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Guerreiro, Luís Filipe Costa. "Automatic drilling improvement and standardization by design-of-experiments (DOE)." Master's thesis, Universidade de Évora, 2019. http://hdl.handle.net/10174/25737.
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Na manufactura aeroespacial,para um dado intervalo de tempo imposto,os requisitos de
qualidade têm de ser cumpridos.O custo operacional tem um pesado impacto,especial
mente em operações repetidas,como a operação de furação decompósitos na indústria
aeroespacial.É realizado um estudo da furação em compósitos,em particular dos bordos
de ataque dos Estabilizadores dos jatos executivos Embraer Legacy 450/500 e Praetor
500/600. Este estudo consiste na análise do desempenho das máquinas pneumáticas
e introdução de máquinas semi-automáticas com parâmetros programáveis.Os dados
recolhidos nas operações de furação com diferentes parâmetros e aplicação do conceito
de Planeamento de Ensaios(hiper cubos Latinos)para uma análise eficiente,visam in
crementar o conhecimento sobre a furação,e de terminar os parâmetros mais adequados
para cada geometria de ferramenta.Neste contexto,aumentou-se a vida útil da broca; ABSTRAT: In aerospace manufacturing, for a given imposed time interval, quality requirements must be met. Operating costs have a significant impact, especially on repeated operations, such as the drilling of composites in the aerospace industry. A composite drilling study is carried out, in particular the leading edges of the Embraer Legacy 450/500 and Praetor 500/600 Executive Jet Stabilizers. This study is accomplished by a performance analysis of pneumatic machines and the introduction of semi-automatic machines with programmable parameters. The data collected in drilling operations with different parameters and the application of the concept of Design of Experiments (specifically Latin hypercubes) for an efficient analysis, aim to increase the knowledge about drilling, and to determine the most appropriate parameters for each tool geometry. In this context, the operational life of the drill was increased
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Choi, Paul Koon Ping. "The use of design of experiments (DOE) : time for company management to decide." Thesis, University of the West of Scotland, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556176.
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Many corporations over the world showed evidence of getting positive benefits from using design and analysis of experiments (DOE), however, some others did not. Companies did not use DOE or failed in using it (for some reasons) might lose their opportunities of getting those benefits which their counterparts received. Despite the advantages of. DOE, the technique is not commonly used by management. The purpose of this research is to investigate why the technique is not applied more often and hence suggestions are made to help rectify the situation. The research covered four main stages: literature review, samples of representative literature, questionnaire survey via the Internet and a case study using action research methodology being carried out in a printed circuit board company in Hong Kong. Triangulation was used in this research in order to uncover knowledge about the topic of study and tradeoff bias caused. A random sampling method and a judgmental sampling method were used in the samples of representative literature. Subsequently, two questionnaire surveys via the Internet were respectively conducted. The snowball sampling method was used to contact targeted companies. Data and information received from the surveyed companies on the use, or not, of DOE were collected and analyzed. The results and findings of the two questionnaire surveys indicated of what, how and why companies use, or not use, of DOE in their operations. A case study using action research methodology was also carried out in a local company. The action research was three-fold: (I) the researcher (i.e. the author) conducted DOE training to a team of staff, (2) trained staff undertook a current industrial problem and resolved it by using DOE, and (3) the company changed from the state of 'non-use of DOE' to the one of 'use of DOE' for better performance practices. Feedbacks from top management and the staff enriched the researcher to answer the posed research questions and achieved the objectives of the whole study.
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Khaddaj-Mallat, Chadi. "Design of experiments approach to the flooding of damaged ships." Ecole centrale de Nantes, 2010. http://www.theses.fr/2010ECDN0024.
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Les navires à passagers sont sensibles à un chavirement rapide dû à l’entrée soudaine de l’eau lors d’accidents maritimes. Durant et après la création de l’endommagement, le navire envahi peut souffrir de phases intermédiaires très dangereuses, qui risquent éventuellement de le détruire. Une investigation expérimentale utilisant la section centrale du navire à passager PRR02 – ITTC/SiW a été menée afin de déterminer les facteurs influençants ainsi que la manière dont ils interagissent entre eux. De plus, elle a pour but d’améliorer la compréhension de la physique de l’envahissement et de vérifier si l’investigation de ce type de navire est adéquate en eau calme. Une méthode innovante en ingénierie océanique, celle des Plans d’expériences (DOE), est utilisée pour planifier et conduire les tests, ainsi qu’analyser leurs résultats. Durant les phases intermédiaires d’envahissement, l’eau et l’air interagissent fortement entre eux et influencent le comportement du navire lui-même. Cette interaction est mise en évidence par la détection de trois pics importants des réponses. De plus, la présence de hautes et basses fréquences est observée dans le compartiment des machines. Ceci dépend de la compressibilité de l’air, et le ballotement de l’eau à l’intérieur de ces compartiments. Les tests confirment que le coefficient de décharge n’est pas constant pendant l’envahissement et ils l’évaluent expérimentalement. En se basant sur un plan factoriel d’expérience, un modèle mathématique caractérisant l’envahissement a été construit, validé, puis optimisé. Il met en évidence, pour le cas d’endommagement par le coté de ce type de navires, une influence marquée de la surface d’ouverture, de l’excitation externe, du tirant d’eau, ainsi que du temps de création de l’endommagement. La géométrie du compartiment des machines (disposition des blocs et perméabilité) a relativement peu d’influence. Les paramètres relatifs à l’air (envahissement transversal et niveau de ventilation) ont assez peu d’influence dans ce cas. Cette étude démontre l’utilité et l’efficacité de la méthode DOE. Elle construit la base d’élaboration d’une nouvelle procédure pour étudier la survivabilité des navires à passagers durant et après avarie. De plus, les modèles théoriques et les codes numériques pourront profiter des résultats obtenus afin d’améliorer leurs performances<br>Roll-On/Roll-Off passenger vessels appear to be sensitive to rapid capsizing due to abrupt ingress of water caused by maritime accidents. As a result of the damage creation, the flooded ship can experience transient and progressive flooding phases (Intermediate Flooding Stages, IFS) which might be more devastating than the final condition, as the sudden loading could significantly alter the ship stability characteristics. An experimental investigation using the midsection of the PRR02 – ITTC/SiW Ro-Ro passenger ferry is undertaken to determine the influential factors within the IFS, and to reveal their individual influence, as well as their interactions. More importantly, it is devoted to hopefully provide profound insight into the flooding physics and look over the adequacy of the calm water condition to assess the IFS of such vessels. A novel-in-ocean-engineering methodology, the Design of Experiments (DOE), is used to plan systematic model tests, perform them, and analyze their results. During the IFS, a strong interaction is found between, on one hand, both implicated fluids, i. E. Water and air, and, on the other hand, the model geometry and behavior. The detection of three conspicuous peaks highlights this interaction. Moreover, a two-fold behavior is observed in the Engine Room partially submerged. These behaviors are drawn by the air compressibility, the water surface, as well as the sloshing occurring inside this room. The tests confirm that the discharge coefficient for realistic flooding situations is not constant during the flooding, and estimate it experimentally. Besides, a mathematical model characterizing the IFS is successfully built, then optimized. Regarding the global behavior of such vessels suffering from side damages, it is pointed out that the Damage Opening area, the external excitation, the initial draught, and the duration of damage creation most affect the IFS; then Engine Room-related parameters (permeability and layout) come with a relatively less influence. A relatively very little influence is found for Air-related parameters (cross-flooding and air-ventilation level). This study demonstrates the validity and efficiency of applying the DOE methodology in Damaged Survivability Domain, and establishes a suitable basis to elaborating a novel assessment procedure based on ‘interactive research’ to reliably assess the damaged survivability of such vessels. Furthermore, theoretical models and numerical codes can benefit of its achievements to improve their performance and credibility
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Johansson, Robin. "Structural optimization of electronic packages using DOE." Thesis, KTH, Hållfasthetslära, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-285859.
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The reliability of a mechanical system containing electronic packages is highly affectedby the environment the system is stationed in. The difference and fluctuationsbetween the ambient temperature and the operating temperature of the electronicpackage cause accumulation of inelastic strains in the package components thusdecreasing the service life. The most common failure modes of an electronic packagehas been identified from inspection of malfunctioning machines as cracks in the solderjoint and delamination between the glue and the die. Knowledge regarding therelationships between parameters affecting these failure modes, which are importantand which are not, is of high interest when developing new and existing products. SAAB AB would like to develop a methodology using design exploration to allow forevaluation of electronic packages using nonlinear finite element methods. A surrogate model was created and parameterized with HyperMorph to be used forthree linear static variations of design of experiments, where both the performance ofthe methods themselves and the relative importance of the parameters were ofinterest. A connectivity condition was also implemented to allow for relativemovement between components while keeping the mesh intact. The designexploration was executed using a Taguchi design, a Modified extensive latticesequence design and a fractional factorial design where the three methods werecompared as well as the parameter significance analysed. An optimization was thenperformed to find the optimal parameter settings within the allowed bounds to beused where a nominal model and an optimized model are evaluated with animplemented creep law. The fatigue life of the two models were then estimated.<br>Tillförlitligheten hos ett mekaniskt system med elektroniska kretsar påverkas starkt av miljön systemet används i. Skillnader och fluktuationer mellan omgivningens temperatur och arbetstemperaturen för de elektroniska kretsarna orsakar ackumulering av inelastiska töjningar, därmed förkortas det mekaniska systemets livstid. Dem vanligaste fel-moderna för en elektronisk krets har identifierats genom inspektion av felande maskiner som sprickbildning i lödfogarna och delaminering mellan processorn och dess lim. Kunskap hur förhållandet mellan parametrar som påverkar dessa fel-moder, vilka som är viktiga och vilka som inte är viktiga är av högt intresse vid utveckling av nya och redan existerande produkter. SAAB AB vill utveckla en metodik som utnyttjar statistisk försöksplanering för analyserande av elektroniska kretsar med hjälp av olinjära finita element metoder för att kunna spegla dess beteende på ett realistiskt sätt. En surrogatmodell skapades och parametriserades med hjälp av HyperMorph för att användas inom tre statiskt linjära varianter av statistisk försöksplanering, där både metodens prestanda och den relativa påverkan från parametrarna var av intresse. Ett kontaktvillkor implementerades för att tillåta relativ rörelse mellan komponenter samtidigt som nätet av finita element hölls intakt. Försöksplaneringsimuleringar utfördes med en Taguchi design, en Modified extensive lattice sequence design och en fractional factorial design, där de tre metoderna jämfördes mot varandra samt analyserades vad gäller respektive parametersignifikansen. Med optimering fanns sedan en optimal modell för att kunna jämföras med en nominell modell där en kryplag implementerades i lödfogen. Livslängden beräknades sedan för båda modeller.
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Verlaan, Eric, Wouter Hendriksen, Rob Meulenbroek, and Prie Devlin du. "Design of Experiments (DOE) for Product and Process Improvements - 130: A Phenolic Syntan Case Study." Verein für Gerberei-Chemie und -Technik e. V, 2019. https://slub.qucosa.de/id/qucosa%3A34176.
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Content:
For sustainable developments the chemical industry is continuously looking for technical innovations with wide potential implications. The Design of Experiments (DOE) approach has been proven to be a powerful tool in determining the relationship between factors affecting certain output variables. This is done to establish a 'cause and effect' relationship and eventually realize output optimization. In order to evaluate whether DOE can be implemented for improving our products and processes, a case study, focusing on the synthesis and production of traditional phenolic syntans was carried out within our R&D department. Although we can influence properties by application, the effect a retanning agent has on leather originates to a large extent from the chemistry involved. To understand interactions and the possibilities of targeted improvements of the production process, a DOE factorial design approach was used to identify the control parameters and their interactions in our phenolic syntan recipes that influence the various properties and effects. Instead of trial-and-error or one-factor-at-a-time practices, DOE made it possible to limit the number of lab experiments to one third (1/3) of the amount needed for completing our study. As a result, a much deeper and more consistent understanding of the building blocks’ interactions and how these influence the chemical process of phenolic syntan synthesis has been gained. This includes the amount of different building blocks, their molar ratios as well as process conditions. Aiming at achieving optimal efficiency for various projects, right now we are looking at possibilities in implementing DOE within Smit & zoon.
Take-Away:
The Design of Experiments (DOE) approach is a powerful tool in realizing process and product improvements.
DOE factorial design can be used to identify control parameters and their interactions in a wide reage of (industrial) applications.
DOE has been proven to be efficient and effective in optimizing phenolic syntan recipes and production process.
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Chini, Marco. "Sviluppo di nuove metodologie di calibrazione per motori da competizione con tecniche di Design of Experiments." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18647/.
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Lo scopo di questa tesi è quello di creare dei modelli di risposta di alcune grandezze fisiche di un motore da competizione, partendo dalla progettazione dell'attività di acquisizione dati al banco prova, per arrivare a dei risultati numerici che descrivano nel modo più fedele possibile il comportamento del motore e, dove possibile, andare a ottimizzarne le prestazioni e l'affidabilità.
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Lindberg, Tomas. "An application of DOE in the evaluation of optimization functions in a statistical software." Thesis, Umeå universitet, Institutionen för matematik och matematisk statistik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-39507.
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Chantarat, Navara. "Modern design of experiments methods for screening and experimentations with mixture and qualitative variables." Columbus, OH : Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1064198056.
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Thesis (Ph. D.)--Ohio State University, 2003.<br>Title from first page of PDF file. Document formatted into pages; contains xiv, 119 p.: ill. (some col.). Includes abstract and vita. Advisor: Theodore T. Allen, Dept. of Industrial and Systems Engineering. Includes bibliographical references (p. 111-119).
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Farias, Marcelo Fernandes. "Determinação da influência de parâmetros de processo de forjamento a quente utilizando DOE (projeto de experimentos)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/170979.
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Atualmente o Projeto de Experimentos (DOE) vem sendo largamente utilizado para determinar os fatores de projetos e processos mais significativos afetando uma variável resposta e para estabelecer modelos empíricos entre os fatores, entretanto este método ainda é pouco utilizado e processo de forjamento a quente. O presente trabalho analisa a influência individual e cumulativa de alguns parâmetros controláveis de um processo de forjamento a quente em matriz fechada na força de prensagem necessária para sua realização. Esta análise foi realizada utilizando a técnica de Projeto de Experimentos (DOE). Para a determinação da influência dos parâmetros de processo selecionados na variável resposta do Projeto de Experimentos (DOE), uma série de ensaios variando o lubrificante utilizado, o diâmetro da geratriz e a temperatura de forjamento foram realizados. A variável resposta para o experimento foi definida como a força de prensagem exigida do equipamento para a realização do forjamento. Para este trabalho foi utilizado o material ABNT 4140 fornecido em barras trefiladas de 28,6mm (1.1/8″) posteriormente forjado a quente em matriz fechada. Os resultados mostraram que o fator que mais influencia na força de prensagem para a situação ensaiada é o lubrificante. Os demais fatores, mesmo combinados, não apresentaram uma influência significativa na variável resposta. O presente estudo demonstra que é possível a utilização de técnicas de ajuste e definição de parâmetros de processo de forjamento a quente de maneira confiável e sem a necesside da aplicação dos complexos programas de simulação computacional e os métodos de tentativa e erro ainda presentes na indústria. Finalmente este trabalho reforça a versatilidade do Projeto de Experimentos (DOE) ainda pouco aplicado em processos de forjamento.<br>Nowadays the Design of Experiments (DOE) has been widely used to determine the most significant project and process factors affecting a response variable and to establish empirical models among the factors, although this method is still little used and the process of hot forging. This work analyzes the individual and cumulative influence of some controllable parameters in a closed die hot forging process in the pressing force required for its realization. This analysis was performed using a Design of Experiments (DOE) method. To determine the influence of variable factors selected in response Design of Experiments (DOE), a several tests varying the lubricant, the diameter of the billet and the forging temperature was performed. The response variable for the experiment was defined as pressing force. For this study, it was used the ABNT 4140 steel provided in drawn bars of 28,6mm (1 1/8 ″). The fator that had more influence over the pressing force was the lubricant. Other factors, whether or not combined, did not show a significant influence on the response variable. This study demonstrates that it is possible use techniques to set hot forging process parameters reliably and without necesside the application of complex computer simulation programs or the trial and error system. Finally, this work reinforces the versatility of Design of Experiments (DOE) wich is still little used in forging processes.
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Clay, Stephen Brett. "Characterization of Crazing Properties of Polycarbonate." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/28648.
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The purpose of this study was to characterize the craze growth behavior of polycarbonate (PC) as a function of stress level, model the residual mechanical properties of PC at various craze levels and strain rates, and determine if the total surface area of crazing is the sole factor in residual properties or if the crazing stress plays a role. To obtain these goals, a new in-situ reflective imaging technique was developed to quantify the craze severity in transparent polymers.
To accomplish the goal of craze growth rate characterization, polycarbonate samples were placed under a creep load in a constant temperature, constant humidity environment. Using the new technique, the relative craze density was measured as a function of time under load at stresses of 40, 45, and 50 MPa. The craze growth rates were found to increase exponentially with stress level, and the times to 1% relative craze density were found to decrease exponentially with stress level. One exception to this behavior was found at a crazing stress of 50 MPa at which over half of the samples tested experienced delayed necking, indicating competitive mechanisms of crazing and shear yielding. The draw stress was found to be a lower bound below which delayed necking will not occur in a reasonable time frame.
The yield stress, elastic modulus, failure stress, and ductility were correlated to crazing stress, relative craze density, and strain rate using a Design of Experiments (DOE) approach. The yield stress was found to correlate only to the strain rate, appearing to be unaffected by the presence of crazes. No correlation was found between the elastic modulus and the experimental factors. The failure stress was found to decrease with an increase in relative craze density from 0 to 1%, increase with an increase in crazing stress from 40 to 45 MPa, and correlate to the interaction between the crazing stress and the strain rate. The ductility of polycarbonate was found to decrease significantly with an increase in relative craze density, a decrease in crazing stress, and an increase in strain rate.
The craze microstructure was correlated to the magnitude of stress during craze formation. The area of a typical craze formed at 40 MPa was measured to be more than 2.5 times larger than the area of a typical craze formed at 45 MPa. The fewer, but larger, crazes formed at the lower stress level were found to decrease the failure strength and ductility of polycarbonate more severely than the large number of smaller crazes formed at the higher stress level.<br>Ph. D.
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Sandqvist, Wedin Emma. "Optimization of Acidic Degradation of Hyaluronic Acid using Design of Experiments." Thesis, Linköpings universitet, Teknisk biologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-156273.
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Hyaluronic acid (HA) is an unbranched polysaccharide consisting of the repeating disaccharide unit β(1→4)-GlcA-β(1→3)-GlcNAc and is a naturally occurring biopolymer in bacteria and vertebras. HA is predominantly found in the extracellular matrix (ECM) and the in vivo function of HA can vary depending on molecular weight (Mw) for instance high Mw HA is reported to be anti-angiogenic while low Mw HA induces angiogenesis. HA is a popular component for hydrogels such as dermal fillers. HA is commonly used in dermal fillers. However, other materials, such as other polymers, can be used as well. The project goal was to investigate different degradation processes for production of target Mw HA. Alkaline and acidic degradation processes in combination with increased temperatures seemed as the most promising methods. Degradation tests performed both in aqueous solution as well as heterogeneously in ethanol were evaluated. The acidic degradation in aqueous solution was proven to have the largest degradation constant. Both a robustness test as well as a Design of Experiments (DoE) was performed to investigate the influence different factors had on the degradation speed. The investigated factors were HA concentration, HCl concentration and temperature. Temperature and HCl concentrations proved to be the most influencing factors and a model was developed in the DoE software MODDE to describe how the factors influenced the degradation constant. The model was established as a good significant model with a Q2 value of 0.998 and relative standard deviation (RSD) value of 0.022 after a logarithmic transformation was performed as well as a simplification of the model by excluding some of the factor interactions. The acidic degradation method also proved to be a highly robust method which easily could be used to produce target Mw HA.
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Smeliková, Lenka. "Kontrola kvality pájeného spoje a Design of Experiments u strojního pájení vlnou." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220991.
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This master´s thesis deals with problems of wave soldering and application methods Design of Experiments for the new product production. Summarizes the basic knowledge of soldering technology, of solder alloys and Design of Experiments methods. Design of Experiments method has been applied to product to find the optimal for wave soldering setting.
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Amanna, Ashwin Earl. "Statistical Experimental Design Framework for Cognitive Radio." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/77331.
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This dissertation presents an empirical approach to identifying decisions for adapting cognitive radio parameters with no a priori knowledge of the environment. Cognitively inspired radios, attempt to combine observed metrics of system performance with artificial intelligence decision-making algorithms. Current architectures trend towards hybrid combinations of heuristics, such as genetic algorithms (GA) and experiential methods, such as case-based reasoning (CBR). A weakness in the GA is its reliance on limited mathematical models for estimating bit error rate, packet error rate, throughput, and signal-to-noise ratio. The CBR approach is similarly limited by its dependency on past experiences. Both methods have potential to suffer in environments not previously encountered. In contrast, the statistical methods identify performance estimation models based on exercising defined experimental designs. This represents an experiential decision-making process formed in the present rather than the past. There are three core contributions from this empirical framework: 1) it enables a new approach to decision making based on empirical estimation models of system performance, 2) it provides a systematic method for initializing cognitive engine configuration parameters, and 3) it facilitates deeper understanding of system behavior by quantifying parameter significance, and interaction effects. Ultimately, this understanding enables simplification of system models by identifying insignificant parameters. This dissertation defines an abstract framework that enables application of statistical approaches to cognitive radio systems regardless of its platform or application space. Specifically, it assesses factorial design of experiments and response surface methodology (RSM) to an over-the-air wireless radio link. Results are compared to a benchmark GA cognitive engine. The framework is then used for identifying software-defined radio initialization settings. Taguchi designs, a related statistical method, are implemented to identify initialization settings of a GA.<br>Ph. D.
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Henriques, Francisco José da Silva. "O uso do DOE em conjunto com FTA no desenvolvimento e melhoria de projetos inovadores." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263938.
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Orientador: Auteliano Antunes dos Santos Junior<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica<br>Made available in DSpace on 2018-08-19T07:33:31Z (GMT). No. of bitstreams: 1
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Previous issue date: 2011<br>Resumo: O presente trabalho tem como objetivo apresentar e aplicar uma metodologia que possa ser utilizada nos diagnósticos de falhas, a priori, com causas desconhecidas ou diferentes das já conhecidas, por equipes de desenvolvimento de novos produtos. Esse tipo de falha acontece principalmente quando trata-se de produtos inovadores e ocorrem durante o processo de validação e mesmo após o início da produção. A metodologia se baseia na aplicação de Planejamento de Experimentos em conjunto com Árvore de Falhas para a quantificação das importâncias das causas raiz. Como resultado do trabalho é possível identificar quais parâmetros são os principais candidatos a causadores da falha e hierarquizar as causas. É possível ainda verificar as interações entre as causas, se existirem. A combinação entre métodos proposta pode ser inserida em metodologias de projeto consagradas, como o Projeto para Seis Sigma (DFSS), criando uma nova forma de desenvolver projetos inovadores<br>Abstract: The present work aims to present and apply a methodology that can be used on failures diagnosis, with unknown or different causes from those already known by the development team. This kind of failure happens mainly along the design of innovative products and occurs during the validation process or in the infant life phase. The methodology is based on Design of Experiments, which is applied together with Failure Tree Analysis to quantify the importance of each root cause. From the results of this work it is possible to identify what are the main causes related to the fault and rank them. It is also possible to verify whether there are interactions between the causes or not. The methodology proposed joining both methods can be inserted unusual design methodologies as Design of Six Sigma, creating a new way to develop and improve innovative designs<br>Mestrado<br>Mecanica dos Sólidos e Projeto Mecanico<br>Mestre em Engenharia Mecânica
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Westbeld, Julius. "Investigation of support structures of a polymer powder bed fusion process by use of Design of Experiment (DoE)." Thesis, KTH, Lättkonstruktioner, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-243867.
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In this thesis, support structures of a polymer powder based process called XXXXXXXX™ are examined. These structures are crucial for most additive manufacturing processes. The effects of several factors on five industrially important characteristics of support structures are examined by use of the Design of Experiment (DoE) method. It describes the planning as well as the analysis of the experiments. The experiments are planned in a fractional factorial 211-5 design with 64 specimens, resulting in a resolution of IV. The analysis of the data is done by use of the ANOVA method, with which the significance of effects and interaction effects are checked.<br>I detta examensarbete undersöks stödstrukturer för en polymer-pulverbaserad process kallad XXXXXXXX. Dessa strukturer är väsentliga för de flesta aditiv tillverkning. Med hjälp av metoden "Design of Experiment" (DoE) undersöks effekten av flera faktorer på fem industriellt viktiga egenskaper för stödstrukturer. DoE beskriver både planeringen och analysen av experiment. Experimenten planeras i en fraktionerad faktoriell 211-5 design med 64 provexemplar vilket resulterar i en upplösning av IV. Dataanalysen genomförs med hjälp av ANOVA-metoden, med vilken signifikansen av effekter och interaktionseffekter kan undersökas.
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Scheffler, Liziane da Luz Seben. "Estudo exploratório de extração de celulose a partir de resíduos vegetais do processo produtivo de conserva de palmito (Archontophoenix alexandrae)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/35616.
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No Brasil, tanto o agronegócio quanto a fabricação de celulose trazem resultados relevantes para a economia. Sob uma perspectiva de sustentabilidade, as indústrias beneficiadoras de materiais vegetais geram grande volume de resíduos, os quais podem servir de fonte de celulose, configurando-se numa alternativa atraente para gerar lucros e diminuir impactos ambientais negativos. O objetivo geral desta dissertação é realizar um estudo exploratório de extração de celulose a partir de resíduo do processo produtivo de empresa beneficiadora de material vegetal, sob perspectiva das dimensões ambiental e econômica da sustentabilidade. O estudo foi desdobrado em cinco etapas: i) identificação na literatura das diretrizes para os processos produtivos sustentáveis, por meio das abordagens que tratam da sustentabilidade; ii) identificação dos processos industriais de extração de celulose e suas características operacionais; iii) definição da empresa para realização do estudo, a sazonalidade e o volume disponível dos resíduos vegetais provenientes do processo de beneficiamento de vegetais; iv) adaptação do processo industrial de extração de celulose para uso com resíduos vegetais e atendimento às restrições da fábrica definida para o estudo e v) realização de testes de extração com o uso de projeto de experimentos para posterior caracterização da polpa de celulose obtida do resíduo. Neste último, foi empregado um Projeto Fatorial Composto de Segunda Ordem (PSCO) com Metodologia de Superfície Resposta (MSR) para analisar a influência dos fatores controláveis sobre as variáveis de resposta. Os fatores controláveis foram definidos de acordo com dados da literatura específica e foram analisadas as variáveis de resposta que caracterizam polpa de celulose, aplicáveis a fins sanitários, como Número Kappa, capacidade de absorção, velocidade de absorção e densidade. Resultados indicaram que limitações quanto ao uso de altas temperaturas no processo de extração é um fator relevante, para atingir maiores teores de deslignificação. Os estudos mostraram a influência do uso de aditivo de processo, antraquinona, carga alcalina e tempo de polpeamento, bem como, tratamento de hidrólise ácida no resíduo na qualidade da polpa.<br>Agribusiness and pulp production bring both relevant results to the Brazilian economy. In a sustainable perspective, the wastes of Industries that benefit vegetable materials may serve as pulp’s source, configuring itself as an attractive alternative for profit generation and reduction of negative environmental impacts. The aim in this dissertation is to carry out an exploratory study of pulp extraction from the waste of productive process of a firm which processes vegetal material, under the perspective of environmental and economic dimensions of sustainability. The study was unfolded in five steps: i) identification, in literature, the guidelines for sustainable productive processes, through approaches that embrace sustainability; ii) identification of industrial processes of pulp extraction and respective operational features; iii) definition of an industrial unit to perform the study, as well as the seasonality and the availability of vegetal wastes coming from the vegetable process; iv) adaptation of the industrial process of pulp extraction for using with vegetable wastes, and attendance to constraints of the current process in the industrial unit chosen for the study; and v) the performance of extraction tests using a project of experiments for further characterization of the cellulose pulp resulting from the waste. It was employed a Factorial composite second-order design in a Surface Response Methodology (SRM) in order to analyze the influence of the controlled variables over the response variables. Variables of the extraction process were defined according with the specific literature’s data, and response variables, adequate to the cellulose pulp characterization as Kappa Number, capability, absortion speed and apparent density were analyzed. Results indicate that constraints related to the high temperature used in the equipment available for extraction is a relevant factor in the process for obtaining higher contents of delignification. Studies show the influence of using additive process, anthraquinone, load time and alkaline pulping, as well as treatment of hydrolysis in the waste of pulp quality. The remarkable difference in the quality of vegetable waste after hydrolysis treatment indicates that a pretreatment stage of such waste is interesting, since the fiber is resistant and requires high alkali and addictive charges.
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Sabová, Iveta. "Plánovaný experiment." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231981.
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This thesis deals with the possibility of applying the method of Design of Experiments (DoE) on specific data. In the first chapter of theoretical part, this method is described in detail. The basic principles and guidelines for the design of the experiment are written there. In the next two chapters, factorial design of the experiment and response surface design are described. The latter one includes a central composite design and Box-Behnken design. The following chapter contains practical part, which focuses on modelling firing range of ball from a catapult using the above three types of experimental design. In this work, the models are analysed together with their different characteristics. Their comparison is made by using prediction and confidence intervals and by response optimizing. The last part of the thesis comprises overall evaluation.
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Nilsson, Marcus, and Johan Ruth. "SPC and DOE in production of organic electronics." Thesis, Linköping University, Department of Science and Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-6240.
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<p>At Acreo AB located in Norrköping, Sweden, research and development in the field of organic electronics have been conducted since 1998. Several electronic devices and systems have been realized. In late 2003 a commercial printing press was installed to test large scale production of these devices. Prior to the summer of 2005 the project made significant progress. As a step towards industrialisation, the variability and yield of the printing process needed to bee studied. A decision to implement Statistical Process Control (SPC) and Design of Experiments (DOE) to evaluate and improve the process was taken.</p><p>SPC has been implemented on the EC-patterning step in the process. A total of 26 Samples were taken during the period October-December 2005. An - and s-chart were constructed from these samples. The charts clearly show that the process is not in statistical control. Investigations of what causes the variation in the process have been performed. The following root causes to variation has been found: </p><p>PEDOT:PSS-substrate sheet resistance and poorly cleaned screen printing drums. </p><p>After removing points affected by root causes, the process is still not in control. Further investigations are needed to get the process in control. Examples of where to go next is presented in the report. In the DOE part a four factor full factorial experiment was performed. The goal with the experiment was to find how different factors affects switch time and life length of an electrochromic display. The four factors investigated were: Electrolyte, Additive, Web speed and Encapsulation. All statistical analysis was performed using Minitab 14. The analysis of measurements from one day and seven days after printing showed that:</p><p>- Changing Electrolyte from E230 to E235 has small effect on the switch time</p><p>- Adding additives Add1 and Add2 decreases the switch time after 1 and 7 days</p><p>- Increasing web speed decreases the switch time after 1 and 7 days </p><p>- Encapsulation before UV-step decreases the switch time after 7 days</p>
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Rådberg, Malin. "Design of Experiment for Laser cutting in Superalloy Haynes 282." Thesis, Karlstads universitet, Science, Mathematics and Engineering Education Research (SMEER), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-44516.
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This project aims to investigate the effect of varying different laser cutting parameters on the laser cut surface. The parameters that were varied were cutting speed, beam effect, gas pressure and focal point. The statistical method Design of Experiment was used to plan the experiments and two full factorial test plans were set up, one with argon as cooling and protective gas and one with nitrogen. Sheet metal consisting of the superalloy HAYNES ® 282 with a thickness of 2,54 mm was investigated. Samples from the material were cut with different laser cutting parameters according to the test plans. The samples were evaluated by measuring cracks, recast layer thickness, surface irregularity, burr height and distance to beam deflection point on the cut surface. The resulting data was inserted as responses into the statistical program Modde 10.1 for analysis. Modde 10.1 provided models of high significance for the responses of Recast layer, Tav; Recast layer, Tmax; Burrheight, max and Distance to deflection point for the argon series and Recast layer, Tav and Recast layer, Tmax for the nitrogen series. The results showed that both recast layer thickness and burr height decreases with increased values of cutting speed, gas pressure and focal point as well as decreased values of beam effect within the parameter window investigated. They also showed that distance to deflection point increased with increasing values of gas pressure and focal point and with decreased values of cutting speed and beam effect within the parameter window. The results also showed that for the samples cut with argon as cooling and assistant gas the parameters that affects the recast layer thickness the most are focal point and gas pressure, whereas for the nitrogen series it is gas pressure and beam effect. The parameter with greatest effect on burr height is the cutting speed and for the distance to deflection point it is focal point and gas pressure that have the greatest effect. When comparing the argon and the nitrogen series to each other it can be seen that the argon series generate less recast layer from the entry of the cut until between 60 – 80 % into the cut, after which the argon series bypasses the nitrogen series in amount of recast layer produced in the cutting process in the majority of the places measured.<br>Projektet syftar till att undersöka effekten på den laserskurna ytan då laserskärningsparametrar varieras. Parametrarna som varierades var skärhastighet, lasereffekt, gastryck och fokalpunkt. Den statistiska metoden Design of Experiments användes för att planera experimenten. Två stycken fullskaligt faktoriella försöksplaner skapades, en med argon som skärgas och en med kväve som skärgas. Undersökningen gjordes på plåt bestående av superlegeringen HAYNES ® 282 med en tjocklek på 2,54 mm. Provbitar från materialet skars ut utifrån försöksplanerna med olika laserinställningar under skärprocessen. Provbitarna utvärderades genom att mäta sprickor, tjockleken på det omsmälta materialet, ytojämnheten, gradhöjden och avståndet till laserstrålens avböjningspunkt på den laserskurna ytan. Resultaten användes för analys i det statistiska programmet Modde 10.1. Modde 10.1 bidrog med modeller av hög signifikans för responserna Recast layer, Tav; Recast layer, Tmax; Burrheight, max and Distance to deflection point för argonserien och Recast layer, Tav och Recast layer, Tmax för kväveserien. Resultaten visar att både tjockleken på omsmält material och gradhöjden avtar med ökande värden på skärhastighet, gastryck och fokalpunkt samt minskande värden på lasereffekt inom det undersökta parameterfönstret. De visade också att till laserstrålens avböjningspunkt på den laserskurna ytan ökade med ökande värden på gastryck och fokalpunkt och med minskande värden på skärhastighet och lasereffekt inom parameterfönstret. Resultaten visade också att de parametrar som i störst utsträckning påverkar tjockleken på det omsmälta materialet för provbitarna i argonserien är fokalpunkt och gastryck, medan det för kväveserien är gastryck och lasereffekt. Parametern som har högst inverkar på gradhöjden är skärhastigheten, medan fokalpunkt och gastryck har störst effekt på avståndet till laserstrålens avböjningspunkt på den laserskurna ytan. Om kväveserien och argonserien jämförs med varandra kan det observeras att argonserien generellt genererar mindre omsmält material än kväveserien från det att laserstrålen träder in i materialet till dess att den är mellan 60 och 80 % in i snittet, vartefter argonserien går förbi kväveserien i mängd omsmält material på majoriteten av mätställen.
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Nelson, Benjamin D. "Using Design of Experiments and Electron Backscatter Diffraction to Model Extended Plasticity Mechanisms In Friction Stir Welded AISI 304L Stainless Steel." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2582.
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Extended plasticity mechanisms (EPM) allow a metal to undergo extended plastic deformation without failure. These mechanisms are responsible for the extended plastic deformation characteristic of hot working processes. In this thesis it is shown that electron backscatter diffraction (EBSD) is capable of detecting EPM artifacts in the final microstructure of AISI 304L stainless steel (304L). Results also indicate that dislocation cells form in hot worked AISI 304L stainless steel. Additionally, in this study EBSD data collection and analysis is used with a design of experiments approach to model the presence of EPM artifacts in the final microstructure of friction stir welded 304L. Texture analysis of the welded material reveals a dominant shear deformation texture and a lack of the rotated cube texture. The shear deformation texture is characteristic of dynamic recovery (DRV) and continuous dynamic recrystallization (CDRX), while the rotated cube texture is characteristic of discontinuous dynamic recrystallization (DDRX). The texture analysis results indicate that dynamic recovery (DRV) and continuous dynamic recrystallization (CDRX) play a role in the final microstructure of the welded material, while DDRX does not. Design of experiments was used to find the relationships between the fraction of cell boundaries and spindle speed, travel speed, location in the stir zone, and tool temperature. The regression analyses reported that predicted fraction of cell boundaries were relatively high (approximately 0.70 or more) and changed by less that 20% in the stir zone and 10% in the TMAZ. The relatively high predictions indicate that in FSW 304L DRV dominates and limited CDRX occurs. The small changes in predictions across the experimental space indicate that the effects, while statistically significant, are not practically significant. Finally, an alternate tool temperature basis was developed, which provides a valid method for selecting welds which should have constant tool temperature.
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Knob, Jan. "Pěnění fermentačních zbytků při vakuovém odpařování." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378403.
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The diploma thesis deals with the processing of digestate, which is the remaining material after biogas production. It aims to experimentally prove how chosen operational parameters of antifoaming agents influence digestate foaming associated with the vacuum evaporating technology. Based on the research of available antifoamers and the issue of digestate foaming itself, it was observed how three selected antifoamers (i.e. rapeseed oil, silicone antifoamer Erbslöh Schaum-ex and oleic acid), together with the decrease in the pH factor of the evaporating digestate, influence the final foam production. For the purposes of the research, an apparatus simulating the vacuum evaporating process was set up in which the heated sample was brought to boil by gradual pressure decrease. The process of foaming was observed in a transparent cylinder of a testing culumn. The essential part of the experimental activity is represented by a planned experiment which by means of a DoE (Design of experiments) method proved rapeseed oil to be very efficient. In contrast, other antifoamers, as well as the influence of the pH factor decrease, manifested themselves as insignificant factors, while the oleic acid even supported the foaming. The supplementary measurements led to a more detailed research of the effects of rapeseed oil and to the construction of a mathematical model describing how the concentration of rapeseed oil undermines the amount of generated foam. The main contribution of the thesis is firstly the evidence that rapeseed oil plays an important part in the reduction process of digestate foaming and secondly the determination of minimum substance concentration leading to the foaming reduction of a particular sample which is considered efficient enough to enable functioning of a vacuum evaporator. The thesis has also experimentally demonstrated the influence of some polymer organic flocculants which have been proved to support the foaming.
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Andersson, David. "Multivariate design of molecular docking experiments : An investigation of protein-ligand interactions." Doctoral thesis, Umeå universitet, Kemiska institutionen, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-35736.
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To be able to make informed descicions regarding the research of new drug molecules (ligands), it is crucial to have access to information regarding the chemical interaction between the drug and its biological target (protein). Computer-based methods have a given role in drug research today and, by using methods such as molecular docking, it is possible to investigate the way in which ligands and proteins interact. Despite the acceleration in computer power experienced in the last decades many problems persist in modelling these complicated interactions. The main objective of this thesis was to investigate and improve molecular modelling methods aimed to estimate protein-ligand binding. In order to do so, we have utilised chemometric tools, e.g. design of experiments (DoE) and principal component analysis (PCA), in the field of molecular modelling. More specifically, molecular docking was investigated as a tool for reproduction of ligand poses in protein 3D structures and for virtual screening. Adjustable parameters in two docking software were varied using DoE and parameter settings were identified which lead to improved results. In an additional study, we explored the nature of ligand-binding cavities in proteins since they are important factors in protein-ligand interactions, especially in the prediction of the function of newly found proteins. We developed a strategy, comprising a new set of descriptors and PCA, to map proteins based on their cavity physicochemical properties. Finally, we applied our developed strategies to design a set of glycopeptides which were used to study autoimmune arthritis. A combination of docking and statistical molecular design, synthesis and biological evaluation led to new binders for two different class II MHC proteins and recognition by a panel of T-cell hybridomas. New and interesting SAR conclusions could be drawn and the results will serve as a basis for selection of peptides to include in in vivo studies.
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Bredda, Eduardo Henrique. "Estudo comparativo e otimização da quantidade de ômega 3 e ômega 6 produzido pelas microalgas nannochloropsis gaditana e dunaliella salina /." Guaratinguetá, 2019. http://hdl.handle.net/11449/183502.
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Orientador: Messias Borges Silva<br>Resumo: O cultivo de microalgas tem sido considerado como uma fonte promissora de lipídeos para a obtenção de ácidos graxos de alto valor agregado, como é o caso dos ômegas 3 (ω3) e ômegas 6 (ω6). O uso do planejamento de experimentos (DOE) permite estabelecer condições apropriadas de cultivo para as microalgas que favorece o acúmulo desses ácidos graxos. Desta forma, o presente trabalho teve como objetivo melhorar o desempenho dos cultivos das microalgas Nannochloropsis gaditana e Dunaliella salina, visando a produção de ω3 e ω6. Primeiramente, foram avaliadas, com o uso de uma matriz ortogonal Taguchi L4, as influências das concentrações de nitrato de sódio (de 25 a 75 mg L-1), de acetato de sódio e bicarbonato de sódio (ambas de 0 a 2 g L-1), sobre a produtividade de biomassa (Pb) e de lipídeos (Po). Como resultado, foi notado que tanto o acetato quanto o nitrato, influenciaram positivamente na Pb e na Po, para ambas as microalgas estudadas. O bicarbonato, por outro lado, não melhorou a Po, sendo excluído das etapas posteriores. Na etapa seguinte do trabalho foi realizado um planejamento fatorial completo 22 com ponto central, focando no estudo da concentração de nitrato (75 a 225 mg L-1) e acetato (2 a 6 gL-1) sobre a produtividade dos cultivos. As maiores Pb obtidas foram: 188,93 mg L-1 dia-1 para a microalga N. gaditana (225 mg L-1 de nitrato e 6 g L-1 de acetato) e 118,93 mg L-1 dia-1 para a D. salina (150 mg L-1 de nitrato e 4 g L-1 de acetato). Nestas condições de cultivo, a... (Resumo completo, clicar acesso eletrônico abaixo)<br>Doutor
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Tosto, Francesco. "Investigation of performance and surge behavior of centrifugal compressors through CFD simulations." Thesis, KTH, Mekanik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-226159.
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The use of turbocharged Diesel engines is nowadays a widespread practice in the automotive sector: heavy-duty vehicles like trucks or buses, in particular, are often equipped with turbocharged engines. An accurate study of the flow field developing inside both the main components of a turbocharger, i.e. compressor and turbine, is therefore necessary: the synergistic use of CFD simulations and experimental tests allows to fulfill this requirement. The aim of this thesis is to investigate the performance and the flow field that develops inside a centrifugal compressor for automotive turbochargers. The study is carried out by means of numerical simulations, both steady-state and transient, based on RANS models (Reynolds Averaged Navier-Stokes equations). The code utilized for the numerical simulations is Ansys CFX. The first part of the work is an engineering attempt to develop a CFD method for predicting the performance of a centrifugal compressor which is based solely on steady-state RANS models. The results obtained are then compared with experimental observations. The study continues with an analysis of the sensitivity of the developed CFD method to different parameters: influence of both position and model used for the rotor-stator interfaces and the axial tip-clearance on the global performances is studied and quantified. In the second part, a design optimization study based on the Design of Experiments (DoE) approach is performed. In detail, transient RANS simulations are used to identify which geometry of the recirculation cavity hollowed inside the compressor shroud (ported shroud design) allows to mitigate the backflow that appears at low mass-flow rates. Backflow can be observed when the operational point of the compressor is suddenly moved from design to surge conditions. On actual heavy-duty vehicles, these conditions may arise when a rapid gear shift is performed.<br>Användningen av turboladdade dieselmotorer ärr numera utbredd inom bilindustrin: i synnerhet tunga fordon som lastbilar eller bussar ärr ofta utrustade med turbo-laddade motorer. En utförlig förståelse av flödesfältet som utvecklas innuti båda huvudkomponenterna hos en turboladdare, dvs kompressor och turbin, är därför nödvändig: den synergistiska användningen av CFD-simuleringar och experimentel-la tester möjliggör att detta krav uppfylls. Syftet med denna avhandling är att undersöka prestanda och det flödesfält som utvecklas i en centrifugalkompressor för turboladdare. Studien utförs genom nu-meriska simuleringar, både steady state och transient, baserat på RANS-modeller (Reynolds Averaged Navier-Stokes-ekvationer). Koden som används för de numeriska simuleringarna är Ansys CFX. Den första delen av arbetet ¨ar ett försöka att utveckla en CFD-metod för att förutsäga prestanda för en centrifugalkompressor med hjälp av steady-state RANS-modeller. De erhållna resultaten jämförs sedan med experimentella observationer. Studien fortsätter med en analys av känsligheten hos den utvecklade CFD-metoden till olika parametrar: Inflytande av både position och modell som används för rotor-statorgränssnitt samt axiellt spel mellan rotor och hus på de globala prestationerna studeras och kvantifieras. I andra delen utförs en designoptimeringsstudie baserad på Design of Experiments (DoE). I detalj används tidsupplösta RANS-simuleringar för att identifiera vilken utformning av ported shroud som minskar backflöde i kompressorn under en snabb minskning av massflöde och varvtal och därmed ger bättre prestanda i transient surge. På tunga fordon kan dessa förhållanden uppstå under växling.
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Hizli, Cem. "Thermal Optimization of Veo+ Projectors (thesis work at Optea AB) : Trying to reduce noise of the Veo+ projector by DOE (Design of Experiment) tests to find anoptimal solution for the fan algorithm while considering the thermal specifics of the unit." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-10382.
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The Veo+ projector is using a cooling system that consists of fan and blowers. This system is cooling the electronic components of the device and the lamp of the projector, however extracting a high noise. To lower this noise the rpm speeds (rotational speed) of the fan and blowers should be decreased. Thus, lowering the speed will result in higher temperature values in whole system (inside the device). While lowering the speed, the higher temperature values should be kept within the thermal design specifications of the electronic components. The purpose of this thesis work is to find an optimal solution with lower rpm speeds of the fan and blowers while keeping the temperatures of the various components of the device (touch temperature of the enclosure and electronic components) within the temperature design limits. Before testing the device to find the optimum state, the design limits of the device are determined. Then, by using the design of experiment methods like Taguchi, the optimum state for the device within the design specifications is obtained. Finally, additional tests are applied within the optimum state to demonstrate a fan algorithm as a final solution. While doing the experiments thermocouples are used for measuring the component temperatures.
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Holec, Tomáš. "Plánovaný experiment." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254455.
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In this thesis, the design of experiment is studied. Firstly, a theoretic background in mathematical statistics necessary for understanding is built (chapter 2). The design of experiment is then presented in chapters 3 and 4. Chapter 3 is divided into several subchapters in which its brief history is provided as well as its complex theoretic description (basic principles, steps for planning, etc.). Chapter 4 deals with particular types of the design of experiment (Factorial experiments or Response surface design). Simple examples are provided to illustrate the theory in chapters 3 and 4. Last part of the thesis is strictly practical and focuses on an application of the theory for particular data sets and its evaluation (chapter 5).
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Venturini, Giacomo. "Design of experiment analysis of air filter performance for helicopter applications." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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Helicopters are used in different situations and in extremely various environments. Sometimes they land or take off to or from rough landing sites where dust, sand and other materials are present. One of the major problem for helicopters engine is the ingestion of these materials. This problem can be solved by using a filter positioned at the engine intake.
The filtration in helicopters is a recent development because, until recent times, research in this field was considered non-profitable and downplayed. Filtration is closely connected with engine efficiency and, in recent years, it has been seen that with a small investiment, helicopter performances were much better. A good filtration means less consumption and more perfomance.
This work is a part of a project conducted by BMC Air Filters, a company known worldwide for the production of high performance air filters and air induction systems. The goal of the main project consists in studying the optimization of the process in the design of filter elements for helicopters.
The two important features to evaluate an Inlet Barrier Filter are the pressure drop and the capture efficiency. In this work the first aspect is treated.
In the engineering design process, the experimentation plays an important role. In this thesis the Design Of Experiment (DOE) method is used to minimize the number of tests conducted, reaching several positive results. Indeed, in order to decrease the pressure loss, the two parameters to change are materials and geometric shape. Thus, two different materials of filter and several different filter geometric shapes are investigated through DOE, leading to identify the best design solution.
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Jakob, Marius. "Methode zur Gestaltung anwendungsabhängiger Mitnehmerverbindungen: Leichtbau und Steigerung der Tragfähigkeit durch dünnwandige Profilwellen." Technische Universität Chemnitz, 2019. https://monarch.qucosa.de/id/qucosa%3A34105.
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Dieser Vortrag beschreibt ein methodisches Vorgehen zur Auslegung von Bauteilen, die von mehreren Eingangsgrößen und mehren Zielgrößen bestimmt sind. Als Praxisbeispiel wird eine dünnwandige Mittnehmerwelle untersucht.
Im Automotivbereich besteht auf Grund der Forderungen nach Leichtbau und höherem Leistungsgewicht verstärkt der Wunsch nach einer hohen Auslastung über das ganze Bauteil hinweg. Eine Gewichtsreduktion kann durch Materialeinsparungen an unkritischen Stellen, wie zum Beispiel im Wellenkern einer Zahnwelle, erreicht werden. Die Verwendung von dünnwandigen Rohren als Ausgangsmaterial, aus denen lastangepasste Zahnprofile umformend hergestellt werden, versprechen eine deutliche Steigerung der Drehmomentübertragbarkeit bezogen auf den Materialeinsatz.
Dazu wird eine neue Verzahnungsgeometrie entwickelt. Das Profil wird über eine Vielzahl an Parametern definiert, welche die Form und damit die Drehmomentübertragbarkeit beeinflussen.
Durch die Verwendung einer bidirektionalen Schnittstelle kann eine Zahn-Geometrie in einem CAD-Programm mit einem FEM-Programm gekoppelt werden. Es zeigt sich, dass sich einige Geometrieparameter bereits durch die Wahl des Ausgangsrohres ergeben oder vorab festgelegt werden können. Mit vorgegebenem Außendurchmesser und Wandstärke des Ausgangsrohres sowie der Zähnezahl verbleiben bei dieser Profilform nur weitere fünf Parameter, welche hinsichtlich der Drehmomentübertragbarkeit zu optimieren sind. Mit Hilfe von numerischen Variantenberechnungen, welche sich nach den Vorgaben eines statistischen Versuchsplanes / Design of Experiments durch Veränderung der Parameter ergeben, kann ein mathematisches Ersatzmodell gebildet werden. Dieses beschreibt die (Wechsel-)Wirkungen der Eingangsgrößen auf die Ausgangsgrößen, wie zum Beispiel der Einfluss des Fußkreisdurchmessers und des Eingriffswinkels auf die dynamische Beanspruchbarkeit. Mit Hilfe von Optimierungsalgorithmen kann ein Optimum der Parameter an Hand des Ersatzmodelles ohne erneute aufwändige FEM-Berechnung gefunden werden.
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Fogliatto, Aloysio Arthur Becker. "Influência dos parâmetros do processo MIG/MAG com curto-circuito controlado sobre a geometria do cordão de solda." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/75921.
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O objetivo deste trabalho é estudar a influência dos parâmetros do processo de soldagem MAG com transferência do metal do tipo Curto-circuito Controlado (CCC) sobre a geometria do cordão de solda. Foi utilizado um dispositivo de soldagem automatizado para realização dos testes de simples deposição sobre um tubo de aço API 5L X65 diâmetro interno 204 mm e espessura 8 mm. Os parâmetros do processo analisados foram a corrente de pico de arco (Ia1), o tempo de atuação desta corrente (ta1), o tempo de atuação da corrente Ia2 (ta2), a velocidade de alimentação do arame (W) e a velocidade de soldagem (v). Tais parâmetros foram ajustados na interface homem-máquina (IHM) de uma fonte de potência microprocessada e do dispositivo de soldagem automatizado. As características geométricas do cordão de solda analisadas foram a largura, a altura do reforço e a penetração. Foi utilizado um Projeto de Experimento Composto de Segunda Ordem para obter a relação entre os parâmetros do processo e as características geométricas do cordão. Os modelos matemáticos obtidos foram considerados adequados, sendo possível determinar estatisticamente o nível de significância de cada um dos parâmetros controláveis – e de suas interações – sobre as respostas analisadas. Foram encontradas sobreposição e falta de fusão lateral em 60% dos corpos de prova avaliados, sendo levantada a hipótese de que a combinação de altos valores da corrente de pico de arco Ia1 com baixos valores do tempo de atuação deste parâmetro – ta1, aliada à utilização de gases de proteção com alta porcentagem de Ar, pode comprometer a eficiência de fusão nas laterais do cordão de solda. Os cordões de solda foram produzidos com quantidade reduzida de salpicos, representando um avanço do processo CCC quando comparado ao processo com transferência do metal por curto-circuito convencional. Os parâmetros controláveis Ia1 e ta1 produziram efeitos muito similares nas respostas de largura e penetração, quando considerados de forma isolada e também quando da interação destes com os demais parâmetros controláveis. A análise dos efeitos das interações principais revelou que Ia1 e ta1 são os parâmetros de maior influência nas respostas da geometria do cordão de solda, porém, com elevada dependência de um ajuste adequado da velocidade de alimentação do arame W para a obtenção de estabilidade do processo.<br>This work aims to study the influence of MAG welding process parameters with controlled short-circuit (CSC) metal transfer mode on weld bead geometry. The simple deposition weld tests were performed using a micro controlled power supply and an automatized device which enabled achievement of weld beads with standard conditions on API 5L X65 steel pipe whose inner diameter is 204 mm and thickness is 8 mm. The welding process parameters analyzed were the peak arcing current (Ia1), times (ta1) and (ta2), wire feed speed (W) and welding speed (v). Such parameters were set on Human-Machine Interface (HMI) of the micro controlled power supply and automatized welding device. The weld bead geometric features evaluated were width, reinforcement height and penetration depth. A Central Composite Face- Centred Design of Experiment was performed to obtain the relationship between the process parameters and the weld bead geometric features. Statistical analysis allowed development of mathematical models and they were found appropriate to determine the significance level of the process parameters – and their interactions – on output responses analyzed. Overlap and lack of fusion was detected on weld beads side in 60% of all specimens evaluated. The hypothesis formulated states that the origin of these discontinuities is from specific combination of parameters – high values of Ia1 and low values of ta1 together with usage of a shielding gas with high percentage of Ar – which would lead to lower fusion efficiency on weld bead side. The weld beads were produced with low spatter rates so it can be considered an improvement of the CSC process if compared with conventional short-circuit metal transfer mode. The peak arcing current Ia1 and time ta1 yielded similar effects on width and penetration depth, and it was valid when that parameters were taken both isolated and on interactions with other welding process parameters. The present study also revealed that Ia1 and ta1 are the most important parameters on influencing weld bead geometry, however, there is also strong dependence on a proper adjustment of wire feed speed W to obtain process stability.
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Borunský, Tomáš. "Optimalizace procesu tlakového lití VN přístrojových transformátorů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228552.
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This thesis deals with choises of using mathematical statistics when optimising the compression casting process of high-voltage device transformer. There is a theoretical consideration to be found in the introduction which concerns the compression casting itself and all necessary information connected with it. Then there is a key numerical analysis part following. In the first instance there are variability problems of individual casting device discussed and then a regression analysis made to demonstrate and prove a link between the partial discharge and the key parameters of casting process. Finally an “optimal” casting sequence is suggested and alternative attitude problems with the assistance of Design of Experiments (DOE) are discussed.
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Laiate, Juliana. "Estudo do processo de cultivo da microalga chlorella minutíssima e caracterização termoquímica de sua biomassa para aplicação em gaseificação." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/157246.
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Previous issue date: 2018-08-31<br>Outra<br>O interesse na diversificação da matriz energética por meio de fontes de energias renováveis tem promovido mudanças no âmbito nacional e internacional, em setores acadêmicos, industriais, sociais e governamentais com foco no desenvolvimento de processos biotecnológicos baseados nos três pilares da sustentabilidade: ambiental, social e econômico. Frente a esse contexto, as microalgas são consideradas uma fonte promissora alternativa para a produção de biocombustíveis por apresentarem alta taxa de crescimento e de concentração de lipídeos. O presente trabalho realizou um estudo do processo de cultivo da microalga marinha Chlorella minutíssima por meio da ferramenta DOE – Design of Experiments para maximização da sua concentração microalgal e do teor lipídico simultaneamente, além de sua caracterização termoquímica para aplicação no processo de gaseificação. O cultivo ocorreu em fotobiorreator tubular descontínuo do tipo coluna de bolhas seguindo o arranjo ortogonal L8 de Taguchi, e as variáveis de processo foram fluxo de CO2 na alimentação, concentração de nitrato, concentração de fosfato, suplementação, temperatura e salinidade. A investigação demonstrou que a concentração de nitrato e fosfato, o fluxo de gás carbônico, a suplementação do meio e a temperatura são fatores influentes na concentração microalgal e no teor lipídico, sendo a melhor configuração para maximização conjunta, utilizando-se a função desirability, com o nitrato operando em nível alto e os demais fatores em nível baixo. A análise elementar forneceu teores condizentes com alguns relatos da literatura, a termogravimetria auxiliou na identificação das faixas de temperatura com maior taxa de decomposição (300 °C a 400 °C), e o poder calorífico superior da biomassa encontrado se demonstrou atrativo para a produção de syngas quando comparado ao de materiais como casca de arroz e lascas de eucalipto já empregados na gaseificação em maior escala. Dessa forma, a metodologia empregada e os resultados apresentados neste trabalho podem auxiliar na busca da viabilização econômica do cultivo, em grande escala, da microalga marinha Chlorella minutíssima para produção de biocombustível pelo processo de gaseificação.<br>The interest in diversifying the energy matrix through renewable energy sources has promoted changes at the national and international levels in academic, industrial, social and governmental sectors, focused on the development of biotechnological processes based on the three pillars of sustainability: environmental, social and economic. In this context, microalgae are considered a strong promising alternative source for the production of biofuels due to their high rate of growth and lipid concentration. The present work carried out a study of the cultivation process of the marine microalgae Chlorella minutíssima using DOE – Design of Experiments to maximize the cell growth and the lipid content simultaneously, besides its thermochemical characterization for application in the gasification process. Cultivation occurred in a discontinuous-tubular photobioreactor, bubble-column type, following Taguchi L8 Orthogonal Array design, and the process variables were: CO2 feed flow rate, nitrate concentration, phosphate concentration, supplementation (metals and vitamins), temperature and salinity. Results showed that the nitrate and phosphate concentration, CO2 feed flow, supplements and temperature are influential factors in the cell growth and lipid content, and the best configuration presenting good results for simultaneous maximization, using desirability, was nitrate operating at high level and the other factors at low level. Ultimate analysis provided levels consistent with some reports in the literature. Thermogravimetric analysis identified the temperature ranges with the highest decomposition rate (300 °C to 400 °C). The higher heating value of the biomass found was attractive for the production of syngas when compared to raw materials such as rice husk and eucalyptus chips already used in the larger scale gasification. In face of, the methodology employed and the results presented in this work can be useful in seeking economic feasibility of the large-scale cultivation of Chlorella minutíssima for the production of biofuels by the gasification process.<br>PRH48 - ANP
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Zavoli, Chiara. "Applicazione del metodo Design of Experiment per l’analisi del ciclo di decontaminazione con H2O2 nell’industria farmaceutica." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
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L'elaborato di tesi descrive l’attività sperimentale e di modellazione effettuata presso I.M.A S.p.A., divisione Life, per l’analisi e l’ottimizzazione del ciclo di decontaminazione con H2O2 vaporizzato all’interno di isolatori.
L’attività sperimentale è stata svolta su un isolatore pilota presente in azienda. In particolare, le prove sono state eseguite su un MTI: esso è un isolatore dal volume ridotto, utilizzato per decontaminare piccoli carichi.
Il ciclo di decontaminazione si compone delle seguenti fasi: deumidifica, conditioning, decontamina, areazione. Quelle analizzate in questo progetto sono areazione ed iniezione (che comprende conditioning e decontamina), attraverso il metodo del Design of Experiment (DoE). Il DoE si definisce come un esperimento statistico programmato, che prevede di eseguire una serie di prove sperimentali opportunamente organizzate, in cui si variano in modo sistematico alcuni fattori di input al ciclo, per osservare le corrispondenti variazioni in uscita dell’output, o risposta. Sono stati realizzati due slot di prove sperimentali, uno per l'areazione e uno per l’iniezione, allo scopo di individuare i fattori più impattanti sul processo e ottimizzarlo di conseguenza.
Per la fase di areazione, variando la durata di iniezione, la portata di aria e la sua temperatura si è ottenuta la combinazione di fattori migliore per minimizzare la durata della fase, in più sono state individuate le condizioni ottimali per favorire il desorbimento di H2O2 da un materiale di test.
Per la fase di iniezione, variando la concentrazione di H2O2, la durata di iniezione, la portata di aria e la sua temperatura, sono stati individuati i requisiti necessari a massimizzare l’efficacia del ciclo.
L’analisi dei risultati sperimentali è stata eseguita con il software CAT: esso consente di identificare i fattori più impattanti sulla risposta in esame e permette di sviluppare un modello matematico che ne mostri l’andamento, nel dominio sperimentale analizzato.
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Haase, Dirk. "Ein neues Verfahren zur modellbasierten Prozessoptimierung auf der Grundlage der statistischen Versuchsplanung am Beispiel eines Ottomotors mit elektromagnetischer Ventilsteuerung (EMVS)." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1129553378853-30864.
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In recent years gasoline engines have become increasingly complex, for example through the introduction of electronic control and monitoring systems for ignition, fuel injection and exhaust aftertreatment. Parallel to this the requirements placed upon engines have also increased hence the need to develop new engine technologies. This demand for new technologies is, in part, due to the self obligation of the automobile industry to reduce the CO2 emissions about 25% by 2005, and also to the increasingly stringent future exhaust limits. Some promising solutions are currently in development, e.g. the direct injection gasoline engine and variable valve trains. All these new technologies are characterised by increasing complexity and significantly higher degrees of freedom. The associated application expenditure rises drastically with the number of free parameters and also with improved quality standards. Possible solutions to meet the future requirements of the development process are based on model-based parameter optimisation and the use of test methods, such as &quot;Design of Experiments&quot; (DoE). The idea behind this approach is to produce models to describe the dependence of the responses of interest (i.e. fuel consumption) on the adjusted engine parameters. With these models offline optimisation of the engine can be carry out, independently of testbench resources. The measured data for the models are produced with the help of statistically designed experiments. Thus, the testing and analysis processes are structured and the expenditure limited. In the following the DoE methodology will be employed of a gasoline engine with electromechanical valve train<br>Der Ottomotor im Kraftfahrzeug hat in den letzten Jahren mit dem Einzug elektronischer Steuer- und Regelsysteme für Zündung, Einspritzung und Abgasnachbehandlung einen sehr hohen technischen Stand erreicht. Die wachsenden Ansprüche an die Motorenentwicklung im Hinblick auf Verbrauchsreduzierung bei gleichzeitiger Erfüllung der zukünftigen Abgasgrenzwerte, verschärfen den Druck zur Entwicklung weiterführender Technologien. Hierbei gibt es bereits einige vielversprechende Lösungsansätze, wie z.B. die Direkteinspritzung oder variable Ventilsteuerungen. All diese neuen Technologien zeichnen sich durch eine wachsende Komplexität durch die signifikant höhere Anzahl von Freiheitsgraden aus. Der damit verbundene Applikationsaufwand steigt drastisch durch die wachsende Anzahl freier Parameter, aber auch durch die steigenden Anforderungen an die Qualität der Applikationsergebnisse. Einen möglichen Lösungsansatz zur Realisierung der zukünftigen Anforderungen an den Entwicklungsprozess stellen die modellgestützte Parameteroptimierung sowie der Einsatz der &quot;Statistischen Versuchsplanung&quot; (SVP) - &quot;Design of Experiments&quot; (DoE) - dar. Der Grundgedanke basiert auf der Erstellung von Modellen zur Beschreibung der Abhängigkeiten variierter Verstellparameter. Mit diesen Modellen können Offline-Optimierungen unabhängig von Prüfstandsressourcen durchgeführt werden. Die für die Modellbildung benötigten Messdaten werden mit Hilfe der statistischen Versuchsplanung erzeugt. Dadurch wird der Prozess strukturiert und der Aufwand wird begrenzt. In der Arbeit wird der Einsatz der DoE-Methodik am Beispiel eines Ottomotors mit elektromechanischer Ventilsteuerung (EMVS) aufgezeigt
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Yurtseven, Saygin. "Analysis Of The Influence Of Non-machining Process Parameters On Product Quality By Experimental Design And Statistical Analysis." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1026863/index.pdf.
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This thesis illustrates analysis of the influence of the non-machining processes on product quality by experimental design and statistical analysis. For the analysis objective<br>dishwasher production in Arcelik Dishwasher plant is examined. Sheet metal forming processes of dishwasher production constitutes the greatest portion of production cost and using the Pareto analysis technique<br>four pieces among twenty six pieces are determined to be investigated. These four pieces are the U Sheet, L Sheet, Inner Door and Side Panel of the dishwasher. By the help of the flow diagrams production process of the determined pieces are defined. Brainstorming technique and cause&<br>effect diagrams are used to determine which non-machining process parameters can cause pieces to be scrapped. These parameters are used as control factors in experimental design. Taguchi&<br>#8217<br>s L16(215) orthogonal array, Taguchi&<br>#8217<br>s L16(215) orthogonal array using S/N transformation and 28-4 fractional factorial design are used on purpose. With repetitions and confirmation experiments the effective parameters are determined and optimum level of these parameters are defined for the improvements on scrap quantity and quality of production.
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Nwagoum, Idriss Chatrian. "aerodynamic performance improvement of a twin scroll turbocharger turbine using the design of experiments method." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
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This dissertation aims to improve the aerodynamic performance of a turbocharger turbine using the design of experiments method (DoE) and optimisation algorithms; the design of experiments aims at predicting the outcome by introducing a change of the preconditions, which are represented by one or more independent variables, also referred to as "input variables" or "predictor variables"; the change in one or more independent variables is
generally hypothesized to result in a change in one or more dependent variables, also referred to as "output variables" or "response variables".
The dissertation is structured in the following main points: a first chapter resuming a literature background on turbomachinery, a second chapter containing the design of experiments and the optimisation methods, then the DoE, which is performed by first setting properly the upper and lower bounds for each turbine geometrical parameter, followed by a Latin hypercube sampling (LHS) of the design space; a third chapter which presents the
turbine geometries building process using Daimler in-house tools; this step is then followed by the CFD simulations and a final chapter where the metamodels for the turbine performance prediction are build through the software OptiSlang and finally the optimisation process using an adaptative response to surface (ARSM) algorithm, an evolutionary algorithm (EA) and the non-linear programming by quadratic lagrangian (NLPQL) algorithm.
This paper present the results obtained from three different optimization algorithms, namely the improved designs predicted by the metamodels and the validation results from the CFD simulations; it is found that in case of a single objective optimization with few constraints which is our specific case, the NLPQL algorithm finds the best improved design with an increment in efficiency of 1:3% with respect to the base turbine, this result is further validated with CFD simulations.
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Panieri, Marco. "Ottimizzazione mediante progetto dell'esperimento del processo di produzione di idrossiapatite drogata con magnesio." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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L’uso dell’idrossiapatite come sostituto osseo è molto diffuso grazie alla comprovata bioattività e osteoconduttività. La sostituzione di ioni calcio con magnesio nel reticolo strutturale dell'idrossiapatite favorisce il miglioramento dell’efficacia biologica del prodotto. Il magnesio è infatti strettamente coinvolto nella mineralizzazione dei tessuti calcificati stimolando direttamente la proliferazione degli osteoblasti. L’elaborato si pone come obiettivo lo studio del processo di produzione di idrossiapatite drogata magnesio, analizzando i parametri critici del processo individuati in studi precedenti e andando a definire le condizioni ottimali di sintesi. Lo scopo finale è l’identificazione di quei parametri che maggiormente influenzano la resa di processo e le caratteristiche reologiche del prodotto con particolare attenzione all’estrudibilità della pasta. Il progetto ha avuto inizio con l'analisi del processo attuale e l'individuazione di potenziali parametri critici (temperatura di reazione, granulometria del reagente calcio idrossido, portata di gocciolamento soluzione acida e tempo di maturazione). La pianificazione della sperimentazione in scala di laboratorio ha seguito le metodiche proposte dal DoE (Design of Experiment). L’output finale della sintesi (polvere e sostituto osseo estrudibile) è stato caratterizzato sia da un punto di vista chimico che fisico mediante misurazione della forza necessaria ad estrudere i prodotti ottenuti. Lo studio ha permesso di individuare una combinazione ottimale dei quattro parametri in relazione alle aspettative sul prodotto. Sulla base di questi risultati conseguiti, sarà valutata l’implementazione di modifiche al processo industriale, quali aumento della portata di gocciolamento e raffreddamento rapido della sospensione a termine reazione. I cambiamenti proposti favorirebbero l’incremento produttivo e la qualità finale del prodotto.
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Abdalrahman, Rzgar. "Design and analysis of integrally-heated tooling for polymer composites." Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/4753.
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Tooling design is crucial for the production of cost-effective and durable composite products. As part of the current search for cost reduction (by reducing capital investment, energy use and cycle time), integrally-heated tooling is one of the technologies available for ‘out-of-autoclave’ processing of advanced thermoset polymer composites. Despite their advantages, integrally-heated tools can suffer from uneven distribution of temperature, variability in heat flow rate and inconsistency in heating/cooling time. This research, therefore, investigates a number of design variables such as shape and layout of heating channels in order to improve the heating performance of an integrally-heated tool. Design of Experiments (DoE) has been carried out using Taguchi’s Orthogonal Array (OA) method to set several combinations of design parameters. Each of these design combinations has been evaluated through numerical simulation to investigate heating time and mould surface temperature variation. The simulation results suggest that the layout of the channels and their separation play a vital role in the heating performance. Signal-to-Noise (S/N) ratio and analysis of variance (ANOVA) have been applied to the results obtained to identify the optimal design combination of the integrally-heated tool. Statistical analysis reveals that the heating performance of an integrally-heated tool can be significantly improved when the channels’ layout is parallel. The shape of the channels has negligible effect and the distance between the channels should be determined based on the production requirement. According to the predicted optimal design, a developed integrally water-heated tool is manufactured. The actual thermal properties of the constituent materials of the produced tool are also measured. Then a numerical model of the experimental tool model is simulated in ANSYS software, with setting the actual material properties and boundary condition to define the temperature uniformity and heating rate of the experimental tool. Comparison of the experimental and numerical results of the experimental tool confirmed the well assigning of the boundary conditions and material properties during simulation the heated tool. The experimental results also confirmed the predicted optimal design of the integrally heated tool. Finally, in order to define its thermomechanical behaviour under the effective (in service) thermal loads, a tool model is simulated. Numerical results presented that the produced extremes of thermal deformation, elastic strain, normal and plane shear stresses, under the effective thermal loading, are within the allowable elastic limits of the participated materials.
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Fukuda, Isa Martins. "Desenvolvimento e otimização de protetores solares empregando os conceitos de qualidade por design (QbD) e tecnologia analítica de processos (PAT)." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/9/9139/tde-12112018-145821/.
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Os protetores solares (PS) são os grandes responsáveis pela proteção da pele quando exposta à radiação solar, por isso a importância sanitária de se otimizar o desenvolvimento deste cosmético tipo II e monitorar para que seja eficaz em seu propósito. O principal objetivo deste trabalho é aplicar os conceitos de Qualidade por Design (QbD), ferramentas estatísticas de desenho experimental (DoE - Design of Experiments) e o conceito de tecnologia analítica de processo (PAT - Process Analytical Technology) para desenvolver uma formulação e processo produtivo de um PS de modo a modernizar os processos da indústria cosmética, fazendo as análises durante o processo e eliminando o controle de qualidade final. Trata-se de um sistema de desenvolvimento sistematizado, onde se executa as ferramentas de QbD para avaliar os dados obtidos ao longo da fase experimental. Para a fase experimental, empregou-se o desenho fatorial e desenho do compósito central (CCD - Central Composite Design) como ferramenta estatística, para a execução do planejamento de experimentos (DoE - Design of Experiments). As respostas foram analisadas através da metodologia de superfície resposta (RSM - Response Surface Methodology). Tais ferramentas são fundamentais para a determinação do desenho de concepção (design space), para se obter o PS com as melhores características físico-químicas e de processo dentro do escopo delineado. Para o desenvolvimento da metodologia de análise in line, optou-se pela utilização da espectrometria UV, utilizando-se ferramentas como análise de regressão dos mínimos quadrados (PLS) devido a praticidade em transforma-la em uma ferramenta PAT, para isto, a quimiometria foi empregada para modelar sistemas que são desconhecidos e complexos, como um PS, e trazendo respostas diretas como a aprovação do produto antes de ser embalado, por exemplo. A abordagem apresentada baseia-se na construção da qualidade ao longo do desenvolvimento e otimização de PS e torna possível o monitoramento da qualidade em tempo real.<br>The sunscreens are great responsible for the skin protection when it is exposed to direct sunlight, so it means a great importance of health to optimize the development of type II cosmetic and monitor for it to be effective in its purpose. The objective of this work is to apply the concepts of Quality by Design and statistical tools of experimental design (DoE - Design of experiments), as well as applying the process analytical technology (PAT - Process Analytical Technology) concept for formulation and manufacturing process development of a topical sunscreen being able to modernize the cosmetic industry processing, including real time analyses and eliminating quarantine step, which waits analysis approval performed by the quality assurance, and then release the product for sale. As it is a systematic development, where critical quality attributes and risk assessment were performed to evaluate over obtained data. During experimental phase, the factorial design was used as a statistical tool for design of experiments implementation, and the responses were analyzed by response surface methodology (RSM - Response Surface Methodology). This mapping is critical to determination of the product design (design space), i.e. get sunscreen with the best physical and chemical characteristics and processing within the outlined scope. For in line methodology development, UV spectrometry was opted to be used due to less effort in sample preparation and due to great easiness to turn it into a PAT tool. For this, chemometrics was used, which brings together chemical and statistical elements to obtain three main elements: empirical modeling, multivariate modeling and chemical data, making it able to model systems that are unknown and complex, as a sunscreen, getting direct answers as product release approval before being packed, for example. The presented approach was based on the construction of quality throughout the sunscreen development and optimization making possible the real time quality monitoring.
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Haase, Dirk. "Ein neues Verfahren zur modellbasierten Prozessoptimierung auf der Grundlage der statistischen Versuchsplanung am Beispiel eines Ottomotors mit elektromagnetischer Ventilsteuerung (EMVS)." Doctoral thesis, Technische Universität Dresden, 2004. https://tud.qucosa.de/id/qucosa%3A24582.
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In recent years gasoline engines have become increasingly complex, for example through the introduction of electronic control and monitoring systems for ignition, fuel injection and exhaust aftertreatment. Parallel to this the requirements placed upon engines have also increased hence the need to develop new engine technologies. This demand for new technologies is, in part, due to the self obligation of the automobile industry to reduce the CO2 emissions about 25% by 2005, and also to the increasingly stringent future exhaust limits. Some promising solutions are currently in development, e.g. the direct injection gasoline engine and variable valve trains. All these new technologies are characterised by increasing complexity and significantly higher degrees of freedom. The associated application expenditure rises drastically with the number of free parameters and also with improved quality standards. Possible solutions to meet the future requirements of the development process are based on model-based parameter optimisation and the use of test methods, such as &quot;Design of Experiments&quot; (DoE). The idea behind this approach is to produce models to describe the dependence of the responses of interest (i.e. fuel consumption) on the adjusted engine parameters. With these models offline optimisation of the engine can be carry out, independently of testbench resources. The measured data for the models are produced with the help of statistically designed experiments. Thus, the testing and analysis processes are structured and the expenditure limited. In the following the DoE methodology will be employed of a gasoline engine with electromechanical valve train.<br>Der Ottomotor im Kraftfahrzeug hat in den letzten Jahren mit dem Einzug elektronischer Steuer- und Regelsysteme für Zündung, Einspritzung und Abgasnachbehandlung einen sehr hohen technischen Stand erreicht. Die wachsenden Ansprüche an die Motorenentwicklung im Hinblick auf Verbrauchsreduzierung bei gleichzeitiger Erfüllung der zukünftigen Abgasgrenzwerte, verschärfen den Druck zur Entwicklung weiterführender Technologien. Hierbei gibt es bereits einige vielversprechende Lösungsansätze, wie z.B. die Direkteinspritzung oder variable Ventilsteuerungen. All diese neuen Technologien zeichnen sich durch eine wachsende Komplexität durch die signifikant höhere Anzahl von Freiheitsgraden aus. Der damit verbundene Applikationsaufwand steigt drastisch durch die wachsende Anzahl freier Parameter, aber auch durch die steigenden Anforderungen an die Qualität der Applikationsergebnisse. Einen möglichen Lösungsansatz zur Realisierung der zukünftigen Anforderungen an den Entwicklungsprozess stellen die modellgestützte Parameteroptimierung sowie der Einsatz der &quot;Statistischen Versuchsplanung&quot; (SVP) - &quot;Design of Experiments&quot; (DoE) - dar. Der Grundgedanke basiert auf der Erstellung von Modellen zur Beschreibung der Abhängigkeiten variierter Verstellparameter. Mit diesen Modellen können Offline-Optimierungen unabhängig von Prüfstandsressourcen durchgeführt werden. Die für die Modellbildung benötigten Messdaten werden mit Hilfe der statistischen Versuchsplanung erzeugt. Dadurch wird der Prozess strukturiert und der Aufwand wird begrenzt. In der Arbeit wird der Einsatz der DoE-Methodik am Beispiel eines Ottomotors mit elektromechanischer Ventilsteuerung (EMVS) aufgezeigt.
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Berglund, Anders. "Criteria for Machinability Evaluation of Compacted Graphite Iron Materials : Design and Production Planning Perspective on Cylinder Block Manufacturing." Doctoral thesis, KTH, Industriell produktion, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-48430.
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The Swedish truck industry is looking for new material solutions to achieve lighter engines with increased strength to meet customer demands and to fulfil the new regulations for more environmentally friendly trucks. This could be achieved by increasing the peak pressure in the cylinders. Consequently, a more efficient combustion is obtained and the exhaust lowered. This, however, exposes the engine to higher loads and material physical properties must therefore be enhanced. One material that could meet these demands is Compacted Graphite Iron (CGI). Its mechanical and physical properties make it ideal as cylinder block material, though there are drawbacks concerning its machinability as compared to other materials that are commonly used for the same purpose. Knowledge about machining of the material and its machinability is consequently inadequate. The main goal of this thesis is to identify and investigate the effect of the major factors and their individual contributions on CGI machining process behaviour. When the relationship between the fundamental features; machinability, material microstructure, and material physical properties, are revealed, the CGI material can be optimized, both regarding the manufacturing process and design requirements. The basic understanding of this is developed mainly through experimental analysis as, e.g., machining experiments and material characterization. The machining model presented in this thesis demonstrates the influence of material and process parameters on CGI machinability. It highlights machinability from both design and production planning perspectives. Another important objective of the thesis is an inverse thermo−mechanical FE model for intermittent machining of CGI. Here, experimental results obtained from a developed simulated milling method are used as input data, both to calibrate and validate the model. With these models, a deeper understanding is obtained regarding the way to achieve a stable process, which is the basis for future optimization procedures. The models can therefore be used as a foundation for the optimization of CGI component manufacturing.<br><p>QC 20111121</p><br>MERA - OPTIMA CGI<br>FFI - OPTIMA phase two
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Abbas, Manzar. "System-level health assessment of complex engineered processes." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37260.
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Condition-Based Maintenance (CBM) and Prognostics and Health Management (PHM) technologies aim at improving the availability, reliability, maintainability, and safety of systems through the development of fault diagnostic and failure prognostic algorithms. In complex engineering systems, such as aircraft, power plants, etc., the prognostic activities have been limited to the component-level, primarily due to the complexity of large-scale engineering systems. However, the output of these prognostic algorithms can be practically useful for the system managers, operators, or maintenance personnel, only if it helps them in making decisions, which are based on system-level parameters. Therefore, there is an emerging need to build health assessment methodologies at the system-level. This research employs techniques from the field of design-of-experiments to build response surface metamodels at the system-level that are built on the foundations provided by component-level damage models.
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Besirevic, Edin, and Anders Dahl. "Variance reduction of product parameters in wire rope production by optimisation of process parameters." Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63634.
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The usage of statistical methods in the production industry has resulted in quality improvements for several organisations during the last decade. However, advanced statistical methods are still underutilised and underappreciated in quality improvement programs and projects in many companies. Therefore it is of interest to investigate how these methods can be used for quality improvements in the production industry. A case study was conducted at Teufelberger’s wire rope production plant in Wels, Austria. Wire rope type BS 909 was studied by utilising the arsenal of tools and methods that Six Sigma provides, with an emphasis on statistical methods -- especially Design of Experiments. Teufelberger is currently (2016) experiencing diameter issues along the rope and it has been found through customer reclamations and quality controls in the production that the variation in a production lot can be substantial. Furthermore, there is no master setting of process parameters and each operator has their own way of setting and adjusting them, as there are different ways to achieve a product which is within given tolerances. The purpose of this study is to investigate how statistical tools can be applied to minimise variance in a Teufelberger rope manufacturing process, by conducting a case study utilising the quality improvement methodology DMAIC. Experiments were conducted in the following four sub processes which produce input components used during the manufacturing of BS909: KL-A, KL-B, IL and Al. In KL-A the following main effects were identified as significant: Postformers Spin and Postformers Diameter. In KL-B the main effect Postformers Spin was significant. In IL the following main effects were identified as significant: Compacting device, Postformers Spin and Postformers Diameter. In AL the main effect Compacting device was significant. Based on the conclusion derived from analysing these experiments theoretical master setups were created in order to address the variance issue and standardise process parameters. Further verification testing must be conducted in order to verify and tune the proposed master setups before they can be utilised.<br>Det senaste årtiondet har användningen av statistiska metoder inom tillverkningsindustrin resulterat i kvalitetsförbättringar för flera organisationer men dessa metoder är fortfarande undervärderade och utnyttjas ej till fullo inom program och projekt för kvalitetsförbättringar. Därför är det av intresse att undersöka hur dessa metoder kan användas för kvalitetsförbättringar inom tillverkningsindustrin. Vid en av Teufelbergers produktionsanläggningar av stålvajrar i Wels, Österrike, har en fallstudie med kvalitetsförbättringsmetodiken DMAIC genomförts. Stålvajer typ BS 909 har studerats genom att använda den arsenal av verktyg och metoder som Six Sigma innefattar, med betoning på statistiska metoder och särskilt försöksplanering. Teufelberger hade för tillfället problem med främst diametern av stålvajern. Det har visat sig genom kundreklamationer och kvalitetskontroller i produktionen att variationen i en produktionsserie kan vara betydande. Dessutom finns det ej några dokumenterade optimala inställningar av processparametrar så varje maskinoperatör har sitt eget sätt att ställa in och justera processparametrarna. Detta är möjligt då det finns olika kombinationer av parameterinställningar som kan ge en produkt som är inom givna toleranser. Syftet med denna studie är att undersöka hur statistikverktyg kan användas för att minimera variansen i en tillverkningsprocess av stålvajer hos företaget Teufelberger, detta genom att utföra en fallstudie med kvalitetsförbättringsmetodiken DMAIC Experiment utfördes i följande fyra processer som producerar ingående komponenter som används vid tillverkningen av BS909: KL-A, KL-B, IL och Al. I processen för KL-A identifierades följande huvudeffekter som aktiva; Postformers-Spin och Postformers-Diameter. Den enda huvudeffekt som identifierades vara aktiv för KL-B var Postformers-Spin. För IL var följande huvudeffekter aktiva: Compacting device, Postformers-Spin och Postformers-Diameter. I processen AL var endast huvudeffekten Compacting device aktiv. Baserat på det resultat som framkom vid analysen av dessa experiment har nya teoretiskt optimala inställningar beräknats, som förväntas minska variationen i responsvariabeln diameter. De nya rekommenderade inställningarna bör tills vidare kunna fungera som ny standard för produktionen, men verifieringsförsök bör ändå utföras för att bekräfta och finjustera inställningarna.
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BATISTA, NETO Leopoldo Viana. "Otimização do processo de disposição de filmes TiN e TiZrN em aço inoxidável utilizando planejamento experimental fatorial." Universidade Federal de Campina Grande, 2014. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/378.
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Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-12T21:33:19Z
No. of bitstreams: 1
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LEOPOLDO VIANA BATISTA NETO - DISSERTAÇÃO PPG-CEMat 2014..pdf: 2575700 bytes, checksum: a10f0685285492d2302637ed070d9631 (MD5)
Previous issue date: 2014-08-28<br>Filmes finos de Nitreto de titânio (TiN) e Nitreto de titânio-zircônio (TiZrN) foram
depositados sobre substratos de aço inoxidável 316 usando o método de Sputtering RF
para deposição dos filmes. O planejamento de experimentos (DOE) tem sido
reconhecido como um método poderoso para otimizar um processo complexo na
indústria. Os efeitos do presente estudo foram verificar a viabilidade e confiabilidade da
aplicação do método DOE em processos de Sputtering RF, otimizar os parâmetros de
processamento para o processo de deposição, identificando os parâmetros sensíveis
que afetam a espessura da camada depositada (E.C.D) e a resistência à corrosão
(Ecorr.). Para o método de Sputtering RF, dois parâmetros, a taxa e tempo de deposição
foram escolhidos para serem os parâmetros do processo. Depois da deposição, a
estrutura de camada depositada foi caracterizada por Difração de Raios X (DRX) e por
Microscopia Eletrônica de Varredura (MEV). Após o ensaio de polarização, a corrosão
foi realizada a fim de investigar a relação entre o início da corrosão e a espessura da
camada depositada. A análise de variância (ANOVA) foi realizada para avaliar os
parâmetros sensíveis e prever as condições ideais. Com base na análise estatística, os
parâmetros mais sensíveis no processo de Sputtering RF foram tanto a taxa como o
tempo de deposição do filme fino. As melhores condições de deposição foram a taxa de
deposição máxima e tempo máximo.<br>Titanium nitride (TiN) and titanium-zirconium nitride (TiZrN) thin films were
deposited on ASTM F 138 stainless steel substrates using de Sputtering RF methods.
Design of experiment (DOE) has long been recognized as a powerful method to
optimize a complex process in industry. The purposes of present study were to verify the
feasibility and reliability of the application of DOE method on de Sputtering RF
processes and optimize the processing parameters for the deposition process, in which
the sensitive parameters that affected the film properties were also identified. For de
Sputtering RF method, two parameters, deposition rate and time were chosen to be the
operating parameters. After deposition, the thin film structure was characterized by X-ray
diffraction (XRD), and high-resolution scanning electron microscopy (SEM). After the
polarization test, the corrosion analysis was carried out in order to investigate the
relationship between the corrosion initiation and the thickness of the deposited layer.
The analysis of variance (ANOVA) was conducted to assess the sensitive parameters
and predict the optimum conditions. Based on the statistical analysis, the most sensitive
parameters in de Sputtering RF process were both the deposition rate and time. The
optimum deposition conditions in each system were maximum deposition rate and time.
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Fu, Tingrui. "PP/clay nanocomposites : compounding and thin-wall injection moulding." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/24655.
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This research investigates formulation, compounding and thin-wall injection moulding of Polypropylene/clay nanocomposites (PPCNs) prepared using conventional melt-state processes. An independent study on single screw extrusion dynamics using Design of Experiments (DoE) was performed first. Then the optimum formulation of PPCNs and compounding conditions were determined using this strategy. The outcomes from the DoE study were then applied to produce PPCN compounds for the subsequent study of thin-wall injection moulding, for which a novel four-cavity injection moulding system was designed using CAD software and a new moulding tool was constructed based upon this design. Subsequently, the effects of moulding conditions, nanoclay concentration and wall thickness on the injection moulded PPCN parts were investigated. Moreover, simulation of the injection moulding process was carried out to compare the predicted performance with that obtained in practice by measurement of real-time data using an in-cavity pressure sensor. For the selected materials, the optimum formulation is 4 wt% organoclay (DK4), 4 wt% compatibiliser (Polybond 3200, PPgMA) and 1.5 wt% co-intercalant (erucamide), as the maximum interlayer spacing of clay can be achieved in the selected experimental range. Furthermore, DoE investigations determined that a screw speed of 159 rpm and a feed rate of 5.4 kg/h are the optimum compounding conditions for the twin screw extruder used to obtain the highest tensile modulus and yield strength from the PPCN compounds. The optimised formulation of PPCNs and compounding conditions were adopted to manufacture PPCN materials for the study of thin-wall injection moulding. In the selected processing window, tensile modulus and yield strength increase significantly with decreasing injection speed, due to shear-induced orientation effects, exemplified by a significantly increased frozen layer thickness observed by optical microscopy (OM) and Moldflow® simulation. Furthermore, the TEM images indicate a strong orientation of clay particles in the flow direction, so the PPCN test pieces cut parallel to the flow direction have 36.4% higher tensile modulus and 13.6 % higher yield strength than those cut perpendicular to the flow direction, demonstrating the effects of shear induced orientation on the tensile properties of thin-wall injection moulded PPCN parts. In comparison to injection speed, mould temperature has very limited effects in the selected range investigated (25-55 °C), in this study. The changes in moulding conditions show no distinctive effects on PP crystallinity and intercalation behaviour of clay. Impact toughness of thin wall injection moulded PPCN parts is not significantly affected by either the changes in moulding conditions or clay concentration (1-5 %). The SEM images show no clear difference between the fracture surfaces of PPCN samples with different clay concentrations. TEM and XRD results suggest that higher intercalation but lower exfoliation is achieved in PPCN parts with higher clay content. The composites in the thin sections (at the end of flow) have 34 % higher tensile modulus and 11 % higher yield strength than in the thicker sections, although the thin sections show reduced d001 values. This is attributed to the significantly enhanced shear-induced particle/molecular orientation and more highly oriented frozen layer, according to TEM, OM and process simulation results. In terms of the reduced d001 values in the thin sections, it is proposed that the extreme shear conditions in the thin sections stretch the PP chains in the clay galleries to a much higher level, compaction of clay stacks occurs as less interspacing is needed to accommodate the stretched chains, but rapid cooling allows no time for the chains to relax and expand the galleries back. Overall, data obtained from both actual moulding and simulation indicate that injection speed is of utmost importance to the thin-wall injection moulding process, development of microstructure, and thus the resulting properties of the moulded PPCN parts, in the selected experimental ranges of this research.
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Eghlio, Ramadan Mahmoud. "Laser net shape welding of steels." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/laser-net-shape-welding-of-steels(c5275bf1-ac62-4195-9d4e-61d1973d1b6f).html.
Full textAbstract:
Laser technologies have made distinguished contributions to modern industry. These have typically been realised through the important role played by lasers in the advancement of manufacturing technology in many areas such as welding, which has become an important joining technique and thus promoted the use of lasers in a wide variety of applications in the oil, gas, aerospace, aircraft, automotive, electronics and medical industries. A detailed review of previous work in the use of lasers for advanced manufacturing, and in particular, laser beam welding is given. The work reported in this thesis aims to develop a new method of laser welding. This is connected with investigations relating to the production of net shape welds for bead-on-plate welding and butt welding of mild steel plates. Based on the nature of its operation, use of a fibre laser was considered most suitable compared to other solid state lasers. Net-shape welds were demonstrated on mild steel plates using an IPG 1 kW single mode fibre laser with a maximum power output of 1000 W.The thesis shows results from experimental and modelling (based on finite element and computational fluid dynamic modelling) to validate the idea and the understanding of underlying scientific principles. The thesis is presented in the form of a collection of published work generated by the author during the course of this project. In addition, some results that are not yet published are also included. Design of experiments and statistical modelling has been used in the experimental work to understand the process parameter interactions. Microstructural and mechanical testing have been carried out to evaluate the performance of the welds. Net shaped (the weld bead is flat to the parent material surface) welds have been achieved and compared with standard welds. The understanding of net-shape weld formation and the effect of the laser welding parameters was enhanced by the theoretical modelling. The thesis concludes with a summary of scientific findings and an overview of future work.
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Ramesh, Dinesh. "The Role of Interface in Crystal Growth, Energy Harvesting and Storage Applications." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1752367/.
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A flexible nanofibrous PVDF-BaTiO3 composite material is prepared for impact sensing and biomechanical energy harvesting applications. Dielectric polyvinylidene fluoride (PVDF) and barium titanate (BaTiO3)-PVDF nanofibrous composites were made using the electrospinning process based on a design of experiments approach. The ultrasonication process was optimized using a 2k factorial DoE approach to disperse BaTiO3 particles in PVDF solution in DMF. Scanning electron microscopy was used to characterize the microstructure of the fabricated mesh. The FT-IR and Raman analysis were carried out to investigate the crystal structure of the prepared mesh. Surface morphology contribution to the adhesive property of the composite was explained through contact angle measurements. The capacitance of the prepared PVDF- BaTiO3 nanofibrous mesh was a more than 40% increase over the pure PVDF nanofibers. A comparative study of dielectric relaxation, thermodynamics properties and impact analysis of electrospun polyvinylidene fluoride (PVDF) and 3% BaTiO3-PVDF nanofibrous composite are presented. The frequency dependent dielectric properties revealed micro structural features of the composite material. The dielectric relaxation behavior is further supported by complex impedance analysis and Nyquist plots. The temperature dependence of electric modulus shows Arrhenius type behavior. The observed non-Debye dielectric relaxation in electric loss modulus follows a thermally activated process which can be attributed to a small polaron hopping effect. The particle induced crystallization is supported with thermodynamic properties from differential scanning calorimetric (DSC) measurements. The observed increase in piezoelectric response by impact analysis was attributed to the interfacial interaction between PVDF and BaTiO3. The interfacial polarization between PVDF and BaTiO3 was studied using density functional theory calculations and atomic charge density analysis. The results obtained indicates that electrospinning offers a potential way to produce nanofibers with desired crystalline nature which was not observed in molded samples. In addition, BaTiO3 can be used to increase the capacitance, desired surface characteristics of the PVDF nanofibers which can find potential application as flexible piezoelectric sensor mimicking biological skin for use in impact sensing and energy harvesting applications.
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Record, Jonathan H. "Statistical Investigation of Friction Stir Processing Parameter Relationships." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd732.pdf.
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Abtini, Mona. "Plans prédictifs à taille fixe et séquentiels pour le krigeage." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEC019/document.
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La simulation numérique est devenue une alternative à l’expérimentation réelle pour étudier des phénomènes physiques. Cependant, les phénomènes complexes requièrent en général un nombre important de simulations, chaque simulation étant très coûteuse en temps de calcul. Une approche basée sur la théorie des plans d’expériences est souvent utilisée en vue de réduire ce coût de calcul. Elle consiste à partir d’un nombre réduit de simulations, organisées selon un plan d’expériences numériques, à construire un modèle d’approximation souvent appelé métamodèle, alors beaucoup plus rapide à évaluer que le code lui-même. Traditionnellement, les plans utilisés sont des plans de type Space-Filling Design (SFD). La première partie de la thèse concerne la construction de plans d’expériences SFD à taille fixe adaptés à l’identification d’un modèle de krigeage car le krigeage est un des métamodèles les plus populaires. Nous étudions l’impact de la contrainte Hypercube Latin (qui est le type de plans les plus utilisés en pratique avec le modèle de krigeage) sur des plans maximin-optimaux. Nous montrons que cette contrainte largement utilisée en pratique est bénéfique quand le nombre de points est peu élevé car elle atténue les défauts de la configuration maximin-optimal (majorité des points du plan aux bords du domaine). Un critère d’uniformité appelé discrépance radiale est proposé dans le but d’étudier l’uniformité des points selon leur position par rapport aux bords du domaine. Ensuite, nous introduisons un proxy pour le plan minimax-optimal qui est le plan le plus proche du plan IMSE (plan adapté à la prédiction par krigeage) et qui est coûteux en temps de calcul, ce proxy est basé sur les plans maximin-optimaux. Enfin, nous présentons une procédure bien réglée de l’optimisation par recuit simulé pour trouver les plans maximin-optimaux. Il s’agit ici de réduire au plus la probabilité de tomber dans un optimum local. La deuxième partie de la thèse porte sur un problème légèrement différent. Si un plan est construit de sorte à être SFD pour N points, il n’y a aucune garantie qu’un sous-plan à n points (n 6 N) soit SFD. Or en pratique le plan peut être arrêté avant sa réalisation complète. La deuxième partie est donc dédiée au développement de méthodes de planification séquentielle pour bâtir un ensemble d’expériences de type SFD pour tout n compris entre 1 et N qui soient toutes adaptées à la prédiction par krigeage. Nous proposons une méthode pour générer des plans séquentiellement ou encore emboités (l’un est inclus dans l’autre) basée sur des critères d’information, notamment le critère d’Information Mutuelle qui mesure la réduction de l’incertitude de la prédiction en tout point du domaine entre avant et après l’observation de la réponse aux points du plan. Cette approche assure la qualité des plans obtenus pour toutes les valeurs de n, 1 6 n 6 N. La difficulté est le calcul du critère et notamment la génération de plans en grande dimension. Pour pallier ce problème une solution a été présentée. Cette solution propose une implémentation astucieuse de la méthode basée sur le découpage par blocs des matrices de covariances ce qui la rend numériquement efficace<br>In recent years, computer simulation models are increasingly used to study complex phenomena. Such problems usually rely on very large sophisticated simulation codes that are very expensive in computing time. The exploitation of these codes becomes a problem, especially when the objective requires a significant number of evaluations of the code. In practice, the code is replaced by global approximation models, often called metamodels, most commonly a Gaussian Process (kriging) adjusted to a design of experiments, i.e. on observations of the model output obtained on a small number of simulations. Space-Filling-Designs which have the design points evenly spread over the entire feasible input region, are the most used designs. This thesis consists of two parts. The main focus of both parts is on construction of designs of experiments that are adapted to kriging, which is one of the most popular metamodels. Part I considers the construction of space-fillingdesigns of fixed size which are adapted to kriging prediction. This part was started by studying the effect of Latin Hypercube constraint (the most used design in practice with the kriging) on maximin-optimal designs. This study shows that when the design has a small number of points, the addition of the Latin Hypercube constraint will be useful because it mitigates the drawbacks of maximin-optimal configurations (the position of the majority of points at the boundary of the input space). Following this study, an uniformity criterion called Radial discrepancy has been proposed in order to measure the uniformity of the points of the design according to their distance to the boundary of the input space. Then we show that the minimax-optimal design is the closest design to IMSE design (design which is adapted to prediction by kriging) but is also very difficult to evaluate. We then introduce a proxy for the minimax-optimal design based on the maximin-optimal design. Finally, we present an optimised implementation of the simulated annealing algorithm in order to find maximin-optimal designs. Our aim here is to minimize the probability of falling in a local minimum configuration of the simulated annealing. The second part of the thesis concerns a slightly different problem. If XN is space-filling-design of N points, there is no guarantee that any n points of XN (1 6 n 6 N) constitute a space-filling-design. In practice, however, we may have to stop the simulations before the full realization of design. The aim of this part is therefore to propose a new methodology to construct sequential of space-filling-designs (nested designs) of experiments Xn for any n between 1 and N that are all adapted to kriging prediction. We introduce a method to generate nested designs based on information criteria, particularly the Mutual Information criterion. This method ensures a good quality forall the designs generated, 1 6 n 6 N. A key difficulty of this method is that the time needed to generate a MI-sequential design in the highdimension case is very larg. To address this issue a particular implementation, which calculates the determinant of a given matrix by partitioning it into blocks. This implementation allows a significant reduction of the computational cost of MI-sequential designs, has been proposed
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Clifford, Dustin M. "Non-Conventional Approaches to Syntheses of Ferromagnetic Nanomaterials." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4205.
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The work of this dissertation is centered on two non-conventional synthetic approaches to ferromagnetic nanomaterials: high-throughput experimentation (HTE) (polyol process) and continuous flow (CF) synthesis (aqueous reduction and the polyol process). HTE was performed to investigate phase control between FexCo1-x and Co3-xFexOy. Exploration of synthesis limitations based on magnetic properties was achieved by reproducing Ms=210 emu/g. Morphological control of FexCo1-x alloy was achieved by formation of linear chains using an Hext. The final study of the FexCo1-x chains used DoE to determine factors to control FexCo1-x, diameter, crystallite size and morphology. [Ag] with [Metal] provide statistically significant control of crystallite size. [OH]/[Metal] predict 100 % FexCo1-x at > 30. To conclude section 1, a morphological study was performed on synthesis of Co3-xFexOy using the polyol process. Co3-xFexOy micropillars were synthesized at various sizes. The close proximity of the particles in the nanostructure produced an optical anisotropy and was magnetically induced which is evidence for the magneto-birefringence effect.
The second non-conventional synthetic approach involves continuous flow (CF) chemistry. Co nanoparticles (Ms=125 emu/g) were newly synthesized by aqueous reduction in a microreactor and had 30 ±10 nm diameter and were produced at >1g/hr, a marker of industrial-scale up viability. The final work was the CF synthesis of FexCo1-x. The FexCo1-x was synthesized with limitation to the composition. The maximum FexCo1-x phase composition at 20 % resulted from the aqueous carrier solvent triggering oxide formation over FexCo1-x.
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Park, Jangho. "Efficient Global Optimization of Multidisciplinary System using Variable Fidelity Analysis and Dynamic Sampling Method." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/91911.
Full textAbstract:
Work in this dissertation is motivated by reducing the design cost at the early design stage while maintaining high design accuracy throughout all design stages. It presents four key design methods to improve the performance of Efficient Global Optimization for multidisciplinary problems. First, a fidelity-calibration method is developed and applied to lower-fidelity samples. Function values analyzed by lower fidelity analysis methods are updated to have equivalent accuracy to that of the highest fidelity samples, and these calibrated data sets are used to construct a variable-fidelity Kriging model. For the design of experiment (DOE), a dynamic sampling method is developed and includes filtering and infilling data based on mathematical criteria on the model accuracy. In the sample infilling process, multi-objective optimization for exploitation and exploration of design space is carried out. To indicate the fidelity of function analysis for additional samples in the variable-fidelity Kriging model, a dynamic fidelity indicator with the overlapping coefficient is proposed. For the multidisciplinary design problems, where multiple physics are tightly coupled with different coupling strengths, multi-response Kriging model is introduced and utilizes the method of iterative Maximum Likelihood Estimation (iMLE). Through the iMLE process, a large number of hyper-parameters in multi-response Kriging can be calculated with great accuracy and improved numerical stability. The optimization methods developed in the study are validated with analytic functions and showed considerable performance improvement. Consequentially, three practical design optimization problems of NACA0012 airfoil, Multi-element NLR 7301 airfoil, and all-moving-wingtip control surface of tailless aircraft are performed, respectively. The results are compared with those of existing methods, and it is concluded that these methods guarantee the equivalent design accuracy at computational cost reduced significantly.<br>Doctor of Philosophy<br>In recent years, as the cost of aircraft design is growing rapidly, and aviation industry is interested in saving time and cost for the design, an accurate design result during the early design stages is particularly important to reduce overall life cycle cost. The purpose of the work to reducing the design cost at the early design stage with design accuracy as high as that of the detailed design. The method of an efficient global optimization (EGO) with variable-fidelity analysis and multidisciplinary design is proposed. Using the variable-fidelity analysis for the function evaluation, high fidelity function evaluations can be replaced by low-fidelity analyses of equivalent accuracy, which leads to considerable cost reduction. As the aircraft system has sub-disciplines coupled by multiple physics, including aerodynamics, structures, and thermodynamics, the accuracy of an individual discipline affects that of all others, and thus the design accuracy during in the early design states. Four distinctive design methods are developed and implemented into the standard Efficient Global Optimization (EGO) framework: 1) the variable-fidelity analysis based on error approximation and calibration of low-fidelity samples, 2) dynamic sampling criteria for both filtering and infilling samples, 3) a dynamic fidelity indicator (DFI) for the selection of analysis fidelity for infilled samples, and 4) Multi-response Kriging model with an iterative Maximum Likelihood estimation (iMLE). The methods are validated with analytic functions, and the improvement in cost efficiency through the overall design process is observed, while maintaining the design accuracy, by a comparison with existing design methods. For the practical applications, the methods are applied to the design optimization of airfoil and complete aircraft configuration, respectively. The design results are compared with those by existing methods, and it is found the method results design results of accuracies equivalent to or higher than high-fidelity analysis-alone design at cost reduced by orders of magnitude.