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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.
111

Konstruktion rörklammer

Dalslätt, Göran January 2007 (has links)
This report describes the development process of a pipe clamp used on exhaust system for cars. It is made based on the manufacturers desire to improve and make the clamp easier to manufacture and to reduce its price to their customers. This should be done either by manufacturing the clamp in one piece without an expensive and work intensive welding process, or by generating ideas of how to develop a brand new type of clamp. Investigating the market for similar products was done to eliminate intrusion of other manufacturers’ patents but also to generate ideas. Making drawings of the many ideas gave a concept of three concepts called existing clamp in one piece, existing clamp by several pieces and innovation solutions. Some of these ideas were investigated further and were 3D modelled in pro-engineer and necessary drawing files were made to be used in the manufacturing of several prototypes. One of the solutions resulted in a prototype that was manufactured by handmade tools and the results of the tests was very positive. The clamp was strong enough to join the pipes together very well without breaking. It was manufactured in one piece and formed in five steps without any welding operations instead of the seven steps, including welding, that is used on the clamp today. The prototype requires 25 % more material and most of it is scrap from the cutting operation.
112

Vibrationsisolering av gruvmaskinshytt

Berg, Kristoffer, Lindholm, Jonas January 2007 (has links)
Detta examensarbete, på uppdrag av Atlas Copco Rock Drills AB, syftar till att kartlägga de problem gällande vibrationer som finns och uppstår vid användandet av produkten Scaletec MC och komma med förslag till lösningar på ett nytt system som bättre hanterar vibrationer än det befintliga. Lösningarna är avgränsade till hytten och hyttens koppling mot ramen. Kartläggningen av Scaletec MC visade att den största problemskaparen är den långa bommen med den tunga hydraulhammaren framtill. Den skapar rörelse i hytten både vid skrotning och vid transport. Vid transport är även den odämpade stolen, de ojämna vägarna och det faktum att axlarna är stela ett stort problem som genererar helkroppsvibrationer hos operatören. Konceptfasen fokuserade på att hitta en robust och kompakt konstruktion som med rätt val av frihetsgrader skulle kunna lösa de existerande problemen med vibrationer. Arbetet resulterade i två lösningar som på ett kontrollerat sätt hanterar de vibrationer som uppstår vid skrotning och transport. Det ena konceptet syftar till att åtgärda de brister dagens system besitter medan det andra även är anpassat för att hantera större vibrationsnivåer. / The aim of this thesis, commissioned by Atlas Copco Rock Drills AB, is to investigate the vibration problems concerning the Scaletec MC and give proposals on new concept solutions that improve the handling of the vibration problems. The solutions are limited to the cabin and the cabins connection to the frame. The conclusion tells us that the most important issue is the long reaching boom with the hydraulic hammer attached to it. This assembly creates movements in the cabin during scaling and transportation. The non-damped transportation chair, the rough roads and the stiff axles are also factors that create problems with whole body vibrations. The concept phase focused on finding a robust and compact design that, with the correct degree of freedoms, reduces the influence of the vibrations. The result consists of two solutions, both controlling and managing the existing vibrations. The first solution focuses on the flaws that the existing system possesses and the other is designed to handle greater vibration levels.
113

Statusbedömning och förbättringsförslag för startkedjemaskineri, startkedja och linspel för stränggjutningsmaskin

Lago, Mattias, Sunesson, Pavel January 2008 (has links)
The main goal with the master thesis has been to do a status evaluation of the chain machinery with its start chain and wire to secure the production on a short basis due to that a reconstruction is not planned at this time. An evaluation of the condition of the start chain and the rollers in the chain depository has been done. An offer has been requested for a new start chain and the evaluation of the start chains may be a basis for the decision taking. The production has been able to go on, although it has arisen some problems which have been difficult to find the causes for. There is no gathered “picture” of the machinery status and a mapping of each machinery has been compiled of comprehensive logs. Observations and measurements have also been done to prove and elucidate the biggest problems. After the compilation a concentration has been done of the two most frequently problems during the last years, that is to say, 2006 to 2008. The work has finally fallen into suggestions for improvements of routines and suggestions for concepts for construction changes to keep a continuous stable production until a bigger reconstruction will be made. The two problems which have been focused on were the “limit-switches” for the wires and the heat-radiation-shields situated under the tilt bridges. The arrangement for the wire problem shown to be quite simple to implement and its cause was due to that the friction was to big in the shackle, which function is to be pressed down by the wire, and thereby didn’t trigger an alarm on the computer screens. To prevent this, lubrication was done for respective shackle to sustain the production for a short period of time. Although there have been done some concepts to sustain the production for a longer period of time. The problems concerning the heat-radiation-shields under the tilt bridges can be solved mainly by changed maintenance routines, which have been attached in the list which has been formed.
114

Finite element modelling of the mechanics of solid foam materials

Ribeiro-Ayeh, Steven January 2005 (has links)
<p>Failure of bi-material interfaces is studied with the aim to quantify the influence of the induced stress concentrations on the strength of the interfaces. A simple point-stress criterion, used in conjunction with finite element calculations, is evaluated to provide strength predictions for bi-material bonded joints and inserts in polymer foam. The influence of local stress concentrations on the initiation of fracture at open and closed wedge bi-material interfaces is investigated. The joint combinations are analysed numerically and the strength predictions obtained from the point-stress criterion are verified in experiments. </p><p>The predictions are made using a simple point-stress criterion in combination with highly accurate finite element calculations. The point-stress criterion was known from earlier work to give accurate predictions of failure at cracks and notches but had to be slightly modified to become applicable for the studied configurations. The criterion showed to be generally applicable to the bi-material interfaces studied herein. Sensible predictions for the tendentious strength behaviour could be made with reasonable accuracy, including the prediction of crossover from local, joint-induced failure to global failure. </p><p>To study the micromechanical properties of a cellular solid with arbitrary topology, various models of a closed-cell foam are created on the basis of random Voronoi tessellations. The foam models are analysed using the finite element method and the effective elastic properties of the model cellular solids are determined. The calculated moduli are compared to the properties of a real reference foam and the numerical results show to be in very good agreement. </p><p>The mechanical properties of closed-cell, low-density cellular solids are governed by the stiffnesses of the cell edges and the cell faces. Models of idealised foam models with planar cell faces, cannot account for the curved faces found on some metal and polymer foams. Finite element models of closed-cell foams were created to analyse the influence of cell face curvature on the stiffness of the foam. By determining the elastic modulus for foams with non-planar cell faces, the effect of cell face curvature could be analysed as a function of the relative density and the distribution of solid material between cell edges and faces. </p><p>Foam models were generated from disturbed point distribution lattices and compared to models obtained from random distributions. The aim was to analyse if and how the geometry of the cells and their spatial arrangement influences the mechanical properties of a foam. The results suggest that the spatial arrangement and the geometry of the cells have significant influence on the properties of a foam. The elastic properties calculated for models from disturbed foam structures underestimated the elastic moduli of the foam, whereas models from random structures provided results which were in very good agreement with a reference foam.</p>
115

User Consideration in Early Stages of Product Development : Theories and Methods

Janhager, Jenny January 2005 (has links)
Traditional design theories have focused on technical functions and more or less disregard a product’s user involvement. The existing methods of ergonomic designare mostly intended for analysis activities. There is a need for new dynamic methods that focus on user-product interactions. The aim of this research work is to develop design methods for user-product interactions, which should support synthesis activities in early product development phases. An observation study and a questionnaire survey were carried out in order to investigate product developers’ work and relation to the users for providing background information about the research problem. Furthermore, student projects in product development were followed, giving essential input. After the theories and methods were developed, a retrospective interview study was carried out in order to confirm the need for the developed methods. The studies showed, for instance, that companies use few formal methods and almost none of these are directed towards the user. It is also indicated that the product developers’ contact with users decreases with increasing company size. Few companies have a defined procedure for defining their intended users. Six methods are developed. They embrace three ways of classifying the users and their relations to products and other users (User identification, Use profile and User relations), an analysis of the users’ Activities, goals and motives behind their use of the product, a scenario technique (User-technical process scenario, UTPS), which shows the user process in parallel with the technical process, and a hierarchical decomposition of technical functions and user actions, which is named the Functionaction tree (FAT). All the methods, apart from FAT, were tested in real product development teams. All the tested methods stimulate communication between the group members of various competencies in the design group. Most of the methods are easy to apply and are valuable for understanding the design problem. The UTPS is also useful for comparing design solutions and generates new ideas about the design task. The other tested methods did not generate many new ideas, but the reason is probably that they were mainly tested on products that are already on the market. Thus, the methods are most valuable in the early design stages, when trying out a product idea or a concept. / QC 20100618
116

Finite element modelling of the mechanics of solid foam materials

Ribeiro-Ayeh, Steven January 2005 (has links)
Failure of bi-material interfaces is studied with the aim to quantify the influence of the induced stress concentrations on the strength of the interfaces. A simple point-stress criterion, used in conjunction with finite element calculations, is evaluated to provide strength predictions for bi-material bonded joints and inserts in polymer foam. The influence of local stress concentrations on the initiation of fracture at open and closed wedge bi-material interfaces is investigated. The joint combinations are analysed numerically and the strength predictions obtained from the point-stress criterion are verified in experiments. The predictions are made using a simple point-stress criterion in combination with highly accurate finite element calculations. The point-stress criterion was known from earlier work to give accurate predictions of failure at cracks and notches but had to be slightly modified to become applicable for the studied configurations. The criterion showed to be generally applicable to the bi-material interfaces studied herein. Sensible predictions for the tendentious strength behaviour could be made with reasonable accuracy, including the prediction of crossover from local, joint-induced failure to global failure. To study the micromechanical properties of a cellular solid with arbitrary topology, various models of a closed-cell foam are created on the basis of random Voronoi tessellations. The foam models are analysed using the finite element method and the effective elastic properties of the model cellular solids are determined. The calculated moduli are compared to the properties of a real reference foam and the numerical results show to be in very good agreement. The mechanical properties of closed-cell, low-density cellular solids are governed by the stiffnesses of the cell edges and the cell faces. Models of idealised foam models with planar cell faces, cannot account for the curved faces found on some metal and polymer foams. Finite element models of closed-cell foams were created to analyse the influence of cell face curvature on the stiffness of the foam. By determining the elastic modulus for foams with non-planar cell faces, the effect of cell face curvature could be analysed as a function of the relative density and the distribution of solid material between cell edges and faces. Foam models were generated from disturbed point distribution lattices and compared to models obtained from random distributions. The aim was to analyse if and how the geometry of the cells and their spatial arrangement influences the mechanical properties of a foam. The results suggest that the spatial arrangement and the geometry of the cells have significant influence on the properties of a foam. The elastic properties calculated for models from disturbed foam structures underestimated the elastic moduli of the foam, whereas models from random structures provided results which were in very good agreement with a reference foam. / QC 20101011
117

Produktutveckling för Cate & Nelson Design : Framtagning av möbel

Abid, Ali, Roback, Joel January 2008 (has links)
<p>Denna rapport behandlar examensarbete utfört för industridesignföretaget Cate & Nelson Design. Företaget ligger i Eskilstuna och jobbar i huvudsakligen med möbeldesign och inredningsprodukter. Projektgruppensuppgift har varit att ta fram en ny möbel för företaget och arbetet har omfattat utveckling av hela produkten från idé till prototyp.</p>
118

Integrering av ToolTracker i X-ponentskåp

Hyttsten, Andreas, Alm, Sebastian January 2010 (has links)
<p>Följande rapport redogör för det utvecklingsarbete som hade som målbild att kombinera två produkter från X-ponent Stålinredningar AB, nämligen ordning-och-reda-systemet ToolTracker och ett verktygsskåp benämnt X-102.</p><p>Detta utvecklingsarbete pågick under kursen KPP305, Examensarbete Produktutveckling, på Mälardalens högskola.</p><p>Uppdragsgivaren X-ponent Stålinredningar AB hade under en tid utvecklat det intelligent ordning-och-reda-system, ToolTracker, och genom en efterfrågan på marknaden har företaget känt ett behov av att vidareutveckla detta system och placera detta i ett verktygsskåp.</p><p>Denna produkt skulle fungera så att användaren loggar in i systemet via en RFID-läsare placerad på utsidan av skåpet, och samtidigt som en godkänd inloggning sker så låses skåpet upp automatiskt och användaren får tillgång till de verktyg som finns i skåpet. Väljer användaren att checka ut ett verktyg registreras tidpunkt för detta samt vem som tagit verktyget i systemets databas för att möjliggöra spårning av verktyget.</p><p>De direktiv som företaget gav för projektet var att det befintliga ToolTracker-systemet skulle verka på samma sätt som tidigare, vilket gav avgränsningar mot att påverka ToolTracker-systemet.</p><p>De problem som skulle lösas var således hur ToolTracker-systemets komponenter skulle placeras i skåpets utrymme, samt hur låskonstruktionen skulle utformas för att uppfylla de krav som ställts. De viktigaste funktioner som låskonstruktionen var tvungen att inneha, var att kunna låsa upp skåpet automatiskt vid inloggning, skåpet ska låsas automatiskt då dörren stängs samt att låset skulle kunna låsas upp manuellt. Dessa krav samt ytterligare en mängd krav kunde formuleras i den kravspecifikation som togs fram och låg som grund för arbetet. Ett genomgående viktigt krav i hela arbetet var att förändra det ursprungliga skåpet så lite som möjligt.</p><p>När kraven tydliggjorts kunde en mängd idéer tas fram och utvecklas vidare till fullgoda koncept. Dessa koncept togs därefter genom en process där koncepten utvecklades och därefter bedömdes efter lämplighet för att sedan utvärderas och ett val av slutligt koncept skedde utifrån resultaten av dessa moment. Det vinnande konceptet uppfyllde de viktiga kraven på funktioner samt hade en väldigt liten påverkan på skåpets ursprungliga konstruktion, vilket var stora bidragande orsaker till att detta koncept valdes. Detta koncept modelleras sedan upp fullständigt med hjälp av CAD-verktyget SolidWorks för att lösa de kvarstående frågetecknen kring hur monteringen av komponenter o.s.v. skulle ske.</p><p>Det slutliga konceptet har ett elektriskt slutbleck som låses upp då en signal läggs på, denna signal kommer då en inloggning sker i RFID-läsaren. Den automatiska låsningen av dörren sker genom att slutbleckets fall är öppet tills dörren stängs och skåpet påverkar fallet till låst läge. Den manuella öppningen sker genom den ursprungliga espanjolettlösningen.</p><p>Analysen av resultatet säger att konceptet uppfyller de krav som ställts upp och besvarar de problemformuleringar som legat till grund för detta arbete. Målet kan därför ses som uppfyllt.</p><p>Slutsatsen av projektet är att arbetet uppfyllde de mål som satts angående problemformuleringen, målet att ta fram en prototyp uppfylldes inte men en CAD-modell att möjliggöra detta i framtiden har tagits fram. En fortsättning på detta arbete bör därför innehålla en framtagning av en fysisk prototyp, för att verifiera att teorin och praktiken överensstämmer på ett tillfredsställande vis.</p> / <p>The following thesis report describes the development that intended to combine two existing products from X-ponents Stålinredningar AB, the orderliness-system ToolTracker and a tool cabinet named X-102.</p><p>This development lasted during the course KPP305, Examensarbete Produktutveckling, at Mälardalen University.</p><p>The outsourcer X-ponent Stålinredningar AB had during a period of time developed an orderliness-system and through a demand from the market, the company felt the need to further develop this product and place the product in a cabinet.</p><p>This product would give the user the opportunity to log on to the system via a RFID-reader placed on the front of the cabinet, and when the approved login appears the cabinet unlocks automatically and the user gets access to the tools placed in the cabinet. If the user chooses to check out a tool then the time and id for the user gets saved in the database to enable tracking of the tool.</p><p>The terms that the company stated for the project was that the original ToolTracker-system should work in the same way, this meant that no work on the ToolTracker-system should be done.</p><p>The problems that would be solved were hence how the components of the ToolTracker-system would be placed inside the cabinet, and how the locking mechanism should be designed to fulfill the demands put on the product. The most important functions that had to be implemented was that the lock should unlock itself automatically when an approved login happened, the locking mechanism also had to lock itself when the door is shut, and the user should also be able to unlock the door by manual force. These demands and more where written in the technical specifications list and became the foundation of this development. An important demand during the entire development process was that the cabinet should be modified as little as possible.</p><p>As the demands clarified a quantity of ideas could take form and develop into concepts. These concepts were thereafter moved through a process were these concepts were developed and then criticized by their feasibility. Thereafter the concepts were evaluated and one final concept could be chosen as a result from these operations. The final draft meets the demands put on functions as well as the modifications on the original cabinet, which were big contributions why this concept were chosen. Thereafter a 3D-model of the construction was made in SolidWorks, this was done to answer the final questions about the assembly and such.</p><p>The final draft possesses an electric strike plate that is unlocked when a signal is sent to it. This signal is sent from the RFID-reader when a login takes place. The automatic locking takes place when the barrier is affected by the door shutting. To open the door manually the user uses the existent espanjolett.</p><p>The analysis of the result states that de final solution fulfills the demands put on the product and also solves the formulated problems which this project where based on. The goal can therefore be stated as reached.</p><p>The conclusion for this project is that the development work fulfilled the goals put. A physical prototype should also be manufactured to verify that the theoretical concept matches reality in a satisfied manner.</p>
119

Optimal Enclosure Doors - Design and Evaluation / Optimala tätningslösningar för utomhusskåp - konstruktion och utvärdering

Karlsson, Tobias January 2008 (has links)
<p>Within the telecommunication business there are a lot of different hardware designs made for outside locations. Many of these outdoor products contain sensitive electronic equipment and all of these designs must be able to function in extreme environments. They might be mounted on the ground, on a wall or on masts at varying altitudes. They need to be enclosed and protected against blizzards, moisture, sandstorms, earthquakes, dust and similar contaminations or nature phenomena in order to assure a reliable and proper function of the device.</p><p>To delimit this thesis the focus is completely set on outdoor enclosures with hinged doors. The sealing solution for the enclosure door is crucial because it is the weakest link in the environmental protection. The aim with this thesis is to find a robust yet versatile sealing solution for Ericsson outdoor cabinets.</p><p>The sealing solution does not only concern the gasket design, it is in fact the entire principle when it comes to seal the door. Interesting features are choice of locking system, the positions of the hinges and other details which might affect the sealing of the enclosure door.</p><p>The project includes the whole product development process from pre-study to concept development and evaluation of proposal design. The pre-study contain extensive literature research, benchmark and a state of the art investigation. A number of concepts are generated, screened, compared and ranked with systematic concept development methods. At last, one final concept is selected for further development. The chosen sealing solution is refined and a functional model is made. A simple prototype of the sealing solution is designed, manufactured and tested to validate the functionality of the concept.</p><p>An economical analysis is performed in order to approximate the manufacturing cost of the gasket proposed in the sealing solution and to compare the unit price for different batch sizes. The water intrusion test indicates that the solution seems promising and that the result is a simple and robust sealing solution that easily can be implemented on various enclosure types.</p> / <p>Inom telecom-industrin finns det många typer av hårdvara som är konstruerad för att placeras utomhus. Många av dessa utomhusprodukter innehåller känslig elektronisk utrustning och alla dessa konstruktioner måste fungera i extrema miljöer. De kan monteras på marken, på väggar eller på master på olika höjder. De måste vara täta och skyddade mot snöstormar, fukt, sandstormar, jordbävningar, damm och liknande föroreningar eller naturfenomen för att säkerställa en tillförlitlig och korrekt funktion hos anordningen.</p><p>För att begränsa detta examensarbete är fokus helt inställt på utomhusskåp med gångjärnsupphända dörrar. Tätningslösningen för skåpdörren är kritisk eftersom den utgör den svagaste länken i väderskyddet. Målet med detta examensarbete är att hitta en robust men samtidigt mångsidig lösning för Ericssons utomhuskabinet.</p><p>Tätningslösningen handlar inte enbart om packningsutformningen utan den täcker faktiskt hela principen för hur dörren tätas. Intressanta delar är val av lås-lösning, placeringen av gångjärnen och andra detaljer som kan påverka tätningen av skåpsdörren.</p><p>Projektet behandlar hela produktutvecklingsprocessen från förstudie till konceptutveckling och utvärdering av föreslagen konstruktion. Förstudien innehöll en utförlig litteraturstudie, en ”benchmark” och en ”state of the art” undersökning. Ett antal koncept genererades, kontrollerades, jämfördes och rankades med hjälp av systematiska konceptutvecklingsmetoder. Till sist valdes ett slutgiltigt koncept ut för vidare utveckling. Den valda tätningslösningen förfinades och en funktionsmodell byggdes. En enkel prototyp av tätningslösningen konstruerades, tillverkades och testades för att validera funktionen hos konceptet.</p><p>En ekonomisk analys utfördes för att uppskatta tillverkningskostnaden för den föreslagna packningen i tätningslösningen och för att jämföra enhetspriset för olika seriestorlekar. Ett vattentäthetstest visar att lösningen verkar lovande och att resultatet är en enkel och robust tätningslösning som på ett enkelt sätt kan implementeras på olika skåpstyper.</p>
120

Trappetrinnets profil : En studie av alternative profiler på trappetrinnet / The shape on a tread : A study on alternative shapes on a tread

Koch, Christian January 2009 (has links)
No description available.

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