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Development of binder systems based on CAB for powder injection moulding (PIM) and micro powder injection moulding (µ-PIM) of Zircon and Invar powders / Le développement de systèmes de liants à base de CAB pour le moulage par injection de poudre (PIM) et l'injection de poudre micro moulage (µ-PIM) de zircon et Invar poudresHidalgo Garcia, Javier 27 January 2014 (has links)
Les contributions de cette thèse de doctorat sont focalisées sur les développements de formulations à base de polymères bio sourcés et déliantable à l’eau basés sur l’emploi d’acétate butyrate de cellulose (CAB) et de polyéthylène glycol (PEG). Ces nouvelles formulations ont été appliquées sur différentes nuances de poudres métalliques (invar) et céramiques (zircones). Ces matériaux possèdent une bonne stabilité dimensionnelle sous une large gamme de température imposée et possèdent de très bas coefficients d’expansion thermique.L’objective est l’étude et la compréhension du comportement des liants à base de CAB et PEG quand ils sont utilisés dans les variantes du procédé MIP (étapes de moulage avec ou sans pression, conditions particulières liées à la micro-injection, …) réalisées avec différentes nuances de poudres et différentes granulométries.Les caractéristiques intrinsèques de chaque CAB, leurs interactions avec le PEG et les poudres, l’influence de la nuance de poudre employée, ainsi que la granulométrie et la morphologie des poudres employées ont été étudiées et analysées en fonction du comportement final de la formulation développé et des taux de charges obtenues.L’homogénéité des mélanges développés, leurs taux de charge critique et maximal, ainsi que leurs comportements mécaniques, thermiques et rhéologiques ont été analysés et investigués par différentes études mécaniques, thermo et physico-chimiques. De nouvelles analyses chimiques et physiques ont été introduites par accroitre les connaissances sur les formulations développées. Les formulations optimales ont été validées pour différentes applications et avec l’emploi de différentes variantes du procédé MIP conduisant à l’élaboration de composants et de micro-composants PIM obtenus sans défauts et possédant d’excellentes propriétés fonctionnelles. L’étape de déliantage ainsi que l’étape de densification ont été optimisées en termes de cinétique et d’atmosphère aboutissant aux propriétés physiques et mécaniques escomptées pour l’ensemble des nuances de poudres considérées dans cette étude.En conclusion, les formulations développés des liants basées sur l’emploie de CAB et PEG sont exploitable au niveau de la recherche et au niveau industriel dans le procédé MIP. Elles apportent des améliorations par rapport aux liants conventionnels grâce à un procédé plus écologique. Cette première contribution représente une avancée significative dans l’émergence d’un procédé MIP plus écologique mais d’autres travaux futurs sont encore possibles. / This PhD Thesis studied the use of binders based on cellulose acetate butyrate (CAB) andpoly(ethylene glycol) (PEG) in different type of materials, including a ceramic, the zirconiumsilicate, and a metallic alloy, the Invar 36. These materials share their low dimensionalstability with temperature with low coefficients of thermal expansion.The scope of this work is the study and comprehension of the behaviour of the mentionedbinder systems when they are employed in different PIM processes and under differentconditions and powder-types. With regard to this matter, different formulations were designedwith several types of PEG and CAB. These formulations were compared with commercialones. The intrinsic characteristics of each CAB were linked with the behaviour of the differentfeedstock also containing PEG and powder particles. The mixtures homogeneity, the optimumand critical solid loading and its flowability were assessed by torque and capillary rheology.Other complementary techniques such as electronic and light microscopy or the measurementof the mixtures densities by pycnometry were carried out to contrast rheology results. Thecompatibility between the feedstocks’ components and their thermal behaviour were analysedby calorimetry and thermogravimetry techniques. These methods were employed by the firsttime to determine the optimal solid loading.The optimal compositions were injected by using low or high pressures or by a micro injectionmoulding process. The debinding and sintering stages were optimised using severalatmospheres. Finally, the physical and mechanical properties of the final consolidated partswere measured.It could be concluded that the studied binder systems based on PEG and CAB presentedsuitable characteristics for PIM, providing improvements with respect to conventional bindersystems and by a more environmental friendly processing. However, that doctoral work wasjust a first approach to the use of these types of binder systems in PIM. Along this workseveral issues were detected and some topics regarding the processing should be furtherinvestigated to obtain the best of these binder systems.
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Cab Door Design : Improvement of door cornersIslam, Akib January 2014 (has links)
This thesis presents a product development process, where an existing solution on a cab door have been analysed and developed, with the aim to result in a cost-effective concept solution for handling tolerances on the door frame. The methodological approach in this thesis is based on Volvo Construction Equipment’s development model; The Global Development Process, which started with a pre-study phase where the problem formulation was established. The problem formulation in short is to find a solution for how to handle narrow tolerances in steel profiles for the door weldment on cab doors. Various solution ideas were discussed and concepts were generated with focus to design a new cab door corner that would solve the problems addressed by the project. The applied method resulted in a final concept consisting of the same steel profiles but with new dimensions, and two new concepts in each corner; one corner module that is placed inside the steel profiles and joined by welding, and a plastic shell that covers the welded corner. The concept was validated using a prototype of the proposed solution, where tests show that the requirements were achieved, besides a few deficiencies. A cost comparison between the existing and the proposed solution was made within limitations for this thesis. The result of the cost comparison shows an indication of that the proposed solution can be more cost-effective than the existing solution. Some of the recommendations after have completing the project are to make a complete cost comparison to ensure that the indication is correct and to analyse the new components to optimize and define the dimensions of them.
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Hybride Prototypen im DesignLorenz, Sebastian, Klemm, Maria, Krzywinski, Jens 19 July 2017 (has links) (PDF)
Aus der Einführung:
"Die Verwendung von Prototypen besitzt eine zentrale Rolle bei der Produktentwicklung und im Designprozess (Camere et al. 2016). Wie Camere und Bordegoni feststellen hat sich der Fokus der Designdisziplin auf Funktionalität um die Aspekte der Usability und der User Experience erweitert. Damit einhergehend hat sich auch die Rolle der Prototypen von Funktionsmustern und Präsentationsobjekten um die Funktionen als Evaluierungs- und Versuchsobjekte ergänzt. Die Integration von Nutzern in den Designprozess ist dabei ein weiterer Punkt bei denen Prototypen ein wichtiges Werkzeug zur Kommunikation und kooperativen Arbeit liefert (Schneider 1996). Die Integration von Prototyping-Methoden in den unterschiedlichen Phasen des Designprozesses führt zu unterschiedlichen Anforderungen hinsichtlich der Form und Aufgabe der Prototypen. Entsprechend vielfältig sind die heute verwendeten Arten von Prototyping. ..."
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The Systematic Development Process Applied on a Cab Rotation Unit : Pre-study, concept generation, embodiment design, material selection and optimization / Applicering av den systematiska utvecklingsprocessen på en rotationsenhet för hytter : Förstudie, konceptgenerering, designspecificering, materialval och optimeringGustafsson, Daniel January 2018 (has links)
This master thesis studies and applies the systematic development process. The process is initially described in general, creating a template for the process, and later on applied on a real case scenario to show the performance. Finally eventual advantages, drawbacks and suggestions for future improvements are given. The systematic development approach has been performed at Laxå Special Vehicles, who produce truck cabs and special truck chassis for Scania CV AB. The project has focused on the cabs, i.e. the Crew Cabs and the Low Entry. Crew Cabs are extended normal truck cabs, containing four doors to make additional passengers possible, suitable for fire trucks etc. Low Entry is a lowered normal truck cab, lowering the approaching height, making this cab type suitable for city applicable usage where the driver or passengers enter and leave the cab frequently. The task given was to develop the current cab rotation unit to be able to handle both cabs, which from the beginning only could handle the Crew Cabs, called CC28 and CC31. The major goal of this project has been to enable rotation of the Low Entry too. Five phases – pre-study, concept generation, embodiment design, material selection and optimization – were carried out. The pre-study generated a fundamental base of knowledge, according to both the systematic development process and information about the tilt. The concept generation contained a problem degradation, generation of possible solutions and finally an evaluation of these. During the embodiment design the best suited concept was described and developed in detail to allow a suitable material to be selected during the material selection phase. The optimization process consisted of investigating properties according to mechanical strength and stiffness. Two construction solutions to accommodate the mounting points height and length difference between the Crew Cab and the Low Entry were developed. These were a covering plate, called K4, and a mounting plate, called K100, handling the problems occurring for length and height respective. The development process is thus considered to be well operating. It generated a useful result, although possibilities for further improvements exists. / Denna masteruppsats studerar och förklarar den systematiska utvecklingsprocessen. Processens olika steg beskrivs inledningsvis generellt, för att sedan appliceras på ett reellt fall för att demonstrera genomförandet. Avslutningsvis ges fördelar, nackdelar och eventuella förbättringsförslag på metoden. Projektet genomfördes på Laxå Special Vehicles som producerar hytter och chassin för fordonstillverkaren Scania. Projektet fokuserade på hytterna som kallas Crew Cab och Low Entry, där den först nämnda är en förlängd hytt med fyra dörrar istället för två. Detta ger mer hyttutrymme, plats för fler passagerare och är därför vanlig i tillämpningar som till exempel brandbilar. Low Entry är en tvådörrarshytt vars insteg är lägre än för vanliga tvådörrarshytter, vilket gör den användbara i stadsnära miljöer där passagerare eller förare ofta lämnar och går in i hytten. Uppgiften som skulle lösas, och därmed målet, var att anpassa en rotationsenehet, även kallad tilt, för även kunna rotera LE. Ursprungligen var den endast anpassad för de två hyttvarianterna av Crew Cab, som kallas CC28 och CC31. Arbetet behandlade fem faser – förstudie, konceptgenerering, designspecificering, materialval och optimering – vilka skulle genomföras för att nå ett användbart resultat. Förstudien fokuserade på att erhålla kunskap om den systematiska utvecklingsprocessen, hur denna skulle genomföras, samt information om hur rotationsenheten fungerade. Konceptgenerering innehöll en problemnedbrytning, konceptskapande och utvärdering av de genererade koncepten. Under designspecificeringen gavs det bästa konceptet/koncepten dimensioner och specificerade funktioner för att under materialvalsprocessen erhålla passande material. Under optimeringsfasen genomfördes analysering och optimering, med avseende på styrka och styvhet. Två konstruktionslösningar utvecklades vilka löste var sitt delproblem som var höjd- och längdskillnad för den bakre monteringspunkten mellan Crew Cab och Low Entry. En omgjord monteringsplatta visade sig lösa höjdskillnaden bäst, kallad K100. Längdskillnaden togs om hand genom att applicera en längre glidskena som skulle täckas av luckor, kallade K4. Eftersom ett väl fungerande resultat erhållits visade den systematiska utvecklingsprocessen sig fungera som efterfrågat men med förbättringspotential.
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Retractable Boarding Step to Scania Crew Cab : Product Development, Design, FEM Simulations and Verification / Utfällbart insteg till Scania Crew Cab lastbilar : Produktutveckling, konstruktion, FEM simulering och verifikationMöllberg, Nadine January 2017 (has links)
This master thesis treats the development of a new solution for a retractable boarding step to Scania trucks, which is a part of the modular system. Some customers have the need to transport additional passengers. For such applications, Scania provides trucks featuring a Crew Cab, which is an extended cab with rear doors. Easy exit through the rear doors is important for many customers who use this type of cabin. Therefore, there is a possibility to get a retractable boarding step, equipped with an upper step and a lower foldable, that enables easy entry and exit. This function is especially important for fire fighters carrying heavy equipment and therefore has more difficulties exiting the truck. The robustness and dependability of the function is critical to ensure the safety. If it fails, the legal requirements are not met while driving or even worse, injury may occur. Pneumatics is used for the fold out of the step and a spring folds it in. The current boarding step needs improvement in order for it to be dependable and robust. If the boarding step have not been folded out, the entry and exit of the cab is not possible. This thesis covers the product development, simulations and verification of a new boarding step concept that shall improve the entry- and exit function, making it more robust and dependable. Through problem identification, a product specification and a thorough concept generation and development process a final concept has produced. Simulations were made in order to verify that the step could be stepped on when entering and exiting the cab. The result was a lower step, sliding on linear bearings in a linear motion. This enabled egress and ingress independent of the extraction or retraction of the step. This makes it more reliable than the current product. The sliding mechanism need to be tested in order to ensure the robustness. A prototype was made in order for the function to be tested. / Detta examensarbete behandlar utvecklingen av en ny lösning för ett fällbart insteg till Scania lastbilar, som är ett modular product Scania utvecklar lastbilar till ett brett spektrum av tillämpningar. Behov av att transportera ytterligare passagerare kan finnas. För sådana tillämpningar erbjuder Scania specialfordon med manskapshytt, en förlängd hytt med bakdörrar. Enkel urstigning genom bakdörrarna är viktigt för många kunder som utnyttjar denna typ av hytt. Därför finns möjligheten att få ett utfällbart steg som förenklar in- och urstigning, utrustad med ett fast övre steg och ett fällbart nedre. Detta är särskilt viktigt för brandmän som bär tung utrustning och därför har svårare att ta sig ur bilen. Det utfällbara steget fälls ut för enkel åtkomst när det behövs och viks in under körning. Detta för att uppfylla lagkrav för fordonsbredd. Tryckluft används för att fälla ut steget och en fjäder används för att fälla in det. Flera fall där problem gällande in- och utfällningsmekanism har påvisats, fälls inte steget ut är det inte möjligt att stiga i och ur hytten. Förbättring av robusthet och pålitlighet behövs genomföras. Examensarbetet ska förbättra instignings- och urstigningsfunktionen och se till att den är robust och pålitlig.Genom att identifiera problemet, upprätta en produktspecifikation och genomföra en grundlig konceptgenerering och utvecklingsprocess har ett slutgiltigt koncept tagits fram. FEM simuleringar gjordes för att kunna verifiera att insteget håller för att kliva på. Resultatet blev ett undre steg, som glider på linjärlager. Detta möjliggör i och urstigning oberoende av i vilket läge steget är. Det gör den mer tillförlitlig än dagens produkt. Glidmekanismen måste testas för att kunna säkerställa dess robusthet. En prototyp har tillverkats för att testa detta.
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Active Minimization of Acoustic Energy Density in a Mock Tractor CabFaber, Benjamin Mahonri 17 March 2004 (has links) (PDF)
An active noise control (ANC) system has been applied to the problem of attenuating low-frequency tonal noise inside small enclosures. The intended target application of the system was the reduction of the engine firing frequency inside heavy equipment cabins. The ANC system was based on a version of the filtered-x LMS adaptive algorithm, modified for the minimization of acoustic energy density (ED), rather than the more traditional minimization of squared acoustic pressure (SP). Three loudspeakers produced control signals within a mock cabin composed of a steel frame with plywood sides and a Plexiglas® front. An energy density sensor, capable of measuring acoustic pressure as well as acoustic particle velocity, provided the error signal to the control system. The ANC system operated on a single reference signal, which, for experiments involving recorded tractor engine noise, was derived from the engine's tachometer signal. For the low frequencies at which engine firing occurs, experiments showed that ANC systems minimizing ED and SP both provided significant attenuation of the tonal noise near the operator's head and globally throughout the small cabin. The tendency was for ED control to provide a more spatially uniform amount of reduction than SP control, especially at the higher frequencies investigated (up to 200 Hz). In dynamic measurement conditions, with a reference signal swept in frequency, the ED control often provided superior results, struggling less at frequencies for which the error sensor was near nodal regions for acoustic pressure. A single control channel often yielded performance comparable to that of two control channels, and sometimes produced superior results in dynamic tests. Tonal attenuation achieved by the ANC system was generally in excess of 20 dB and reduction in equivalent sound level for dynamic tonal noise often exceeded 4 dB at the error sensor. It was shown that temperature changes likely to be encountered in practice have little effect on the initial delay through the secondary control path, and are therefore unlikely to significantly impact ANC system stability in the event that a fixed set of system identification filter coefficients are employed.
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Les opérations logiques dans les calculatrices digitalesRouxel, Roland 07 July 1956 (has links) (PDF)
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Manhattanská metrika ve výuce na základní škole / Taxicab Metric in Teaching-Learning Process at Basic SchoolBruna, Jiří January 2014 (has links)
This master's thesis explores the possibility of including Taxicab metric as a subject matter into instruction at lower secondary level of education and it does so in several ways. Firstly, it looks into a curricular document of state level (Framework Educational Programme) and discusses instances at which the subject matter and the concept of lower secondary education are in agreement. Secondly, this thesis analyses a selected series of textbooks with respect to exercises that can be seen as linked to non-Euclidean metrics. Furthermore an experiment is described and evaluated, whose purpose, as a part of this thesis, was to find out if selected pupils can successfully solve problems in the context of the Taxicab metric and if related instruction influenced pupils' understanding of the concept of line segment and circle in a desired way. The teaching material which constituted an integral part of the experiment is presented as well.
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Analysis of Customisation in a Modular System : Development of a New Seat SolutionPettersson, Josefine, Colling, Johanna January 2019 (has links)
Today there is a shift from mass production to mass customisation due to changing customer needs in the global market. This thesis report analyses customisation in a modular system through a case study in the truck industry with focus on development of a new seat solution. The customer requests showed a demand for one to two additional seats in the cab. In order to answer to various customer needs, companies implement modular product development principals which enables them to produce in a rapid speed, minimize costs, increase performance and produce a high mix of products. The established RQ:s were: RQ1: How do companies improve competitiveness by translating customer needs into technical requirements? RQ2: What are the challenges and possibilities when making changes in a modular system? The thesis followed the first steps in the product development process due to delimitations in time, scope, and research quality. The data was collected through a literature study, interviews with customers and archival records and documentations at the case company. The study resulted in two final concepts, namely a seat solution and a bench solution which answered to the customer need of one to two additional seats in the cab. A conclusion was that it is crucial for companies to understand the in-depth customer needs to provide higher customer value, which in turn can contribute to strengthen the companies’ competitiveness. The correct translation of customer needs to technical requirements is essential for the development of a modular system. Challenges and possibilities when making changes in a modular system was found to be design complexity along with opportunity to reuse existing components. Both the translation of customer needs and design decisions regarding a modular system is achieved in the earlier stages of the product development process. It is thus of high importance to translate the customer needs correctly and make thoughtful decisions of the modules in the modular system to ensure company competitiveness.
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Estimation of Radial RunoutNilsson, Martin January 2007 (has links)
<p>The demands for ride comfort quality in today's long haulage trucks are constantly growing. A part of the ride comfort problems are represented by internal vibrations caused by rotating mechanical parts. This thesis work focus on the vibrations generated from radial runout on the wheels. These long haulage trucks travel long distances on smooth highways, with a constant speed of 90 km/h resulting in a 7 Hz oscillation. This frequency creates vibrations in the cab, which can be found annoying. To help out with the vibration diagnosis when a truck enters a mechanical workshop, this work studies methods for radial runout detection using the wheel speed sensors.</p><p>The main idea is to represent the varying radius signal with a sinusoid, where the calculations are based on Fourier series. The estimated radial runout value is then the amplitude of the sinusoid. In addition to the detection part, the work also present results regarding how the relative phase difference between two wheels with radial runout effects the lateral motion of the cab.</p><p>This thesis work was performed at Scania CV AB in Södertälje, Sweden and all measurements have been full scale experiments on real trucks.</p>
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