch-up in the hopes of generating economic development. The scenario of a re-emerging complex sector where the capabilities of firms are under construction, allows the examination of the dynamics behind the organization of the industry through the analysis the different technological interfaces involved. The research begins by first analyzing the evolution and dynamics of the shipbuilding sector worldwide and later, it explores the recent shape, scope and dynamics of the Brazilian Shipbuilding Industry by assessing, describing and analyzing the set of technological interfaces and bounded capabilities found at one shipyard. Results show that despite of the policies designed to promote the development of the sector, the industry depends on the ability of the various economic agents absorb the necessary knowledge and give cohesion to technological interfaces. Paradoxically, project stability seems to precede industrial dynamics in order to accelerate learning process and effectively succeed in catching-up. It depends on the internal and external integration of the different actors involved. While the analyzed site has current specific assets that denote a competitive potential, it sought to overcome the limits of knowledge through the intensification of technology transfer. Instability at the interfaces play against learning. This is increasingly improving through the intensification of knowledge transfer with the international partner. Despite the favorable institutional environment intended to provide the industry with some time to catch up, the window of opportunity created by it may not be long enough. Therefore, the industry needs to find a way to learn faster. Technological transfer mechanisms should be used to reduce the costs of building capabilities.

Este trabalho tem como objetivo analisar a relação entre a Base Industrial de Defesa (BID) e o Desenvolvimento Econômico nacional no contexto das Relações Internacionais. Em relação ao campo de Estudos Estratégicos e Relações Internacionais, aborda-se o debate entre os teóricos da Revolução em Assuntos Militares (caráter disruptivo das inovações tecnológicas e militares) e os advogados das Gerações da Guerra (caráter evolutivo das inovações tecnológicas e militares), suas decorrências para a análise do Poder Naval, para a polaridade do Sistema Internacional e para a inserção internacional dos países. Após a análise dos principais autores e teorias que abordam a existência de uma sinergia entre esses aspectos da realidade, adotou-se como estudos de caso a indústria naval civil e militar na China e no Brasil, de forma a averiguar tendências e indicadores que corroborem, ou não, as teorias supracitadas. Conclui-se que há de fato possibilidades de sinergia entre a BID e o desenvolvimento econômico, o que pode ser inferido pelos casos estudados. Entretanto, o modelo de desenvolvimento escolhido, os Arranjos Institucionais entre Estado, setor privado e terceiro setor, e as parcerias estratégicas internacionais variam entre os países, gerando resultados diferenciados quanto à modernização tecnológica e à ampliação da escala produtiva. Neste sentido, os conceitos de Sistema Nacional de Inovação (SNI), Clusters, Complexo Militar-Industrial e Cooperação Técnica Internacional auxiliam na análise dos aspectos auxiliares da sinergia entre a BID e a estratégia de desenvolvimento. / This study aims to analyze the relationship between the Defence Industrial Base (DIB) and the Economic Development in the context of International Relations. Concerning the Strategic Studies and International Relations fields, it aproaches the debate between the Revolution on Military Affairs (disruptive aspects of technological and military innovations) and the proponents of the generations of warfare (evolutionary character of technological and military innovations) and its consequences for naval power analysis, for the polarity of the international system, and for foreign policy. After the analysis of the main authors and theories that approach the synergy between these aspects, two case studies were adopted to verify trends and indicators that could corroborate or not the aforementioned theories: China’s and Brazil’s civilian and military shipbuilding. The findings of this exercise is that there are possible synergies between the DIB and Economic Development, which can be inferred from the case studies. However, the development model, the institutional arrangements between State, the private sector, the third sector, and the International Strategic Partnerships vary between countries, generating different results for the technological modernization and scale of production. In this sense, the concepts of National Innovation System (NIS), Clusters, Military-Industrial Complex and International Technical Cooperation assist in the analysis of the management aspects of synergy between DIB and the Development Strategy.

O processo de soldagem no estado sólido Soldagem por Fricção e Mistura Mecânica (SFMM), tradução do original em inglês ¨Friction Stir Welding¨ (FSW), já foi estudado extensivamente e obteve resultados muito bem sucedidos em ligas de Alumínio. Especificamente para ligas de aplicação naval existe uma lacuna muito grande de conhecimento. Este trabalho tem por objetivo caracterizar e analisar juntas soldadas da liga de aço naval GL E36 através de SFMM. A espessura das chapas soldadas foi de 6 mm em junta de topo com ferramenta de Nitreto de Boro Cúbico Policristalino (NBcp). A velocidade de rotação da ferramenta foi mantida constante em 500 rpm e foram usadas velocidade lineares de 1, 2 e 3 mm/s objetivando-se diferentes aportes térmicos. Foram obtidas soldas de 1,2 metros de comprimento com características estéticas muito boas e homogêneas na superfície ao longo do comprimento das juntas. Todas as juntas foram produzidas com aquisição dos ciclos térmicos através de termopares colocados próximos a região da face da solda em diferentes posições no início, meio e final da solda. A ferramenta, mesmo após aproximadamente 8,5 metros de soldas, apresentou um bom comportamento ao desgaste sem perdas apreciáveis nas dimensões do pino. Para avaliação das propriedades das juntas foram retirados corpos de prova para análise microestrutural e de microdureza, ensaio de tração e dobramento, no início, meio e final da solda. Adicionalmente, foi usado ensaio radiográfico para detecção de defeitos e possíveis fragmentos da ferramenta proveniente de desgaste. E para a análise do comportamento da tenacidade à fratura foi usado o corpo de prova do tipo ¨compact tension¨ (CT-50) posicionado com a boca do entalhe na região da zona de mistura da solda. Todas as amostras de tração romperam no material de base. Os perfis de microdureza mostraram picos de até 400 Vickers para todas as juntas. A microestrutura consistiu principalmente de ferrita, martensita e bainita com diferentes níveis de refinamento e diferentes morfologias. Os melhores comportamentos em relação a tenacidade à fratura avaliados por meio da construção das curvas de resistência foram das juntas processadas com 2 mm/s e 3 mm/s. / The solid state welding process Friction Stir Welding (FSW) has been studied extensively and achieved very successful results on aluminum alloys. Nevertheless, to apply FSW on steel alloys more research is required. Specifically for steel grades for shipbuilding applications there is a wide knowledge gap. Thus, this work aims to evaluate the mechanical and microstructural properties of processed joints for the shipbuilding steel grade GL E36 using FSW. The weld plate thickness used was 6 mm using butt joint configuration with polycrystalline cubic boron nitride (pcBN) tool. The rotational speed of the tool was kept constant at 500 rpm with welding speeds of 1, 2 and 3 mm/s seeking to achieve different heat inputs, i.e., different mechanical and metallurgical properties. Joints of 1.2 meters long with very good aesthetic features and homogenous surface along the length were obtained, proving the stability of the process. Thermal profile of all joints were taken using thermocouples placed near the joint region of the weld face at different positions: beginning, middle and ending of the weld. The tool even after approximately 8.5 meters of welds showed good wear behavior without appreciable loss on the dimensions of the probe. To evaluate the joint behavior, specimens for microstructural analysis and hardness, tensile test and bending were removed at the beginning, middle and ending of the weld. Additionally, radiographic test was used for defects inspection and detection of possible debris from tool wear. For the analysis of the fracture toughness behavior was used Compact Tension (CT-50) specimens positioned with the notch at the stirred zone. All tensile samples failed at the base material, i.e. the produced joints achieved a greater resistance than the base material after processing. The microhardness profiles showed peaks of up to 400 Vickers for all the conditions. The microstructure found consisted mainly of ferrite, martensite and bainite with different levels of refinement and different morphologies. The best behavior concerning the fracture toughness evaluation using the crack resistance curves were for the joints processed with 2 mm/s and 3 mm/s of welding speeds.

A competição atualmente vivida pelas organizações tem despertado o interesse em desenvolver formas de superar a concorrência e com isso, prosperar no mercado. Uma das formas de superar a concorrência é gerir os custos de forma estratégica para que seja possível superar a concorrência. A gestão estratégica de custos tem por finalidade ampliar os horizontes da análise de custos, ou seja, ela visa cobrir as deficiências existentes nos sistemas tradicionais de custeio, pois em sua análise irá considerar a cadeia de valor como um todo e não somente os processos internos em que há agregação de valor por parte da empresa. Assim, o objetivo da presente pesquisa foi investigar as características dos sistemas de custos e como as empresas da indústria de construção naval do Estado do Rio de Janeiro estão utilizando informações de custos para dar suporte à gestão estratégica, procurando investigar aspectos relativos a esta prática; assim, tem-se como propósito verificar a aplicação da teoria no setor. Para isso, foram realizados estudos casos em cinco empresas da indústria de construção naval, as empresas estudadas, constituem uma amostra não probabilística, ou seja, amostra por acessibilidade. O estudo constatou que mesmo às empresas não utilizando o método de custeio recomendando pela literatura, é dada uma especial atenção nas transações ocorridas ao longo da cadeia de valor, o que permite gerir os custos de maneira eficiente. Isso mostra a proximidade de diversas ações tomadas pelas empresas estudadas e a literatura sobre gestão estratégica de custos / The competition currently experienced by organizations has raised interest in developing ways to overcome the competition and consequently thrive in the marketplace. One way to overcome the competition is to manage costs strategically to the company can overcome your competitors. The strategic cost management aims to broaden the horizons of cost analysis, in other words, it is intended to overcome the deficiencies in traditional costing systems, because in his analysis will consider the value chain as a whole and not only internal processes where there is added value for the company. Therefore, the objective of this research was to investigate the characteristics of cost systems of shipbuilding industry in Rio de Janeiro and how these companies are using cost information to support strategic management, seeking to investigate aspects of this practice; thus, this article aims to verify the application of theory in the sector. For this, studies were performed in five cases of companies shipbuilding industry, the companies studied are a non-probabilistic sample, in other words, sample accessibility. The study found that even companies not using the cost method recommended by the literature, they give a special attention to transactions occurring along the value chain, which allows companies to manage costs efficiently. This shows the proximity of several actions taken by the companies studied and the literature on strategic cost management

The constantly increasing complexity of marine and offshore machinery is a consequence of a constant improvement in ship powering, automation, specialisation in cargo transport, new ship types, as well as an effort to make the sea transport more economic. Therefore, the criteria of reliability, availability and maintainability have become very important factors in the process of marine machinery design, operation and maintenance. An important finding from the literature exposed that failure to marine machinery can cause both direct and indirect economic damage with a long-term financial consequence. Notably, many cases of machinery failures reported in databases were as a result of near misses and incidents which are potential accident indicators. Moreover, experience has shown that modelling of past accident events and scenarios can provide insights into how a machinery failure can be subsisted even if it is not avoidable, also a basis for risk analysis of the machinery in order to reveal its vulnerabilities. This research investigates the following modelling approach in order to improve the efficiency of marine and offshore machinery operating under highly uncertain environment. Firstly, this study makes full use of evidential reasoning’s advantage to propose a novel fuzzy evidential reasoning sensitivity analysis method (FER-SAM) to facilitate the assessment of operational uncertainties (trend analysis, family analysis, environmental analysis, design analysis, and human reliability analysis) in ship cranes. Secondly, a fuzzy rule based sensitivity analysis methodology is proposed as a maintenance prediction model for oil-wetted gearbox and bearing with emphasis on ship cranes by formulating a fuzzy logic box (diagnostic table), which provides the ship crane operators with a means to predict possible impending failure without having to dismantle the crane. Thirdly, experience has shown that it is not financially possible to employ all the suggested maintenance strategies in the literature. Thus, this study proposed a fuzzy TOPSIS approach that can help the maintenance engineers to select appropriate strategies aimed at enhancing the performance of the marine and offshore machinery. Finally, the developed models are integrated in order to facilitate a generic planned maintenance framework for robust improvement and management, especially in situations where conventional planned maintenance techniques cannot be implemented with confidence due to data deficiency.

No description available.