A gestão da Cadeia de Suprimentos (SCM) é hoje parte essencial do nosso dia a dia. Ela tem uma influência crescente sobre um grande número de atividades humanas e econômicas e, portanto, é um assunto crítico para a indústria e para a academia. Existe a necessidade de se entender como as pessoas podem ajudar no sucesso da Cadeia de Suprimentos. No entanto, há uma escassez de investigações empíricas das contribuições das variáveis humanas, em especial a cultura, para a Integração da Cadeia de Suprimentos (SCI). Este trabalho tem por objetivo investigar as relações entre as dimensões culturais e a SCI por meio de um estudo de caso exploratório em uma empresa do setor aeronáutico brasileiro. Estabeleceram-se considerações teóricas que determinadas práticas organizacionais contribuiriam para a maior integração de uma Cadeia de Suprimentos genérica (orientação a resultado, orientação a funcionário, sistema aberto, controle frouxo de trabalho, profissionalismo e pragmatismo) o que foi constatado na investigação empírica. Além disso, levou-se em conta a influência da cultura brasileira sobre as práticas organizacionais, de forma que a alta distância do poder e alta aversão à incerteza, por exemplo, dificultariam a orientação a resultado e de sistema aberto, enquanto o alto coletivismo e a relativa feminilidade facilitariam a orientação a funcionário e controle de trabalho frouxo. Este trabalho contribui para propor novas perspectivas e insights que possam levar ao aprofundamento dos estudos das relações entre a cultura e a Cadeia de Suprimentos, além da consideração de aspectos culturais locais no estudo das práticas gerenciais. / The Supply Chain management (SCM) is an essential part of our daily lives. It has a growing influence on a large number of human and economic activities and therefore is a critical issue for the industry and the academy. There is a need to understand how people can help the effectiveness of Supply Chain, however, there is a lack of empirical investigations of the human variables contributions, especially culture, for the Supply Chain Integration (SCI). This work aims to investigate the relations between cultural dimensions and SCI through an exploratory case study in a company in the aeronautical industry. Theoretical considerations were settled in which certain organizational practices contribute to the further integration of a generic Supply Chain (result orientation, employee orientation, open system, loose work control, professionalism and pragmatism) which was corroborated in the empirical research. In addition, we took into account the influence of Brazilian culture on organizational practices so that high power distance and high uncertainty avoidance, for example, hinder the results orientation and an open system, while the high collectivism and the relative femininity facilitate the employee orientation and the loose work control. This work contributes to propose new perspectives and insights that may lead to deeper studies of the relationship between culture and the Supply Chain, beyond the consideration of local cultural aspects in the study of management practices.

O trabalho visou realizar um estudo sobre o comportamento mecânico e de inflamabilidade de estruturas aeronáuticas de interior fabricadas a partir de compósitos reforçados por fibras naturais, especificamente compósitos de resina fenólica com fibras de algodão e de sisal, verificando assim, a possibilidade de substituir compósitos sintéticos. Num primeiro momento, análises experimentais foram executadas para determinar as propriedades mecânicas dos materiais. Em seguida, análises computacionais foram realizadas, empregando as propriedades referentes aos compósitos sintéticos e reforçados por fibras naturais, utilizando critérios de falha e tendo como referência o desempenho do compósito sintético para uma dada estrutura aeronáutica de interior. Além disso, foram efetuadas análises do seu comportamento quanto à inflamabilidade. A incorporação de retardantes de chama foi necessária para que os compósitos reforçados por fibras naturais atendessem aos requisitos de certificação aeronáutica. Após o processo de aditivação, observou-se um aumento do módulo de elasticidade à flexão (55% para o compósito de algodão, 16% para o compósito de sisal) e a diminuição da tensão de ruptura à flexão dos compósitos reforçados por fibras naturais analisados (45% para o compósito de algodão, 55% para o compósito de sisal). No entanto, com o aumento da espessura da estrutura aeronáutica adotada (5,2% para o compósito de algodão, 10,7% para o compósito de sisal), conclui-se que a substituição do compósito sintético pelo natural seria viável. Isto acarretaria em um aumento de massa em 6,2%, caso a estrutura fosse fabricada em compósito reforçado por fibra de sisal. Finalmente, constatou-se que a fração mássica de aditivo utilizada tem grande potencial de otimização e, que a eficiência dos compósitos reforçados por fibras naturais ainda pode ser melhorada. / This dissertation has aimed to study the mechanical behavior and the flammability of aeronautical interior structures manufactured from composites reinforced by natural fibers, specifically phenolic resin and cotton and sisal fibers composites, verifying the possibility of synthetic composites replacement. Firstly, experimental analyses were performed to determine the mechanical properties of the materials. Then, computational analyses were carried out, using properties of synthetic composites and composites reinforced by natural fibers. Also, failure criteria were applied, considering the synthetic composite performance of an interior aeronautical structure as reference. Furthermore, the behavior regarding flammability was analyzed. The addition of flame retardants was necessary for the composites reinforced by natural fibers in order to attend the aeronautical certification requirements. After the addition of flame retardants, an increase in the flexural modulus of elasticity (55% for the cotton composite, 16% for the sisal composite) and a decrease in the flexural stress at break (45% for the cotton composite, 55% for the sisal composite) were observed. However, with an increase of the thickness of the aeronautical structure (5.2% for the cotton composite, 10.7% for the sisal composite), it was concluded that the replacement would be feasible, which would lead to a increase of the mass equal 6.2% for the sisal fiber composite. Finally, it was evidenced that the used flame retardant mass fraction has a great potential for optimization and that the natural composites efficiency can be improved.

Orientador: Fernando Sarti / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Economia / Made available in DSpace on 2018-08-14T17:49:29Z (GMT). No. of bitstreams: 1 Ferreira_MarcosJoseBarbieri_D.pdf: 2564132 bytes, checksum: 2cf683fae8753aeb90490cdb99add485 (MD5) Previous issue date: 2009 / Resumo: Este trabalho procura avançar no entendimento da dinâmica da inovação e das mudanças estruturais na indústria aeronáutica mundial, analisando os determinantes da capacidade competitiva da indústria. Na seqüência, é interpretado o desempenho competitivo dos principais países produtores de aeronaves e das suas respectivas empresas líderes. Por fim, o trabalho propõe um estudo mais aprofundado da indústria aeronáutica brasileira e da sua inserção internacional, com destaque para a avaliação da sua empresa líder, a Embraer. Para tanto, a metodologia está fundamentada na Teoria Neoschumpeteriana, além de se utilizar de conceitos das Teorias Institucionalista e dos Custos de Transação. O período estudado parte da origem da indústria aeronáutica no início do século XX e alcança os dias atuais, contudo, está focado nas recentes mudanças do setor aeronáutico mundial. O principal argumento relaciona-se ao fato de que a indústria está passando por profundas transformações, especialmente centradas na exacerbação da dinâmica da inovação e na maior concentração da estrutura produtiva. Sendo assim, a posição de destaque conquistada pela indústria aeronáutica brasileira, na figura da Embraer, passa a ser colocada em xeque pela nova configuração do setor aeronáutico. Nesse contexto, a Embraer terá de construir novas vantagens competitivas para se manter entre as empresas líderes do mercado aeronáutico internacional. / Abstract: This study seeks to advance in the comprehension of the dynamics of innovation and structural modifications in the global aeronautical industry, analyzing the determinants of its competitive capacity. Subsequently, the competitive performance of the main aircraftproducing countries and their respective leading companies is interpreted. Finally, the study proposes a deeper investigation of the Brazilian aeronautical industry and its international insertion, with special emphasis on the evaluation of its leading company, Embraer. To that end, the methodology is founded on the Neoschumpeterian Theory, in addition to using concepts of the Institutional Environment and Transaction Costs Theories. The studied period goes from the origins of the aeronautical industry in the beginning of the 20th Century to reach the current days, although it focuses the recent changes occurring in the global aeronautical sector. The main argument is related to the fact that the industry is going through profound transformations, especially centered in the exacerbation of innovative dynamics and greater concentration of the productive structure. Therefore, the outstanding position conquered by the Brazilian aeronautical industry, represented by Embraer, is now challenged by the new configuration of the aeronautical sector. In this context, Embraer will have to build new competitive advantages to remain among the leading companies of the international aeronautical market. / Doutorado / Teoria Economica / Doutor em Ciências Econômicas

Estudou-se o comportamento de desgaste sob deslizamento em múltiplos passes de pinos fixos de liga metálica friccionados contra discos rotativos de laminados compósitos de matriz polimérica fortalecidos com fibras contínuas de carbono (C), para distintas cargas aplicadas e temperaturas de ensaio. Determinou-se a perda de volume por desgaste dos diversos pares tribológicos, e avaliaram-se os principais aspectos das superfícies e dos produtos gerados durante o processo de desgaste. Concluiu-se que o par formado pelo aço inoxidável martensítico PH 15-5 e o laminado compósito termoplástico C-PPS (poli-sulfeto de fenileno) apresentou o menor desgaste na maioria das circunstâncias avaliadas. A liga Ti6Al4V foi a pior opção dentre os pinos metálicos, independentemente do laminado compósito empregado, devido à baixa resistência ao cisalhamento e alta rugosidade superficial do metal, a qual prejudicou o ancoramento de filmes poliméricos de transferência. O ótimo desempenho do aço PH resultou de sua alta dureza e da adequada rugosidade superficial para o efetivo ancoramento do filme de transferência. O laminado compósito C-PPS se mostrou mais susceptível às variações na carga de contato, enquanto que o C-EPX (Epóxi) foi mais sensível à temperatura de ensaio. Filmes poliméricos de transferência atuaram como lubrificante do sistema tribológico, preservando ambos o pino metálico e o disco compósito de um desgaste excessivo. A natureza dos produtos de desgaste, sua geometria, seu tamanho médio e sua distribuição de tamanhos dependeram fortemente do disco rotativo de laminado compósito e das condições de ensaio de desgaste, e afetaram sobremaneira, como terceiro corpo abrasivo, o subseqüente processo de desgaste dos pares de fricção metal-compósito. Os resultados obtidos são potencialmente úteis na especificação de juntas mecânicas aeronáuticas mais apropriadas de laminados compósitos de matriz polimérica unidos por intermédio de prendedores metálicos. / Multipass sliding wear behavior of static metal alloy pins rubbing against rotating carbon fiber reinforcing polymer matrix composite laminate disks has been studied for different applied loads and test temperatures. The volume loss due wear has been determined for several tribological metal / composite systems, and the main aspects of wear surfaces and debris have been evaluated. It has been concluded that the best performance was achieved in very most cases by the PH15-5 steel pin contacting the C-PPS (poly-phenylene sulphide) disk. The Ti6Al4V alloy displayed the worst performance among the metal pins, regardless the employed composite laminate, as a result of the metal´s low shear strength and high surface roughness, which impaired the formation of polymer transfer films. The outstanding performance of PH steel pins derived from its high hardness and proper surface roughness that favored the transfer film formation. The C-PPS composite laminate was more sensitive to contact load variations, whereas the C-EPX laminate was more susceptible to the test temperature. Polymer transfer films acted as lubricant in the tribological system, preserving both the metallic pin and the composite disk from wearing in excess. The nature of wear debris, their geometry, mean size, and size distribution strongly depended on the composite laminate disk as well as on testing conditions, and affected overwhelmingly, as third body abrasive particles, the subsequent wear process of metal / composite friction pairs. The obtained results are potentially useful for the specification of more equalized aircraft mechanical joints comprising polymer matrix composite laminates and metallic fasteners.

A novel approach employing 4G LTE Cellular Technology for Test Range Telemetry is presented. Providing aeronautical mobile telemetry using commercial off the shelf (COTS) cellular equipment poses many challenges, including: Three-dimensional (3D) coverage, need for uninterrupted high data throughputs, and very high Doppler speeds of the Test Articles (TA). Each of these requirements is difficult to meet with a standard cellular approach. We present a novel architecture that provides 3D coverage over the span of a test range, allowing the TA to establish a radio link with base stations that have a manageable Doppler due to the reduced projected TA speed on the radio link line. Preliminary results illustrate that a variety of flight plans can be accommodated with commercial LTE technology by employing LTE’s mobility mechanisms and adding centralized control. The resulting network architecture and Radio Access Network topology allow very high throughputs to be delivered throughout the test range with a judicious placement of base stations.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Actually in Brasil there there is a fleet around 1500 agricultural aircraft working on different aplications. The spray aplication by na airplane of crop defenses is increasing on the last years, generating a demand on spraying airplanes, pilots, spare parts for maintenance, fuel and, first of all, operational cost reduction. Base on this, the present master thesis is working as knowledge generator ans presenting results for, in the future, to project an ethanol aeronautical engine that will use on agricultural/spraying airplanes. Operational costs for agricultural airplanes is based on maintenance and in the fuel, that the major part uses aviation gasoline AvGas as fuel. Ethanol comes with a great chance to reduces such costs, due to the price of this fuel is only around 25% of AvGas. The aeronautical engines that flies nowadays with ethanol as fuel are a conversions from AvGas engines, wich generates some problems, the main is consumption increasing. The possibility to reduces operational costs with using a fuel from renewable source and challenge to get an aeronautical engine dedicated to run with ethanol as fuel is what motivates and derecting this research. Development process of a technical system, as an ethanol engine, is complex and requires human and material resources administration, information colect, research and a strenght management of whole development process. Methodology for this work development is based on exploratory research of existing bibliography about development product process, technical systems, aeronautical engines, agricultural aviation and homologation standards for aeronautical engines and your parts and components. Information acquired are presented to provide a data base to meet the need of companies, engineers and designers on a future development. After organization and threatment the data supply the base of influence factors for a project of aeronautical ethanol engine for agricultural airplane. The knowledge about brasilian agricultural airplane fleet and engines used on such airplanes provide detailed information about size and capacity of each airplane and their aplications, including information about their technical and operating characteristics. With this, was able to make entire influence factors for a project of aeronautical ethanol engine for agricultural airplane, such influence factors are divided in four groups that is: Project Scope, Benchmarking, Operating Characteristics and Standards & Homologation. Technical data and information of aeronautical engines and their characteristics was evaluated and compared to observ the tendency of engines with power in a range beetween 151 and 300kW, where more than 80% of those engines in whole brasilian fleet is inside of this range, the major part using AvGas as fuel. Engines running with ethanol generates more power if compared the same engine running with AvGas, for other side, there is a consumption increasing, aorund 40% more and the emissions are decreased, what is a positive point with ethanol use as fuel. / No Brasil, hoje, há uma frota aproximada de 1500 aeronaves agrícolas efetuando operações diversas. A aplicação aérea de defensivos nas culturas agrícolas tem sido crescente nos últimos anos, gerando uma necessidade maior de aeronaves, pilotos agrícolas, peças de reposição e combustível, bem como, e principal quesito, a necessidade de redução dos custos operacionais. É neste ponto que este trabalho entra como gerador de conhecimento apresentando dados e resultados para a obtenção, no futuro, de um motor projetado para o uso de etanol equipar aeronaves de aplicação agrícola.Os custos operacionais das aeronaves agrícolas está baseado na manutenção e no combustível que ela utiliza, na grande maioria é a AvGas gasolina de aviação. O etanol vem com grande chance de reduzir significativamente estes custos, pois seu preço é inferior ao da AvGas, podendo chegar apenas 25% do preço desta. Os motores de aeronaves que voam atualmente com etanol são conversões, o que gera alguns problemas, dentre eles o mais significativo que é o aumento de consumo de combustível. A possibilidade de redução dos custos operacionais com a utilização de combustível produzido de fonte renovável e o desafio de se ter um motor projetado especificamente para o uso de etanol como combustível é o que motiva o estudo e direciona a pesquisa. O processo de desenvolvimento do projeto de sistema técnico, como o de um motor a etanol, é complexo e exige administração dos recursos humanos e materiais, coleta de informações, pesquisa e um rígido gerenciamento de todo o processo para tal desenvolvimento. A metodologia para desenvolvimento do estudo está baseada na pesquisa exploratória de bibliografia existente acerca de desenvolvimento de produtos e sistemas técnicos, motores aeronáuticos, aviação agrícola e normas para homologação de produtos e peças aeronáuticas para aplicação em aeronaves agrícolas. As informações obtidas estão apresentadas de maneira a fornecer uma base de dados capaz de suprir a necessidade de empresas, engenheiros e projetistas num desenvolvimento futuro. Os dados compilados e organizados formam a base para a apresentação dos fatores de influência no projeto de um motor a etanol para aplicação em aeronaves agrícolas. O conhecimento sobre a frota brasileira de aeronaves e os motores utilizados fornecem informações detalhadas sobre o tamanho e capacidade de cada aeronave e suas aplicações, bem como os motores necessários em cada uma destas aeronaves e suas características técnicas e operacionais. Obtêve-se a elaboração completa de todos os fatores de influência para o projeto de um motor aeronáutico a etanol direcionado para aplicação agrícola, tais fatores de influência estão subdivididos em quatro grupos que são: Escopo do projeto, análise comparativa dos motores, características da operação e normas e homologação. Informações e dados técnicos de motores e suas características foram avaliadas e comparadas entre si, de maneira a observar a tandência de utilização de motores na faixa de 151 à 300kW, onde mais de 80% dos motores empregados estão dentro desta faixa e na grande maioria consumindo AvGas. Motores a etanol geram maior potência em detrimento de aumento de consumo, da ordem de 40%, porém, as emissões de gases tóxicos são reduzidas, o que é fator positivo no uso do etanol como combustível.

UAVs employed for low altitude jobs are more liable to collide with the urban structures on their way to the goal point. In this thesis, the problem of reactive obstacle avoidance is addressed by an innovative partial integrated guidance and control (PIGC) approach using the Six-DOF model of real UAV unlike the kinematic models used in the existing literatures. The guidance algorithm is designed which uses the collision cone approach to predict any possible collision with the obstacle and computes an alternate aiming direction for the vehicle. The aiming direction of the vehicle is the line of sight line tangent to the safety ball surrounding the obstacle. The point where the tangent touches the safety ball is the aiming point. Once the aiming point is known, the obstacle is avoided by directing the vehicle (on the principles of pursuit guidance) along the tangent to the safety ball. First, the guidance algorithm is applied successfully to the point mass model of UAV to verify the proposed collision avoidance concept. Next, PIGC approach is proposed for reactive obstacle avoidance of UAVs. The reactive nature of the avoidance problem within the available time window demands simultaneous reaction from the guidance and control loop structures of the system i.e, in the IGC framework (executes in single loop). However, such quick maneuvers cause the faster dynamics of the system to go unstable due to inherent separation between the faster and slower dynamics. On the contrary, in the conventional design (executes in three loops), the settling time of the response of different loops will not be able to match with the stringent time-to-go window for obstacle avoidance. This causes delay in tracking in all the loops which will affect the system performance adversely and hence UAV will fail to avoid the obstacle. However, in the PIGC framework, it overcomes the disadvantage of both the IGC design and the conventional design, by introducing one more loop compared to the IGC approach and reducing a loop compared to the conventional approach, hence named as Partial IGC. Nonlinear dynamic inversion technique based PIGC approach utilizes the faster and slower dynamics of the full nonlinear Six-DOF model of UAV and executes the avoidance maneuver in two loops. In the outer loop, the vehicle guidance strategy attempts to reorient the velocity vector of the vehicle along the aiming point within a fraction of the available time-to-go. The orientation of the velocity vector is achieved by enforcing the angular correction in the horizontal and vertical flight path angles and enforcing turn coordination. The outer loop generates the body angular rates which are tracked as the commanded signal in the inner loop. The enforcement of the desired body rates generates the necessary control surface deflections required to stir the UAV. Control surface deflections are realized by the vehicle through the first order actuator dynamics. A controller for the first order actuator model is also proposed in order to reduce the actuator delay. Every loop of the PIGC technique uses nonlinear dynamic inversion technique which has critical issues like sensitiveness to the modeling inaccuracies of the plant model. To make it robust against the parameter inaccuracies of the system, it is reinforced with the neuro-adaptive design in the inner loop of the PIGC design. In the NA design, weight update rule based on Lyapunov’s theory provides online training of the weights. To enhance fast and stable training of the weights, preflight maneuvers are proposed. Preflight maneuvers provide stabilized pre-trained weights which prevents any misapprehensions in the obstacle avoidance scenario. Simulation studies have been carried out with the point mass model and with the Six-DOF model of the real fixed wing UAV in the PIGC framework to test the performance of the nonlinear reactive guidance scheme. Various simulations have been executed with different number and size of the obstacles. NA augmented PIGC design is validated with different levels of uncertainties in the plant model. A comparative study in NA augmented PIGC design was performed between the pre-trained weights and zero weights as used for weight initialization in online training. Various comparative study shows that the NA augmented PIGC design is quite effective in avoiding collisions in different scenarios. Since the NDI technique involved in the PIGC design gives a closed loop solution and does not operate with iterative steps, therefore the reactive obstacle avoidance is achieved in a computationally efficient manner.

Historically, the endeavor of scale testing flight vehicles at supersonic Mach numbers, especially for long durations, has required the development of closed-loop wind tunnels, which are extremely expensive both to build and operate due to the high complexity and incredible power required to drive such a system. The intermittent blowdown wind tunnel, indraft tunnel, and shock tunnel have alleviated many of these cost requirements to some degree, whilst facilitating testing at very high Mach numbers and enthalpies; however, these systems require the handling of gases at pressures and temperatures that can be prohibitive for many university settings. The Ludwieg tube provides a simple, elegant method for producing testable supersonic flows at price points significantly lower than the aforementioned test-system architectures. Unfortunately, the spacial footprint and moderate cost required for driver tube and nozzle hardware can make it difficult to implement for many non-research universities. In this thesis, a new supersonic test system architecture is conceived, designed, implemented, and validated for the purpose of making supersonic aerodynamic testing capability attainable for most universities, by combining properties of the Ludwieg Tube and indraft wind tunnel to reduce the cost needed to produce this capability. This system, the Indraft Tube Tunnel, requires no long driver-tube or test-section hardware, aside from a vacuum chamber. Furthermore, it is safe to operate, as high pressure containment systems are not required for the Indraft Tube Tunnel System. It is designed and operated to draw stagnant atmospheric air through a converging-diverging nozzle to achieve a steady-state Mach number of 2.5. Sufficient pressure ratio to reach the desired Mach number is attained by evacuating the vacuum chamber and placing a thin cellophane diaphragm across the inlet of the nozzle, thus separating the vacuum section from ambient atmosphere. To initiate gas flow, the diaphragm is mechanically burst with a puncture device. This design requires much less hardware to implement than a typical Ludwieg tube, and had an operating cost of less than one dollar per test. Using this method, steady, uninterrupted Mach 2.44 is attained for a duration of 13.6 ms and a test section diameter of 7 inches. The standard deviation of the Mach number measurements is .08 Mach. A shadowgraph imaging setup is used to view and measure the angle of oblique shockwaves on a simple wedge test-model. The Indraft Tube Tunnel is novel in the field of high-speed aerodynamic testing, and may be implemented by other universities to produce supersonic flows with a relatively small investment in hardware and laboratory space.

A numerical study was conducted to determine the effect of changing the camber of a winglet on the efficiency of a wing in two distinct flight conditions. Camber was altered via a simple plain flap deflection in the winglet, which produced a constant camber change over the winglet span. Hinge points were located at 20%, 50% and 80% of the chord and the trailing edge was deflected between -5° and +5°. Analysis was performed using a combination of three-dimensional vortex lattice method and two-dimensional panel method to obtain aerodynamic forces for the entire wing, based on different winglet camber configurations. This method was validated against high-fidelity steady Reynolds Averaged Navier-Stokes simulations to determine the accuracy of these methods. It was determined that any winglet flap deflections increased induced drag and parasitic drag, thus decreasing efficiency for steady level flight conditions. Positive winglet flap deflection at higher lift conditions may increase efficiency, but the validity of the vortex lattice method results for these conditions are dubious. A high-fidelity method should be used for the high lift condition to obtain accurate efficiency data.

The concept of human-powered vertical flight was studied in great depth. Through the manipulation of preexisting theory and analytical methods, a collection of design tools was created to expediently conceptualize and then analyze virtually any rotor. The tools were then arranged as part of a complete helicopter rotor design process. The lessons learned as a result of studying this process—and the tools of which it consists—are presented in the following discussion. It is the belief of the author that by utilizing these tools, as well as the suggestions that accompany them, future engineers may someday build a human-powered helicopter capable of winning the Sikorsky Prize.