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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
621

Análise crítica da rota tecnológica adotada no desenvolvimento de equipamento sinalizador de faltas para redes aéreas de distribuição de energia elétrica. / Critical analysis of the technological route adopted for development of faulted circuit indicator equipment for aerial power distribution network.

Fábio José de Andrade 20 April 2012 (has links)
Um equipamento sinalizador luminoso de faltas foi desenvolvido pela Companhia Paulista de Força e Luz (CPFL) em parceria com a Escola Politécnica da USP e a empresa Expertise Engenharia Ltda., através de uma série de projetos de pesquisa incluídos no programa de pesquisa e desenvolvimento (P&D) regido pela Agência Nacional de Energia Elétrica (ANEEL) brasileira. Neste trabalho é feita uma análise crítica da rota tecnológica adotada no desenvolvimento do sinalizador de faltas, apontando detalhes e justificativas das escolhas tecnológicas adotadas, além de novas possibilidades de melhoria do equipamento face aos avanços tecnológicos detectados nos últimos anos. Para tanto, é proposto e aplicado um novo método, associado a uma sistematização, para análise comparativa de tecnologias, que considera dados quantitativos, qualitativos e estratégicos diretamente comparáveis entre si. Ao longo do trabalho são analisados as escolhas dos princípios de detecção de faltas e funcionalidades agregadas, o desenvolvimento da eletrônica e dos circuitos integrados do detector de faltas, a fonte de alimentação, a sinalização luminosa e o gabinete do equipamento. Como resultado da linha de pesquisa do sinalizador luminoso de faltas foram obtidos protótipos de prova de conceito, cabeça-de-série e de lote pioneiro, estes últimos prontos e certificados para inserção no mercado. Obtiveram-se também diversas publicações em congressos nacionais, a geração de dois pedidos de patentes e um sistema computacional de alocação otimizada de sinalizadores de faltas em redes de distribuição aérea de energia elétrica. / Within the R&D program governed by the National Agency of Electric Energy of Brazil, a luminous faulted circuit indicator equipment (FCI) was developed by the Companhia Paulista de Força e Luz (CPFL) in partnership with the Escola Politécnica da USP and the company Expertise Engenharia Ltda. In this work it is presented a critical analysis of the technological route adopted for development of this new FCI, indicating details and justifications of technological choices adopted, and new detected possibilities for improvements, taken into account the technological advances in recent years. For such purpose, it is proposed a new method, associated to a practical systematization, for comparative analysis of technologies that accounts for quantitative, qualitative and strategic data directly comparable. The work presents analyses on the choices of fault detection principles and related functions, the development of integrated circuits and fault detector electronics, the power supply, the luminous signaling and the equipment case. As results of the research and development of the FCI there were obtained proof of concept, prototype and pilot equipments, the last ones certified and ready for sale. There were also obtained several publications in national conferences, submission of two patent applications and a software for optimization of FCIs allocation on overhead power distribution networks.
622

E-Sea Power : The Design and Standardization of Chargers for Electric Boats

Bjurenborg, Amanda January 2018 (has links)
The current concerns about global warming are increasing the demands for electric vehicles (Ou- chi, Bando, Kodani, Hirata & Mubin, 2012).With the increasing demands, electric boats have now come into focus (Sierzchula, 2014). However, there is yet to be developed standards for charging of electric boats.This is where this thesis project comes in, as this thesis is a part of the E-Sea Power project,which is a project to develop a new and safe standard for charging of electric boats.The thesis project was completed at the company No Picnic in Stockholm, through the work of my final master degree course, in the education of Industrial Design Engineering, taught at Luleå Uni- versity of Technology. The objective of the thesis project was to provide a basis for the facilitation of the standardization of chargers for boats, with the possibility of full-scale tests. Where the final aim of the project was to develop both a normal charger standard and a quick charger that is to be mounted in a harbor, being able to utilize the harbor’s own electricity grid.Where in this context, a normal charger is a slower charger that charges with the users own cord and where a quick charger is a fast charger which has a built-in charger cord and handle. The project was divided into need, design, and function to make it structured and easy to follow, going through the design phases Immersion, Ideation, and Implementation.Throughout the project the current state was firsts analyzed, going on to several brainstorming and evaluation techniques and then ending with the building of final CAD prototypes, of both a normal charger and a quick charger, through the use of the software Solidworks, Keyshot, Photoshop and Maxwell.The projects focus has been on finding creative and ergonomic new solutions, with good user experience and accessibility. The final result of the project is two modular new chargers, with belonging to the same product family. Both a quick charger, which has had the thesis main focus and a normal charger, which has also been developed. The quick charger is a tall charging post that has a built-in lamp consisting of four fluorescent lamps and a, on the outside hanging, charging cord mounted at the top.The charger has two component houses which house necessary components. One that houses the CCS charger female and infor- mation label and one that houses the screen, IR sensor and emergency stop. The main feature of the final quick charger is its charging arm, which bends down with a hidden hinge, enabling the required total reach of 5 meters, while helping lift the charging cord for the user and giving the best possible light were the user is. The normal charger is also a charging post with the same type of house as the quick charger. How- ever the charger post is much shorter and it has only one house, which houses two Type 2 females instead of one CCS female.The normal charger also has a different lamp consisting of small LEDs, so that the user is not disturbed by its brightness at its lower hight, but still gaining enough light during use, where the surrounding light is lacking. / Den nuvarande oron för global uppvärmning ökar kraven på el-fordon (Ouchi, Bando, Kodani, Hirata & Mubin, 2012). Med de ökande kraven har nu de elektriska båtarna kommit i fokus (Sier- zchula, 2014). Det har emellertid ännu inte utvecklats standarder för laddning av elektriska båtar. Det är här det här master projektet kommer in, då detta projekt ingår i E-Sea Power-projektet, som är ett projekt för att utveckla en ny och säker standard för laddning av elektriska båtar. Projektet slutfördes på företaget No Picnic i Stockholm, genom mitt examensarbete, vid utbildningen civil- ingenjörsutbildningen i teknisk design, undervisad vid Luleå tekniska universitet. Målet med projektet var att skapa en grund för att underlätta standardiseringen av laddare för båtar, med möjlighet till fullskaliga tester. Där det slutliga målet med projektet var att utveckla både en normalladdare standard och en snabbladdare som ska monteras i en hamn och kunna utnyttja ham- nens egna elnät. I det här sammanhanget är en normalladdare en långsammare laddare som laddar med användarens egen kabel och en snabbladdare är en snabb laddare som har en egen inbyggd kabel med ett handtag. Projektet var uppdelat i behov, design och funktion för att göra det strukturerat och lätt att följa. Det gick även igenom designfaserna Immersion, Ideation och Implementation. Hela projektet bör- jade med analyseradet av det nuvarande tillståndet och fortsatte sedan med diverse brainstorming och utvärderingstekniker och slutade sedan med byggandet av slutliga CAD-prototyper, både av en normalladdare och en snabbladdare, med hjälp av programmen Solidworks, Keyshot, Photoshop och Maxwell. Projektets fokus har varit att hitta kreativa och ergonomiska nya lösningar med bra användarupplevelse och tillgänglighet. Det slutliga resultatet av projektet är två modulära nya laddare, som tillhör samma produktfamilj. Både en snabbladdare, som har haft huvudfokus och en normalladdare, som också har utvecklats. Snabbladdaren är en hög laddningsstolpe som har en inbyggd lampa som består av fyra lysrörslam- por och en utvändigt hängande laddningssladd monterad på toppen. Laddaren har två komponent- hus ett som rymmer CCS laddarens hona och informationsetikett och ett som rymmer skärmen, IR sensorn och nödstoppet. Huvudfunktionen hos den slutliga snabbladdaren är dess laddarm som böjer sig ned med ett dolt gångjärn, vilket möjliggör den totala räckvidden på 5 meter, samtidigt som den hjälper till att lyfta laddkabeln åt användaren och ger bästa möjliga ljus där användaren är. Den vanliga laddaren är också en laddstolpe med samma typ av hus som snabbladdaren. Laddstolpen är dock mycket kortare och den har bara ett hus, som rymmer två Type 2-honor i stället för en CCS-hona. Normalladdaren har också en annan lampa än snabbladdaren som består av små lysdio- der, så att användaren inte störs av ljusstyrkan vid dess lägre placering, men fortfarande får tillräckligt med ljus vid användning, där det omgivande ljuset är bristande.
623

The Effect of Mismatch of Total Knee Replacement Components with Knee Joint : A Finite Element Analysis

Kanyal, Rahul January 2016 (has links) (PDF)
It has been noticed that the need for total knee replacement surgery is increasing for Asian region. A total knee replacement is a permanent surgical solution for a patient having debilitating pain in knee joint suffering from arthritis. In this surgery, knee joint is replaced with components made up of bio-compatible materials after which the patient can resume the normal day to day activities. Western population has bigger build compared to Asian population. Most of the total knee replacement prosthesis are designed for western population. When these total knee prosthesis are used for Asian population, they cause a mismatch leading to various clinical complications such as reduced range of motion and pain. The studies have been limited to clinical complications caused by the mismatch. To address this limitation, current study is aimed to find the mechanical implications such as stress distribution, maximum stresses, maximum displacements etc., caused by mismatch of total knee replacement components with knee. A surgeon selects total knee components for a patient based on some critical dimensions of femur and tibia bone of knee. In addition, a method to accurately calculate these dimensions of the femur and tibia bone of a real knee was developed in the current study. This method calculated the points of curvature greater than a threshold (decided based on the radius of the curvature) found out using the formula of curvature. Further, the highest point was calculated based on maximum height from a line drawn between initial and final point within the captured points, also the extreme points were calculated based on the sign change in slope of points within the captured points, giving multiple points on the boundary of bones extracted in an MRI image of a patient. The distance between two selected farthest points, out of these points, in specific direction was the basis for selection of the TKR components. Total knee replacement components were modeled in Geomatics Studio 12 software, bones were modeled in Rhinoceros 5 software, assembly of bones and total knee replacements components was done in Solid works 2013 software, the finite element model of the assembly was developed in Hyper mesh 11 software and, the stress analysis and post processing was done in ABAQUS 6.13 software. A static, implicit non linear analysis was performed. Simulations were performed for two conditions: at standing (0o of flexion) and at hyper-flexed (120o of flexion). In order to figure out if there were any mechanical implications of mismatch, the full model of assembly consisting of femur, tibia and fibula bones assembled with total knee replacement components, and the reduced model consisting of only total knee replacement components were simulated separately, results of which have been discussed in the current thesis. In this work, the effect of change of length of ligaments at 120o of flexion in detail was also studied. This study brought out various outcomes of contact mechanics and kinematics between the components of total knee replacement prosthesis.
624

Feature-based Approach for Semantic Interoperability of Shape Models

Gupta, Ravi Kumar January 2012 (has links) (PDF)
Semantic interoperability (SI) of a product model refers to automatic exchange of meaning associated with the product data, among applications/domains throughout the product development cycle. In the product development cycle, several applications (engineering design, industrial design, manufacturing, supply chain, marketing, maintenance etc.) and different engineering domains (mechanical, electrical, electronic etc.) come into play making the ability to exchange product data with semantics very significant. With product development happening in multiple locations with multiple tools/systems, SI between these systems/domains becomes important. The thesis presents a feature-based framework for shape model to address these SI issues when exchanging shape models. Problem of exchanging semantics associated with shape model to support the product lifecycle has been identified and explained. Different types of semantic interoperability issues pertaining to the shape model have been identified and classified. Features in a shape model can be associated with volume addition/subtraction to/from base-solid, deformation/modification of base-sheet/base surface, forming of material of constant thickness. The DIFF model has been extended to represent, classify and extract Free-Form Surface Features (FFSFs) and deformation features in a part model. FFSFs refer to features that modify a free-form surface. Deformation features are created in constant thickness part models, for example, deformation of material (as in sheet-metal parts) or forming of material (as in injection molded parts with constant thickness), also referred to as constant thickness features. Volumetric features covered in the DIFF model have been extended to classify and represent volumetric features based on relative variations of cross-section and PathCurve. Shape feature ontology is described based on unified feature taxonomy with definitions and labels of features as defined in the extended DIFF model. Features definitions are used as intermediate and unambiguous representation for shape features. The feature ontology is used to capture semantics of shape features. The proposed ontology enables reasoning to handle semantic equivalences between feature labels, and is used to map shape features from a source to target applications. Reasoning framework for identification of semantically equivalent feature labels and representations for the feature being exchanged across multiple applications is presented and discussed. This reasoning framework is used to associate multiple construction paths for a feature and associate applicable meanings from the ontology. Interface is provided to select feature label for a target application from the list of labels which are semantically equivalent for the feature being exchanged/mapped. Parameters for the selected feature label can be mapped from the DIFF representation; the feature can then be represented/constructed in the target application using the feature label and mapped parameters. This work shows that product model with feature information (feature labels and representations), as understood by the target application, can be exchanged and maintained in such a way that multiple applications can use the product information as their understandable labels and representations. Finally, the thesis concludes by summarizing the main contributions and outlining the scope for future work.
625

Finite Element Modeling of Knee Joint to Study Tibio-Femoral Contact Machanics

Raghunathan, Bhaskar January 2014 (has links) (PDF)
Articular cartilage covers the articulating ends of diarthrodial joints. It plays a vital role in the function of the musculoskeletal system by allowing almost frictionless motion to occur between the articular surfaces of a diarthrodial joint. Study of cartilage contact behavior will help to understand the intrinsic biomechanical properties related to cartilage degeneration and related pathology. In order to study the mechanical behavior of the cartilage a FEM based computational model of the knee-joint was developed from MRI data. A heuristic algorithm was developed based on Image processing techniques using Evolve2D toolbox and edge detection. An indigenous path following algorithm to capture minute details of bone and soft tissue curvature was developed using Image Processing Toolbox of Matlab. Parts including femur, tibia, femoral and tibial cartilages, lateral & medial menisci were extracted as a point cloud from each of the slices and rendered into a 3D model using GUI driven CAD package RHINOCEROS 4.0. Commercial FE software HYPERMESH 9.0 was used to develop FE model from geometric model. Cartilage and Menisci were modeled using eight node hexahedral elements and bones were modeled using four node quadrilateral elements. Bones were assumed to be rigid. Cartilage and menisci were assumed to be linearly elastic, isotropic and homogenous. The knee joint was subjected to a uniaxial compressive load with tibia remaining fixed and femur subjected to two primary boundary conditions: 1.Flexion - extension and Varus - Valgus rotation constrained; 2.Only Varus - Valgus rotation constrained. Parameters such as contact area, contact pressure, contact force, centre of contact pressure, mises stress distribution; maximum and minimum principal stresses were studied at maximum compressive load condition and also in intermittent steps. This model considered both geometric and contact non-linearity. From the FE analysis, it was observed that peak contact deformation and contact area on both femoral and tibial medial cartilage was found to be greater than the lateral side under full extension condition. More than 50% of the load transmission was through the medial side - which could be an indication of cartilage degeneration. Deformation of lateral meniscus was more than the medial meniscus under angular constrained conditions. Loading history during intermittent steps suggested that contact area on lateral tibial cartilage increased with load, indicating joint asymmetry. These results indicate the importance of the rotational constraints (boundary conditions) and represent more accurate physiological behavior of knee joint. Role of menisci in this study was analyzed, which indicated that consideration of menisci is essential in biomechanical estimation of load transmission. In conclusion, detailed segmentation to develop geometric model, precise boundary conditions & time dependent behavior of cartilage and menisci helped in understanding knee joint load bearing capacity to a better accuracy and can potentially give rise to designing better cartilage implants.
626

Material Library : A sense of material / Materialbibliotek

Ståhl, Daniel January 2014 (has links)
This day of age when an increasing demands for better and more environmental friendlymaterial is requested. At the same time is also higher demands on the designers todevelop new products for the future. To design new products which express a futuristicfeeling and a “must-have-feeling”. Therefore is there a need to educate better designersand architects for the future a better knowledge for material. Both for existing designersand architects but also for new designers. To encourage learning and discover newmaterial is new tools important, a tool such as a meeting point in which people meet, talkand discover new materials. A meeting place in which a material library has its naturalplace, a place designers, architects and laymen can visit. The great advantages of a material library is the possibility to touch and feel the materialsamples. To invite people to use their senses and learn about materials. This report focus on how to best build and present a material library in the facility of apublic place. But also how to construct a mobile module used as a tool for education.Each scenario has their own dilemma and needs, for example, in the University library atJönköping has criterion for a module that fits into the regular exhibition. To present newand innovative material samples in a manner that reminds of how people search forbooks on the shelves. For the mobile module is focus more towards presenting material samples used in theproduction today. The presentation is more focus on presenting material samples during alecture in which the teacher stands in front of a class and pointing towards the materialand students are allowed to touch and feel the material samples when they have thepossibility to do so. Besides this will the mobile module also work as mobile storagelocation for each department’s material samples.
627

A postcolonial critique of industrial design : a critical evaluation of the relationship of culture and hegemony to design practice and education since the late 20th century

Begum, Taslima January 2015 (has links)
This thesis specifically focuses on the professional practices and training of Western industrial designers using postcolonial theory to inform working practices in a complex global ecology. It investigates the culturally hegemonic construction of design solutions in man-made products. By adopting key ideas from postcolonial and cultural studies as a lens to evaluate fields of industrial design discourse, practice and pedagogy, the work proceeds from the premise that design is not intrinsic to a product but the result of a myriad different forces and factors acting on it externally including hegemonic potencies. By reinterpreting technological formations in light of research emerging from post-colonial studies, it attempts to broaden our intellectual understanding of how product design in theory, practice and education can often rely upon western [hegemonic] aesthetic and deep cultural archetypes. The purpose of this enquiry is to highlight the potentials that exist to explore a synergy between east and west in industrial design with a prospective vision for global, trans-cultural design. The research claims that current design practice often leads to culturally determined - rather than universal - conceptions in design and it attempts to re-conceptualise design as practice within a necessarily hegemonic culture. This hegemony needs to be acknowledged and redressed via increased awareness and changes to the intellectual heritage and autonomy of West European and American industrial design, in its dialogue, practice and education. As an epistemological project to identify knowledge within this discourse, it suggests new methodological and strategic approaches to engage with the crisis the discipline faces in light of globalisation so as to open up future discussions in design discourse and give a voice to the many silences that make up the noise of the world. It attempts to: • Further understand the trajectory of hegemony and globalisation in relation to design, technology and culture. • Critically engage with cross- and trans-cultural, global and social design implications. • Address the discrepancies between designers’ culture and users’ culture, to expose the necessity for more culturally-cognizant design practice and pedagogic provision. The research was initiated by identifying a number of questions that designers and users may consciously or subconsciously confront when faced with products that problematise the imagined universal values of designed products in terms of gender and culture. It explores how certain design solutions produced and developed in the west and their diffusion into global, international markets and foreign cultures could affect those cultures by asking in what ways the usability, aesthetic and symbolic characteristics of these artefacts often unwittingly contribute to the privilege or marginalisation of people from particular socio-cultural backgrounds. The thesis intervention is that product designers are neither explicitly trained to comprehend nor surmount their respective cultural constraints and design education both nationally and internationally is not sufficiently equipped with the tools to acknowledge and confront this. The key arguments presented in this thesis are: 1. Products can often be deconstructed to identify cultural connotations or omissions in their design. 2. Global, a-cultural design and universal usability are fallacies that frequently deny the existence of an underlying cultural hegemony at play. 3. Mass-produced products can gradually homogenise and eradicate cultural diversity contributing to the negative effects of colonialist attitudes and/or globalisation. 4. Academia and educational institutions have the potential to extend awareness in this field to inform and train future designers and graduates to better advance design obligations in global, trans-cultural, cross-cultural and multicultural contexts.
628

本地化玉米餅:台灣多力多滋傳播策略案例研究 / Localizing the tortilla chips: a case study of Doritos' communicative strategies in Taiwan

加何塞, José Manuel Galiano García Unknown Date (has links)
無 / This study examines the strategies adopted by the global brand Dorito’s in Taiwan, and contrasts the communicative strategies with those used in Mexican market. The foundation of this analysis resided in Hofstede’s Cultural Dimensions. This research has sampled filmic advertisements used in previous and current campaigns in both countries available in social media and video sharing platforms. Cultural values, marketing appeals, and value paradoxes were analyzed, as well as other elements like product design and packaging have been assessed to understand the implications and the role that national culture plays when creating marketing strategies. Product localization and standardization have their implications in this study. Doritos’ brand communicative strategies have been modified to fit into the taste of Taiwanese buyers, adopting different appeals and values than those utilized in Mexican market. Recurrent use of value paradox, in harmony with Doritos’ brand values is found to be consistent in Mexico and Taiwan. One of the most remarkable value paradoxes adopted in branding is irreverence it extends the reach of campaigns, and brand memorability. Product standardization across markets has been a long-time strategy adopted by Doritos, although, some characteristics like flavor and spiciness level were modified in order to fit Taiwanese buyers’ taste. The data set utilized for the purposes of this study was constrained and dramatically reduced by the availability of video-based advertisements publicly available on social media channels of Doritos in each market. Doritos’ brand communicative strategies have been modified to fit into the taste of Taiwanese buyers, adopting different appeals and values than those utilized in Mexican market. Product standardization across markets has been a long-time strategy adopted by Doritos, although, some characteristics like flavor and spiciness level were modified in order to fit Taiwanese buyers’ taste.
629

Poudres et mélanges de poudres pour la fonctionnalisation et l’imprégnation de textiles à sec : formulation de poudres bifonctionnelles / Powder and powder mixture in textile dry impregnation and functionalization process

Groos, Karine 04 December 2015 (has links)
S’intéressant aux interactions entre la formulation, le procédé et le produit, ce travail original axé sur la fonctionnalisation ignifuge de textiles utilisés dans les transports et le bâtiment porte sur le développement de poudres non feu. La ligne conductrice de cette étude étant de comprendre comment les propriétés ignifuges du textile technique peuvent être influencées par les choix de formulation ou de procédé de mélange. L'identification des besoins, c.-à-d. la réalisation d’un produit fini ignifuge, la conception de mélanges de granulométrie définie qui s’écoulent facilement et qui possèdent une sensibilité à l’inflammation faible, a permis de proposer et d’examiner diverses formulations. En matière de méthodologie ce projet combine l’approche sécurité à l’ingénierie produit. La sélection finale des mélanges sera fonction des résultats de cette analyse technique globale. Le travail expérimental a permis de sélectionner le polymère et l’agent ignifuge à la concentration de 40 % pour l’obtention en mélangeur interne de particules bifonctionnelles répondant aux spécifications fixées. Contrairement aux mélanges à retournement ou haute vitesse, les grains préparés par granulation Hot-Melt ont des liaisons mécaniques renforcées. Ce résultat semble s’expliquer par la bonne affinité, le bon rapport en termes de taille de particules entre les composants et une morphologie favorable à la formation de ce type de structures. Ce mode de fabrication a également permis de lever les deux principaux verrous à savoir préparer une poudre bifonctionnelle à haute teneur en agent ignifuge et réaliser un mélange qui ne se démélange pendant l’étape d’imprégnation du procédé DPreg / This original work deals with the functionalization of textile fire retardant used in transport and the building focused on the development of fire retardant powders while studying the interactions of three criteria: the formulation, process and product. The main line of this study is the understanding and quantification of the flame retardant properties of the textile, which can be influenced by the choice of formulation or mixing process. The identification of needs, i.e. the realization of a finished fire retardant, the design of defined particle size mixtures, which flow easily and possess low sensitivity to inflammation, allowed to propose and consider various formulations. This project methodology is a good example of the combination between two approaches: the product engineering and a safety approach. The final selection of mixtures will be based on the results of a comprehensive technical analysis. The experimental work allows us to select the polymer and the flame retardant at a concentration of 40% in order to obtain in an internal mixer of bifunctional particles meet the specifications set out in this study. Unlike conventional mixtures by inversion or high speed, the grains prepared by Hot-Melt granulation have enhanced mechanical linkages. This result seems to be due to the good affinity and good particle size ratio between the components and a good morphology to the formation of such structures. This manufacturing method also overcomes two obstacles; the preparation of a bifunctional powder with high content of flame retardant and the realization of a mixture which does not demix under the action of the electric field of the DPreg impregnation process
630

Etude du procédé d'expansion à froid des alésages au sein des structures aéronautiques en métaux durs / Study of the cold expansion process in hard metal aeronautical structures

Achard, Victor 27 September 2016 (has links)
Ces travaux de thèse ont pour objectif de contribuer au développement de procédés innovants pour les assemblages contenant des métaux durs. Le procédé d’expansion à froid, dont l’efficacité a été prouvée à de nombreuses reprises sur les alliages d’aluminium et dont les qualités sont nombreuses, a attiré notre attention. L’objectif de la thèse est d’apporter des éléments de réponse quant à l’intérêt de l’utilisation du procédé d’expansion au sein des métaux durs, mesuré notamment par son impact sur la performance en fatigue. Plus généralement, il s’agit de comprendre son fonctionnement et son mode d’action au sein de ces alliages à hautes performances. Dans les travaux réalisés, les challenges scientifiques et techniques s’articulent autour de plusieurs thématiques d’étude. Des essais expérimentaux ont été effectués en vue de prouver la faisabilité du procédé mais aussi de mesurer de son impact sur la tenue fatigue d’alésages en alliages de titane (Ti-6Al-4V), en acier inoxydables à durcissement structural (15-5PH) mais aussi en superalliages à base Nickel (Inconel 718). L’efficacité du procédé a été prouvée et les gains apportés par la technologie sont importants. D’un autre côté, la problématique de la détermination des champs résiduels en bord de trou reste un réel défi pour la communauté intéressée par l’expansion à froid. La considération cette fois-ci des métaux durs apporte un degré supplémentaire de nouveauté et d’inconnu. La méthodologie générale employée réside dans la considération d’études numériques et expérimentales afin d’étudier la réponse des métaux durs à l’expansion à froid. Des modèles éléments finis axisymétriques ont été développés en vue de simuler le procédé complet d’expansion à froid réalisée au sein d’alésages et d’empilages de divers métaux durs. Les résultats numériques fournis ont été mis en parallèle avec ceux issus de mesures expérimentales, telles que la méthode du trou incrémental. Le but étant ainsi d’obtenir les cartographies les plus fiables possibles des contraintes résiduelles triaxiales générées en bord de trou mais aussi de rechercher de stratégies d’optimisations du procédé / This thesis aims to contribute to the development of innovative processes for mechanical components made of hard metals (Titanium, steels and superalloys). In the aeronautical field, the design of ever more efficient and reliable structures remains a technical challenge. In mechanical assemblies, hole edges are the seats of high stress concentrations and are a major risk site for crack initiation. To fight against this damage, manufacturing technologies such as cold expansion are widespread for aluminium applications but not for hard metal. The objective of this study is to provide answers concerning the impact of the cold expansion on the fatigue performance of holes and understand the mechanisms of the process in these high performance alloys. In the present work, the methodology proposed is to carry out both experimental and numerical studies of the response of hard alloy holes subjected to cold expansion. An extensive experimental campaign has been set up. It includes several materials (Ti-6Al-4V αβ and β annealed, 15-5PH & Inconel 718) and aims to test many parameters. The process has proved very effective on the fatigue performance in these high performance alloys. On the other hand, the main technical and scientific challenge lies in determining the stress fields generated within the material after cold expansion, especially in hard metals, the behaviour of which can be diverse and complex. The numerical modelling strategy chosen has led to the development of polyvalent axisymmetric models that are dedicated to simulation of the split sleeve process. Experimental and numerical results were compared using various methodologies, such as the incremental hole drilling technique. Measurements have validated the finite element simulations, with the purpose of mapping the residual fields in the expanded metallic section and the proposal of optimisation techniques.

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