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This study is devoted to some of the most important issues for advancing inkjet printing for possible application in the coating industry with a focus on piezoelectric droplet on demand (DOD) inkjet technology. Current problems, as embodied in liquid filament breakup along with satellite droplet formation and reduction in droplet sizes, are discussed and then potential solutions identified. For satellite droplets, it is shown that liquid filament break-up behavior can be predicted by using a combination of two pi-numbers, including the Weber number, We and the Ohnesorge number, Oh, or the Reynolds number, Re, and the Weber number, We. All of these are dependent only on the ejected liquid properties and the velocity waveform at the print-head inlet. These new criteria are shown to have merit in comparison to currently used criteria for identifying filament physical features such as length and diameter that control the formation of subsequent droplets. In addition, this study performs scaling analyses for the design and operation of inkjet printing heads. Because droplet sizes from inkjet nozzles are typically on the order of nozzle dimensions, a numerical simulation is carried out to provide insight into how to reduce droplet sizes by employing a novel input waveform impressed on the print-head liquid inflow without changing the nozzle geometry. A regime map for characterizing the generation of small droplets based on We and a non-dimensional frequency, Ω is proposed and discussed. In an attempt to advance inkjet printing technology for coating purposes, a prototype was designed and then tested numerically. The numerical simulation successfully proved that the proposed prototype could be useful for coating purposes by repeatedly producing mono-dispersed droplets with controllable size and spacing. Finally, the influences of two independent piezoelectric characteristics - the maximum head displacement and corresponding frequency, was investigated to examine the quality of filament breakup quality and favorable piezoelectric displacements and frequencies were identified.

Highway roughness is a concern for both the motoring public and highway authorities. Roughness may even increase the risk of crashes. Rail-highway grade crossings are particularly problematic. Roughness may be due to deterioration or simply due to the way the crossing was built to accommodate grade change, local utilities, or rail elevation. With over 216,000 crossings in the US, maintenance is a vast undertaking. While methods are available to quantify highway roughness, no method exists to quantitatively assess the condition of rail crossings. Conventional inspection relies on a labor-intensive process of qualitative judgment. A quantifiable, objective and extensible procedure for rating and prioritizing improvement of crossings is thus desired. In this dissertation, a 3D infrastructure condition assessment model is developed for evaluating the condition and performance of rail highway grade crossings. Various scanning techniques and devices are developed or used to obtain the 3D “point cloud” or surface as the first step towards quantifying crossing roughness. Next, a technique for repeatable field measurement of acceleration is presented and tested to provide a condition index. Acceleration-based metrics are developed, and these can be used to rate and compare crossings for improvement programs to mitigate potential vehicle damage and provide passenger comfort. A vehicle dynamic model is next customized to use surface models to estimate vertical accelerations eliminating the need for field data collection. Following, crossing roughness and rideability is estimated directly from 3D point clouds. This allows isolation of acceleration components derived from the surface condition and original design profile. Finally, a practice ready application of the 3D point cloud is developed and presented to address hump crossing safety. In conclusion, the dissertation presents several methods to assess the condition and performance of rail crossings. It provides quantitative metrics that can be used to evaluate designs and construction methods, and efficiently implement cost effective improvement programs. The metrics provide a technique to measure and monitor system assets over time, and can be extended to other infrastructure components such as pavements and bridges.

Este trabalho inicia com uma contextualização histórica e motivação, seguida por revisão bibliográfica nos tópicos discutidos: segurança veicular, crash box, crashworthiness, absorvedores de energia, tubos de impacto, metamodelos, algoritmos genéticos, Planejamento de Experimentos (DoE - Design of Experiments), origami e engenharia, e métodos de otimização na engenharia. Em seguida, o pesquisador propõe um experimento baseado em simulações, avaliando diversas crash box em forma de origami criadas a partir da variação de seus parâmetros dimensionais. Através de um algoritmo baseado em metamodelos, o autor realiza uma análise com o objetivo de maximizar a energia absorvida específica (Specific Energy Absorption - SEA) e a uniformidade de carga (Load Uniformity - LU). A fronteira de Pareto resultante dos dois objetivos é analisada de acordo a exemplos de critérios de decisão, e a configuração escolhida é então comparada a uma crash box da indústria. A configuração escolhida apresenta uma massa quatro vezes menor, e uma uniformidade de carga semelhante à crash box da indústria. Conclui com novas proposições de trabalhos, envolvendo outros métodos de otimização disponíveis. / This research begins with a historical background and motivation, followed by a bibliographic review on the discussed topics: vehicle safety, crash box, crashworthiness, energy absorbers, impact tubes, metamodels, Design of Experiments (DOE), origami and engineering, and optimization in engineering. Next, the researcher proposes a simulation-based experiment, evaluating origami crash boxes created through the variation of several dimensional parameters. Through a metamodel-based algorithm, the author performs an analysis with the objective of maximizing the Specific Energy Absorption (SEA) and the load uniformity (LU). The resultant Pareto frontier of the two objectives is analyzed according to examples of decision criteria, and the chosen design is compared to a crash box from industry. The chosen design presents four times less mass, and a load uniformity similar to the crash box from industry. The research concludes with propositions for new themes, involving other optimization methods available.

Este estudo tem por objetivo estabelecer os principais critérios de seleção de uma arquitetura elétrica adequada a mercados emergentes, considerando as necessidades de mercado, de legislação, de inovações e/ou novas funções a serem empregadas durante o ciclo de vida de um veículo. Para tanto, o resultado da pesquisa bibliográfica deste trabalho, apresentada na revisão teórica, primeiramente define o significado de arquitetura elétrica, e conta a sua evolução desde os primórdios da indústria automotiva até os dias de hoje, apontando quais são os principais sistemas elétricos existentes atualmente, deixando clara a fundamental importância da eletrônica embarcada na evolução do automóvel. Mostram, ainda, suas principais tendências tecnológicas, além de um descritivo sobre técnicas, critérios e metodologia de desenvolvimento de projetos de arquitetura elétrica empregados hoje na indústria. Na seqüência, o trabalho define os conceitos de mercado emergente e mercado desenvolvido, apontando suas particularidades, volumes de negócio (histórico e projetado), deixando evidente a importância dos mercados emergentes nos dias de hoje para a indústria automotiva mundial e a necessidade de se estabelecer estratégias específicas para estes mercados. Com base na própria pesquisa bibliográfica, somada à análise documental e a entrevistas não-estruturadas com membros ativos da indústria automotiva, foram concebidos os critérios para seleção de arquiteturas elétricas veiculares para mercados emergentes, assim como seus descritores e taxas de substituição (pesos). A definição de pesos e descritores é necessária para a utilização do método de agregação aditiva, método este de tomada de decisão empregado devido a sua capacidade de avaliar simultaneamente diversas alternativas, através de parâmetros qualitativos. Tal método, discutido na metodologia, mostrou-se muito eficiente por permitir uma avaliação dinâmica da análise proposta perante modificações em quaisquer parâmetros existentes. Por fim, o método e os critérios foram finalmente aplicados em dois estudos de caso, selecionados com base em casos reais vivenciados pela indústria automotiva no desenvolvimento de dois projetos: um veículo hatch popular e um veículo sedan médio de luxo, ambos destinados a mercados emergentes. Através do estudo de caso, foi possível confrontar soluções de arquiteturas adotadas no passado, no presente e para um futuro próximo, além de confrontar também soluções adotadas para mercados desenvolvidos e para mercados emergentes. O resultado deste estudo comprovou a necessidade da existência de critérios específicos para mercados emergentes, a coerência destes critérios e a robustez do modelo apresentado. Convém ressaltar que, para o tema em questão (ou estudos de caso), a robustez e consistência do modelo de avaliação obtido e a importância comprovada dos critérios selecionados são pertinentes e válidos, considerando-se o fato de que a definição dos pesos e notas atribuídas ao modelo serem feitas pelo avaliador, nas quais são diretamente dependentes do conhecimento adquirido pela empresa (seja ela montadora ou fornecedora) e vivência do responsável pela avaliação, sujeitando-as, desta forma, a seus próprios conceitos. / The aim of this study is to establish the criteria of election of an electrical architecture tailor-made for the emergent markets, considering the necessities of market, legislation, innovations and/or new functions to be applied during the whole vehicles life-cycle. Due to this, the result of the bibliographical research of this study, defines the meaning of electrical architecture, and shows its evolution since the beginning of the automotive industry up to now, also presenting the main electrical systems available today, making clear the huge importance of the embedded electronics for the evolution of the automobile. This study also presents the technological trends and a brief description of techniques, criteria and development methodology for electrical architecture projects available today in the industry. Here after, the study defines the concepts of emergent market and developed market, showing their characteristics, market share and production volumes (historical and forecast), showing the importance of the emergent markets for the world-wide automotive industry nowadays and the needs for development of specific strategies for these markets. Based on the bibliographical research, documentary analysis and the unstructured interviews with active members of the automotive industry, the criteria for election of electrical architectures for emergent markets was established, as well as their describers and swing-weights. The definition of weights and describers is necessary for the use of the additive aggregation method a decision taking method which has the capacity to evaluate several alternatives simultaneously, through qualitative parameters. Such method, presented in the methodology chapter, was very efficient for dynamic evaluation of the proposals even before changes in its parameters. Finally, the method and the criteria were finally applied in two studies of case, based on real cases of automotive industry when developing two projects: a low-cost hatch vehicle and a mid-size luxury sedan vehicle, both designed for emergent markets. By the study of cases, it was possible to compare solutions of architectures adopted in the past, in the present and for a near future, and also to compare solutions adopted for developed markets and emergent markets. The results of this study proved the necessity of specific criteria for emergent markets, the coherence of the established criteria and the robustness of the adopted model. Regarding the studies of cases, the robustness and consistency of the evaluation model and the proved importance of the criteria are relevant and valid, even considering that the definition of the weights values and grades are always made by the evaluators. It means that they directly depend on the companys know-how and best practices (from carmakers or suppliers) and the professional experience of the evaluator, resulting, someway, in their own values for different companies.

O controle de emissões em veículos pesados está em foco desde a década de 90, com a criação de regulamentações nacionais e internacionais que impõe limites cada vez mais rígidos para as concentrações de poluentes emitidos por estes veículos. O desenvolvimento de novas tecnologias possui papel fundamental neste processo, buscando redução nos níveis de emissões com mínimo impacto negativo no desempenho e no consumo do veículo. Para tanto, o presente trabalho visa avaliar a influência da posição dos dutos de admissão de ar de cabeçotes de motores a combustão interna, especificamente em motores de ignição por compressão (MIC) de 4 válvulas, no escoamento de ar dentro do cilindro. O escoamento do ar e o movimento de swirl são fatores importantes para a mistura e distribuição do combustível injetado, e quando otimizados para uma queima melhor distribuída, contribuem para redução nos níveis de emissões. Procura-se investigar quais direções características dos dutos são determinantes para o escoamento e para o comportamento de swirl do motor através de simulações em fluidodinâmica computacional (Computational Fluid Dynamics - CFD) utilizando o programa CD-adapco STAR-CCM+®. Os resultados de alguns dos cenários simulados são comparados a resultados de testes experimentais realizados em bancada de medição de swirl, no âmbito de outro trabalho sendo desenvolvido no mesmo grupo de projeto. / The emissions control in heavy-duty vehicles has been in focus since the 1990\'s, with the creation of national and international regulations which impose strict limits for pollutant concentrations released by these vehicles. The development of new technologies has a fundamental role in this process, aiming the reduction of emission levels with minimum impact on the performance and fuel consumption of the vehicle. Therefore, the present study aims to evaluate the influence of the position of intake ports in cylinder heads from internal combustion engines, specifically 4-valves compression-ignition (CI) engines, in the in-cylinder air flow. The air flow and swirl motion are important factors for the mixture and distribution of injected fuel, and when optimized for a better distributed combustion, contribute for the reduction of emission levels. This study investigates the characteristic directions of ports which are determinant for the air flow and swirl behaviour of the engine through Computational Fluid Dynamics (CFD) simulations using CD-adapco software STAR-CCM+®. The results from a group of simulated cases are compared to experimental test results from another project, developed on the same project group, performed in a swirl meter test rig.

<p>Generally, heavier noise control treatments are favored over lighter ones since heavier acoustical materials tend to insulate (block) noise sources more effectively than do lighter materials. In automotive applications, however, heavier materials cannot always be adopted because of concerns over the total weight of the vehicle. Thus, it would be useful to identify lightweight acoustical treatments that can mitigate vehicle interior noise. Automotive sound packages have both absorption and barrier characteristics, and there is inevitably a trade-off between these two. Therefore, it is important to study the exchange between the absorption and transmission of acoustical materials particularly as it pertains to weight. Here, a procedure based on plane wave analysis is described that can be used to identify weight reduction opportunities by adjusting the acoustical properties of a generic sound package, consisting of a fibrous layer and a flexible microperforated panel surface treatment, so that it meets a target sound pressure level in a downstream interior space. It has been found, for the configuration studied here, that there are lightweight sound package configurations that can maintain acoustical performance equivalent to that of heavier noise treatments, and further, it has been found that the lightest treatments tend to favor barrier performance rather than absorption. Further, the impact of acoustical leaks has been considered, and it has been found that even very small leaks can result in a very substantial weight penalty if a specified level of acoustical performance is to be ensured. Further, the impact of changing the underlying panel mass and altering the frequency weighting used in the optimization process has also been considered.</p> <p>The optimizer used in the proposed procedure requires considerable calculation time; hence, the acoustic pressure calculation time needs to be minimized to enhance the efficiency of the solution process. Thus, the transfer matrix method (TMM) for a two-dimensional case was used to calculate the interior acoustic pressure for a simple geometry as a starting point in the process of identifying the minimum-weight sound packages. The TMM is a widely used analytical approach to predicting the sound pressure (and particle velocity) for a system that can be represented as a series of subsystems. Although the TMM can offer fast and simple calculations for the acoustic system, its application is limited to a plane-wave-based model. Thus, the TMM is not the best option for the acoustic pressure prediction in a complex geometry such as a vehicle interior, that involves non-planar wave propagation. Therefore, a hybrid TMM-FEA method is proposed in this research to evaluate the acoustical performance of the sound package in more complex geometries (here, a vehicle-like cavity). So, in this research, the TMM was introduced to obtain the initial solutions that can be used in conjunction with the FEA tool to calculate the sound pressure field in the complex geometry case. The correlation between the results of these two approaches was then analyzed to develop a space-averaged pressure prediction model for various absorptive cases in the interior space. Finally, this SAP prediction model was used to generate an acoustic map that can be used to graphically estimate the SAPs in the complex geometry case.</p> <p>In order to validate the usage of the developed equation for different sets of boundary conditions, several case studies were performed to study the effects of the surface impedance arrangements, geometrical shapes, and, lastly, the presence of extra features in the interior space. Finally, the SAP difference between the area near the driver’s right ear and the total interior cavity was studied to show that the SAP of the total cavity can be adjusted to evaluate the acoustic performance of the sound packages along the lines of conventional industry practice. </p>

Existem muitos estudos e publicações focadas no planejamento e desenvolvimento de novos produtos. Porém, o mesmo não é notado em estudos relativos à implantação destes novos produtos e seus processos na área de manufatura. Para tal, é desenvolvido neste trabalho um modelo de referência consistente para a implantação de novos processos de montagem no setor automotivo. O citado modelo contém a descrição das etapas, as verificações de qualidade, as ações e as necessárias validações do produto produzido no processo de produção em série. O teste da consistência e relevância dessa metodologia ocorre por meio da aplicação do modelo proposto, no desenvolvimento de um processo da montagem de componentes na montagem final. Para a sua avaliação, compararam-se os indicadores de um processo existente em dois momentos: um primeiro, com o processo desenvolvido utilizando-se o método tradicional, e em segundo, com o desenvolvimento e implantação deste mesmo processo, utilizando-se o método proposto de desenvolvimento do processo produtivo, somado a uma avaliação qualitativa do modelo de referência, por meio de uma pesquisa, com especialistas reconhecidos do meio automotivo, validando-se assim o modelo proposto. / Currently, there are many studies and publications focused on the planning and development of new products. However, the same is not noted in studies related to the implementation of these new products and their processes in manufacturing area. For this, a consistent reference model is developed for implementation of new assembly processes in the automotive sector. This model contains a description of steps, quality checks, actions and validations required by the product manufactured in the serial production process. The test of consistency and relevance of this methodology occurs through the application of the proposed model, in the development of a process of component assembly in the final assembly. For its evaluation, the indicators of an existing process were compared in two time points: with the process developed using the traditional method, and secondly, with the development and implementation of this same process, using the proposed development method of the production process. This occurred alongside a qualitative evaluation of the reference model through a survey with recognized experts of the automotive environment, thus validating the proposed model.

Este trabalho visa o estudo de uma metodologia de simulação numérica aplicada ao processo de troca térmica do motor de um veículo de passeio. O processo de troca térmica é essencial para evitar o superaquecimento do motor, que provoca o rompimento do filme de óleo lubrificante dos pistões e, conseqüentemente, o seu travamento. Essa metodologia será útil nos estudos preliminares do sistema de arrefecimento de um veículo na fase inicial de projeto por meio de simulações virtuais, o que possibilitará a redução de protótipos, além de proporcionar um ganho em tempo de resposta. A metodologia utiliza um programa comercial de CFD para a simulação do processo de troca térmica no interior do compartimento do motor do veículo. As simulações foram realizadas com base nos testes físicos em túnel de vento que fazem parte do desenvolvimento e projeto de automóveis em condições de operação que representam situações críticas integrantes da vida operacional. Essas condições operacionais de teste, tais como a velocidade do veículo, as cargas térmicas, a potência dos ventiladores e outros parâmetros foram utilizadas como condições de contorno na validação do modelo do veículo. O processo de validação de modelos é composto por: validações de itens isolados do sistema de arrefecimento, avaliação do efeito da densidade de malha computacional de um modelo completo na vazão de ar nos trocadores de calor e simplificações no modelo para a redução do tempo de processamento. Neste trabalho três modelos distintos de veículos foram utilizados, sendo que dois deles para a validação na comparação com os resultados de túnel vento, enquanto o terceiro modelo foi utilizado para a validação da metodologia através de comparações com os dados obtidos nos testes em pista circular. Os resultados das simulações mostraram variações máximas de 5,5% na temperatura do líquido de arrefecimento na entrada do radiador em relação aos testes. A metodologia de simulação mostrou ser uma poderosa ferramenta de otimização durante a fase de desenvolvimento do projeto e complementando os testes físicos para o sistema de arrefecimento veicular. / The present work is applied to a development of a numerical simulation methodology for a passenger vehicle engine cooling process. The heat exchange process is essential to avoid the engine overheat which may result in the piston oil film separation and consequently its halt. This methodology will be useful for the preliminary studies of the cooling system at the initial phase through the virtual simulations which can reduce the number of prototypes and save proposals\' time response. The methodology uses commercial CFD software for airflow simulation and the thermal process at under hood. The simulations were based on the physical wind tunnel tests that are part of the automotive development, with operational conditions representing critical situations experienced by a vehicle in its operating life. The test conditions, such as vehicle speed, thermal loads, fan power and other parameters were used as the boundary conditions for the model validation. The validation process is based on the following phases: validation of the isolated cooling system components, the effect of mesh density at cooling airflow using a complete vehicle model and model simplification in order to improve the processing time. In this work development, three different models were used; two of them for validation with test tunnel data and the third, was used for methodology validation through the circular road test. The simulation results for tunnel and circular road showed 5.5% of differences for the radiator coolant inlet temperature when compared with physical tests. The methodology of the simulation is a powerful tool for optimization during the development phase and complementing the physical tests for the vehicle cooling systems.

<p>Inaccurate cost estimates contribute to lost implementation opportunity of novel manufacturing technologies or lost revenue due to under-bidding or loss of an over-bid contract. High-volume, long-term orders, such as those the automotive industry begets, are desired as they lock in revenue streams for months into years. However, high-rate composite materials and their manufacturing processes are novel among the industry and traditional costing methods have not advanced at a proportional rate. This research effort developed a method to reduce the complex composite manufacturing systems to fungible, upgradable, and linkable individual processes that derive their manufacturing parameters from the performance part design process. Employing technical cost modeling, this method accurately quantifies the value of pursuing composite manufacturing by integrating impregnation, solidification, heat transfer, kinetics, and additional technical data from computer-aided part design simulation tools to deliver an accurate cost estimate. </p> <p>Cost modeling provides a quantitative result that weighs heavily in the decision making process for adoption of a new manufacturing method. In this dissertation, three case studies were investigated for three different management decision cases: part production management, in-house manufacturing management, and global manufacturing management. </p> <p>Part production management is the decision making process for selecting a certain manufacturing method. A case study with a Tier 1 Part Producer was conducted to provide a comparison of two emerging novel preforming systems versus their in-use, metals based high-rate manufacturing line in manufacturing a structural automotive part. Determining material usage was the primary cost driver focus. Equipment Supplier A’s process operated by seaming single layers of thermoplastic tape into rolls and then stacking prior to consolidation and resulted in a scrap rate of 23-28% with a cost of $32.87-36.01 per kilogram saved depending on the input tape width. Equipment Supplier B’s layup process, essentially a multi-head automatic tape layup machine, resulted in scrap rate of 20-27% with a cost of $34.48-36.67 per kilogram saved depending on the input tape width. This exceeded the Tier 1 Part Producer’s requirement of $6.6-11 per kilogram saved and led to them to abandon this application as a feasible project and instead look for a different part with a higher return regarding cost for weight saved.</p> <p>In-house manufacturing management is the decision making process governing manufacturing operating procedures. A case study for the Manufacturing Design Laboratory’s (MDLab) hybrid molding line was undertaken to determine the manufacturing cost for a composite test coupon. Processing parameters were obtained from three sources: performance design computer aided engineering (CAE), common industry transfer estimation times, and a calculated preform layup time. Compared to a similarly shaped test coupon made of aluminum, highly-automated manufacturing realizes weight savings of 46.25% and cost savings of 16.5%. Low-automation manufacturing captures the same weight savings, but has a cost for weight saved penalty, cost increase, of $9.89 per kilogram, showing how influential the labor contribution is to manufacturing cost. </p> <p>Global manufacturing management is the decision making process governing manufacturing location. Various manufacturing cost drivers are location dependent, thus a dataset was developed to alter these parameters for the U.S. states. Global comparisons are accomplished through indexing of global cost of living allowances and labor rates. Within the U.S., high-automation manufacturing costs in the West Coast/Pacific are 20.1% greater compared to the Midwest and similarly, low-automation costs are 21.2% greater. Globally, high-automation manufacturing costs in North America are 52.1% greater compared to Asia while low-automation costs are 116.5% greater. These variations highlight why we see geographically clustered manufacturing centers within the states and major manufacturing relocations due to cost sensitive and labor sensitive production. </p>