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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.
1

Grounds for Implementation of Solid Mechanics Calculations in an Existing Cad Programme

Verde, Marina January 2007 (has links)
<p>This thesis is intended to be a ground for the implementing of solid mechanics calculations of an expander axle in an existing CAD programme. The main parameters to be calculated are: effective stress, stress components in axial and radial direction, shear stress as well as maximum force and fatigue analysis. In order to achieve the above mentioned goal, calculations were made by hand. At the end of any of the chapters, a diagram on the input/output data and the equations needed for performing the calculations was drawn.</p>
2

Grounds for Implementation of Solid Mechanics Calculations in an Existing Cad Programme

Verde, Marina January 2007 (has links)
This thesis is intended to be a ground for the implementing of solid mechanics calculations of an expander axle in an existing CAD programme. The main parameters to be calculated are: effective stress, stress components in axial and radial direction, shear stress as well as maximum force and fatigue analysis. In order to achieve the above mentioned goal, calculations were made by hand. At the end of any of the chapters, a diagram on the input/output data and the equations needed for performing the calculations was drawn.
3

Investigation of the potential of e-axles for trucks / Undersökning av potentialen för e-axlar för lastbilar

Fernandez Carnota, Marina January 2020 (has links)
As a step to reduce emissions of trucks, Scania investigates different solutions related to electrification to contribute with more environmental friendly vehicles. The aim of this project is to investigate the potential of electrified axles, e-axles, to use in Scania trucks. Not only from a performance point of view but also from a business and industrialisation point of view. The e-axle is a compact unit which integrates an electric motor, power electronics and transmission. It is used as a power source for the vehicle and it is a more efficient solution for the electric vehicles, eliminating losses and saving space. Through a market analysis, gathering of information and knowledge about electrified solutions for trucks, interviews with Scania staff and product specification five different concept are identified, evaluated and compared. These concepts are the following:   Concept 1- Electric motor within a mechanically driven axle   Concept 2- Electric motors in a non-driven axle   Concept 3- In-wheel motors   Concept 4- Electric motors in a rear support axle   Concept 5- Electric motor in a diesel truck with a generator A concept selection matrix was set-up to find the best solution. In the evaluation of the concepts different CAD models are developed, based on mainly existing models at Scania. The difference between the concepts is based on the different axle possibilities to locate the electric motors. The best two concepts were identified as concept 2 and concept 4. For future work, the two best concepts should be used for a deeper study, obtaining a final design layout and realising an structure analysis of them to verify the designs. The market analysis shows that there will be a market for the product, but it will require an extensive design and development phase. This thesis sets the ground for the development of a new product towards the electrification of trucks. / Som ett steg för att minska utsläppen från lastbilar undersöker Scania olika lösningarrelaterade till elektrifiering för att bidra med mer miljövänliga fordon. Syftet med dettaprojekt är att undersöka potentialen hos elektrifierade axlar, e-axlar, att använda i Scaniaslastbilar, inte bara ur prestandasynpunkt utan även ur affärs- och industrialiseringssynpunkt.E-axeln är en kompakt enhet som integrerar en elmotor, kraftelektronik ochtransmission. Den används som en kraftkälla för fordonet och är en mer effektiv lösningför elfordonen, vilket eliminerar förluster och sparar utrymme.Genom en marknadsanalys, insamling av information och kunskap om elektrifierade lösningarför lastbilar, intervjuer med Scanias personal och produktspecifikation har fem olikakoncept identifieras, utvärderas och jämförts. Dessa koncept är följande:  Koncept 1- Elektrisk motor i en mekaniskt driven axel  Koncept 2- Elektriska motorer i en icke-driven axel  Koncept 3- Hjulmotorer  Koncept 4- Elektriska motorer i en bakre stödaxel  Koncept 5- Elmotor i en diesel lastbil med en generator En konceptvalsmatris sattes upp för att hitta den bästa lösningen. Vid utvärderingen avkoncepten utvecklas olika CAD-modeller baserade på huvudsakligen befintliga modellerpå Scania. Skillnaden mellan koncepten baseras på de olika axelmöjligheterna för attplacera elmotorerna. Det bästa konceptet identifierades som koncept 2 och koncept 4.För framtida arbete bör de två bästa koncepten användas för en djupare studie, för att fåen slut lig design layout och genomföra en strukturanalys av dem för att verifiera designen.Marknadsanalysen visar att det kommer att finnas en marknad för produkten, men detkommer att kräva en omfattande design- och utvecklingsfas. Detta examensarbete läggergrunden för utvecklingen av en ny produkt mot elektrifiering av lastbilar.
4

Finite element analysis of pre-ROPS tractor axle housing strength

Wen, Dongfang 24 October 2005 (has links)
Tractor rollover protective structures (ROPS) have been found effective for protecting people from serious injury or death when tractors overturn. Extension agricultural engineers and safety specialists are promoting the retrofitting of ROPS on pre-ROPS tractors. ROPS, meeting to ASAE standards, are available for these older tractors. However, effective protection not only depends on the proper design of ROPS, but also on the structural adequacy of the rear axle housing on which ROPS are mounted, and on the means of attachment. Adequate information on the strength of pre-ROPS tractor axle housings 1s still lacking. A research project to develop a technique for determining the suitability of tractor axle housing when adding ROPS to pre-ROPS tractors was initiated by the Biological Systems Engineering Department at Virginia Tech in 1991. A finite element procedure was developed for the rear axle assembly of John Deere 720 tractor and models were built with a commercial software ANSYS Engineering Analysis Program. The models were employed to analyze the stress distributions under the static, crush, and dynamic ROPS tests recommended by ASAE. Laboratory tests were conducted to validate the models, and to assess the suitability of the shell element model and the general solid element model. Results of the analyses show that the rear axle housing assembly of John Deere 720 tractor has a safe margin for the static and crush tests under the condition of this study. Results also show that can support the dynamic test if the ROPS is mounted with a larger contact area with the axle assembly. The study concluded that the finite element procedure is effective to assess the strength adequacy of tractor axle housing and to determine the feasibility of retrofitting ROPS on pre-ROPS tractors. / Ph. D.
5

Investigação das falhas do sistema de acionamento de embreagem do tipo cilindro escravo concêntrico em veículos comerciais pesados sob as condições operacionais do mercado brasileiro. / Investigation of failures clutch drive system of concentric slave cylinder type in heavy commercial vehicles under operational conditions in Brazil.

Souza, Jairo de Lima 28 July 2006 (has links)
A evolução dos sistemas de transporte no modal rodoviário tem criado novas demandas operacionais devido à crescente concorrência e aumento da pressão para a redução de custos. Em face dessas novas demandas, muitas delas advindas da globalização, geraram uma mudança no perfil da frota de veículos comerciais pesados no mercado brasileiro. Frotas que anteriormente eram compostas por veículos comerciais pesados 4x2 (4 pontos de apoio no solo com tração em 2 pontos) operando com carretas de três eixos com capacidade de transporte de 45 toneladas, passaram a ser gradativamente substituídas por aquelas compostas por veículos comerciais pesados 6x2 (6 pontos de apoio no solo com tração em 2 pontos) com carretas do tipo bi-trem e rodo-trem com capacidade de transporte de 57 e 74 toneladas respectivamente. Esta mudança foi acompanhada pelo aumento da pressão do custo de aquisição dos veículos comerciais pesados, com isso, verificou-se que os principais frotistas brasileiros passaram a adaptar eixos de apoio nos veículos 4x2, aumentando assim as solicitações mecânicas impostas ao sistema de embreagem. Neste trabalho desenvolve-se, portanto, um estudo sobre as falhas ocorridas no sistema de acionamento de embreagem por cilindro escravo concêntrico no mercado brasileiro, avaliando-se a seleção de materiais empregados na construção do sistema através de ensaios químico-laboratoriais e testes de funcionalidade através de ensaios em condições reais de operação com veículos comerciais pesados devidamente instrumentados, mantendo o foco nos novos parâmetros operacionais impostos pelo novo perfil da composição tratora. Como resultado, apontam-se duas alternativas para a solução das falhas encontradas no mercado brasileiro: 1. Proposição de nova solução técnica construtiva para o sistema de acionamento da embreagem a fim de aumentar a robustez do componente de maior suscetibilidade às falhas. 2. Proposição de um modelo matemático para a predição do intervalo mínimo de manutenção para o sistema de acionamento da embreagem por cilindro escravo concêntrico. / The evolution of highway transportation of goods in the brazilian market has created new operation requirements due to the increased competition allied to the cost reduction demands. This new demands, most of them coming from globalization, have generated a significant change on the profile of heavy commercial vehicles. Fleets that were mainly composed of 4x2 tractors coupled to three wheeled semi-trailers with towing capacity of 45 tons, were in small steps exchanged by new compositions of tractors 6x2 coupled to bi-trains and road-trains with total towing capacity of 57 and 74 tons, respectively. This change have been followed by the new purchasing demands from fleet owners by lowering acquisition costs of new heavy commercial vehicles, as a consequence, most of 4x2 trucks have been adapted with tag-axles in order to increase towing capacity, which means increasing the stresses over the clutch system. On this research, a case study is developed about failures on clutch systems actuators by the concentric slave cylinder concept in the brazilian market. The research is developed by the evaluation of types of materials selected to the system components through chemical test and functionality tests carried on actual operation conditions on instrumented vehicles, keeping always the focus on the new operational demands imposed by the new profile of vehicle compositions (bi-trains and road-trains). As a final result, two alternatives are appointed to solve the failures in the brazilian market: 1. By the determination of the most failure susceptible component, it is possible to propose a mathematical and theoretical model to determine the minimum maintenance interval to the clutch actuation system by concentric slave cylinder concept. 2. Proposition of a new technical construction to the system in order to increase the robustness of the component most susceptible to the failures.
6

Investigação das falhas do sistema de acionamento de embreagem do tipo cilindro escravo concêntrico em veículos comerciais pesados sob as condições operacionais do mercado brasileiro. / Investigation of failures clutch drive system of concentric slave cylinder type in heavy commercial vehicles under operational conditions in Brazil.

Jairo de Lima Souza 28 July 2006 (has links)
A evolução dos sistemas de transporte no modal rodoviário tem criado novas demandas operacionais devido à crescente concorrência e aumento da pressão para a redução de custos. Em face dessas novas demandas, muitas delas advindas da globalização, geraram uma mudança no perfil da frota de veículos comerciais pesados no mercado brasileiro. Frotas que anteriormente eram compostas por veículos comerciais pesados 4x2 (4 pontos de apoio no solo com tração em 2 pontos) operando com carretas de três eixos com capacidade de transporte de 45 toneladas, passaram a ser gradativamente substituídas por aquelas compostas por veículos comerciais pesados 6x2 (6 pontos de apoio no solo com tração em 2 pontos) com carretas do tipo bi-trem e rodo-trem com capacidade de transporte de 57 e 74 toneladas respectivamente. Esta mudança foi acompanhada pelo aumento da pressão do custo de aquisição dos veículos comerciais pesados, com isso, verificou-se que os principais frotistas brasileiros passaram a adaptar eixos de apoio nos veículos 4x2, aumentando assim as solicitações mecânicas impostas ao sistema de embreagem. Neste trabalho desenvolve-se, portanto, um estudo sobre as falhas ocorridas no sistema de acionamento de embreagem por cilindro escravo concêntrico no mercado brasileiro, avaliando-se a seleção de materiais empregados na construção do sistema através de ensaios químico-laboratoriais e testes de funcionalidade através de ensaios em condições reais de operação com veículos comerciais pesados devidamente instrumentados, mantendo o foco nos novos parâmetros operacionais impostos pelo novo perfil da composição tratora. Como resultado, apontam-se duas alternativas para a solução das falhas encontradas no mercado brasileiro: 1. Proposição de nova solução técnica construtiva para o sistema de acionamento da embreagem a fim de aumentar a robustez do componente de maior suscetibilidade às falhas. 2. Proposição de um modelo matemático para a predição do intervalo mínimo de manutenção para o sistema de acionamento da embreagem por cilindro escravo concêntrico. / The evolution of highway transportation of goods in the brazilian market has created new operation requirements due to the increased competition allied to the cost reduction demands. This new demands, most of them coming from globalization, have generated a significant change on the profile of heavy commercial vehicles. Fleets that were mainly composed of 4x2 tractors coupled to three wheeled semi-trailers with towing capacity of 45 tons, were in small steps exchanged by new compositions of tractors 6x2 coupled to bi-trains and road-trains with total towing capacity of 57 and 74 tons, respectively. This change have been followed by the new purchasing demands from fleet owners by lowering acquisition costs of new heavy commercial vehicles, as a consequence, most of 4x2 trucks have been adapted with tag-axles in order to increase towing capacity, which means increasing the stresses over the clutch system. On this research, a case study is developed about failures on clutch systems actuators by the concentric slave cylinder concept in the brazilian market. The research is developed by the evaluation of types of materials selected to the system components through chemical test and functionality tests carried on actual operation conditions on instrumented vehicles, keeping always the focus on the new operational demands imposed by the new profile of vehicle compositions (bi-trains and road-trains). As a final result, two alternatives are appointed to solve the failures in the brazilian market: 1. By the determination of the most failure susceptible component, it is possible to propose a mathematical and theoretical model to determine the minimum maintenance interval to the clutch actuation system by concentric slave cylinder concept. 2. Proposition of a new technical construction to the system in order to increase the robustness of the component most susceptible to the failures.
7

Baja SAE Vehicle Design / Návrh vozidla Baja SAE

Hajdušek, Zdeněk January 2012 (has links)
This master’s thesis describes the design of the Baja SAE vehicle according to the applicable rules. In the beginning is the work focused on search competing vehicles and subsequently on design the first Baja SAE vehicle in the Czech republic. This thesis is systematically divided into chapters according process to the vehicle design. The main part of a master's thesis is design of axle kinematics in software Adams and frame design. The model was designed in Catia V5. The frame was analysed of torsional stiffness and stress in software ANSYS.
8

Análise da paisagem no entorno dos eixos viários: o exemplo do Rodoanel Mario Covas na RMSP / Landscape analysis over the road axles proximities: the example of Mario Covas Expressway on RMSP

Volpe, Larissa Lucciane 23 November 2009 (has links)
A construção de uma rodovia pode interferir na dinâmica urbana, transformando a paisagem em seu entorno, e isto pode ocorrer devido a diversos fatores como instalações de empreendimentos, novas ocupações residenciais, mudanças na dinâmica e na fisionomia das áreas já ocupadas. Neste trabalho, o objetivo do estudo da paisagem urbana ao longo de um eixo viário, que tem como função interligar outras rodovias, é analisar de que forma ocorrem as alterações na paisagem urbana e sua abrangência. O estudo das transformações da paisagem urbana no entorno do eixo viário Rodoanel trecho oeste nos bairros de Perus e Jaraguá na cidade de São Paulo foi trabalhada por meio de levantamento de dados de diversas fontes e utilização de geotecnologias. As geotecnologias unidas às informações provenientes de documentos e trabalhos de campo, auxiliaram na organização, gerenciamento e quantificação dos dados. Os resultados obtidos foram organizados nos mapas temáticos de área construída, área verde densa, gramínea e árvores esparsas, área de solo exposto e galpões. Estes mapas temáticos permitiram uma caracterização de um cenário no entorno do trecho oeste do Rodoanel Mario Covas nos bairros Perus e Jaraguá, com as alterações ocorridas desde o ano de 1994 até 2002, isto é, uma análise temporal. Para alcançar estes resultados foi trabalhado em ambiente SIG dois tipos de classificação digital, a analógica e a automática, sendo o método analógico realizado na imagem IKONOS e também nas fotografias aéreas; e o método automático realizado apenas na imagem de alta resolução IKONOS. Foram comparados os dois métodos e observado que a classificação analógica foi mais adequada para a realização da análise multitemporal por ter sido realizada da mesma forma nas duas fontes, nas fotos aéreas de 1994 e na imagem IKONOS de 2002; e também permitiu uma melhor visualização nos mapas temáticos por considerar áreas maiores que a classificação automática. Com a análise temporal foi possível concluir que, do ano de 1994 ao ano de 2002, a área verde densa aumentou, a área de gramínea e árvores esparsas diminuiu, a área de solo exposto diminuiu, a área construída aumentou e a área de galpões de 1984 a 2002 também aumentou. As imagens aéreas de 1994 e 2002 também foram comparadas com os trabalhos de campo realizados nos anos de 2006, 2007, 2008 e 2009, onde foi possível observar as transformações ocorridas neste período. Nesta análise, os resultados foram divididos em alterações positivas, neutras e negativas, como sugere relatório desenvolvido pela empresa responsável pela construção do trecho oeste do Rodoanel Mario Covas, e de acordo com as observações realizadas em campo e no âmbito bibliográfico. Concluiu-se aproximadamente 48% de alterações consideradas negativas, 41% positivas e 12% neutras na área de estudo. / The construction of a highway may interfere on the urban dynamics and transform the landscape in its surroundings and this might occur due to several factors as installations of new undertakings, new residential constructions, changes on the dynamics and appearance in already occupied areas. In this work, the objective in the study of the urban landscape on the surroundings of a expressway axle, that have the function to link other highways, is to analyze in which way the landscape changes occur and its range. The transformations study of the urban landscape on the surroundings of the Mario Covas Expressway, east part, on the districts of Perus and Jaraguá, was developed through the gathering of data from several sources and the use of geotechnologies. The geotechnologies united to the data from documents and field works, aided the organization, managing and quantification of the data. The results obtained were organized on thematic maps of the built area, dense green area, grass and sparse trees, exposed soil and warehouses. These thematic maps allowed a characterization of the surroundings scenario of the East part of the Mario Covas Expressway on the São Paulo districts of Perus an Jaraguá, with a temporal analysis of the changes that took place from the year of 1994 through 2002. To reach these results two types of digital classification were worked over a GIS environment: the analogic and the automatic, being the analogical method constructed over the IKONOS imagery and also over aerial photographs; and the automatic method constructed exclusively over the IKONOS high resolution imagery. The two methods were compared and observed that the analogic classification was more suited to the multitemporal analysis due to the use of the same methods on both sources, on 1994 aerial imagery and 2002 high resolution imagery; and also allowed a better visualization on the thematic maps for considering larger regions than the automatic classification. With the multitemporal analysis was possible to conclude that, from 1994 through 2002 year, the dense green area increased, the grass and sparse tree area decreased, the exposed soil area decreased, the constructed area increased and warehouses area, from 1984 to 2002 also increased. The aerial images from 1994 and 2002 also were compared with the field work developed on 2006, 2007, 2008 and 2009, where was possible to observe the transformations that took place throughout this period. In this analysis, the results was divided in positive, neutral and negative alterations, as suggests report developed by the responsible company for the construction of the East part of the Mario Covas Expressway and according to the observations carried out on the field and over the bibliography extent. The conclusion is that approximately 48% of the transformations are considered negative, 41% positive and 12% neutral over the study area.
9

UTVÄRDERING OCH UTVECKLING AV TRANSPORTFIXTURER FÖR BAKAXLAR : / EVALUATION AND DEVELOPMENT OF TRANSPORT FIXTURES FOR REAR WHEEL AXLES

Ahlqvist, Max, Hammarström, Niklas January 2011 (has links)
Examensarbetet har genomförts i samarbete med Meritor HVS AB i Lindesberg som tillverkar fram- och bakhjulsaxlar till buss- och lastbilsindustrin. Projektet behandlar de fixturer som används vid transport av bakhjulsaxlar. Målet med arbetet var att utveckla en ny transportfixtur som passar majoriteten av deras bakaxelmodeller och som förebygger skador vid transport. Projektet har genomförts enligt metodiken systematisk konstruktion som beskrivs enligt Johannesson, Persson och Petterssons (2004). Systematisk konstruktion kan delas in i fem steg: produktspecificering, konceptgenerering, utvärdering och val av koncept, detaljkonstruktion samt slutkonstruktion. De problem som Meritor har med transportfixturerna är att de i hög grad slits och att skyddsbeläggningarna inte håller. Det finns för projektet 30 aktuella bakaxelmodeller som skall kunna transporteras med samma fixtur. Meritor använder sig av en grundfixtur och diverse nödlösningar för att kunna hantera alla modeller. De nya fixturkoncepten begränsas av de nuvarande stålrackens dimensioner och fixturernas positioner i dem. Utifrån de konceptförslag som tagits fram i arbetet, fördes de två mest lämpade koncepten vidare till slutkonstruktion. Det första konceptet, T-fixturen, bygger på den fixtur som används idag och är således ett förbättringsförslag. Förbättringarna består av en ökad anläggningsyta, bättre skyddsbeläggning samt vikt- och hållfasthetsoptimeringar. Det andra konceptet, pinnfixturen, bygger även den på samma grundfixtur men använder sig av två öglor som finns på varje axelmodell. Genom att placera axelns öglor över två pinnar i fixturen uppnås en total fixering av axeln. / This thesis has been carried out in cooperation with Meritor HVS AB in Lindesberg that manufactures front and rear wheel axles for the bus and truck industry. The project focuses on fixtures used in the transportation of rear wheel axles. The goal of the project was to develop a new transport fixture that suits the majority of rear axle models and prevents damage during transport. The project is based on the systematic design methodology described by Johannesson, Persson and Pettersson (2004). Systematic design can be divided into five stages: product specification, concept generation, concept evaluation and selection, detailed design and final design. The main issue with Meritors fixtures is that they wear out easily and that the protective coating breaks. One fixture type needs to be able to handle the 30 rear axle models relevant to this project. Meritor currently uses a basic structure combined with miscellaneous temporary solutions to handle all models. The new conceptual fixture is limited by the current steel rack, it´s dimensions and fixture positions within the construction. Based on the concept designs put forward in the work, the two most suitable concepts were brought through to final design. The first concept, the T-fixture, was based on the fixture in use today and is thus an improvement. The improvement consists of an increased contact surface, better protective coating as well as weight and strength optimizations. Concept two, the Rod fixture, is also based on the same basic fixture but uses two loops that are available on every axle model. By placing the axle loops over the two rods in the fixture, a total immobilization of the axle is achieved.
10

Planification et exécution de mouvements pour un robot bi-guidable: une approche basée sur la platitude différentielle

Hermosillo, Jorje 23 June 2003 (has links) (PDF)
Aucun

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