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Hoffman, John W. "Some Problems in Additive Number Theory." Kent State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=kent1408298984.
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Kodira, Ganapathy D. "Investigation of an Investment Casting Method Combined with Additive Manufacturing Methods for Manufacturing Lattice Structures." Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc283786/.
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Cellular metals exhibit combinations of mechanical, thermal and acoustic properties that provide opportunities for various implementations and applications; light weight aerospace and automobile structures, impact and noise absorption, heat dissipation, and heat exchange. Engineered cell topologies enable one to control mechanical, thermal, and acoustic properties of the gross cell structures. A possible way to manufacture complex 3D metallic cellular solids for mass production with a relatively low cost, the investment casting (IC) method may be used by combining the rapid prototyping (RP) of wax or injection molding. In spite of its potential to produce mass products of various 3D cellular metals, the method is known to have significant casting porosity as a consequence of the complex cellular topology which makes continuous fluid's access to the solidification interface difficult. The effects of temperature on the viscosity of the fluids were studied. A comparative cost analysis between AM-IC and additive manufacturing methods is carried out. In order to manufacture 3D cellular metals with various topologies for multi-functional applications, the casting porosity should be resolved. In this study, the relations between casting porosity and processing conditions of molten metals while interconnecting with complex cellular geometries are investigated. Temperature, and pressure conditions on the rapid prototyping – investment casting (RP-IC) method are reported, thermal stresses induced are also studied. The manufactured samples are compared with those made by additive manufacturing methods.
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Rawson, Paul Stansfield Christy-Anne. "Field method for detection of metal deactivator additive in jet fuel." Fishermans Bend, Victoria : Defence Science and Technology Organisation, 2009. http://nla.gov.au/nla.arc-24592.
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Akcin, Haci Mustafa. "Direct adjustment method on Aalen's additive hazards model for competing risks data." unrestricted, 2008. http://etd.gsu.edu/theses/available/etd-04182008-095207/.
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Thesis (M.S.)--Georgia State University, 2008.Title from file title page. Xu Zhang, committee chair; Yichuan Zhao, Jiawei Liu, Yu-Sheng Hsu, committee members. Electronic text (51 p.) : digital, PDF file. Description based on contents viewed July 15, 2008. Includes bibliographical references (p. 50-51).
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Carlsson, Rebecca. "Comparison of turning blades produced by a conventional- and additive manufacturing method." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-69032.
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Additive manufacturing has developed radical through the years. Sandvik has invested in the area by building a center specific for additive manufacturing. Due to problems with the material- and product properties and high production costs no products have been used with additive manufacturing method. These aspects have improved over the years and therefore the master thesis was made with an objective: to compare two different produced blades with focus on the aspects of material- and product properties and production costs. One of the blades was produced through additive manufacturing (AM) and the other blade was produced in today’s production at Sandvik Coromant in Gimo. If the blade can be produced through AM there is a possibility to lower the production costs and improve the degree of design freedom. The material that will be used is SS2230 (50CrV4) which are used in conventionally produced blades and 1.2709 which are used in AM produced blades. The investigation consisted of five different tests (flow rate, pressure force, vibration, fatigue and keyhole wear) and a study on production aspects with focus on value stream mapping, investments and production costs. The main objective in the result was to compare each test between the two different produced blades, not to investigate the optimal value. Therefore, was the test designed to have continuity with as small deviation as possible between the tests. This resulted in choosing values which were not optimal for the blades but focused on continuity and deviation. The coolant channels flow rate improved with 35% on the AM produced blades but pressure force, fatigue and keyhole wear resistance did not deviate much from conventionally produced blades. Fatigue tests were made twice with two different inserts because the result from the first test differentiated too much from the expected results on both blades. Production costs will be higher with AM but on a long-term may an investment improve the degree of design freedom on a product and a possibility to produce towards costumer (just in time). This will need an expensive investment with a bigger perspective on the timeframe. The value of the product may increase but the production costs will increase too.
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Fan, Zongyue. "A Lagrangian Meshfree Simulation Framework for Additive Manufacturing of Metals." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1619737226226133.
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Iqbal, Shaheer. "Characterization of Viscoelastic Properties of a Material Used for an Additive Manufacturing Method." Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc407787/.
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Recent development of additive manufacturing technologies has led to lack of information on the base materials being used. A need arises to know the mechanical behaviors of these base materials so that it can be linked with macroscopic mechanical behaviors of 3D network structures manufactured from the 3D printer. The main objectives of my research are to characterize properties of a material for an additive manufacturing method (commonly referred to as 3D printing). Also, to model viscoelastic properties of Procast material that is obtained from 3D printer. For this purpose, a 3D CAD model is made using ProE and 3D printed using Projet HD3500. Series of uniaxial tensile tests, creep tests, and dynamic mechanical analysis are carried out to obtained viscoelastic behavior of Procast. Test data is fitted using various linear and nonlinear viscoelastic models. Validation of model is also carried out using tensile test data and frequency sweep data. Various other mechanical characterization have also been carried out in order to find density, melting temperature, glass transition temperature, and strain rate dependent elastic modulus of Procast material. It can be concluded that melting temperature of Procast material is around 337°C, the elastic modulus is around 0.7-0.8 GPa, and yield stress is around 16-19 MPa.
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Brennan-Craddock, James. "The investigation of a method to generate conformal lattice structures for additive manufacturing." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/9146.
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Additive manufacturing (AM) allows a geometric complexity in products not seen in conventional manufacturing. This geometric freedom facilitates the design and fabrication of conformal hierarchical structures. Entire parts or regions of a part can be populated with lattice structure, designed to exhibit properties that differ from the solid material used in fabrication. Current computer aided design (CAD) software used to design products is not suitable for the generation of lattice structure models. Although conceptually simple, the memory requirements to store a virtual CAD model of a lattice structure are prohibitively high. Conventional CAD software defines geometry through boundary representation (B-rep); shapes are described by the connectivity of faces, edges and vertices. While useful for representing accurate models of complex shape, the sheer quantity of individual surfaces required to represent each of the relatively simple individual struts that comprise a lattice structure ensure that memory limitations are soon reached. Additionally, the conventional data flow from CAD to manufactured part is arduous, involving several conversions between file formats. As well as a lengthy process, each conversion risks the generation of geometric errors that must be fixed before manufacture. A method was developed to specifically generate large arrays of lattice structures, based on a general voxel modelling method identified in the literature review. The method is much less sensitive to geometric complexity than conventional methods and thus facilitates the design of considerably more complex structures. The ability to grade structure designs across regions of a part (termed functional grading ) was also investigated, as well as a method to retain connectivity between boundary struts of a conformal structure. In addition, the method streamlines the data flow from design to manufacture: earlier steps of the data conversion process are bypassed entirely. The effect of the modelling method on surface roughness of parts produced was investigated, as voxel models define boundaries with discrete, stepped blocks. It was concluded that the effect of this stepping on surface roughness was minimal. This thesis concludes with suggestions for further work to improve the efficiency, capability and usability of the conformal structure method developed in this work.
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Yim, Sungshik. "A Retrieval Method (DFM Framework) for Automated Retrieval of Design for Additive Manufacturing Problems." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14553.
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Problem: The process planning task for a given design problem in additive manufacturing can be greatly enhanced by referencing previously developed process plans. However, identifying appropriate process plans for the given design problem requires appropriate mapping between the design domain and the process planning domain. Hence, the objective of this research is to establish mathematical mapping between the design domain and the process planning domain such that the previously developed appropriate process plans can be identified for the given design task. Further more, identification of an appropriate mathematical theory that enables computational mapping between the two domains is of interest. Through such computational mapping, previously developed process plans are expected to be shared in a distributed environment using an open repository.
Approach: The design requirements and process plans are discretized using empirical models that compute exact values of process variables for the given design requirements. Through this discretization, subsumption relations among the discretized design requirements and process plans are identified. Appropriate process plans for a given design requirement are identified by subsumption relations in the design requirements. Also, the design requirements that can be satisfied by the given process plans are identified by subsumption relations among the process plans. To computationally realize such mapping, a description logic (ALE) is identified and justified to represent and compute subsumption relation. Based on this investigation, a retrieval method (DFM framework) is realized that enables storage and retrieval of process plans.
Validation: Theoretical and empirical validations are performed using the validation square method. For the theoretical validation, an appropriate description logic (ALE) is identified and justified. Also, subsumption utilization in mapping two domains and realizing the DFM framework is justified. For the empirical validation, the storing and retrieval performance of the DFM framework is tested to demonstrate its theoretical validity.
Contribution: In this research, two areas of contributions are
identified: DFM and engineering information management. In DFM, the retrieval method that relates the design problem to appropriate process plans through mathematical mapping between design and process planning domain is the major contribution. In engineering information management, the major contributions are the development of information models and the identification of their characteristics. Based on this investigation, an appropriate description logic (ALE) is selected and justified. Also, corresponding computational feasibility (non deterministic polynomial time) of subsumption is identified.
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Yim, Sungshik. "A retrieval method (DF FRAMEWORK) for automated retrieval of design for additive manufacturing problems." Available online, Georgia Institute of Technology, 2007, 2007. http://etd.gatech.edu/theses/available/etd-03012007-113030/.
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Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2007.Nelson Baker, Committee Member ; Charles Eastman, Committee Member ; Christiaan Paredis, Committee Member ; Janet Allen, Committee Member ; David Rosen, Committee Chair.
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Borille, Anderson Vicente. "Decision support method to apply Additive Manufacturing Technologies for plastic components in the aircraft industry." Instituto Tecnológico de Aeronáutica, 2009. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1916.
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Additive Manufacturing Technologies (AMT) are a collection of manufacturing processes driven by CAD data to produce physical models and parts by means of additive techniques. They are based on a layer-by-layer material consolidation process instead of the traditional methods. Due to machine and material developments, such processes may be used to produce final products, not only prototypes. The use of AMT to produce end-use parts is known as Rapid Manufacturing (RM). The main advantages AMT are related to the ability to build geometrically complex shapes without tooling and with high process automation. At small lot sizes, such as with customized products, traditional manufacturing technologies become expensive due to high costs of required tooling. Small lot sizes and complex shaped parts are typical features encountered in the aircraft industry. Nowadays, two Additive Manufacturing Technologies are able to process plastic materials which comply flammability requirements: Fused Deposition Modeling (FDM) and Selective Laser Sintering (SLS). The main objective of this work is to propose a decision support method based on processes technological information concerning Rapid Manufacturing of plastic parts for aircraft cabin interiors. Thus, both FDM and SLS process are compared regarding their functionality (software interface), tensile strength, accuracy and part definition, surface roughness, build time and costs. The analyzed materials are the Polyamide with flame retardant (PA2210FR) additives and the Polyphenylsulfone (PPSF) for SLS and FDM process respectively. These materials were selected because they were the available flame retardant materials for AMT as the beginning of this work. A method is proposed to consider AMT possible advantages and restrictions when considering the manufacturing process. It is proposed that design modifications to improve part';s functionality or performance may be manufactured by AMT. Further, the method proposes the decision procedure to evaluate quality, production time and cost. The author illustrates the method with examples on the selection of manufacturing technology to produce a customized decoration part and an air duct. Typical costs and manufacturing time of injection molding processes were also compared and analyzed with the proposed method. It is possible to define the break-even point, when conventional processes become preferred then AMT.
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Geoffroy, donders Perle. "Homogenization method for topology optmization of struc-tures built with lattice materials." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX100/document.
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Les développements récents des méthodes de fabrication additive permettent aujourd'hui d'envisager l'usinage de pièces à la topologie complexe, composées de microstructures. Ceci ranime l'intérêt pour les méthodes d'optimisation topologique par méthode d'homogénéisation, développées dans les années 80 et quelque peu oubliées par manque d'applications industrielles.L'objectif de cette thèse est de fournir des méthodes d'optimisation topologique pour des structures constituées de matériau lattice localement périodique, c'est-à-dire dont la microstructure est modulée au sein de la pièce.Trois phases ont été définies. La première consiste à calculer les propriétés élastiques homogénéisées de microstructures en fonction de paramètres définissant leur géométrie. Dans la seconde étape, on optimise la structure constituée de matériau homogénéisé selon les paramètres géométriques de la microstructure ainsi que son orientation. Une structure homogénéisée n'est pas usinable en l'état. En effet, l'homogénéisation revient à considérer que la taille des cellules la composant converge vers zéro. Dans une troisième étape, on propose donc de déshomogénéiser la structure optimisée, c'est-à-dire de construire une suite de structures convergeant vers elle. Pour cela, on introduit un difféomorphisme déformant une grille régulière de sorte que chaque cellule soit orientée selon l'orientation optimale.Nous présentons dans cette thèse les détails de cette méthode, pour des microstructures élastiques isotropes et orthotropes, en deux et en trois dimensions.Nous proposons également un couplage de cette méthode avec la méthode d'optimisation de forme par les lignes de niveau, ce qui permet notamment d'inclure des contraintes géométriques sur les structures finalesThanks to the recent developments of the additive manufacturing processes, structures built with modulated microstructures and featuring a complex topology are now manufacturable. This leads to a resurrection of the homogenization method for shape optimization, an approach developed in the 80’s but which progressively faded away because yielding too complex structures for manufacturing processes at this time.The goal of this thesis is to develop shape optimization methods for structures built with modulated locally periodic lattice microstructures.Three steps have been defined. The first consists in computing the homogenized, or effective, elastic properties of microstructures according to few parameters characterizing their geometry. In the second step, the geometric properties of the microstructure and its orientation are optimized in the working domain, yielding a homogenized optimized structure. Such a structure is nevertheless not straightforwardly manufacturable. Indeed, the homogenization is equivalent to have a structure featuring cells whose size is converging to zero. Hence, in the third and last step, a deshomogenization process is proposed. It consists in building a sequence of genuine structures converging to the homogenized optimal structures. The key point is to respect locally the orientation of the cells, which is performed thanks to a grid diffeomorphism.In this thesis, we present the details of the whole method, for isotropic and orthotropic microstructures, in 2D and in 3D.A coupling of this method with the level-set shape optimization method is also presented, thanks which the set of geometric constraints on the final structures may be enlarged
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Rathod, Gaurav Dilip. "An improved effective method for generating 3D printable models from medical imaging." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/80415.
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Medical practitioners rely heavily on visualization of medical imaging to get a better understanding of the patient's anatomy. Most cancer treatment and surgery today are performed using medical imaging. Medical imaging is therefore of great importance to the medical industry.
Medical imaging continues to depend heavily on a series of 2D scans, resulting in a series of 2D photographs being displayed using light boxes and/or computer monitors. Today, these 2D images are increasingly combined into 3D solid models using software. These 3D models can be used for improved visualization and understanding of the problem at hand, including fabricating physical 3D models using additive manufacturing technologies.
Generating precise 3D solid models automatically from 2D scans is non-trivial. Geometric and/or topologic errors are common, and often costly manual editing is required to produce 3D solid models that sufficiently reflect the actual underlying human geometry. These errors arise from the ambiguity of converting from 2D data to 3D data, and also from inherent limitations of the .STL fileformat used in additive manufacturing.
This thesis proposes a new, robust method for automatically generating 3D models from 2D scanned data (e.g., computed tomography (CT) or magnetic resonance imaging (MRI)), where the resulting 3D solid models are specifically generated for use with additive manufacturing. This new method does not rely on complicated procedures such as contour evolution and geometric spline generation, but uses volume reconstruction instead. The advantage of this approach is that the original scan data values are kept intact longer, so that the resulting surface is more accurate. This new method is demonstrated using medical CT data of the human nasal airway system, resulting in physical 3D models fabricated via additive manufacturing.Master of Science
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Morretton, Elodie. "Une démarche de conception de pièces légères pour la fabrication additive basée sur l'optimisation topologique." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI017.
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Les procédés de fabrication additive sont en pleine essor ces dernières années. De nombreux industriels cherchent à évaluer leur potentiel et leurs avantages. Ces nouvelles technologies impliquent des changements au niveau des manières de fabriquer mais également au niveau des manières de concevoir. Ce travail de thèse s’est intéressé à ce second aspect et apporte plus particulièrement des réponses à la question de recherche suivante :Quel guide méthodologique suivre pour une étude dont le but est de reconcevoir des pièces afin de s’approcher de l’optimum en termes de masse ?Pour traiter cette question, le problème a été abordé au regard de plusieurs questions sous-jacentes afin de combler les manques identifiés dans l’état de l’art réalisé que ce soit sur les problématiques du paramétrage de l’optimisation topologique ou sur celles des techniques de reconstruction. Nous avons réalisé plusieurs études de cas afin de pouvoir répondre à ces différentes questions et pouvoir ainsi lister les points critiques. Ce travail de thèse a été réalisé en partenariat avec un acteur de l’aéronautique : Zodiac Seats France. Ceci nous a permis de réaliser des études de cas sur des pièces existantes qui possédaient un certain niveau de complexité. Parmi ces études de cas, nous avons distingué deux types d’étude :- Une étude élémentaire pour effectuer des boucles rapides en faisant varier les choix et- Une série d’études industrielles pour regarder s’il y a convergence ou divergence entre les conclusions de l’étude élémentaire et des cas d’applications plus complexes.Puis, nous avons donné une description détaillée d’une méthode de conception pour la fabrication additive basée sur 5 grandes phases :- l’évaluation de la pièce candidate ou des pièces,- la modélisation,- l’optimisation topologique : obtention d’une forme de géométrie,- la reconstruction de la pièce à partir du résultat de l’optimisation topologique et intégration des contraintes de fabrication- l’optimisation dimensionnelle : affiner les dimensions de la géométrie reconstruite.A ces phases, viennent s’ajouter des étapes de contrôle via des analyses éléments finis. Cette démarche s’est construite autour d’observations faites lors du déroulement des études de cas. Pour chacune de ces phases, un ensemble de recommandations a été défini pour aider le concepteur dans l’obtention d’une pièce optimale en termes de masse. Enfin, nous avons donné ce descriptif de la méthode à un concepteur relativement novice pour avoir un nouveau regard sur celle-ci et pouvoir ainsi identifier des points à améliorer. A l’issue de ce travail de conception, ce concepteur a pointé plusieurs points manquants ainsi que plusieurs faiblesses dans l’argumentaire du guide méthodologique. Ses observations et son opinion, nous ont permis de prendre du recul vis-à-vis de notre travail.Les apports majeurs de ce travail de thèse sont :- La description détaillée d’une méthode composée de 5 grandes phases- Dans cette démarche, nous avons dénombré plusieurs étapes clés : une étape préliminaire d’évaluation du potentiel des pièces à reconcevoir au regard de la fabrication additive et plusieurs phases d’optimisation complémentaires (topologie et dimensions),- La mise en avant de l’importance de bien délimiter le périmètre de l’étude (pièce isolée ou dans le mécanisme),- L’identification des étapes au cours desquelles les contraintes de fabrication devront être intégrées- Le positionnement du concepteur au cœur de la méthode : les outils numériques permettent de ne réaliser qu’une partie du travail de conceptionAdditive manufacturing processes have been growing in recent years. Many industries seek to assess their potentials. These new technologies involve changes in terms of manufacturing but also in terms of designing. This work is interested in this second aspect. It brings answers to the following research question:What methodological guide to follow for a study whose goal is to redesign pieces in order to approach the optimum in terms of mass?To answer to this question, the problem is decomposed into several sub questions. These questions must fill the identified lacks in the state of the art, and deal with topological optimization parameters or reconstructions techniques for example. Several case studies are realized to answer to these sub questions and to list the critical points. This work is realized in partnership with an aerospace company: Zodiac Seats France. This allowed us to work on existing parts which have a certain complexity level. Two types of studies can be distinguished:- Basic study: to experiment different strategies and to make variation on the parameter choices rapidly.- Practical study: to check on more complex cases if there is a convergence with basic study conclusions.Then, a detailed description of a design method for additive manufacturing is provided. It is composed in 5 phases:- Evaluation of parts potential.- Model of parts.- Optimization of parts with topological optimization tools: obtaining the shape of the parts.- Reconstruction of parts from the topological result: integration of manufacturing constraints.- Optimization of reconstructed parts with dimensional optimization tools: refinement of the dimensions of reconstructed parts.Between these phases, checked step are added, based on finite element analysis. This method is built on practical observations obtained from the different case studies. For each phase, a set of recommendations is provided to help designers to design lightweight parts. Finally, this descriptive method is given to a novice designer to have the method tested. The aim of this test is having a new vision on this detailed method and identifying points to be improved. At the achievement of this design work, the designer noticed several missing points as well as several weaknesses in the method argument. His observations and his opinions gave us to take a step back from our work.The major contributions of this work are:- The description of a detailed method in 5 large phases.- In this method, there are several key steps : 1 step of evaluation of parts potential with regard to additive manufacturing as well as two complementary steps of optimization (shape and dimensions)- The perimeter of the parts study must be delimited clearly (isolated parts or in the mechanism),- The identification of the stages in which the manufacturing constraints have to be integrated- The position of the designer to the method heart: digital tools realize only one part of the design work
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Moradlou, Hamid. "Investigation into re-shoring UK manufacturing using additive manufacturing as a method to enable manufacturing postponement." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/23752.
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This thesis describes case study research investigation into re-shoring UK manufacturing using Additive Manufacturing as a method to enable manufacturing Postponement. After identifying the gap in the knowledge by conducting a literature review, the author aims to understand the primary motivation behind the re-shoring phenomenon in the UK. The initial investigation is done by targeting the UK based organisations that have been involved in supporting the re-shoring phenomenon. As a result, lack of responsiveness was found to be the key factor behind re-shoring in the UK. This is then followed by an investigation considering this issue from countries to which manufacturing has been offshored in the past, in particular, India. The research studies the factors that influence this decision from Indian industries perspectives and investigates what the key issues are behind the lack of responsiveness in India. This is whilst India is one of the most attractive offshoring destinations among the other low-cost countries. This introduces the next objective of this research which is to identify a strategy that could help the industries to address such issues. Consequently the concept of Postponement was selected as a strategy and Additive Manufacturing (AM) was identified as a manufacturing method that could enable Postponement. Such a combination can enable companies to shorten their lead-time and be more responsive to their domestic customers. This study also develops a clear picture of re-shoring in the UK and bridges this phenomenon to the new generation of technologies and emerging mega trends. It particularly focuses on AM technologies as an enabling manufacturing method the Industry 4.0. The results obtained from the survey study indicate that there is a positive view towards applicability of AM technologies within the supply chain of the re-shoring companies. The final section of this thesis aims to iii provide a series of case studies where AM technologies are used to further enable companies to reduce their lead time and achieve more customisation. It shows that the companies can re-shore their production activities back to the home country by using AM technologies and engage in a local supply chain. Therefore this study adds insight into manufacturing challenges related to re-shoring and provides a potential solution for the companies that are involved in the production of high value added production. The results from this section indicate that the re-shoring companies will be capable of accommodating product changes and process changes. They can also reduce their inventories, production lead-time, and transportation costs, meanwhile increase product customisation.
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Charles, Amal Prashanth, and Taylor Claudio Alexander Gonzalez. "Development of a Method to Repair Gas Turbine Blades using Electron Beam Melting Additive Manufacturing Technology." Thesis, KTH, Industriell produktion, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-202367.
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This study focuses in using the electron beam melting additive manufacturing process to develop a framework to repair high performance gas turbine blades. These are currently fabricated using highly engineered super alloys, more specifically Inconel 738LC. The thesis focusses on the research on the current production methods of gas turbine blades, the operating environment inside the gas turbine, the most common failure modes as well as current methods of blade repair. This investigation includes studying the methods of production of metallic powders and the alloying effects of different elements in our required powder. A brief analysis was made to determine the economic viability for the usage of AM technology for mass production, and a proposition has been developed for the repair of turbine blades using additive manufacturing.
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Limaye, Ameya Shankar. "Multi-objective process planning method for Mask Projection Stereolithography." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19717.
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Mask Projection Stereolithography (MPSLA) is a high resolution manufacturing process that builds parts layer by layer in a photopolymer. In this research, a process planning method to fabricate MPSLA parts with constraints on dimensions, surface finish and build time is formulated.
As a part of this dissertation, a MPSLA system is designed and assembled. The irradiance incident on the resin surface when a given bitmap is imaged onto it is modeled as the Irradiance model . This model is used to formulate the Bitmap generation method which generates the bitmap to be imaged onto the resin in order to cure the required layer.
Print-through errors occur in multi-layered builds because of radiation penetrating beyond the intended thickness of a layer, causing unwanted curing. In this research, the print through errors are modeled in terms of the process parameters used to build a multi layered part. To this effect, the Transient layer cure model is formulated, that models the curing of a layer as a transient phenomenon, in which, the rate of radiation attenuation changes continuously during exposure. In addition, the effect of diffusion of radicals and oxygen on the cure depth when discrete exposure doses, as opposed to a single continuous exposure dose, are used to cure layers is quantified. The print through model is used to formulate a process planning method to cure multi-layered parts with accurate vertical dimensions. This method is demonstrated by building a test part on the MPSLA system realized as a part of this research.
A method to improve the surface finish of down facing surfaces by modulating the exposure supplied at the edges of layers cured is formulated and demonstrated on a test part.
The models formulated and validated in this dissertation are used to formulate a process planning method to build MPSLA parts with constraints on dimensions, surface finish and build time. The process planning method is demonstrated by means of a case study.
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Abdul, Kudus Syahibudil I. "The value of personalised consumer product design facilitated through additive manufacturing technology." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/34616.
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This research attempted to discover how Additive Manufacturing (AM) can best be used to increase the value of personalised consumer products and how designers can be assisted in finding an effective way to facilitate value addition within personalisable product designs. AM has become an enabler for end-users to become directly involved in product personalisation through the manipulation of three-dimensional (3D) designs of the product using easy-to-use design toolkits. In this way, end-users are able to fabricate their own personalised designs using various types of AM systems. Personalisation activity can contribute to an increment in the value of a product because it delivers a closer fit to user preferences. The research began with a literature review that covered the areas of product personalisation, additive manufacturing, and consumer value in product design. The literature review revealed that the lack of methods and tools to enable designers to exploit AM has become a fundamental challenge in fully realising the advantages of the technology. Consequently, the question remained as to whether industrial designers are able to identify the design characteristics that can potentially add value to a product, particularly when the product is being personalised by end-users using AM-enabled design tools and systems. A new value taxonomy was developed to capture the relevant value attributes of personalised AM products. The value taxonomy comprised two first-level value types: product value and experiential value. It was further expanded into six second-level value components: functional value, personal-expressive value, sensory value, unique value, co-design value, and hedonic value. The research employed a survey to assess end-users value reflection on personalised features; measuring their willingness to pay (WTP) and their intention to purchase a product with personalised features. Thereafter, an experimental study was performed to measure end-users opinions on the value of 3D-printed personalised products based on the two value types: product value and experiential value. Based on the findings, a formal added value identification method was developed to act as a design aid tool to assist designers in preparing a personalisable product design that embodies value-adding personalisation features within the product. The design method was translated into a beta-test version paper-based design workbook known as the V+APP Design Method: Design Workbook. The design aid tool was validated by expert designers. In conclusion, this research has indicated that the added value identification method shows promise as a practical and effective method in aiding expert designers to identify the potential value-adding personalisation features within personalisable AM products, ensuring they are able to fully exploit the unique characteristics and value-adding design characteristics enabled by AM. Finally, the limitations of the research have been explained and recommendations made for future work in this area.
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Tepe, Julius. "Development of a Data Transformation Method for a Customized Stent usingAdditive Manufacturing." Thesis, KTH, Industriell produktion, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-226523.
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Conventionally manufactured stents are available in uniform sizes and straight forms. These standard products are not suitable for all patients and research indicates that this is the reason for migration of stents in the vessel, and tubular structure in general, after deployment. The occurrence of migration makes readmission into hospital and the removal of the deployed stent necessary. This thesis develops a method which results in patient-customized stents which can be manufactured through additive manufacturing. These individualized stents intent to offer the same advantages of conventional stents while mitigating the disadvantages. The work’s core part is thedesign of a stent based on the geometric information through a medical scan. It converts the relevant areas from the medical scan data which is in the DICOM format to the STL file format. After cleaning and further processing, the shape will be the base for the design process of a stent using CAD software. Additionally, it also gives insight into the subjacent technologies such as medical scanning, additive manufacturing, choice of material and necessary further processing steps. A process chain from scanning, data transformation, 3D printing and post processing is described.The developed method delivers a reliable model and results in a fully individualized stent. In the current stage, it involves manual work since the representation of data in the steps is different. Further suggestions for steps to automate the process and an estimation of economic efficiency is given.Det finns konventionellt tillverkade stenter i likformiga storlekar och raka former. Dem här standardprodukter är inte lämpliga för alla patienter och forskning tyder på att detta är orsaken till migrationen av stenter i blodkärl efter placering. Förekomsten av migration skapa återtagande på sjukhus och avlägsnande av den placerade stenten är nödvändig. Den här avhandlingen utvecklar en metod som resulterar i patient anpassade stenter som kan varatillverkad genom additiv tillverkning. Dessa individualiserade stenter avser att erbjuda samma fördelar som konventionella stenter och mildra nackdelarna. Arbetets kärna är designen av en stent baserad på den geometriska informationen baserande på en medicinsk bildteknik. Det omvandlar relevanta kroppsdelar från det medicinska bildteknik som finns i DICOM-formatet till STLfilformatet. Efter rengöring och vidare bearbetning kommer formen att vara basen för stentens designprocess med CAD-mjukvara. Dessutom ger den också inblick i de underliggande teknikerna som medicinsk bildteknik, tillsatsframställning, materialval och nödvändig vidarebehandling steg. En processkedja från skanning, datatransformation, 3D-utskrift och efterbehandling är beskrivits.Den utvecklade metoden ger en tillförlitlig modell och resulterar i en helt individualiserad stent. I det aktuellt stadium, innebär det manuellt arbete eftersom representationen av data i stegen är annorlunda. Ytterligare förslag till åtgärder för att automatisera processen och en uppskattning av ekonomisk effektivitet är given.
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Cao, Jiguo. "Generalized profiling method and the applications to adaptive penalized smoothing, generalized semiparametric additive models and estimating differential equations." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102483.
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Many statistical models involve three distinct groups of variables: local or nuisance parameters, global or structural parameters, and complexity parameters. In this thesis, we introduce the generalized profiling method to estimate these statistical models, which treats one group of parameters as an explicit or implicit function of other parameters. The dimensionality of the parameter space is reduced, and the optimization surface becomes smoother. The Newton-Raphson algorithm is applied to estimate these three distinct groups of parameters in three levels of optimization, with the gradients and Hessian matrices written out analytically by the Implicit Function Theorem it' necessary and allowing for different criteria for each level of optimization. Moreover, variances of global parameters are estimated by the Delta method and include the variation coming from complexity parameters. We also propose three applications of the generalized profiling method.First, penalized smoothing is extended by allowing for a functional smoothing parameter, which is adaptive to the geometry of the underlying curve, which is called adaptive penalized smoothing. In the first level of optimization, the smooth ing coefficients are local parameters, estimated by minimizing sum of squared errors, conditional on the functional smoothing parameter. In the second level, the functional smoothing parameter is a complexity parameter, estimated by minimizing generalized cross-validation (GCV), treating the smoothing coefficients as explicit functions of the functional smoothing parameter. Adaptive penalized smoothing is shown to obtain better estimates for fitting functions and their derivatives.
Next, the generalized semiparametric additive models are estimated by three levels of optimization, allowing response variables in any kind of distribution. In the first level, the nonparametric functional parameters are nuisance parameters, estimated by maximizing the regularized likelihood function, conditional on the linear coefficients and the smoothing parameter. In the second level, the linear coefficients are structural parameters, estimated by maximizing the likelihood function with the nonparametric functional parameters treated as implicit functions of linear coefficients and the smoothing parameter. In the third level, the smoothing parameter is a complexity parameter, estimated by minimizing the approximated GCV with the linear coefficients treated as implicit functions of the smoothing parameter. This method is applied to estimate the generalized semiparametric additive model for the effect of air pollution on the public health.
Finally, parameters in differential equations (DE's) are estimated from noisy data with the generalized profiling method. In the first level of optimization, fitting functions are estimated to approximate DE solutions by penalized smoothing with the penalty term defined by DE's, fixing values of DE parameters. In the second level of optimization, DE parameters are estimated by weighted sum of squared errors, with the smoothing coefficients treated as an implicit function of DE parameters. The effects of the smoothing parameter on DE parameter estimates are explored and the optimization criteria for smoothing parameter selection are discussed. The method is applied to fit the predator-prey dynamic model to biological data, to estimate DE parameters in the HIV dynamic model from clinical trials, and to explore dynamic models for thermal decomposition of alpha-Pinene.
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Starkloff, Hans-Jörg, and Ralf Wunderlich. "Stationary solutions of linear ODEs with a randomly perturbed system matrix and additive noise." Universitätsbibliothek Chemnitz, 2005. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200501335.
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The paper considers systems of linear first-order ODEs with a randomly perturbed system matrix and stationary additive noise. For the description of the
long-term behavior of such systems it is necessary to study their stationary solutions. We deal with conditions for the existence of stationary solutions as well as
with their representations and the computation of their moment functions.
Assuming small perturbations of the system matrix we apply perturbation techniques to find series representations of the stationary solutions and give asymptotic
expansions for their first- and second-order moment functions. We illustrate the findings with a numerical example of a scalar ODE, for which the moment functions of
the stationary solution still can be computed explicitly. This allows the assessment
of the goodness of the approximations found from the derived asymptotic expansions.
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Robl, Jan. "Využití kovové aditivní technologie při výrobě oběžného axiálního kola turbínového motoru pomocné energetické jednotky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417561.
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The thesis deals with the possible use of additive technology in the production of strong thermally exposed components of turbine engines. The first part of the thesis is dedicated to the issue of processing heat-resistant materials by SLM method, introduction of conventional production of selected part and outline of currently used progressive methods in precision casting technology. These theoretical findings are further applied in the practical part of the thesis, which deals with the analysis of mechanical properties of cast and printed material IN 939. Experimental part also includes production of the blisk of the first stage turbine of the auxiliary power unit S5L by SLM additive technology. The thesis also includes analysis of fracture surfaces and metallographic analysis of samples using light and scanning electron microscopy. The thesis ends with the evaluation of the achieved results.
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Hajiha, Reza. "A Novel Method in Additive Manufacturing of Titanium Matrix Composites with Ceramic Reinforcement by Thermal Decomposition of Aluminum Sulfate." Thesis, California State University, Long Beach, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10838545.
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Metal matrix composites (MMCs) microstructure consists of a metallic alloy and a particular reinforcing component, ceramic in the case of this research. They are of high interest due to their high temperature strength, improved thermal stability, improved friction and wear resistant. Defining a low-cost additive manufacturing process that can fabricate high-quality MMC parts will combine the benefit of additive manufacturing and MMC together, which is highly desirable in today’s manufacturing.
This research introduces a novel method to fabricate MMC by introduction of uniformly distributed and dispersed ultra-fine ceramic particles within a metal substrate to form metal-ceramic composite during bulk sintering and to further develop three dimensional printing for fabrication of MMC structures reinforced by ceramic particles. This novel process is capable to fabricate metal-ceramic composite structures with a lower cost and shorter lead time in manufacturing compared to other existing additive manufacturing processes.
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Ng, Priscilla, Priscilla Ng, and Priscilla Ng. "Simulating Particle Packing During Powder Spreading For Selective Laser Melted Additive Manufacturing Using The Discrete Element Method In Abaqus." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2162.
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Metal additive manufacturing allows for the rapid production of complex parts that are otherwise impractical using conventional subtractive manufacturing techniques. Applications for additive manufacturing span across a broad array of industries including aerospace, automotive, and medical, among many others. One metric of printing success is material properties, including part density. While there has been extensive research completed for the density of printed parts, there is little published work concerning powder packing density on the build plate associated with powder spreading.
In this thesis, a Discrete Element Method (DEM) model was created in Abaqus to simulate the spreading behavior of particles through a single sweep of a spreader blade . Spreading behavior was investigated for three different build plate configurations: a flat build plate, a build plate with a small protruding feature, and a build plate with the same protruding feature split into quarters. For each configuration, the 2D packing behavior of the particles were analyzed during the powder spreading process. Different packing patterns seen in the 2D packing behavior were further analyzed to determine particle packing density, analogous to unit cell packing, and to predict 3D packing behavior and packing density. Additionally, particle packing density was measured following simulation using 2D image analysis to quantify powder spreading around, and interaction with, previously fused structures on the build plate. We found that the local packing fraction is measurably disrupted when particles interact with build plate features, providing insights into part density and short loading during part fabrication.
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Hensen, Tucker Joseph. "Development of a Novel Additive Manufacturing Method| Process Generation and Evaluation of 3D Printed Parts Made with Alumina Nanopowder." Thesis, Colorado State University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10640617.
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Direct coagulation printing (DCP) is a new approach to extrusion-based additive manufacturing, developed during this thesis project using alumina nanopowder. The fabrication of complex ceramic parts, sintered to full density, was achieved and the details of this invention are described. With the use of additive manufacturing, complex features can be generated that are either very difficult or unattainable by conventional subtractive manufacturing methods. Three unique approaches were taken to create a slurry suitable for extrusion 3D-printing. Each represented a different method of suspending alumina nanopowder in a liquid; a bio-polymer gel based on chitosan, a synthetic polymer binder using poly-vinyl acetate (PVA), and electrostatic stabilization with the dispersant tri-ammonium citrate (TAC). It was found that TAC created a slurry with viscosity and coagulation rate that were tuneable through pH adjustment with nitric acid. This approach led to the most promising printing and sintering results, and is the basis of DCP. Taguchi and fractional factorial design of experiments models were used to optimize mixing of the alumina slurry, rheological properties, print quality, and sinterability. DCP was characterized by measuring the mechanical properties and physical characteristics of printed parts. Features as small as ~450 ?m in width were produced, in parts with overhangs and enclosed volumes, in both linear and radial geometries. After sintering, these parts exhibited little to no porosity, with flexural modulus and hardness comparing favorably with conventionally manufactured alumina parts. A remarkable aspect of DCP is that it is a completely binderless process, requiring no binder removal step. In addition, DCP can employ nanopowders, allowing for enhanced mechanical properties as observed in nano-grained materials. Perhaps most importantly, any material that acquires a surface charge when in aqueous media has the potential to be used in DCP, making it a method of additive manufacturing using many metals and ceramics other than alumina.
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Kongnakorn, Thitima. "Development and Test of a New Method for Preference Measurement for Multistate Health Profiles." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4946.
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This dissertation aims at developing and testing a new method that can better capture preferences for multistate health profiles. The motivation arose from the failure of the QALY (Quality-Adjusted Life Year) model in adequately capturing preferences in multistate health profiles. The current QALY-based technique captures preferences for multistate health profiles by evaluating each health state in the profile independently of other states. As the past literature showed, this additive independence condition does not hold in practice and hence such approach is inadequate. To address this issue, this study proposes a novel approach to measure preferences for multistate health profiles by looking at two consecutive health states at a time. It hypothesizes that an evaluation of the future health state is dependent or "conditioned" on the level of the preceding, or current, health state. Characteristics of the current health state that are suspected to impact the resulting conditional preference scores for future health state are systematically explored in a carefully designed empirical study. The interested factors include duration of the current health state, direction of change and amplitude of change between the current and future health states. A 2
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Lucci, Lisa. "Valutazione della resistenza a fatica di provini in Maraging Steel realizzati in Additive Manufacturing." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/19826/.
Full textAbstract:
Questo elaborato ha lo scopo di testare a fatica una serie di provini realizzati con tecniche di Additive Manufacturing e sviluppati per avere strutture tolleranti ai danni a fatica. Queste strutture sono caratterizzate dall’essere delle “Impossible Design”, cioè non possono essere create tramite le tecniche di manifattura tradizionale.
Ci si focalizzerà su delle prove a flessione rotante in cui il provino di forma tradizionale viene sostituito da un tubo cavo avente lo stesso peso del provino tradizionale, con una geometria interna gerarchica. In questo modo, quando dalla superficie o dal punto più stressato del provino si origina una cricca, si può fermare o rallentare la sua propagazione attraverso un meccanismo estrinseco.
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Jansson, Anton. "Only a Shadow : Industrial computed tomography investigation, and method development, concerning complex material systems." Licentiate thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-54880.
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The complexity of components fabricated in today's industry is ever increasing. This increase is partly due to market pressure but it is also a result from progress in fabrication technologies that opens up new possibilities. The increased use of additive manufacturing and multi-material systems, especially, has driven the complexity of parts to new heights. The new complex material systems brings benefits in many areas such as; mechanical properties, weight optimisation, and sustainability. However, the increased complexity also makes material integrity investigations and dimensional control more difficult. In additive manufacturing, for example, internal features can be fabricated which cannot be seen or measured with conventional tools. There is thus a need for non-destructive inspection methods that can measure these geometries. Such a method is X-ray computed tomography. Computed tomography utilizes the X-rays ability to penetrate material to create 3D digital volumes of components. Measurements and material investigations can be performed in these volumes without any damage to the investigated component. However, computed tomography in material science is still not a fully mature method and there are many uncertainties associated with the investigation technique. In the work presented in this thesis geometries fabricated by various additive manufacturing processes have been investigated using computed tomography. Also in this work, a dual-energy computed tomography tool has been developed with the aim to increase the measurement consistency of computed tomography when investigating complex geometries and material combinations.MultiMatCT
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Wang, Hao. "The Hot Optimal Transportation Meshfree (HOTM) Method for Extreme Multi-physics Problems." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1607533458323004.
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Su, Wiliam Tean 1986. "Manufatura aditiva da liga Ti-6Al-4V aplicada em uma biela automotiva." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263584.
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Orientador: Cecília Amélia de Carvalho Zavaglia, Maria Aparecida LarosaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Atualmente, o mercado automotivo tem buscado cada vez mais a redução de peso e aumento de resistência mecânica de seus componentes. Dentro deste contexto, este trabalho tem como objetivo verificar se uma biela automotiva feita da liga de titânio Ti-6Al-4V obtida pelo processo de manufatura aditiva chamado Sinterização Direta de Metais por Laser (DMLS) apresenta os mesmos resultados estruturais que uma biela de Ti-6Al-4V laminada e recozida (comercial) ou que uma biela feita de aço C70, bastante utilizada no mercado. A liga Ti-6Al-4V é utilizada principalmente nas áreas aeronáutica e biomédica, mas também possui aplicações na indústria automotiva, principalmente no segmento de alta performance, graças a fatores como boa resistência mecânica, excelente resistência à corrosão e baixa densidade. As características mecânicas e microestruturais de amostras da liga Ti-6Al-4V prototipada por DMLS e de amostras da liga Ti-6Al-4V laminada e recozida foram avaliadas e comparadas através de ensaios de tração e microdureza, de análises em microscópio óptico e eletrônico de varredura (para a verificação da microestrutura e da porosidade), de ensaios de difração de raios-X (DRX) (para a análise das fases presentes no material), da análise da composição química por espectroscopia de energia dispersiva (EDS) e da análise de densidade pelo princípio de Arquimedes. Bielas de Ti-6Al-4V também foram produzidas por DMLS e ensaios de tração experimentais foram realizados, simulando uma condição de contorno típica utilizada em desenvolvimentos de bielas pela indústria automotiva. Com base nos resultados experimentais, foram realizadas análises de elementos finitos utilizando a mesma condição de contorno dos ensaios, com o intuito de se obter uma correlação entre os resultados experimentais e os virtuais. De uma maneira geral, todos os resultados indicam que a biela de Ti-6Al-4V produzida pelo processo DMLS possui um comportamento estrutural similar à biela de Ti-6Al-4V laminada e recozida
Abstract: Nowadays, the automotive market has been looking for more and more lightweight and better strength components. In this context, the objective of this work is to verify if a connecting rod made of the titanium alloy Ti-6Al-4V produced by an additive manufacturing process named Direct Metal Laser Sintering (DMLS) would have equivalent structural results of a connecting rod made of rolled annealed Ti-6AL-4V or even the C70 steel (widely used on the market for this application). This Titanium alloy is primary used in aerospace and biomedical areas, but is also used in the automotive industry, especially on the high performance segment, due to factors like good mechanical strength, excellent corrosion resistance and low density. The mechanical and microstrutural properties of Ti-6Al-4V samples obtained by DMLS and rolling and annealing processes were compared through the realization of tensile and micro hardness tests and through the microstructural characterization, composed of scanning electron microscopy (microstructure verification), optical microscopy (porosity verification), X-ray diffraction analysis for phases quantification, energy dispersive spectroscopy (chemical composition verification) and density analysis using the Arquimedes principle. Ti-6Al-4V connecting rods were also produced by the DMLS process and tensile experimental tests were performed using the same boundary condition as commonly seen on connecting rod development at automotive industry. Based on the experimental results, finite element analyses were performed in order to correlate the experimental and the virtual results. Generally, all the results indicate that the Ti-6Al-4V connecting rod produced by DMLS process has a structural behavior similar to the Ti-6Al-4V connecting rod produced by rolling and annealing process
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
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Chen, Shuai. "Investigation of FEM numerical simulation for the process of metal additive manufacturing in macro scale." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI048/document.
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La fabrication additive (FA) est devenue une nouvelle alternative pour la fabrication des pièces dans l'industrie. Cependant, il existe encore des limites pour ce procédé, en particulier la forme finale défavorable et les propriétés macroscopiques indésirables des pièces métalliques construites dans les systèmes de FA. La distorsion ou la fissure due à la contrainte résiduelle de ces pièces pose généralement de graves problèmes pour certains types de technologie de la FA métallique. Dans un système de FA, la qualité finale d'une pièce métallique dépend de nombreux paramètres de procédé, qui sont normalement optimisés par une série d'expériences sur des machines de FA. La simulation macroscopique dédiée au procédé de FA est une alternative potentielle pour les pièces métalliques fabriquées par la fabrication additive. Dans cette thèse, nous étudions d'abord le pré-processing de la simulation de FA par la méthode des éléments finis (FEM). Le procédé de fabrication additive est un phénomène multi-physique des champs couplés (champs thermique, mécanique et métallurgique). La simulation macroscopique est réalisée à deux niveaux différents. Au niveau de la couche, la reconstruction du modèle 3D est effectuée à partir du fichier de chemin de balayage de la machine de FA, basée sur la manipulation inverse de l'algorithme d'offsetting-clipping. Au niveau de la pièce, le modèle 3D de CAO est reconstruit dans un maillage des voxels, ce qui est pratique pour une pièce avec une géométrie complexe. Avec les températures de préchauffage différentes et les paramètres du procédé différents, la contrainte résiduelle d'une pièce est analysée. Ces simulations impliquent la technique potentielle pour réduire la contrainte résiduelle par l'optimisation des paramètres du procédé, au lieu de moyens traditionnels par augmenter la température de préchauffage. Basées sur la plateforme de simulation de FEM ci-dessus, deux simulations au niveau de ligne sont également étudiées dans cette thèse, visant à la relation entre le procédé de FA et la qualité finale de la pièce. Ces exemples démontrent la possibilité d'utiliser des simulations macroscopiques pour améliorer le contrôle de la qualité pendant le procédé de FA. Dans la première tâche, l'ensemble de données des paramètres de chauffage et la contrainte résiduelle sont générés par la simulation de FA. La corrélation entre eux est étudiée en utilisant des algorithmes de régression, tel que le réseau neuronal artificiel. Dans la deuxième tâche, un contrôleur de PID pour la boucle de rétroaction puissance-température est intégré dans la simulation de procédé de FA et l'auto-réglage de PID est numériquement étudié au lieu d'utiliser la machine de FA. Les deux tâches montrent le rôle important de la simulation de procédé macroscopique de FA, qui peut remplacer ou combiner les nombreuses expériences essai-erreur dans la fabrication additive métalliqueAdditive manufacturing (AM) has become a new option for the fabrication of metallic parts in industry. However, there are still some limitations for this application, especially the unfavourable final shape and undesired macroscopic properties of metallic parts built in AM systems. The distortion or crack due to the residual stress of these parts leads usually to severe problems for some kinds of metal AM technology. In an AM system, the final quality of a metallic part depends on many process parameters, which are normally optimized by a series of experiments on AM machines. In order to reduce the considerable time consumption and financial expense of AM experiments, the numerical simulation dedicated to AM process is a prospective alternative for metallic part fabricated by additive manufacturing. Because of the multi-scale character in AM process and the complex geometrical structures of parts, most of the academic researches in AM simulation concentrated on the microscopic melting pool. Consequently, the macroscopic simulation for the AM process of a metallic part becomes a current focus in this domain. In this thesis, we first study the pre-processing of AM simulation on Finite Element Method (FEM). The process of additive manufacturing is a multi-physics problem of coupled fields (thermal, mechanical, and metallurgical fields). The macroscopic simulation is conducted in two different levels with some special pre-processing work. For the layer level, the reconstruction of 3D model is conducted from the scan path file of AM machine, based on the inverse manipulation of offsetting-clipping algorithm. For the part level, the 3D model from CAD is reconstructed into a voxel-based mesh, which is convenient for a part with complex geometry. The residual stress of a part is analysed under different preheat temperatures and different process parameters. These simulations imply the potential technique of reducing residual stress by the optimisation of process parameters, instead of the traditional way by increasing preheat temperature. Based on the FEM simulation platform above, two simulations at line level are also studied in this thesis, aiming at the relation between the AM process and part's final quality. These examples demonstrate the feasibility of using macroscopic simulations to improve the quality control during the AM process. In the first task, dataset of heating parameters and residual stress are generated by AM simulation. The correlation between them is studied by using some regression algorithm, such as artificial neural network. In the second task, a PID controller for power-temperature feedback loop is integrated into AM process simulation and the PID auto-tuning is numerically investigated instead of using AM machine. Both of the two tasks show the important role of AM macroscopic process simulation, which may replace or combine with the numerous trial and error of experiments in metal additive manufacturing
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Davis, Taylor Matthew. "Feasibility and Impact of Liquid/Liquid-encased Dopants as Method of Composition Control in Laser Powder Bed Fusion." BYU ScholarsArchive, 2021. https://scholarsarchive.byu.edu/etd/9256.
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Additive manufacturing (AM) – and laser powder bed fusion (LPBF) specifically – constructs geometry that would not be possible using standard manufacturing techniques. This geometric versatility allows integration of multiple components into a single part. While this practice can reduce weight and part count, there are also serious drawbacks. One is that the LPBF process can only build parts with a single material. This limitation generally results in over-designing some areas of the part to compensate for the compromise in material choice. Over-designing can lead to decreased functional efficiency, increased weight, etc. in LPBF parts. Methods to control the material composition spatially throughout a build would allow designers to experience the full benefits of functionality integration. Spatial composition control has been performed successfully in other AM processes – like directed energy deposition and material jetting – however, these processes are limited compared to LPBF in terms of material properties and can have inferior spatial resolution. This capability applied to the LPBF process would extend manufacturing abilities beyond what any of these AM processes can currently produce. A novel concept for spatial composition control – currently under development at Brigham Young University – utilizes liquid or liquid-encased dopants to selectively alter the composition of the powder bed, which is then fused with the substrate to form a solid part. This work is focused on evaluating the feasibility and usefulness of this novel composition control process. To do this, the present work evaluates two deposition methods that could be used; explores and maps the laser parameter process space for zirconia-doped SS 316L; and investigates the incorporation of zirconia dopant into SS 316L melt pools. In evaluating deposition methods, inkjet printing is recommended to be implemented as it performs better than direct write material extrusion in every assessed category. For the process space, the range of input parameters over which balling occurred expanded dramatically with the addition of zirconia dopant and shifted with changes in dopant input quantities. This suggests the need for composition-dependent adjustments to processing parameters in order to obtain desired properties in fused parts. Substantial amounts of dopant material were confirmed to be incorporated into the laser-fused melt tracks. Individual inclusions of 100 $nm$ particles distributed throughout the melt pool in SEM images. Howewver, EDX data shows that the majority of the incorporated dopant material is located around the edges of the melt pools. Variations of dopant deposition, drying, and laser scanning parameters should be studied to improve the resulting dopant incorporation and dispersion in single-track line scans. Area scans and multi-layer builds should also be performed to evaluate their effect on dopant content and dispersion in the fused region.
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Ceco, Mima. "Evaluation and optimization of cation exchanging materials for life-span optimization of engine oil." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-98986.
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Requirements of high performing engine oil are today necessary since the development of new machinery with modern standardsis a cutting edge technology demanding highly optimized components. One way of increasing the lubricating properties of engineoil is through the addition of antioxidants. Antioxidants included in lubricants have a number of functions, one being buffering theinorganic acids sulphuric acid and nitric acid.A novel method expected to lower the hydrogen ion concentration in acidified engine oil was evaluated in this thesis. Thecapability of four different types of cation exchangers to serve as complements for buffering additives in heavy vehicle engineswas assessed. Two cation exchangers were weak and two were strong. The analysis techniques used to evaluate what effect thecation exchangers have on engine oil were standard test method ASTM D4739, for measurements of the total base number (TBN),and inductively coupled plasma – atomic emission spectroscopy (ICP-AES). With ASTM D4739 it was found that weak cationexchangers give positive results with respect to the ability to decrease the hydrogen ion concentration in acidified engine oil.However, after begin subjected to strong cation exchangers, ASTM D4739 indicated that the hydrogen ion concentration in theacidified engine oil remains the same or increases.With additional literature studies of a variety of cation exchangers currently on the market, further optimization of the cationexchanging material could likely be achieved. In addition, the preparation method used during the evaluation of the cationexchangers should be optimized to give more reliable results.
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Desai, Prathamesh. "Tribosurface Interactions involving Particulate Media with DEM-calibrated Properties: Experiments and Modeling." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1123.
Full textAbstract:
While tribology involves the study of friction, wear, and lubrication of interacting surfaces, the tribosurfaces are the pair of surfaces in sliding contact with a fluid (or particulate) media between them. The ubiquitous nature of tribology is evident from the usage of its principles in all aspects of life, such as the friction promoting behavior of shoes on slippery water-lubricated walkways and tires on roadways to the wear of fingernails during filing or engine walls during operations. These tribosurface interfaces, due to the small length scales, are difficult to model for contact mechanics, fluid mechanics and particle dynamics, be it via theory, experiments or computations. Also, there is no simple constitutive law for a tribosurface with a particulate media. Thus, when trying to model such a tribosurface, there is a need to calibrate the particulate media against one or more property characterizing experiments. Such a calibrated media, which is the “virtual avatar” of the real particulate media, can then be used to provide predictions about its behavior in engineering applications. This thesis proposes and attempts to validate an approach that leverages experiments and modeling, which comprises of physics-based modeling and machine learning enabled surrogate modeling, to study particulate media in two key particle matrix industries: metal powder-bed additive manufacturing (in Part II), and energy resource rock drilling (in Part III). The physics-based modeling framework developed in this thesis is called the Particle-Surface Tribology Analysis Code (P-STAC) and has the physics of particle dynamics, fluid mechanics and particle-fluid-structure interaction. The Computational Particle Dynamics (CPD) is solved by using the industry standard Discrete Element Method (DEM) and the Computational Fluid Dynamics (CFD) is solved by using finite difference discretization scheme based on Chorin's projection method and staggered grids. Particle-structure interactions are accounted for by using a state-of-the art Particle Tessellated Surface Interaction Scheme and the fluid-structure interaction is accounted for by using the Immersed Boundary Method (IBM). Surrogate modeling is carried out using back propagation neural network. The tribosurface interactions encountered during the spreading step of the powder-bed additive manufacturing (AM) process which involve a sliding spreader (rolling and sliding for a roller) and particulate media consisting of metal AM powder, have been studied in Part II. To understand the constitutive behavior of metal AM powders, detailed rheometry experiments have been conducted in Chapter 5. CPD module of P-STAC is used to simulate the rheometry of an industry grade AM powder (100-250microns Ti-6Al-4V), to determine a calibrated virtual avatar of the real AM powder (Chapter 6). This monodispersed virtual avatar is used to perform virtual spreading on smooth and rough substrates in Chapter 7. The effect of polydispersity in DEM modeling is studied in Chapter 8. A polydispersed virtual avatar of the aforementioned AM powder has been observed to provide better validation against single layer spreading experiments than the monodispersed virtual avatar. This experimentally validated polydispersed virtual avatar has been used to perform a battery of spreading simulations covering the range of spreader speeds. Then a machine learning enabled surrogate model, using back propagation neural network, has been trained to study the spreading results generated by P-STAC and provide much more data by performing regression. This surrogate model is used to generate spreading process maps linking the 3D printer inputs of spreader speeds to spread layer properties of roughness and porosity. Such maps (Chapters 7 and 8) can be used by a 3D-printer technician to determine the spreader speed setting which corresponds to the desired spread layer properties and has the maximum spread throughout. The tribosurface interactions encountered during the drilling of energy resource rocks which involve a rotary and impacting contact of the drill bit with the rock formation in the presence of drilling fluids have been studied in Part III. This problem involves sliding surfaces with fluid (drilling mud) and particulate media (intact and drilled rock particles). Again, like the AM powder, the particulate media, viz. the rock formation being drilled into, does not have a simple and a well-defined constitutive law. An index test detailed in ASTM D 5731 can be used as a characterization test while trying to model a rock using bonded particle DEM. A model to generate weak concrete-like virtual rock which can be considered to be a mathematical representation of a sandstone has been introduced in Chapter 10. Benchtop drilling experiments have been carried out on two sandstones (Castlegate sandstone from the energy rich state of Texas and Crab Orchard sandstone from Tennessee) in Chapter 11. Virtual drilling has been carried out on the aforementioned weak concrete-like virtual rock. The rate of penetration (RoP) of the drill bit has been found to be directly proportional to the weight on bit (WoB). The drilling in dry conditions resulted in a higher RoP than the one which involved the use of water as the drilling fluid. P-SATC with the bonded DEM and CFD modules was able to predict both these findings but only qualitatively (Chapter 11)
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Jacques, Marjorie. "Développement d'une méthode de conception de moules et noyaux hybrides en fonderie." Thesis, Reims, 2019. http://www.theses.fr/2019REIMS021.
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Ces travaux de recherche ont pour objectif de définir une méthodologie de conception de moules hybrides en fonderie. Cette méthodologie est définie à partir des limites technico-économiques des procédés traditionnels de moulage et de l’impression 3D sable. Dans un premier temps, ces limites sont évaluées par la caractérisation mécanique et dimensionnelle des moules imprimés. Cette caractérisation mécanique a été réalisée à partir d’essais de flexion 3 points et de compression en fonction de différents paramètres. La capabilité dimensionnelle de l’imprimante 3D a été évaluée par la mesure d’éprouvettes imprimées dans différentes directions. Dans un second temps, la méthode de conception des moules traditionnels a été formalisée à partir du recueil de l’expertise des partenaires fondeurs du projet ANR MONARCHIES et testée sur différents cas. Les règles métiers inhérentes à l’imprimante 3D sable ont été établies à partir des travaux du laboratoire ITHEMM et complétées par l’étude de pièces. Le processus de conception des moules imprimés a été élaboré à partir de ces règles métiers et validé sur des études de cas. Le coût de fabrication des moules imprimés a été défini par une méthode analytique et paramétrique. La méthodologie de conception des moules hybrides s’appuie sur l’ensemble des travaux précédents et sur la notion d’indice de complexité. En fonction de la valeur de ces indices de complexité, des contraintes de remmoulage et de coût de fabrication, le choix optimal du procédé de fabrication est défini pour les différentes parties du moule. Enfin, cette méthodologie a été testée sur un panel représentatif de pièces de fonderie permettant d’évaluer sa robustesseThe aim of this works is to define a design methodology of hybrids casting molds. This methodology is based on technical and economical limits of conventional process and 3D sand printing. Firstly, these limits were evaluated by mechanical and dimensional characterization of 3D sand printing molds. Mechanical characterization was realised by three points bending test and compression testing with different parameters. 3D printer dimensional capability was determined by samples measure printed in different directions. Secondly, the design method of conventional molds was established from smelters know-how which are ANR MONARCHIES project partner from different case study. Inherent design rules of sand 3D printer were defined from the ITHEMM laboratory research works and completed with parts studies. 3D printing molds design process was created by design rules and validated with studies cases. Manufacturing cost of printing molds was defined by analytic and parametric method. The hybrids molds design methodology relies on all previous works and on complexity index. Optimal manufacturing process for different molds parts was selected according to the complexity index value, mould assembly restraint and manufacturability cost. Finally, this methodology was tested on representative sample group of casting parts, allowed to evaluate the robustness
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Stenford, Rebecka, and Rebecca Röing. "Den nya revolutionen? Additiv tillverknings potential för spridning till modeindustrin." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-10240.
Full textAbstract:
Teknisk utveckling och innovation är drivande för samhällets ekonomiska tillväxt. Vilja och förmåga att innovera är också avgörande för företags överlevnad då lyckosam innovation skapar konkurrensfördelar. Additiv tillverkning är en ny produktionsmetod som har potential att revolutionera hur produkter tillverkas. Tekniken kastar om förutsättningarna för hur företag konkurrerar genom att möjliggöra kostnadseffektiv tillverkning av små serier, produktion nära kundorderpunkten och kundanpassning. Modeindustrin är en komplex och hårt konkurrensutsatt bransch där företag befinner sig i en konstant strävan efter differentiering. För att nå framgång måste företag skapa fördelar gentemot konkurrenterna. Flera branscher har redan börjat använda additiv tillverkning och företag skapar framgångsrikt konkurrensfördelar genom att implementera tekniken. Inom modebranschen har dock additiv tillverkning använts begränsat och inte för produktion av konsumentprodukter. Vårt intresse väcktes för att vidare utreda huruvida det är lämpligt att implementera additiv tillverkning på bredare front. Studiens syfte är att fördjupa diskussionen kring spridning av ny teknik genom att studera additiv tillverknings potential för spridning till modeindustrin. Studien har genomförts med en deduktiv ansats där teorikärnan utgjorts av Schumpeters teorier kring innovation och Rogers teorier om innovationsdiffusion. Studien har varit av kvalitativ karaktär där empiriinsamlingen skett genom semi-strukturerade intervjuer med representanter från företag som använder additiv tillverkning samt forskare inom det textila området. Studiens slutsats är att additiv tillverkning inte lämpar sig för produktion av kläder så som vi känner dem idag. När empirin analyseras i förhållande till studiens teorier framkommer aspekter som indikerar ett flertal matchningar mellan fördelarna med additiv tillverkning och modeindustrins karaktärsdrag framkommit. Att implementera additiv tillverkning kan, i framtiden, vara en möjlighet för modeföretag att i framtiden skapa konkurrensfördelar.Technological development and innovation are driving forces behind economic growth. Having the will and ability to innovate are also crucial factors for companies as successful innovation creates competitive advantage. Additive manufacturing is a new production process with the potential to revolutionise the way products are being manufactured. The technique disrupts competitive conditions by enabling cost-effective production of small lot sizes, production close to the decoupling point and customisation. The fashion industry is a complex and highly competitive industry, companies are in a constant quest for means of differentiation. In order to be successful, companies must create advantages over the competitors. Several sectors have already started using additive manufacturing and companies create successful competitive advantage by implementing the technology. In the fashion industry however, additive manufacturing has been used sparsely and not for production of consumer products. Our interest was awaked to further investigate whether or not it is appropriate to extend the use of this new technology. The purpose of this study is to immerse the discussion of diffusion of new technology by studying additive manufacturing’s potential of spreading to the fashion industry. The study was conducted with a deductive approach and the central theories have been Schumpeter’s theories of innovation and Rogers’ theories of diffusion of innovations. The study has been of a qualitative nature and semi-structured interviews with representatives from companies using additive manufacturing and researchers in the textile field were conducted to collect the empirical data. The conclusion is that additive manufacturing is not yet suitable for production of clothing. Nonetheless, when the empirical data was analysed in relation to the theories used, multiple matches between the benefits of additive manufacturing and the characteristics of the fashion industry were revealed. Consequently, implementing additive manufacturing can, in the future, pose opportunities for fashion companies to create competitive advantage. The thesis is written in Swedish.
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Колотков, К. Д., and K. D. Kolotkov. "Анализ и оценка детерминант производительности труда (на примере Свердловской области) : магистерская диссертация." Master's thesis, б. и, 2021. http://hdl.handle.net/10995/100694.
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Оценка факторов производительности труда на региональном уровне является важным аспектом в процессе повышения общего уровня экономического благосостояния территории. Целью магистерской диссертации является развитие теоретико-методических основ анализа и оценки детерминант производительности труда в регионе. В работе рассматриваются теоретические и методические вопросы исследования производительности труда. В качестве источников использовалась научно-исследовательская и учебно-методическая литература, нормативно-правовые акты и статистические данные Федеральной службы государственной статистики по тематике исследования. В магистерской диссертации был предложен методический подход к оценке факторов производительности труда в регионе, особенностью которого является комбинированное использование данных объективных статистических показателей и экспертных мнений, применение статистического инструментария корреляционно-регрессионного анализа, а также реализация аддитивного подхода, предполагающего анализ детерминант производительности труда, рассчитанной различными способами.Assessment of labor productivity factors at the regional level is an important aspect in the process of increasing the overall level of economic well-being of the territory. The aim of the master's thesis is to develop the theoretical and methodological foundations for the analysis and assessment of the labor productivity determinants of in the region. The paper deals with theoretical and methodological issues in the study of labor productivity. Scientific research and educational-methodical literature, regulatory legal acts, and statistical data of the Federal State Statistics Service on the research topic were used as sources. Master thesis suggest a methodological approach to assessing labor productivity factors in the region, with a feature of the combined use of objective statistical indicators and peer review, application of statistical tools for correlation and regression analysis, and implementation of an additive approach that involves analysis of the determinants of labor productivity, calculated in various ways.
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Curwen, Vincent, and Alexander Saxin. "Analysis and optimal design of a titanium aircraft bracket using topology optimization." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-20004.
Full textAbstract:
Sustainable engineering within product development is becoming increasingly important with the ever-growing amounts of resources used to sustain the human way of life in modern times. An effective way of helping to deal with this problem is to reduce the resources used in products and components across the world. This thesis explores the effectiveness of the topology optimization method in achieving significant material reductions whilst maintaining structural strength and integrity when designing an aircraft component. The part is an engine handling mounting bracket which will be optimized to be produced by additive manufacturing, and so restrictions imposed by traditional manufacturing methods are not considered, allowing for larger material reductions to be achieved. The original bracket part was provided by GE Electric, and the computer software Abaqus computer aided engineering with integrated TOSCA was used to solve the problem. Two trials were conducted, with the first being used to gain knowledge and understanding of the optimization features of the software. The basic requirements for the optimized design were that it should be able to withstand four given static load cases without undergoing plastic deformation, and these load cases were applied separately in trial 1 for simplicity. The second trial was conducted with a higher complexity, utilising multi-objective topology optimization which allowed the load cases to be weighted individually whilst being applied simultaneously during optimization. The resulting bracket part that was created with the help of the optimized topology from trial 2 reduced the volume of the original part by over 75%. This also left potential for further material reductions as the optimized part did not undergo plastic deformation when subject to any of the four load cases of the study. In conclusion, topology optimization seems to be extremely helpful when designing components that have clearly defined load cases, producing results that designers and engineers can have confidence in. The method does however have its flaws, such as difficulties in utilising the optimized topology directly to create a computer aided design part file. The post-processing process needed to achieve such a part is also time-consuming although it must be implemented to create a digital part that can be analysed and verified by FEA.
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Liang, Xiaoyu. "Comportement en fatigue à grand nombre de cycle d’un acier inoxydable 316L obtenu par fabrication additive : effets de la microstructure, de la rugosité et des défauts." Thesis, Paris, HESAM, 2020. http://www.theses.fr/2020HESAE017.
Full textAbstract:
Cette étude vise à étudier l'influence de la microstructure, de la rugosité et des défauts de surface sur le comportement en fatigue à grand nombre de cycles (FGNC) d'un acier inoxydable 316L obtenu par fabrication additive (FA). Composée d’un volet expérimental et d’un volet numérique, elle est motivée par le fait que les matériaux issus du procédé de FA présentent souvent un état de surface et une microstructure très distincts des couples procédés de fabrication / matériaux conventionnels. Afin de clairement identifier le rôle joué par chacun des facteurs influents sur la réponse en fatigue, différentes techniques de caractérisation (Profilométrie, EBSD, Tomographie RX, dureté …) sont employées et permettent de mettre en évidence un niveau de rugosité important après fabrication ainsi que des textures morphologiques et cristallographiques marquées. Pour ce qui est du comportement sous chargement mécanique, des essais cycliques à déformation totale imposée mettent en évidence un écrouissage cyclique avec durcissement puis adoucissement. Une importante campagne d’essais en fatigue est conduite sous différents modes de chargement (traction, flexion, torsion) et pour différentes configurations d’état de surface (brut de fabrication, poli). L’analyse des faciès de rupture fait apparaître le rôle prépondérant joué par les défauts de type « lack of fusion » sur les mécanismes d’amorçage en surface des fissures de fatigue. Un diagramme de type Kitagawa-Takahashi est construit à partir de l’observation de la taille des défauts à l’amorçage et le rôle des amas de défaut est clairement démontré. L’étude numérique comporte deux parties distinctes avec, d’abord, un travail préliminaire relatif à la construction d’une méthode non locale adaptée à la prise en compte des effets de microstructure en fatigue dans le cas d’un acier 316L corroyé. A partir des données collectées lors de la campagne expérimentale portant sur l’acier SLM 316L, un modèle d'éléments finis tenant compte de la rugosité, des défauts et de la microstructure est construit. Les calculs sont conduits en utilisant un comportement de type élasticité cubique associé ou pas à de la plasticité cristalline. À l'aide d’une approche faisant appel à la statistique des extrêmes, les résultats des simulations EF sont analysés de manière à quantifier les effets respectifs de la rugosité de surface, de la taille et morphologie des grains, de la texture cristallographique et des défautsThis study aims to investigate the influence of both the microstructure and surface defects on the high cycle fatigue (HCF) behavior of a 316L stainless steel obtained by additive manufacturing (AM). Surface defects and microstructure are dominant factors of fatigue behavior, while the AM materials often exhibit distinguished surface state and microstructure compared to conventional materials. The current study begins with an investigation of the material properties that are related to fatigue behavior. Microstructure observations of the powder and fabricated specimens are undertaken. Profilometry and tomography analyses make the inherent defects visible. The hardness, elastic behavior and elastic-plastic behavior are studied via mechanical tests. Then, load-controlled fatigue tests concerning different surface-treated specimens under different loading types are conducted. To reveal the mechanism of fatigue failure in the studied specimens, a comprehensive fractography analysis is carried out. Experimental research reveals the weakening of fatigue strength due to lack-of-fusion defects. Yet, the effect of the microstructural attributes is difficult to evaluate without numerical tools. A preliminary numerical study about the application of the non-local method in an explicit microstructure sensitive model is undertaken to complement the microstructure-sensitive modeling framework. Based on the data collected in the experimental campaign, a finite element model that can take into consideration of the defects and the microstructure of the SLM SS 316L is built up. Finite element analyses are performed with both cubic elasticity and polycrystal plasticity constitutive laws. With the help of the statistical method, the results from the FE model are used to quantitatively assess the influence of surface roughness and microstructural attributes on the fatigue performance of SLM SS 316L
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Thouvenot, Vincent. "Estimation et sélection pour les modèles additifs et application à la prévision de la consommation électrique." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS184/document.
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L'électricité ne se stockant pas aisément, EDF a besoin d'outils de prévision de consommation et de production efficaces. Le développement de nouvelles méthodes automatiques de sélection et d'estimation de modèles de prévision est nécessaire. En effet, grâce au développement de nouvelles technologies, EDF peut étudier les mailles locales du réseau électrique, ce qui amène à un nombre important de séries chronologiques à étudier. De plus, avec les changements d'habitude de consommation et la crise économique, la consommation électrique en France évolue. Pour cette prévision, nous adoptons ici une méthode semi-paramétrique à base de modèles additifs. L'objectif de ce travail est de présenter des procédures automatiques de sélection et d'estimation de composantes d'un modèle additif avec des estimateurs en plusieurs étapes. Nous utilisons du Group LASSO, qui est, sous certaines conditions, consistant en sélection, et des P-Splines, qui sont consistantes en estimation. Nos résultats théoriques de consistance en sélection et en estimation sont obtenus sans nécessiter l'hypothèse classique que les normes des composantes non nulles du modèle additif soient bornées par une constante non nulle. En effet, nous autorisons cette norme à pouvoir converger vers 0 à une certaine vitesse. Les procédures sont illustrées sur des applications pratiques de prévision de consommation électrique nationale et locale.Mots-clés: Group LASSO, Estimateurs en plusieurs étapes, Modèle Additif, Prévision de charge électrique, P-Splines, Sélection de variablesFrench electricity load forecasting encounters major changes since the past decade. These changes are, among others things, due to the opening of electricity market (and economical crisis), which asks development of new automatic time adaptive prediction methods. The advent of innovating technologies also needs the development of some automatic methods, because we have to study thousands or tens of thousands time series. We adopt for time prediction a semi-parametric approach based on additive models. We present an automatic procedure for covariate selection in a additive model. We combine Group LASSO, which is selection consistent, with P-Splines, which are estimation consistent. Our estimation and model selection results are valid without assuming that the norm of each of the true non-zero components is bounded away from zero and need only that the norms of non-zero components converge to zero at a certain rate. Real applications on local and agregate load forecasting are provided.Keywords: Additive Model, Group LASSO, Load Forecasting, Multi-stage estimator, P-Splines, Variables selection
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Tornatore, Dario. "Damping Capability of Lattice Structures: a Numerical Study." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Find full textAbstract:
Lattices are recognized as ultra-lightweight materials with high specific stiffness and high specific strength. The applications of this architectural material range from the aerospace and automotive industry up to the biomedical one.
In the literature, most of the studies address the mechanical responses of lattice structures under static, dynamic (impact) and fatigue loading conditions while only few works deal with the damping capabilities of such structures.
This study focuses on the damping capability of classical lattice configurations whose architecture is made of struts (i.e. CC, CBCC, ACC, Octet, Rhombic dodecahedron). The influence of three aspects has been investigated: the geometrical parameters defining the structure of the lattice cell, the introduction of a compressive pre-stress field within the cell and the plastic constitutive behaviour of the material used for the struts. A broad sensitivity campaign has been performed in order to evaluate the amount of dissipated energy for the different cell architectures according to the variation of the strut diameter and to the presence of local instabilities (post-buckling behaviour of the struts).
The numerical results highlight how the damping capability of the considered cell, for the same loading condition, is strongly related to the topology of the cell and to its relative density. By smartly tailoring these parameters, the damping capability without pre-stress can be increased up to 23% and, if the pre-stress is introduced within the cell, the damping effects can be ulteriorly intensified .
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Augustine, Joyal, and Steven Simons. "Improving the surface finish of the rubber weight plate : Master thesis in mechanical engineering." Thesis, Högskolan i Halmstad, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-45005.
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Flash is the unwanted or excessrubber material that presents on the outersurface of themolded rubber product. This will affect the surface finish; it is a cosmetic defect andit can be removed. It forms because of the leak or the excess molded rubber materialbetween the surface of the mold, typically on the parting line, (Jordan Anderson,2014). The presence of flash will reduce customer satisfaction. There are manymethods to remove the flash. The method is selected according to the degree of flashextension and the location where it occurs.The project aims to design a semi/full automated machine, which helps for having asmooth and fine surface finish of the weight plates. These plates are made up of rubberfor the ELEIKO group. The weight plates have different weights from 10 to 20 kg,but the diameter of each plate stays the same, but the thickness will be different foreach plate. The machine should be designed that removes all the excess rubber andshould smoothen the outer surface of the weight. The purpose of this work is to gainknowledge about different product development methods, respective tools, andtechniques that are used. The machine should be user- friendly, should not becomplicated, should not damage the workpiece (marks or trace of the blade), shouldnot put the employer in danger, and economically feasible.This report presents the progress of designing of the product, product development,methods, and literature study. The designed model can construct in the industry fortheir problem they are faced by the flash. The model is very simple and unique so thateveryone can perform the task without any previous experience. Material alternativeswere evaluated as well as manufacturing possibilities. The designed machine was theoffered for free as means for further research and development. Keywords: flashing, additive manufacturing, Ullman method, Pugh matrix, rubberweight plates, lever arm, smoothening tool.
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Liu, Xin. "Numerical modeling and simulation of selective laser sintering in polymer powder bed." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI012/document.
Full textAbstract:
La fabrication additive est l’un des secteurs industriels les plus en développent ces dernières années. L’une de ces technologies de fabrication les plus prometteuses est la fusion laser sélective (SLS), et relève d’un intérêt croissant aussi bien industriel qu’académique. Néanmoins, beaucoup de phénomène mis en jeu par ce procédé demeure non encore bien compris, entravant ainsi son développement pour la production de pièces de bonne qualité pour des applications industrielles. L’objectif de cette thèse est de développer un cadre de simulation numérique permettant la simulation du procédé SLS pour des poudres de polymère afin de comprendre les multiples et complexes phénomènes physiques qui se produise lors du frittage laser et d’étudier l’influence des paramètres du procédé sur la qualité du produit final. Contrairement aux approches classiques de modélisation numérique, basées sur la définition de matériaux homogène équivalents pour la résolution des équations de bilan, nous proposons une simulation globale du procédé du frittage laser de poudres, en utilisant la méthode des Eléments Discrets (DEM). Cela consiste en un couplage entre quatre sous-modèles : transferts radiatif dans le milieu granulaire semi-transparent, conduction thermique dans les milieux discrets, coalescence puis densification. Le modèle de transferts par rayonnement concerne l’interaction du faisceau laser avec le lit de poudre. Plusieurs phénomènes sont ainsi pris en compte, notamment la réflexion, la transmission, l’absorption et la réfraction. De plus, une méthode de Monte-Carlo couplée à la méthode du Lancer de rayons est développée afin d’étudier l’influence de la réfraction sur la distribution de l’énergie du laser dans le lit de poudre. Le modèle de conduction dans des milieux discrets décrit la diffusion thermique inter-particules. Finalement, le modèle de frittage décrit les cinétiques de coalescence et de diffusion de l’air dans le polymère et densification du milieu. Cela permet de décrire les cinétiques de fusion des grains, dont l’énergie de surface et la diffusons de l’air sont les deux moteurs principaux. Le couplage entre les différents modèles nous a permis de proposer un modèle numérique global, validé grâce à des comparaisons à des résultats de simulations théoriques et expérimentales, trouvés dans la littérature. Une analyse paramétrique est alors proposée pour la validation du modèle et l’étude du procédé. L’influence de différents paramètres aussi bien du procédé que du matériau sur le champ de température, la densité relative du matériau sa structure, etc , est ainsi investiguée. Les résultats montrent une bonne précision dans la modélisation des différents phénomènes complexes inhérents à ce procédé, et ce travail constitue un potentiel réel pour la modélisation et l’optimisation des procédés de fabrication additive par matériaux granulairesMany industrial and academic interests concerning the additive manufacturing processes are developed in the last decades. As one of the most promising technique of additive manufacturing, the Selective Laser Sintering (SLS) has been valued by both industry and academic. However, it remains that several phenomena are still not well understood in order to properly model the process and propose quality improvement of parts made. The goal of this Ph.D. project is to develop a framework of numerical simulation in order to model the SLS process in polymer powder bed, meanwhile understanding multiple physical phenomena occurring during the process and studying the influence of process parameters on the quality of final product. In contrast to traditional approach, based on the equivalent homogeneous material in numerical modeling of partial differential equations derived from conservation laws, we propose a global model to simulate powder-based additive manufacturing by using the Discrete Element method (DEM). It consists in a coupling between four different physical models: radiative heat transfer, discrete heat conduction, sintering and granular dynamics models. Firstly, the submodel of radiative heat transfer concerns the interaction between the laser beam and powder bed. Several phenomena are considered, including the reflection, transmission, absorption and scattering. Besides, a modified Monte Carlo ray-tracing method is developed in order to study the influence of scattering on the distribution of the deposited laser energy inside the powder bed Furthermore, the submodel of discrete heat conduction describes the inter-particles heat diffusion. Moreover, the sintering submodel concerns the phenomena of coalescence and air diffusion. It describes the melting kinetics of grains, driven by surface tension and the release of entrapped gases inside powder bed. Finally, the granular dynamics submodel concerns the motions and contacts between particles when depositing a new layer of powders. The coupling between these submodels leads to propose a global numerical framework, validated by comparing the results to both simulated and experimental ones from literatures. A parametric study is then proposed for model validation and process analysis. The Influence of different material and process parameters on the evolution of temperature, relative density and materials structure and characteristics are investigated. The results exhibit accurate modeling of the complex phenomena occurring during the SLS process, and the work constitute a great potential in modeling and optimization of additive processes
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Kudlinskienė, Ieva. "Ekstruduoto baltyminio priedo virškinamumas, jo poveikis karvių produktyvumui ir pieno sudėčiai." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140519_092438-45301.
Full textAbstract:
UAB „Naujasis Nevėžis“ 2012 metais buvo sukurta ekstruduoto baltyminio priedo LAKTOMIL-1 receptūra, šis produktas skirtas melžiamoms karvėms skirtingais produktyvumo tarpsniais. Baltyminio priedo LAKTOMIL – 1 poveikio, karvių produktyvumui ir pieno kokybei, įvertinimui Lukšių žemės ūkio bendrovėje (Lauciškių komplekse) buvo atliktas 90 dienų trukmės bandymas.
Bandymui analogų principu atrinkta 30 Lietuvos juodmargių karvių, jos suskirstytos į dvi grupes (kontrolinę ir bandomąją), po 15 gyvulių kiekvienoje. Kontrolinės grupės karvės buvo šeriamos įprastiniu racionu, sudarytu iš kukurūzų siloso, žolių šienainio, kukurūzų grūdainio, rapsų išspaudų, sojų išspaudų ir mineralų. Bandomosios grupės karvės šertos analogišku racionu, tačiau sojų išspaudos pakeistos baltyminiu priedu LAKTOMIL-1. Siekiant nustatyti LAKTOMIL-1 baltymų virškinamumo laipsnį didžiajame prieskrandyje ir plonosiose žarnose, bendradarbiavome su valstybiniu Estijos „Gyvybės Mokslų Universitetu“, Mitybos ir gyvūnų produktų kokybės katedra (Tartu).
Baltymų ir sausosios medžiagos virškinamumas didžiajame prieskrandyje buvo nustatytas in sacco metodu. Tyrimui atrinktos trys karvės, kurioms į didįjį prieskrandį įvestos fistulos.
Pašarų mėginiai buvo inkubuojami prieskrandyje 2, 4, 8, 16, 24, 48 ir 72 valandas.
Darbo tikslas – nustatyti ekstruduoto baltyminio priedo LAKTOMIL-1 virškinamumą in sacco metodu ir įvertinti skirtingo šėrimo poveikį karvių produktyvumui ir pieno sudėčiai.
Darbo uždaviniai: 1. in sacco metodu... [toliau žr. visą tekstą]Object and tasks of work: Investigate extruded protein additive LAKTOMIL-1 ruminal digestibility, determine influence on cow productivity and milk composition. 1. Explore extruded protein additive ruminal digestibility using in sacco method; 2. Set extruded protein additive impact on dairy cows milk production and composition. Research methodology: In 2012 JSC „Naujasis Nevėžis“ specialists developed new extruded protein additive LAKTOMIL-1, for dairy cows in different stages of productivity. To investigate influence of extruded protein additive to cow’s productivity and milk composition, 90 days experiment was carried out in Lukšiai agricultural company (Lauciškiai farm). Analogues of the principle selected thirty Lithuanian Black/white breed cows, they were divided into 2 groups (control and experimental), each group containing 15 animals. The control group was fed a normal cow ration consisting of corn silage, grass silage, maize, rapeseed meal, soybean cake, and minerals. Experimental cows fed a similar diet, but soybean cake was replaced to extruded protein additive LAKTOMIL-1. During the investigation milk yield was determined by the control milking. Milk quality indices have been analyzed in PE “Milk Analysis” (“Pieno tyrimai”). Been studied milk protein, fat, lactose and urea concentration in milk content. Effective degradability of protein and dry matter was determined by the in sacco method using three fistulated cows. The cows were fed the same basal ration... [to full text]
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Clark, Nicholas. "Microwave methods for additive layer manufacturing." Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/102996/.
Full textAbstract:
This thesis presents the novel application of microwave technology to the process of additive layer manufacturing (ALM). A particle size sensor, based on microwave cavity perturbation, is described and subsequently demonstrated by the measurement of the complex permeability of a series of Titanium powders. The results are compared with existing theory and finite element simulations of metallic powders. The ability to discern changing particle size distributions is important in ensuring the reliable operation of selective laser melting machines but, to remain industrially relevant, it is vital that the proposed system can be produced at low cost. By way of demonstration, the design and construction of an inexpensive scalar network analyser was completed. A systematic study of surface resistance of a number of metal surfaces, produced by Selective Laser Melting, was undertaken. Using a dielectric resonator with a “lift-off” calibration procedure, the losses of surfaces manufactured in orthogonal orientations and different surface finishes were compared. Surface roughness measurements showed that microwave losses were not monotonically dependent on root-mean-square surface roughness; this was attributed to differing roughness feature size distributions. For microwave characterization of materials over a wide temperature range, it is often desirable to perform cavity perturbation measurements at elevated temperatures. However, it is shown here that heat treatment can permanently modify the surface resistance of a metal surface and potentially lead to inaccurate perturbation results. X-Ray diffraction measurements confirm the source of modification is due to changes in surface stress and the appearance of solution precipitates. The sensitivity of microwave measurements to surface stress also demonstrates the potential for microwave assessment of surfaces produced by ALM. Finally, to stimulate further work in this area, the design of a single mode microwave heating system was discussed and a prototype developed.
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Ting, Huang, and Nordqvist Daniel. "Design and manufacturing of SLM printed tooling for plastic injection molding." Thesis, Jönköping University, Tekniska Högskolan, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-54170.
Full textAbstract:
The thesis work is to show that the use of SLM (Additive Manufacturing) compared with the traditional process to make injection molds will have advantages in design, especially in waterways. This thesis work gives seven different versions of design applied to the SLM method to analyze and compare them in Solidworks® and Moldflow® to figure out what design is suitable for the SLM method. Through analysis of different versions, the finding of this thesis work is that the conformal waterway of design and lighter but stead structure in the SLM method causes the SLM molds' cooling performance to be almost 15% better than the conventional way and shorten the production time by 18% per product. Based on the advantages of the SLM method in cooling system design and structure optimization, the company can use the SLM method in the production process to improve economic and environmental benefits.
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Ramakrishna, Yogendra Jayanth. "Image Analysis Methods For Additive Manufacturing Applications." Thesis, Högskolan Väst, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-15891.
Full textAbstract:
There is an upsurge of research interest on Ni-based superalloys additively manufactured (AM) in aerospace sectors. However, achieving the accuracy and quality of the AM part is a challenging task because it is a process of adding material layer by layer with different process parameters. Hence, defects can be observed, and these defects have a detrimental effect on the mechanical properties of the material. Also, AM materials commonly portray a columnar grain structure which also makes it difficult to determine the average grain size because while using the commonly used intercept method, the grain boundaries do not intercept to the test line appropriately. It is important to measure the defects and grain size before performing mechanical testing on the material. Defect measurement and grain size measurements are usually measured manually which results in longer lead time. This work is addressed towards testing recipes in the automated image analysis software to optimize the lead time with good accuracy. Haynes 282, a γ' strengthened superalloy is used in this work. It was assumed that 1,5mm of material from the surface will be machined away so defects had to be measured in this region of interest. The image analysis tools used to test its potentials are MIPAR and ImageJ. Initially, five images in MIPAR and Image J were tested keeping the manual measurements as a benchmark. From this part, it was concluded that metallography and image quality play an important role in the automated measurement. Also, basic Image J software cannot give the measurements of lack of fusion in terms of caliper diameter (longest measurable diameter). Hence, MIPAR was chosen for the application because it was more promising. In the next part, 15 samples were used with manual measurements from a stitched sample and batch processing with MIPAR. The total caliper diameter results were plotted to compare manual measurements and MIPAR. It was observed that scratches were measured as lack of fusion defects at few instances by MIPAR which were further refined using a post-processing function. The defect density results were plotted and compared as well. Due to the difference in calculation of region of interest, the difference in results was observed.To perform the grain size measurement, Haynes 282 was used in HIP and heat treated condition, achieving equiaxed grains. The etchant should be appropriate to reveal the grains. Hence four different etchants were used in this study hydrogen peroxide+HCl, Kallings (electro etch), Kallings (swab) and diluted oxalic acid. This measurement was performed on the material which was cut along the build direction as well as 90º to the growth direction. Since there is no standard for additively manufactured material yet, the results were tested with hall-petch equation to be convinced of the results obtained. It was observed that MIPAR recipe portrayed good results. The results of manual measurements and MIPAR measurements were plotted and compared. It was observed that Hydrogen peroxide and Kallings (swab) showed the grains evidently but twin boundaries were revealed as well. MIPAR calculated the twin boundaries as grains so it over calculated than manual measurements. Kallings (electro etch) and diluted oxalic acid did not reveal the grains so it was difficult for MIPAR to identify the grains.
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Palin, Marcelo Facio. "Técnicas de decomposição de domínio em computação paralela para simulação de campos eletromagnéticos pelo método dos elementos finitos." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-08012008-122101/.
Full textAbstract:
Este trabalho apresenta a aplicação de técnicas de Decomposição de Domínio e Processamento Paralelo na solução de grandes sistemas de equações algébricas lineares provenientes da modelagem de fenômenos eletromagnéticos pelo Método de Elementos Finitos. Foram implementadas as técnicas dos tipos Complemento de Schur e o Método Aditivo de Schwarz, adaptadas para a resolução desses sistemas em cluster de computadores do tipo Beowulf e com troca de mensagens através da Biblioteca MPI. A divisão e balanceamento de carga entre os processadores são feitos pelo pacote METIS. Essa metodologia foi testada acoplada a métodos, seja iterativo (ICCG), seja direto (LU) na etapa de resolução dos sistemas referentes aos nós internos de cada partição. Para a resolução do sistema envolvendo os nós de fronteira, no caso do Complemento de Schur, utilizou-se uma implementação paralisada do Método de Gradientes Conjugados (PCG). S~ao discutidos aspectos relacionados ao desempenho dessas técnicas quando aplicadas em sistemas de grande porte. As técnicas foram testadas na solução de problemas de aplicação do Método de Elementos Finitos na Engenharia Elétrica (Magnetostática, Eletrocinética e Magnetodinâmica), sejam eles de natureza bidimensional com malhas não estruturadas, seja tridimensional, com malhas estruturadas.This work presents the study of Domain Decomposition and Parallel Processing Techniques applied to the solution of systems of algebraic equations issued from the Finite Element Analysis of Electromagnetic Phenomena. Both Schur Complement and Schwarz Additive techniques were implemented. They were adapted to solve the linear systems in Beowulf clusters with the use of MPI library for message exchange. The load balance among processors is made with the aid of METIS package. The methodology was tested in association to either iterative (ICCG) or direct (LU) methods in order to solve the system related to the inner nodes of each partition. In the case of Schur Complement, the solution of the system related to the boundary nodes was performed with a parallelized Conjugated Gradient Method (PCG). Some aspects of the peformance of these techniques when applied to large scale problems have also been discussed. The techniques has been tested in the simulation of a collection of problems of Electrical Engineering, modelled by the Finite Element Method, both in two dimensions with unstructured meshes (Magnetostatics) and three dimensions with structured meshes (Electrokinetics).
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Tanner, Gregory Mark. "Generalized additive Runge-Kutta methods for stiff odes." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6507.
Full textAbstract:
In many applications, ordinary differential equations can be additively partitioned
\[y'=f(y)=\sum_{m=1}^{N}\f{}{m}(y).]
It can be advantageous to discriminate between the different parts of the right-hand side according to stiffness, nonlinearity, evaluation cost, etc. In 2015, Sandu and G\"{u}nther \cite{sandu2015gark} introduced Generalized Additive Runge-Kutta (GARK) methods which are given by
\begin{eqnarray*}
Y_{i}^{\{q\}} & = & y_{n}+h\sum_{m=1}^{N}\sum_{j=1}^{s^{\{m\}}}a_{i,j}^{\{q,m\}}f^{\{m\}}\left(Y_{j}^{\{m\}}\right)\\
& & \text{for } i=1,\dots,s^{\{q\}},\,q=1,\dots,N\\
y_{n+1} & = & y_{n}+h\sum_{m=1}^{N}\sum_{j=1}^{s^{\{m\}}}b_{j}^{\{m\}}f^{\{m\}}\left(Y_{j}^{\{m\}}\right)\end{eqnarray*}
with the corresponding generalized Butcher tableau
\[\begin{array}{c|ccc} \c{}{1} & \A{1,1} & \cdots & \A{1,N}\\\vdots & \vdots & \ddots & \vdots\\
\c{}{N} & \A{N,1} & \cdots & \A{N,N}\\\hline & \b{}{1} & \cdots & \b{}{N}\end{array}\]
The diagonal blocks $\left(\A{q,q},\b{}{q},\c{}{q}\right)$ can be chosen for example from standard Runge-Kutta methods, and the off-diagonal blocks $\A{q,m},\:q\neq m,$ act as coupling coefficients between the underlying methods. The case when $N=2$ and both diagonal blocks are implicit methods (IMIM) is examined.
This thesis presents order conditions and simplifying assumptions that can be used to choose the off-diagonal coupling blocks for IMIM methods. Error analysis is performed for stiff problems of the form
\begin{eqnarray*}\dot{y} & = & f(y,z)\\
\epsilon\dot{z} & = & g(y,z)\end{eqnarray*}
with small stiffness parameter $\epsilon.$ As $\epsilon\to 0,$ the problem reduces to an index 1 differential algebraic equation provided
$g_{z}(y,z)$ is invertible in a neighborhood of the solution. A tree theory is developed for IMIM methods applied to the reduced problem. Numerical results will be presented for several IMIM methods applied to the Van der Pol equation.
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Bengtsson, Katarina. "Additive manufacturing methods and materials for electrokinetic systems." Licentiate thesis, Linköpings universitet, Ytors Fysik och Kemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-121252.
Full textAbstract:
Fabrication of miniaturized devices is usually time-consuming, costly, and the materials commonly used limit the structures that are possible to create. The techniques most often used to make microsystems involve multiple steps, where each step takes considerable time, and if only a few systems are to be made, the price per device becomes excessive. This thesis describes how a simple syringebased 3D-printer, in combination with an appropriate choice of materials, can reduce the delay between design and prototype and simplify fabrication of microsystems. This thesis suggest two types of materials that we propose be used in combination with 3D-printing to further develop microsystems for biology and biochemistry. Analytical applications in biology and biochemistry often contain electrodes, such as in gel electrophoresis. Faradaic (electrochemical) reactions have to occur at the metal electrodes to allow electron-to-ion transduction through an electrolyte-based system to drive a current when a potential is applied to the electrodes in an electrolyte-based system. These electrochemical reactions at the electrodes, such as water electrolysis, are usually problematic when miniaturizing devices and analytical systems. An alternative to metal electrodes can be electrochemicallyactive conducting polymers, e.g. poly(3,4-ethylenedioxythiophene) (PEDOT), which can be used to reduce electrolysis when driving a current through water-based systems. Paper 1 describes gel electrophoresis where the platinum electrodes were replaced with the conductive polymer PEDOT, without affecting the separation. Manufacturing and prototyping of microsystems can be simplified by using 3Dprinting in combination with a sacrificial material. A sacrificial template material can further simplify bottom-up manufacturing of more complicated forms such as protruding and overhanging structures. We showed in paper 2 that polyethylene glycol (PEG), in combination with a carbonate-based plasticizer, functions well as a 3D-printable sacrificial template material. PEG2000 with between 20 wt% and 30 wt% ethylene carbonate or propylene carbonate has properties advantageous for 3D-printing, such as shear-thinning rheology, mechanical and chemical stability, and easy dissolution in water.In the printed version the thesis number 1720 on the cover is incorrect. The correct thesis number is 1724 which is corrected in the electronic version.