Dissertations / Theses on the topic 'Vehicle component'
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1
Carr, Christopher. "The competitiveness of UK vehicle component manufacturers." Thesis, University of Warwick, 1985. http://wrap.warwick.ac.uk/34624/.
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This dissertation presents the results of using a multidisciplinary "business policy" approach to examine the competitive situation of UK vehicle component manufacturers. With the cooperation of the companies involved in six product sectors, detailed studies have been made comparing the strategies and performances of UK competitors over several years, as well as those of selected competitors in Japan, Germany and the USA. The UK vehicle component industry has undergone an unprecedented decline in performance. The causes of this decline are many. External factors outside the control of the companies concerned include the declining competitiveness of UK based vehicle manufacturers and the exceptionally unfavourable UK business environment including the pressure on real wages. But the decline in competitiveness of UK vehicle component manufacturers is not solely due to these factors outside their own control. Just as important is the lack of strategic management capability at the top management level of the companies themselves. Before the recession many of the companies failed to see the changes that were occurring in the pattern of competition and that their competitive position was slipping. Few recognised that competition was becoming more European or even more global. Even fewer were able to effectively analyse the situation, select a viable long term strategy and pursue it with commitment. Such a strategy required a choice of the part of the market in which to compete as well as how to compete particularly as far as longer term production strategy (productivity, quality, flexible manufacturing systems etc) was concerned. The recession only added to this problem and obscured the underlying cause. Many companies were forced to retrench but still have not recognised the longer term strategic issues which must be addressed if the long term decline is to be reversed.
2
Pournelle, Phillip E. "Component based simulation of the Space Operations Vehicle and the common Aero Vehicle." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA363022.
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Thesis (M.S. in Operations Research) Naval Postgraduate School, March 1999."March 1999". Thesis advisor(s): Arnold H. Buss. Includes bibliographical references (p. 117-118). Also available online.
3
Salomonsson, David, and Erik Eng. "A Component-based Model of a Fuel Cell Vehicle System." Thesis, Linköpings universitet, Fordonssystem, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-176698.
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Improving the efficiency and performance of vehicle propulsion systems has always been desirable, and with increasing environmental awareness this has become increasingly topical. A particularly strong focus today is at fossil-free alternatives, and there is a strong trend for electrification. Hybrid powertrains of different types can bring benefits in certain aspects, and there is a lot of research and development involved in the making of a new powertrain. In this thesis, a complete powertrain for a fuel cell hybrid electric vehicle is modeled, with the intention of contributing to this trend. The model can be used to investigate design choices and their impact on energy consumption. A component-based library is developed, with the purpose of being easy to implement for different configurations. The results show that it is possible to assemble and simulate a complete hybrid drivetrain, using the modeled components, while not being very computationally heavy. The developed models correspond well with reality while being modular and easy to implement.
4
Wennerstrand, Esther. "Recycling of Textile and Plastic from an Interior Vehicle Component." Thesis, KTH, Fiber- och polymerteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300896.
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På grund av den rådande klimatförändringen och de globala problem som plast orsakar i miljön blir det allt viktigare att dagens linjära materialanvändning ändras till en cirkulär användning. Inom fordonsindustrin har kravet på ökad tillgänglighet och kvalitet på återvunna material identifierats. Som följd startades forskningsprojektet Sustainable Vehicle Interior Solutions (SVIS) samordnat av RISE IVF där behovet av en mer hållbar produktion av fordonsinteriörer tas upp. Ett mål är att minska och återvinna produktionsavfall. Den här studien undersöker möjligheten att återvinna textil och plast från en interiör komponent av multimaterial, som i detta fall är en textilklädd plaststolpe. Stolpen är gjord av polykarbonat (PC)/poly(akrylnitril-butadien-styren) (ABS) plast och polyestertextil (PET). Mekanisk återvinning utfördes på den textilklädda stolpen. Möjligheten att separera textil från plast undersöktes och testades i en kvarn med en dammavskiljare. Prover innehållande olika mängder PET förberedes och återvanns för att studera påverkan av PET på materialegenskaperna. Två olika kompatibiliseringsmedel användes för att undersöka om blandningarnas kompatibilitet ökade. Hur väl textil separerats från plast analyserades genom jämförelse av bulkdensitet mellan proverna. För att undersöka effekten av kompatibiliseringsmedel och hur förekomsten av PET påverkar PC/ABS utfördes mekanisk testning, DSC och SEM. Resultaten visade att separationen av textil från plast inte var fullständig på grund av mycket hög vidhäftning mellan textilen och plasten. Bibehållna mekaniska egenskaper, förutom brottförlängning, erhölls för alla återvunna prover oavsett PET-mängd. Därför var det möjligt att dra slutsatsen om att förekomsten av PET inte påverkar materialets egenskaper negativt och att separation eller tillsats av kompatibiliseringsmedel inte är nödvändigt. Vidare visar resultaten att PET blir blandbar med PC men inte påverkar ABS-fasen. Kemisk återvinning genom glykolys utfördes på svart och beige polyestertextil av PET erhållet som avklipp från produktionen av stolparna. Glykolysen utfördes i laboratorieskala med etylenglykol (EG) som lösningsmedel. Reaktionen ägde rum vid 230℃ under 1 timme med överskott av lösningsmedel och en Mg-Al blandad oxidkatalysator. Slutprodukten separerades från rester genom flera filtreringssteg och analyserades med DSC. Från resultatet observerades det att den erhållna slutprodukten var den önskade bis(2-hydroxyetyl) tereftalat (BHET) monomeren. Färgämnen från textilen fanns fortfarande kvar i monomeren efter depolymerisation. Därför utfördes avfärgning. För den svarta textilen testades adsorption med aktivt kol och extraktion med etylenglykol som avfärgningsmetoder. För den beige textilen utfördes enbart adsorption med aktivt kol. De avfärgade produkterna analyserades genom färgmätning och/eller genom jämförelse med varandra. Resultatet visade att adsorption med aktivt kol är en effektiv avfärgningsmetod för den beige textilen, men inte för den svarta textilen. Framgångsrik avfärgning av den svarta textilen erhölls istället genom extraktion med etylenglykol. Sammanfattningsvis, mekanisk återvinning av den textilklädda stolpen resulterar i bibehållna värden för de mekaniska egenskaperna hos det återvunna materialet, förutom för brottförlängnigen. Detta bör göra det återvunna materialet lämpligt för användning i fordonsapplikationer, men inte för återvinning i ett slutet kretslopp (closed loop recycling) på grund av säkerhetsaspekter hos stolpen. Om hög kraft appliceras måste materialet kunna ändra form utan att gå sönder. Återvinning genom glykolys visar potential för att den avklippta polyestertextilen kan återvinnas i ett slutet kretslopp eftersom den avfärgade monomeren skulle kunna ompolymeriseras till ny PET. Det kan undersökas i framtida studier.Due to the current climate change and the global problems plastics cause in the environment, it becomes increasingly important that today’s linear use of materials is changed to a circular use. In the automotive industry, the demand for increased availability and quality of recycled materials has been recognized. Following this, the research project Sustainable Vehicle Interior Solutions (SVIS) coordinated by RISE IVF was started in which the need for a more sustainable production of vehicle interiors is addressed. An objective is to reduce and recycle production waste. This study investigates the possibility to recycle textile and plastic from an interior multi-material component which in this case is a textile dressed plastic pillar. The pillar is made of polycarbonate (PC)/poly(acrylonitrile butadiene styrene) (ABS) plastic and polyester (PET) textile. Mechanical recycling was performed on the textile dressed pillar. The possibility to separate textile from plastic was investigated and tested in a mill with a dust separator. Samples containing different amounts of PET were prepared and recycled to study the influence of PET. Two different compatibilizers were used to investigate potential improvement in compatibility of the blends. The level of separation of textile from plastic was analyzed by comparison of bulk density between the samples. To investigate the effect of compatibilizers and how the presence of PET influences the PC/ABS, mechanical testing, DSC and SEM were performed. The results showed that the separation of textile from plastic was not complete due to very high adhesion between the textile and plastic. Retained mechanical properties, except for the strain at break, were obtained for all recycled samples. Therefore, it could be concluded that the presence of PET does not affect the properties of the material negatively and separation or addition of compatibilizer is unnecessary. The results further show that PET becomes miscible with PC but does not affect the ABS phase. Chemical recycling through depolymerization with glycolysis was performed on black and beige polyester (PET) textile waste obtained as cut-off from the production of the pillars. The glycolysis was performed in lab-scale with ethylene glycol (EG) as solvent. The reaction took place at 230℃ for 1h with excess of solvent and a Mg-Al mixed oxide catalyst. The final product was separated from residues through several filtration steps and analyzed with DSC. From the result it could be observed that the obtained final product was the desired bis(2-hydroxyethyl) terephthalate (BHET) monomer. Dyes from the textile were still present in the monomer after depolymerization. Therefore, decolorization was performed. For the black textile, adsorption with active carbon and extraction with ethylene glycol were tested as decolorization methods. For the beige textile, solely adsorption with active carbon was performed. The decolorized products were analyzed by color measurement and/or through comparison to each other. The result showed that adsorption with active carbon is an effective decolorization method for the beige textile, but not for the black textile. Successful decolorization of the black textile was instead obtained by extraction with ethylene glycol. To conclude, mechanical recycling of the textile dressed pillar results in retained values of the mechanical properties of the recycled material, except for the strain at break. This should make the recycled material suitable for use in automotive application, though not closed loop recycling because of safety aspects of the pillar. If high force is applied, the material needs to be able to change shape without breaking. Recycling through depolymerization shows potential for closed loop recycling of the polyester textile cut-off since the decolorized monomer could be repolymerized into new PET. This could be investigated in future studies.
5
Nyström, Dag. "COMET: a component-based real-time database for vehicle control-systems." Licentiate thesis, Mälardalen University, Department of Computer Science and Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-97.
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Nyström, Dag. "COMET: a component-based real-time database for vehicle control-systems /." Västerås : Mälardalen University, 2003. http://www.mrtc.mdh.se/publications/0533.pdf.
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7
Narkhede, Yashdeep. "Simscape modeling of motor generator unit component for hybrid electric vehicle." Thesis, Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/55047.
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The thesis introduces the user to programming in Simscape language. A permanent magnet synchronous machine torque control drive system for hybrid electric vehicles has been analyzed, programmed, using Simscape language, and tested in this
thesis. The thesis walks the reader through the process of creating custom components in Simscape language explaining details and syntax of the language at every step. Important excerpts of code for all the components designed, created and used in
the process are explained in the thesis and the complete code for the same is provided in the Appendix. ix
8
Brown, William Shaler. "Technology for Designing the Steering Subsystem Component of an Autonomous Vehicle." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/34960.
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Autonomous vehicles offer means to complete unsafe military operations without endangering the lives of soldiers. Such solutions have fueled many efforts towards designing autonomous, or unmanned, systems. Military and academic research efforts alike continue to focus on developing these systems. While many different autonomous vehicles have been introduced, however, such complex systems have limited drive-by-wire operability. The complete process to up-fit a vehicle to fully autonomous operation involves the design, up-fit, testing and verification of many different subsystems. The objective of this thesis is to design and model an autonomous steering system requiring little modifications to an existing steering system. It is desirable to still operate the vehicle manually as well as preserve the vehicleâ s visual appearance. Up-fit and implementation of the designed steering system and verification of its functionality has been documented as well. Utilization of the supplied controller and software has enabled the testing and characterization of the system. The proposed design offers a solution to a wide variety of wheeled vehicles steered via the traditional and common steering wheel method. In addition, modifications have been made to an existing simulation of an unmanned vehicle in a military testbed environment (Fort Benning). The simulation accounts for the control methodology as it has been designed and tested with, which offers the ability to analyze the dynamics of the unmanned system.Master of Science
9
Moeller, Robert D. (Robert David). "Optimization in-line vehicle sequencing systems : applications to Ford component manufacturing." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10158.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1997, and Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1997.Includes bibliographical references (p. 155-156).
by Robert D. Moeller.
M.S.
10
Murphy, Patrick F. R. "Load-haul-dump vehicle component life prediction using experimentally acquired load histories." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2002. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ65641.pdf.
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Al-Nuaimi, Mina, and Lina Widegren. "Component remanufacturing for improved lifecycle utilization." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-52845.
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Remanufacturing is the process of collecting end-of-life products from customers and then being dissembled, reprocessed and reassembled to create new products to meet the customers’ needs. The economic viability of the implementation of a remanufacturing strategy has being shown among many companies in the automobile industry. Also, the economic profitability of the remanufacturing process has been proven in many industrial case studies. Cummins Scania XPI Manufacturing in Södertälje considers implementing a remanufacturing process for their returned components, but there is a lack of a foundation of whether this process will provide an economic profitability or not. In order to decide whether the remanufacturing is profitable for the company, there are some factors to consider. This research aims to identify the reasons behind implementing a remanufacturing process and the factors that affect the economical profitability of it. In order to answer the research questions, a theoretical investigation as well as several interviews with Cummins Scania XPI Manufacturing in Södertälje and Cummins XPJ in Mexico has been done. The aim with the interviews with Cummins Scania XPI in Södertälje was to identify what factors they want to consider when determining whether the remanufacturing process can be economic beneficial for them. The interview with Cummins XPJ was done in order to get an understanding how their remanufacturing process work. The result shows that there can be three main reasons behind implementing a remanufacturing process: economic benefits, environmental benefits as well as legislation. When it comes to the considered factors when implementing the remanufacturing process, the reverse logistic with the aim to remanufacture is important to consider since the remanufacturing is a fundamental process of it. Thereafter the possible factors that can be occurred are one-time costs such as prices of machines, fixed costs such as operators’ costs and where to implement the process. The results of this research provide a possibility for companies to determine whether the remanufacturing process is economically profitable for them.
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Edfeldt, Wiktor. "Design and Analysis of a Carbon Fiber Reinforced Polymer Structural Chassis Component for a EU Long Distance Truck." Thesis, KTH, Lättkonstruktioner, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-265644.
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A Scania S-series front chassis module feasibility study is carried out to investigate the potential gains and losses by changing to a composite material system. The existing front chassis module comprises multiple steel, sheet metal and plastic components. The design space is fixed by the location of adjacent components in the current design. A new methodology is put together on the basis of "The GAP Methodology: A new way to design composite structures" by F. Neveu et al. (2019)[1] for facilitating the complex nature of multivariable composite structures design. By applying the methodology a set of hand sketches based on vari-ous geometry classes and applicable manufacturing processes can be created for a technical screening, where one concept is brought forward for detailed analysis. The concept design is refined by the use of the surface modeller tool in CATIA V5 and a structural analysis is undertaken using the finite element method software for composites ANSYS ACP. The composite laminate layup is designed by using aerospace design rules as guidelines for the given material system. The proposed design solution satisfies the design requirements and improves the benchmark Scania Chassis module by lowering the amount of components with about 30%, has a recommended metal to composite joining method, reduces the mass by around 40% (53.5% excluded the suggested joining method) and has a safety factor to material failure strains. The feasibility study demonstrates that the proposed methodology and design of the new composite chassis component is plausible using a simplified analysis.Detta arbete är en genomförbarhetsstudie för undersöka för- och nackdelar med att byta ut nuvarande material till fiberkomposit, i ett av de främre chassihörnen i en Scania S-serie bil. Det nuvarande chassihörnet består av flera komponenter i stål, plåt och plast. Desingutrymmet är bestämt av placeringen av angränsande komponenter i dagens bil. En ny metodik är sammansatt baserat på ”The GAP Methodology: A new way to design composite structures” av F. Neveu et al. (2019) [1] för att underlätta den komplexa karaktären av produktframtagning av komponenter i fiberkomposit. Genom att använda metodiken kan en uppsättning handskisser genereras baserade på olika geometriklasser och tillämpliga tillverkningsprocesser. Detta tas sedan vidare till en teknisk screening, där ett koncept väljs för fortsatt mer detaljerad analys. Konceptdesignen förfinas med användning av ytmodellverktyget i CATIA V5 och en strukturanalys utförs med användning av ANSYS ACP för finit elementmetod för kompositer. Kompositlaminatdesignen med det givna materialsystemet är gjord med hjälp av konstruktionsregler från flygindustrin.Den framtagna designen tillfredställer designkraven och förbättrar den nuvarande Scania designen för chassihörnet. Detta genom att minska antalet komponenter med ungefär 30%, har en rekommenderad fästmetod för metall till fiberkomposit, minskar vikten med ungefär 40% (53.5% exkluderat den föreslagna fästmetoden) och har en säkerhetsmarginal till maxtöjningar för materialsystemet. Genomförbarhetsstudien visar att den föreslagna metodiken och designen av den nya chassikomponenten i fiberkomposit är möjlig med en förenklad analys.
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Aghaei, Shayan. "Acoustic Radiation Of An Automotive Component Using Multi-Body Dynamics." Thesis, KTH, Fordonsdynamik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-288710.
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An important facet of creating high-quality vehicles is to create components that are quiet and smooth under operation. In reality, however, it is challenging to measure the sound that some automotive components make under load because it requires specialist facilities and equipment which are expensive to acquire. Furthermore, the motors used in testbeds drown out the noise emitted from much quieter components, such as a Power Transfer Unit (PTU). This thesis aims to solve these issues by outlining the steps required to virtually estimate the acoustic radiation of a PTU using the Transmission Error (TE) as the input excitation via multi-body dynamics (MBD). MBD is used to estimate the housing vibrations, which can then be coupled with an acoustic tool to create a radiation analysis. Thus, creating a viable method to measure the acoustic performance without incurring significant expenses. Furthermore, it enables noise and vibration analyses to be incorporated more easily into the design stage. This thesis analysed the sound radiated due to gear whine which arises due to the TE and occurs at the gear mesh frequency and its multiples. The simulations highlighted that the TE can be accurately predicted using the methods outlined in this thesis. Similarly, the method can reliably obtain the vibrations of the housing. The results from this analysis show that at 2000 rpm the PTU was sensitive to vibrations at 500, 1000 and 1500 Hz, the largest amplitude being at 1000 Hz. Furthermore, the Sound Power Level (SWL) was proportional to the vibration amplitudes in the system. Analytical calculations were conducted to verify the methods and showed a strong correlation. However, it was concluded that experiments are required to further verify the findings in this thesis.En viktig aspekt i att skapa fordon av hög kvalitet är att skapa komponenter som är tysta och smidiga under drift. I verkligheten är det dock svårt att mäta ljudet som vissa fordonskompo- nenter ger under belastning eftersom det kräver specialanläggningar och utrustning, vilket är dyrt att skaffa. Dessutom maskerar motorerna som används i testbäddar ut bullret från mycket tystare komponenter, till exempel en kraftöverföringsenhet (PTU). Detta examensar- bete syftar till att lösa dessa problem genom att beskriva de steg som krävs för att virtuellt uppskatta den akustiska strålningen av en PTU med hjälp av transmissionsfelet (TE) som ingångsexcitation via flerkroppsdynamik (multi-body dynamics, MBD). MBD används för att uppskatta kåpans vibrationer, som sedan kan kopplas till ett akustiskt verktyg för att skapa en ljudutstrålningsanalys. Således skapas en genomförbar metod för att mäta den akustiska pre- standan utan att medföra betydande kostnader. Dessutom möjliggör det att lättare integrera ljud- och vibrationsanalyser i designfasen. Detta examensarbete analyserade ljudet som utstrålats på grund av kugghjulsljud, som uppstår på grund av TE och uppträder vid kuggingreppsfrekvensen och dess multiplar. Simuleringarna belyste att TE kan förutsägas exakt med de metoder som beskrivs i detta examensarbete. På samma sätt kan metoden på ett tillförlitligt sätt uppnå kåpans vibrationer. Resultaten från denna analys visar att vid 2000 rpm var PTU känslig för vibrationer vid 500, 1000 och 1500 Hz, den största amplituden var vid 1000 Hz. Dessutom var ljudeffektsnivån (SWL) proportionell mot vibrationsamplituderna i systemet. Analytiska beräkningar genomfördes för att verifiera metoderna och visade en stark korrelation. Dock drogs slutsatsen att experiment krävs för att ytterligare verifiera resultaten i detta arbete.
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Hawkins, Philip Nigel. "Biological studies of serum amyloid P component : a specific targeting vehicle in amyloidosis." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46810.
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Lindberg, Eskil. "A Vibro-Acoustic Study of Vehicle Suspension Systems : Experimental and Mathematical Component Approaches." Doctoral thesis, KTH, MWL Strukturakustik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121575.
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The objective of the present work is to study the vehicle suspension as a vibro-acoustic system of high complexity, consisting of many sub-systems with fundamentally different acoustical properties. In a parallel numerical and experimental modelling effort, important contributions to the understanding of its behaviour have been achieved. These findings are based on a balance between component investigations and global modelling of the complete system; they have been formulated for the transmission of both tyre-road excitation and friction-induced vibrations in the brake system. Initially an experimental study was conducted on a full vehicle test rig studying the broadband interior brake noise problem of, here named, roughness noise. The purpose of the study was twofold: first, to determine if the transmission from the source to the interior of the vehicle was structure-borne; second, to study the complexity of the suspension as a vibro-acoustic system. Parameters a_ecting the vibro-acoustic source were varied to gain understanding of the source mechanisms. This experimental study laid the foundation of the first part of this thesis (paper A) and provided the directions for the second part, the development of a mathematical modelling approach (paper B and C). In these two papers, methods for analysing the complex vibro-acoustic transfer of structure-borne sound in a vehicle suspension system were developed. The last part was then focussed on the wheel rim influence on the vibro-acoustic behaviour (paper D) of the suspension system. As a whole, the work clearly demonstrates that it is possible to conduct component studies of subsystems in the vehicle suspension system; and from these component studies it is possible draw conclusions that very well may avoid severe degradations in the interior noise of future vehicle generations.QC 20130503
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Novick, David Keith. "Implementation of a sensor fusion-based object-detection component for an autonomous outdoor vehicle." [Gainesville, Fla.] : University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE1000148.
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Thesis (Ph. D.)--University of Florida, 2002.Title from title page of source document. Document formatted into pages; contains xi, 147 p.; also contains graphics. Includes vita. Includes bibliographical references.
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Choi, Tayoung Gabriel. "Modeling, Sizing and Control of Plug-in Light Duty Fuel Cell Hybrid Electric Vehicle." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1230712944.
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Beduk, Mustafa Durukan. "Impact Of Damper Failure On Vehicle Handling During Critical Driving Situations." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12611223/index.pdf.
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Capturing what is going on and what may happen related to vehicle handling
behaviour in cases of desired or non-desired actions and interventions has a crucial
importance. Strategies implemented to improve vehicle stability or algorithms and
control modules designed to compensate the non-desired effects on handling
behavior may appear to be inadequate as the vehicle goes through uncountable
experiences. The importance of understanding and introducing the possible sources
of undesired effects which may be encountered throughout driving action cannot be
underemphasized.
One of the possibilities that may lead the driver face with unexpected results
concerning vehicle&rsquos handling is suspension damper failure, which has not yet been dealt with adequately in the literature. The fast developing technology and consequently the expanding utilization of chassis electronics and electronic vehicle components make the investigation of damper failure phenomenon essential since reliability decreases by the continuously increasing introduction of electronic means. In this study, possible failure types of dampers including electrical failure are taken into account, their effects on vehicle stability under critical driving conditions are examined. Shortcomings and comments are made on criticality of failed damper and its failure point. This work as a result, constitutes a particular contribution to the literature in that it brings up a concrete knowledge to the stated research area.
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Ozden, Burak Samil. "Modeling And Optimization Of Hybrid Electric Vehicles." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615583/index.pdf.
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The main goal of this thesis study is the optimization of the basic design parameters of hybrid electric vehicle drivetrain components to minimize fuel consumption and emission objectives, together with constraints derived from performance requirements. In order to generate a user friendly and flexible platform to model, select drivetrain components, simulate performance, and optimize parameters of series and parallel hybrid electric vehicles, a MATLAB based graphical user interface is designed. A basic sizing procedure for the internal combustion engine, electric motor, and battery is developed. Pre-defined control strategies are implemented for both types of hybrid configurations. To achieve better fuel consumption and emission values, while satisfying nonlinear performance constraints, multi-objective gradient based optimization procedure is carried out with user defined upper and lower bounds of optimization parameters. The optimization process is applied to a number of case studies and the results are evaluated by comparison with similar cases found in literature.
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Jansen, van Nieuwenhuizen Rudolph Johannes. "Development of an automated robot vision component handling system." Thesis, Bloemfontein : Central University of Technology, Free State, 2013. http://hdl.handle.net/11462/213.
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Thesis (M. Tech. (Engineering: Electrical)) -- Central University of technology, Free State, 2013In the industry, automation is used to optimize production, improve product quality and increase profitability. By properly implementing automation systems, the risk of injury to workers can be minimized. Robots are used in many low-level tasks to perform repetitive, undesirable or dangerous work. Robots can perform a task with higher precision and accuracy to lower errors and waste of material. Machine Vision makes use of cameras, lighting and software to do visual inspections that a human would normally do. Machine Vision is useful in application where repeatability, high speed and accuracy are important. This study concentrates on the development of a dedicated robot vision system to automatically place components exiting from a conveyor system onto Automatic Guided Vehicles (AGV). A personal computer (PC) controls the automated system. Software modules were developed to do image processing for the Machine Vision system as well as software to control a Cartesian robot. These modules were integrated to work in a real-time system. The vision system is used to determine the parts‟ position and orientation. The orientation data are used to rotate a gripper and the position data are used by the Cartesian robot to position the gripper over the part. Hardware for the control of the gripper, pneumatics and safety systems were developed. The automated system‟s hardware was integrated by the use of the different communication protocols, namely DeviceNet (Cartesian robot), RS-232 (gripper) and Firewire (camera).
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Lindberg, Eskil. "Vehicle Disc Brake Roughness Noise : Experimental Study of the Interior Noise andVibro-Acoustic Modelling of Suspension Systems." Licentiate thesis, KTH, MWL Strukturakustik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-39554.
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Prediction of vehicle disc brake roughness noise is a non-trivial challenge. In fact, neither the source mechanisms, nor the transfer paths are so far well understood. Traditionally, disc brake noise problems are studied as part of the friction-induced noise field, where the source is considered to be a more or less local phenomenon related to the brake disc and brake pad. However, for the roughness noise of interest here this viewpoint is not adequate when attempting to solve the interior noise problem since the transfer of vibro-energy from the brake into the vehicle body is a crucial aspect and plays an important role in the understanding and solution to the problem. The vibroacoustic energy transfer associated with the brake roughness noise is a problem where geometrical complexity and material combinations, including rubber bushings, pose an intricate modelling problem. Additionally, system altering effects from moving parts and loadings are important, e.g. due to the steering or brake systems. In addition, the source mechanisms themselves must also be understood to be able to solve the problem. The current work constitutes a combined experimental and theoretical investigation, aiming at an increased understanding of the source, the transfer paths and how they are a affected by change in the operational state. The experimental study of the vehicle disc brake roughness noise, is based on measurements conducted in a laboratory using a complete passenger car. It is found that the interior noise is a structural-borne broadband noise event well correlated to vehicle speed and brake pressure. The results suggest that the friction source may be divided into vibrations created in the sliding direction and vibrations created normal to the contact plane, where the sliding direction levels appear to be proportional to brake pressure according to Coulomb’s friction law; the vibration level in the normal direction of the contact plane on the other hand has behaviour proportional to Hertz contact theory. The measurements also indicate that the brake force created carried by the suspension system when braking will also alter the vibro-acoustic response of the system. To facilitate the theoretical simulations, an approach for modelling of the suspension system is developed. The vibro-acoustic transfer path model developed is using a modal based on the Craig-Bampton method where a restriction on the coupling modes is suggested. The approach suggested uses undeformed coupling interfaces, to couple structures of fundamentally different stiffness such as may be the case in a vehicle suspension system where for instance rubber bushings are combined with steel linking arms. The approach show great potential inreducing computational cost compared to the classical Craig-Bampton method.QC 20110913
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Ek, David. "Material parameter study for aheavy-vehicle exhaust manifoldusing the finite element method : to increase component lifetime and decrease its environmental impact." Thesis, Linköpings universitet, Konstruktionsmaterial, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-165869.
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The thesis originates from a need to meet stricter environmental regulations for Scania, to reduce fuel consumption and emission from heavy-vehicles. Scania aims to fulfil these requirements by increasing combustion pressure and temperature. These conditions are tougher for the engine components and they shorten their lifetime. This thesis aims to improve Scania’s ability to increase the lifetime of a heavy-vehicle exhaust manifold, an engine component that collects exhaust from several engine cylinders into one pipe. This was done by conducting a material comparison and a parameter study, both used the FEM software Abaqus CAE. The material comparison consisted of three ferritic and austenitic ductile cast irons (SiMo51, SiMo1000 and Ni-resist) subjected to thermal stress. Their max stress was compared for two thermo-mechanical fatigue cases, out-of-phase and in-phase. A parameter study was also conducted to clarify the influence of thermal conductivity, thermalexpansion, Young’s modulus and yield strength on max stress for OP and IP in the exhaust manifold. The FEM simulation results from the parameter study were used to create functions that can be used to decide how to treat/process a material to minimise the stress in the exhaust manifold. They can also be used in material selection to choose a material that minimises stress. The research questions and their shortened answers can be seen below. 1. Which of SiMo51, SiMo1000 and Ni-resist produces the lowest tensile stresses? ForOP, SiMo1000 produced a slightly lower max principal stress than SiMo51. For IP, Ni-resistproduced the lowest max principal stress by a large margin. 2. How do different material properties affect the maximum stress during operation of thegiven component? Thermal conductivity has a decreasing relation to max stress. Thermalexpansion and Young’s modulus have a similar relation to max stress, stress increases forboth properties as they increase. A decreased yield strength decreases the max stress forstresses above the yield limit but has no effect on stress below it. 3. How should an objective function to minimise max stress in the component with regard to material properties be expressed? functions of OP and IP can be seen in the actual abstract.
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Murphy, Robert T. "Developing, Demonstrating, and Validating a Vehicle Test Bed to Extend the Capabilities of a Chassis Dynamometer Test System." Ohio University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1226630699.
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Ratliff, Adam R. "Designing a Surrogate Upper Body Mass for a Projectile Pedestrian Legform." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1204662790.
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Gruneau, Joar. "Investigation of deep learning approaches for overhead imagery analysis." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232208.
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Analysis of overhead imagery has a great potential to produce real-time data cost-effectively. This can be an important foundation for decision-making for businesses and politics. Every day a massive amount of new satellite imagery is produced. To fully take advantage of these data volumes a computationally efficient pipeline is required for the analysis. This thesis proposes a pipeline which outperforms the Segment Before you Detect network [6] and different types of fast region based convolutional neural networks [61] with a large margin in a fraction of the time. The model obtains a prediction error for counting cars of 1.67% on the Potsdam dataset and increases the vehiclewise F1 score on the VEDAI dataset from 0.305 reported by [61] to 0.542. This thesis also shows that it is possible to outperform the Segment Before you Detect network in less than 1% of the time on car counting and vehicle detection while also using less than half of the resolution. This makes the proposed model a viable solution for large-scale satellite imagery analysis.Analys av flyg- och satellitbilder har stor potential att kostnadseffektivt producera data i realtid för beslutsfattande för företag och politik. Varje dag produceras massiva mängder nya satellitbilder. För att fullt kunna utnyttja dessa datamängder krävs ett beräkningseffektivt nätverk för analysen. Denna avhandling föreslår ett nätverk som överträffar Segment Before you Detect-nätverket [6] och olika typer av snabbt regionsbaserade faltningsnätverk [61] med en stor marginal på en bråkdel av tiden. Den föreslagna modellen erhåller ett prediktionsfel för att räkna bilar på 1,67% på Potsdam-datasetet och ökar F1- poängen for fordons detektion på VEDAI-datasetet från 0.305 rapporterat av [61] till 0.542. Denna avhandling visar också att det är möjligt att överträffa Segment Before you Detect-nätverket på mindre än 1% av tiden på bilräkning och fordonsdetektering samtidigt som den föreslagna modellen använder mindre än hälften av upplösningen. Detta gör den föreslagna modellen till en attraktiv lösning för storskalig satellitbildanalys.
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Marquette, Adrien [Verfasser], and Wolfgang [Akademischer Betreuer] Rosenstiel. "Design of a component that learns dynamic driving behavior and vehicle characteristics, in known situations, for a later fuel consumption prediction on roads that have not been driven before / Adrien Marquette ; Betreuer: Wolfgang Rosenstiel." Tübingen : Universitätsbibliothek Tübingen, 2014. http://d-nb.info/1163235288/34.
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Schultz, Grant George. "Developing a methodology to account for commercial motor vehicles using microscopic traffic simulation models." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/111.
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The collection and interpretation of data is a critical component of traffic and transportation engineering used to establish baseline performance measures and to forecast future conditions. One important source of traffic data is commercial motor vehicle (CMV) weight and classification data used as input to critical tasks in transportation design, operations, and planning. The evolution of Intelligent Transportation System (ITS) technologies has been providing transportation engineers and planners with an increased availability of CMV data. The primary sources of these data are automatic vehicle classification (AVC) and weigh-in-motion (WIM). Microscopic traffic simulation models have been used extensively to model the dynamic and stochastic nature of transportation systems including vehicle composition. One aspect of effective microscopic traffic simulation models that has received increased attention in recent years is the calibration of these models, which has traditionally been concerned with identifying the "best" parameter set from a range of acceptable values. Recent research has begun the process of automating the calibration process in an effort to accurately reflect the components of the transportation system being analyzed. The objective of this research is to develop a methodology in which the effects of CMVs can be included in the calibration of microscopic traffic simulation models. The research examines the ITS data available on weight and operating characteristics of CMVs and incorporates this data in the calibration of microscopic traffic simulation models. The research develops a methodology to model CMVs using microscopic traffic simulation models and then utilizes the output of these models to generate the data necessary to quantify the impacts of CMVs on infrastructure, travel time, and emissions. The research uses advanced statistical tools including principal component analysis (PCA) and recursive partitioning to identify relationships between data collection sites (i.e., WIM, AVC) such that the data collected at WIM sites can be utilized to estimate weight and length distributions at AVC sites. The research also examines methodologies to include the distribution or measures of central tendency and dispersion (i.e., mean, variance) into the calibration process. The approach is applied using the CORSIM model and calibrated utilizing an automated genetic algorithm methodology.
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Haq, Z. U. "Hypersonic vehicle interference heating." Thesis, University of Southampton, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336171.
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Möller, Anders. "Software Component Technologies for Heavy Vehicles." Licentiate thesis, Mälardalen University, Department of Computer Science and Electronics, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-34.
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Control-systems for heavy vehicles have advanced from an area where Industrial Requirements on Component Technologies for Embedded Systemsmainly mechanic and hydraulic solutions were used, to a highly computerised domain using distributed embedded real-time computer systems. To cope with the increasing level of end-customer demands on advanced features and functions in future vehicle systems, sophisticated development techniques are needed. The development techniques must support software in numerous configurations and facilitate development of systems with requirements on advanced functionality, timeliness, and safety-criticality. In order to meet these requirements, we propose the use of component-based software engineering. However, the software component-technologies available on the market have not yet been generally accepted by the vehicular industry. In order to better understand why this is the case, we have conduced a survey - identifying the industrial requirements that are deemed decisive for introducing a component technology. We have used these requirements to evaluate a number of existing component technologies, and one of our conclusions is that none of the studied technologies is a perfect match for the industrial requirements. In addition, we have implemented and evaluated the novel component model SaveCCM, which has been designed for safety-critical automotive applications. Our evaluation indicates that SaveCCM is a promising technology which has the potential to fulfil the industrial requirements. However, tools are still immature and incomplete. In the final part of this work, we propose the use of monitored software components, as a general approach for engineering of embedded systems. In our approach, a component's execution is continuously monitored and experience regarding the behaviour is accumulated. As more and more experience is collected the confidence in the component grows.
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Klemt, Christian. "Verfahrensentwicklung zur Einbringung endlosfaserverstärkter Thermoplaste in metallische Strukturen mittels Patchen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-218647.
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Im Automobilbau kommt zunehmend das sog. Multimaterial-Design zum Einsatz, um kostenattraktiven Leichtbau in Großserienanwendungen umzusetzen und das Leichtbaupotential von strukturellen Bauteilen in bislang meist monolithischer Bauweise zu erweitern. Die Patch-technologie, bei der die Strukturertüchtigung durch die lokale und anforderungsgerechte Einbringung von endlosfaserverstärkten Faser-Kunststoff-Verbunden (FKV) in dünnwandige metallische Bauteile erfolgt, ist eine zielführende Technologie, um einen hohen Leichtbaugrad zu generieren. Eine besondere Herausforderung stellt dabei die dauerhafte, flächige Verbindung von Metall und thermoplastbasiertem FKV (TP-FKV) dar. Da die verwendeten Werkstoffe keine hinreichende chemische Kompatibilität aufweisen, wurden bislang Klebstoffe als Fügehilfsstoff genutzt, wodurch jedoch zusätzliche Prozessschritte notwendig wurden und damit verbunden häufig höhere Prozesszeiten auftraten.
In dieser Arbeit werden Möglichkeiten zur Kompatibilisierung der beiden, das hybride Bauteil kennzeichnenden, Werkstoffkomponenten erarbeitet. Der Schwerpunkt wird dazu auf die Entwicklung und Charakterisierung einer inlinefähigen Vorbehandlungsmethode des metallischen Fügepartners in Kombination mit einer Modifikation des thermoplastischen FKV-Halbzeugs bzw. dessen Matrixsystems gelegt. Dabei werden die Einflüsse unterschiedlicher Vorbehandlungen und zugeordneter Vorbehandlungsparameter auf die physikalische und chemische Oberflächenbeschaffenheit des Metalls und das Haftniveau im TP-FKV/Metallverbund untersucht. Darüber hinaus werden mit Hilfe von Füllstoffen und Additiven verschiedene chemische Veränderungen des thermoplastischen Matrixsystems vorgenommen und deren Auswirkung auf die Adhäsion zwischen den Verbundpartnern charakteri-siert. Für die Anwendung des Verbundsystems TP-FKV/Metall in einem Automobil werden neben hohen mechanischen Eigenschaften (Verbundfestigkeit) insbesondere sehr gute Temperatur-, Klimawechsel- und Korrosionsbeständigkeiten gefordert, die in praxisnahen Untersuchungen nachgewiesen werden. Die gewonnenen Erkenntnisse zur prozessintegrativen Anpassung der Komponenten des Werkstoffverbundes werden anschließend in die Praxis übertragen. Dafür wird ein seriennaher Fertigungsprozess entwickelt und prototypisch umgesetzt. Der Einfluss der grundlegenden Prozessparameter Druck, Temperatur und Zeit auf die Güte der Verbindung wird evaluiert. Einfache bauteilnahe Demonstratoren werden genutzt, um die Tauglichkeit der Verbundstrategie und des entwickelten Fertigungskonzeptes der TP-FKV-Patchtechnologie für deren wirtschaftliche Anwendung in der Großserienfertigung im Umfeld der Automobilindustrie nachzuweisen.
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Morgan, Clive. "The dynamic characterisation and modelling of lead-acid batteries for electric vehicle applications." Thesis, University of South Wales, 1985. https://pure.southwales.ac.uk/en/studentthesis/the-dynamic-characterisation-and-modelling-of-leadacid-batteries-for-electric-vehicle-applications(aad46cbd-48b7-4245-a447-8d16b67bebe6).html.
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In an effort to increase the available capacity of a lead-acid battery, the effects of pulsed discharge currents as opposed to the effects of continuous discharge currents on the battery were investigated, for a wide range of frequency, mark/space ratio and peak current of the discharge waveform. It was found that for certain conditions of pulsed discharge, the use of pulsed currents can provide a considerable increase in available capacity when compared to that obtained from using conventional continuous currents. In order to increase the efficiency and reduce the time of the lead-acid battery charge, the effects of using pulsed charging currents with ·and without depolarisation discharge pulses interspersed throughout the charging period as opposed to using conventional continuous current charging was investigated. For the tests performed, it was found that pulsed current charging without depolarisation pulses offers no advantages over conventional continuous current charging for three-stage and single-stage charging techniques. The use of pulsed currents with depolarisation pulses was found to be less effective than using conventional continuous current or straight pulsed current charging. A model for the cell terminal voltage and state-of-charge of the battery is derived from the results of an extensive series of tests performed by the author. In this writing for the first time a model accurately accounts for the dependence of recuperation, regeneration and wide variations in the discharge rate on the temperature of the electrolyte and the effects of these factors on the terminal voltage and state-of-charge. Additionally, for the first time a comprehensive model for use with pulsed discharge currents is derived. The models were tested under dynamic conditions of battery operation and were found to be able to predict battery state to a high degree of accuracy, and were also found to be more accurate than existing models.
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Santos, Luís Henrique Mendes dos. "O impacto das fontes de poluição na distribuição de tamanho em número e massa do material particulado atmosférico em São Paulo." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/14/14133/tde-27092018-224325/.
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Diversos estudos tiveram como objetivo determinar e caracterizar o aerossol atmosférico na cidade de São Paulo, quanto a seu tamanho e composição química, bem como encontrar as suas fontes emissoras e contribuições em massa para a região estudada. A coleta dos constituintes atmosféricos foi realizada na estação de amostragem do Laboratório de Análises dos Processos Atmosféricos (LAPAt) do Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG) da Universidade de São Paulo (USP), localizada na zona oeste da cidade de São Paulo, geograficamente em 23°3334 S e 46°4400 O. O experimento foi realizado de 15 de agosto a 16 de setembro de 2016. Foram realizadas coletas de material particulado para análise da concentração em massa de sua fração fina inalável e composição química. A distribuição de tamanho para massa de material particulado foi determinada através da coleta com um impactador em cascata. A distribuição de tamanho para número foi obtida a partir de medidas com um Scanning Mobility Particle Sampler (SMPS) com o cálculo da concentração número de partículas (PNC) para o intervalo de 9 a 450 nm de diâmetro. Para estudar as relações entre os gases presentes na região amostrada com a radiação ultravioleta e com o PNC utilizamos os valores horários de concentrações dos gases (O3, NO, NO2 e NOX) e UV medidos na Rede Telemétrica da CETESB (Companhia de Tecnologia Ambiental do Estado de São Paulo). Os filtros coletados foram analisados pela técnica de Fluorescência de Raios-X dispersivo em energia (EDX). As concentrações de Black Carbon (BC) foram obtidas por refletância. Para a determinação das fontes de material particulado fino (MP2,5) foram utilizados os seguintes modelos receptores: Análise de Componentes Principais (ACP) e Fatoração de Matriz Positiva (FMP). Para análise de dispersão do poluente, utilizamos dados meteorológicos da estação climatológica do IAG situada no Parque do Estado. A concentração média de MP2,5 foi de 18,6 (±12,5) g/m³ e a concentração média de BC foi de 1,9 (±1,5) g/m³. As principais fontes encontradas, por ambos modelos receptores ACP e FMP, foram: veículos pesados (a diesel), veículos leves, queima de biomassa, ressuspensão de poeira de solo, pavimentos e construção, processos secundários e misturas de fontes. Os elementos-traço foram definidos em diferentes modas de tamanho: Al, Ca, Si e Ti com picos nas modas de acumulação, traçadores de ressuspensão de pavimento; Fe, Mn, P, K e Cr com picos na fração mais grossa da moda de acumulação, traçadores de emissões veiculares e queima de biomassa. Cu, Zn, Br, Pb, S e BC apresentam picos na fração mais fina da moda de acumulação, traçadores de emissões veiculares e queima de biomassa.Several studies aimed to determine and characterize the atmospheric aerosol in the city of São Paulo, not only to its size and chemical composition, but as well as to find its emitting sources and mass contributions in the studied area. The atmospheric constituents were collected at the Laboratório de Análise dos Processos Atmosféricos (LAPAt) of the Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG) of the University of São Paulo (USP), located in the western zone of the city of São Paulo Paulo, geographically at 23°33\'34\"S and 46°44\'00\" W. The experiment was conducted from August 15 to September 16 of 2016. Samples of particulate matter were collected to analyze the mass concentration and chemical composition of its inhalable fine fraction. The particulate mass size distribution was determined through the collection with a cascade impactor. The number size distribution was obtained from measurements with a Scanning Mobility Particle Sampler (SMPS) with the calculated number of particle concentration (PNC) for the range of 9 to 450 nm of the diameter. In order to study the relationships among the compounds present in the region and the PNC, we used the hourly values of the gaseous concentrations (O3, NO, NO2 and NOx) and UV measured in CETESB\'s Air Quality Telemetric Network in the State of São Paulo. The sampled filters were analyzed by the energy dispersive X-ray Fluorescence (EDX) technique to determine the elemental composition. The concentrations of Black Carbon (BC) were obtained by reflectance analysis. In order to determine the sources of fine particulate matter (PM2.5), the following Receptors Models were used: Principal Component Analysis (PCA) and Positive Matrix Factorization (PMF). For air pollution dispersion analysis, we used meteorological data from the IAG climatological station located in the Southeast of the city. The mean MP2.5 concentration was 18.6 (± 12.5) g/m³ and the mean concentration of BC was 1.9 (± 1.5) g/m³ for the sampling period. The main sources found by both ACP and PMF models were heavy-duty vehicles (diesel), light-duty vehicles, biomass burning, resuspension of soil dust, pavements and construction, secondary processes and mixed sources. The trace elements were defined at different size distributions: Al, Ca, Si and Ti with peaks in accumulation fraction (related to pavement resuspension tracers); Fe, Mn, P, K and Cr with peaks in the largest fraction of accumulation mode, characteristic of vehicular emissions tracer and biomass burning. Cu, Zn, Br, Pb, S and BC presented peaks in the finer fraction of the accumulation mode, related to vehicle emissions tracer and biomass burning.
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Gutierrez, Bonilla Andres Felipe. "Maintenance Scheduling and Vehicle Routing Optimisation with Stochastic Components." Thesis, Troyes, 2018. http://www.theses.fr/2018TROY0023.
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Cette thèse est dédiée aux problèmes de tournées de véhicules stochastiques (SVRP) abordés dans un contexte de planification de tâches de maintenance. Le paradigme de solutions À Priori est choisi pour inclure les incertitudes au moment de la planification. Deux SVRP sont étudiés, d’abord le problème avec demandes stochastiques, qui est résolu par un algorithme mémétique (MA) hybridé avec une procédure de recherche adaptative randomisée. La méthode s’est montrée compétitive en comparaison à d’autres approches disponibles dans la littérature. Ensuite le SVRP avec fenêtre de temps sur le service, et temps de trajets et de services stochastiques est considéré. Un algorithme mémétique parallèle est conçu pour le résoudre efficacement. Un troisième problème traitant de l’ordonnancement de la maintenance pour un parc d’éoliennes est étudié dans cette thèse. D’abord une version déterministe et bi-objective est modélisée sous forme d’un programme linéaire à variables mixtes, puis résolue par une méthode de type epsilon contraintes. Une extension du problème sur un horizon de planification long et considérant les stratégies de maintenance est également proposée, et le problème est résolu par une méthode basée sur la simulation. Les méthodes développées mettent en évidence, pour les deux derniers problèmes, le conflit entre la minimisation des coûts de maintenance et la maximisation de la production énergétiqueThis thesis studies Stochastic Vehicle Routing Problems (SVRPs) in the context of maintenance tasks scheduling. Stochastic programming under an A Priori paradigm is used to incorporate the uncertainties. Two SVRPs are addressed, the first one deals with Stochastic Demands which is solved by a hybrid approach combining a memetic algorithm (MA) and a Greedy Randomized Adaptive Search Procedure (GRASP). The designed hybrid method is shown to be competitive compared to other published approaches. Second, the SVRP with stochastic travel and service times and hard time windows investigated. A parallel Memetic Algorithm is designed to solve efficiently this last problem. A third problem devoted to maintenance scheduling in wind farm context is also studied in this work. First the problem is formulated as a deterministic linear bicriteria mixed integer program, then an epsilon constraint is developed to solve it. An extension to a maintenance planning problem involving a long horizon is also addressed using a simulation approach. This last part also considers maintenance strategies selection. Both developed approaches show the existing conflicts between energy production maximization and maintenance costs minimization
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Filho, Luis Hanna. "Production development and automation in Brazilian autopart manufacturing." Thesis, Imperial College London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319608.
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Johnsen, Sofia, and Sarah Felldin. "Improving Knowledge of Truck Fuel Consumption Using Data Analysis." Thesis, Linköpings universitet, Reglerteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-130047.
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The large potential of big data and how it has brought value into various industries have been established in research. Since big data has such large potential if handled and analyzed in the right way, revealing information to support decision making in an organization, this thesis is conducted as a case study at an automotive manufacturer with access to large amounts of customer usage data of their vehicles. The reason for performing an analysis of this kind of data is based on the cornerstones of Total Quality Management with the end objective of increasing customer satisfaction of the concerned products or services. The case study includes a data analysis exploring how and if patterns about what affects fuel consumption can be revealed from aggregated customer usage data of trucks linked to truck applications. Based on the case study, conclusions are drawn about how a company can use this type of analysis as well as how to handle the data in order to turn it into business value. The data analysis reveals properties describing truck usage using Factor Analysis and Principal Component Analysis. Especially one property is concluded to be important as it appears in the result of both techniques. Based on these properties the trucks are clustered using k-means and Hierarchical Clustering which shows groups of trucks where the importance of the properties varies. Due to the homogeneity and complexity of the chosen data, the clusters of trucks cannot be linked to truck applications. This would require data that is more easily interpretable. Finally, the importance for fuel consumption in the clusters is explored using model estimation. A comparison of Principal Component Regression (PCR) and the two regularization techniques Lasso and Elastic Net is made. PCR results in poor models difficult to evaluate. The two regularization techniques however outperform PCR, both giving a higher and very similar explained variance. The three techniques do not show obvious similarities in the models and no conclusions can therefore be drawn concerning what is important for fuel consumption. During the data analysis many problems with the data are discovered, which are linked to managerial and technical issues of big data. This leads to for example that some of the parameters interesting for the analysis cannot be used and this is likely to have an impact on the inability to get unanimous results in the model estimations. It is also concluded that the data was not originally intended for this type of analysis of large populations, but rather for testing and engineering purposes. Nevertheless, this type of data still contains valuable information and can be used if managed in the right way. From the case study it can be concluded that in order to use the data for more advanced analysis a big-data plan is needed at a strategic level in the organization. The plan summarizes the suggested solution for the managerial issues of the big data for the organization. This plan describes how to handle the data, how the analytic models revealing the information should be designed and the tools and organizational capabilities needed to support the people using the information.
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Good, Marissa Ann. "Developing a component reuse strategy for space launch vehicles." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112486.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, in conjunction with the Leaders for Global Operations Program at MIT, 2017.Thesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management, in conjunction with the Leaders for Global Operations Program at MIT, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 84).
Launch vehicle hardware is traditionally very expensive to design, develop, produce and certify, because it must operate in extreme environments with high reliability. The result is that most hardware for NASA-funded launch vehicles is custom built to execute a specific mission on a single platform. In contrast to other industries (e.g. automotive), very few components are used across product platforms, a strategy known as reuse that has the potential to decrease the cost, schedule and risk of new product introduction. Budget constraints on NASA's next launch vehicle, the Space Launch System (SLS), brought about a desire to realize some of the benefits associated with reuse. However, the reuse strategy as employed has met limited success. This brings about the fundamental question: is there something inherently unique about launch vehicle design that prevents or limits reuse? If not are there strategies that can be implemented to realize the benefits of proactive reuse during launch vehicle design? The Boeing Company, the prime contractor of the SLS cryogenic stages, would like to develop a reuse approach as they begin work on the next phase of the SLS, the Exploration Upper Stage (EUS), to improve project affordability. To develop this approach, a case study of the Core Stage (CS) was performed to identify lessons learned, resulting in the following insights: 1. Capturing the benefits of reuse is enabled by modularity and platforms within single-vehicle architectures rather than across vehicles. The time offset between any two launch vehicles is too great (20-30 year product lifecycles) for reuse across vehicles. Furthermore, manned and unmanned vehicles carry different requirements which must be considered when evaluating the potential for shared assets. 2. Race should be defined as the baseline, rather than as an opportunity. This requires aligning incentives and architecting the organization to enforce reuse from the outset. 3. Plan for forward reuse. Consider future requirements when designing the current vehicle. Reuse will not happen by coincidence; it must be designed into the system. These insights form the basis of a reuse approach for the Exploration Upper Stage (EUS). In combination with some organization and process-based suggestions, a strategy to realize the benefits of reuse has been developed for the EUS and other future launch vehicles.
by Marissa Ann Good.
S.M.
M.B.A.
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Napier, Parhys L. "The individual contribution of automotive components to vehicle fuel consumption." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68851.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 47-51).
Fuel consumption has grown to become a major point of interest as oil reserves are depleted. The purpose of this study is to determine the key components that cause variation in the instantaneous fuel consumption of vehicles and their level of impact using an in-depth literature review of technical papers. The literature is rigorously screened using an algorithm that excluded unreliable studies by criteria defined herein. Papers that are identified using this strategy are stratified according to vehicle subsystem and component. Relationships are established between external factors and fuel consumption using linear regression models and ranked by level of importance. Results show that coolant, air conditioning, alternator, rolling resistance and lubricants have an impact on vehicle fuel consumption and its variation. More specifically, coolant flow rate, oil viscosity, ambient temperature and tire pressure are found to be significant factors to fuel economy for the automobile.
by Parhys L. Napier.
S.B.
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Jinks, Stuart. "Integrating supply chain simulation, component geometry, and unit cost estimation." Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/348807/.
Full textAbstract:
This thesis shows how utilising dynamic simulation to estimate unit costs and manufacturing resources, can aid design decisions. A framework specification is introduced that integrates Computer Aided Design (CAD), Discrete Event Simulation (DES) and Activity Based Cost (ABC) methodology. The framework aids a design team in understanding the consequences of design decisions in terms of unit cost and manufacturing resources, by returning aggregated unit cost and manufacturing based data, directly to the design team, within the design environment. Dynamic Resource Estimation System (DRES) has been developed to implement the framework and conduct two case studies based on representative aerospace components. The purpose of the first case study is to determine the benefits and applications of integrating a dynamic supply chain simulation and unit cost estimation. The second case study is used to show that the framework is capable of handling significantly different components and to highlight the effort required to implement a new component within the framework. This thesis concludes that there are three primary benefits provided by the framework, which are: firstly, the framework can accurately predict required resources to fulfil a supply chain for a specific production rate, which can be utilised by manufacturing engineers to aid production planning; secondly, the framework increases refinement of a component unit cost estimate, by including manufacturing time and dynamically determined resource requirements into an ABC cost model; and thirdly, the framework has the ability to compare multiple supply chain options and different supply chain types at the same time from component geometry.
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Lin, Shao Hua. "Multi-Physics Model of Key Components In High Efficiency Vehicle Drive." Doctoral diss., University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5971.
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Hybrid Electric Vehicles (HEVs) and Electric Vehicles (EVs) are crucial technologies for the automotive industry to meet society's demands for cleaner, more energy efficient transportation. Meeting the need to provide power which sustains HEVs and EVs is an immediate area of concern that research and development within the automotive community must address. Electric batteries and electrical motors are the key components in HEV and EV power generation and transmission, and their performance plays very important role in the overall performance of the modern high efficiency vehicles. Therefore, in this dissertation, we are motivated to study the electric batteries, interior permanent motor (IPM), in the context of modern hybrid electric/electric drive systems, from both multi-physics and system level perspectives. Electrical circuit theory, electromagnetic Finite Element Analysis (FEA), and Computational Fluid Dynamic (CFD) finite volume method will be used primarily in this work. The work has total of five parts, and they are introduced in the following.
Firstly, Battery thermal management design is critical in HEV and EV development. Accurate temperature distribution of the battery cells during vehicle operation is required for achieving optimized design. We propose a novel electrical-thermal battery modeling technique that couples a temperature dependent battery circuit model and a physics-based CFD model to meet this need. The electrical circuit model serves as a heat generation mechanism for the CFD model, and the CFD model provides the temperature distribution of the battery cells, which can also impact the heat generation of the electrical battery model. In this part of work, simulation data has been derived from the model respective to electrical performance of the battery as well as the temperature distribution simultaneously in consideration of the physical dimensions, material properties, and cooling conditions. The proposed model is validated against a battery model that couples the same electrical model with a known equivalent thermal model.
Secondly, we propose an accurate system level Foster network thermal model. The parameters of the model are extracted from step responses of the CFD battery thermal model. The Foster network model and the CFD model give the same results. The Foster network can couple with battery circuit model to form an electric-thermal battery model for system simulation.
Thirdly, IPM electric machines are important in high performance drive systems. During normal operations, irreversible demagnetization can occur due to temperature rise and various loading conditions. We investigate the performance of an IPM using 3d time stepping electromagnetic FEA considering magnet's temperature dependency. Torque, flux linkage, induced voltage, inductance and saliency of the IPM will be studied in details. Finally, we use CFD to predict the non-uniform temperature distribution of the IPM machine and the impact of this distribution on motor performance.
Fourthly, we will switch gear to investigate the IPM motor on the system level. A reduced order IPM model is proposed to consider the effect of demagnetization of permanent magnet due to temperature effect. The proposed model is validated by comparing its results to the FEA results.
Finally, a HEV is a vehicle that has both conventional mechanical (i.e. internal combustion engine) and electrical propulsion systems. The electrical powertrain is used to work with the conventional powertrain to achieve higher fuel economy and lower emissions. Computer based modeling and simulation techniques are therefore essential to help reduce the design cost and optimize system performance. Due to the complexity of hybrid vehicles, multi-domain modeling ability is preferred for both component modeling and system simulation. We present a HEV library developed using VHDL-AMS.Ph.D.
Doctorate
Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering
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Mohan, Ganesh. "A toolbox for multi-objective optimisation of low carbon powertrain topologies." Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/10292.
Full textAbstract:
Stricter regulations and evolving environmental concerns have been exerting ever-increasing pressure on the automotive industry to produce low carbon vehicles that reduce emissions. As a result, increasing numbers of alternative powertrain architectures have been released into the marketplace to address this need. However, with a myriad of possible alternative powertrain configurations, which is the most appropriate type for a given vehicle class and duty cycle? To that end, comparative analyses of powertrain configurations have been widely carried out in literature; though such analyses only considered limited types of powertrain architectures at a time. Collating the results from these literature often produced findings that were discontinuous, which made it difficult for drawing conclusions when comparing multiple types of powertrains.
The aim of this research is to propose a novel methodology that can be used by practitioners to improve the methods for comparative analyses of different types of powertrain architectures. Contrary to what has been done so far, the proposed methodology combines an optimisation algorithm with a Modular Powertrain Structure that facilitates the simultaneous approach to optimising multiple types of powertrain architectures. The contribution to science is two-folds; presenting a methodology to simultaneously select a powertrain architecture and optimise its component sizes for a given cost function, and demonstrating the use of multi-objective optimisation for identifying trade-offs between cost functions by powertrain architecture selection.
Based on the results, the sizing of the powertrain components were influenced by the power and energy requirements of the drivecycle, whereas the powertrain architecture selection was mainly driven by the autonomy range requirements, vehicle mass constraints, CO2 emissions, and powertrain costs. For multi-objective optimisation, the creation of a 3-dimentional Pareto front showed multiple solution points for the different powertrain architectures, which was inherent from the ability of the methodology to concurrently evaluate those architectures. A diverging trend was observed on this front with the increase in the autonomy range, driven primarily by variation in powertrain cost per kilometre.
Additionally, there appeared to be a trade-off in terms of electric powertrain sizing between CO2 emissions and lowest mass. This was more evident at lower autonomy ranges, where the battery efficiency was a deciding factor for CO2 emissions.
The results have demonstrated the contribution of the proposed methodology in the area of multi-objective powertrain architecture optimisation, thus addressing the aims of this research.
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Wallén, Johanna. "Modelling of Components for Conventional Car and Hybrid Electric Vehicle in Modelica." Thesis, Linköping University, Department of Electrical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2367.
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Hybrid electric vehicles have two power sources - an internal combustion engine and an electric motor. These vehicles are of great interest because they contribute to a decreasing fuel consumption and air pollution and still maintain the performance of a conventional car. Different topologies are described in this thesis and especially the series and parallel hybrid electric vehicle and Toyota Prius have been studied.
This thesis also depicts modelling of a reference car and a series hybrid electric vehicle in Modelica. When appropriate, models from the Modelica standard library have been used. Models for a manual gearbox, final drive, wheel, chassis, air drag and a driver have been developed for the reference car.
For the hybrid electric vehicle a continuously variable transmission, battery, an electric motor, fuel cut-off function for the internal combustion engine and a converter that distributes the current between generator, electric motor and internal combustion engine have been designed.
These models have been put together with models from the Modelica standard library to a reference car and a series hybrid electric vehicle which follows the NEDC driving cycle. A sketch for the parallel hybrid electric vehicle and Toyota Prius have also been made in Modelica.
Developed models have been introduced into the Modelica library VehProLib, which is a vehicle propulsion library under development by Vehicular Systems, Linköpings universitet.
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Malmqvist, Anna. "Definition of restraint components for vehicle occupant safety : Using Design of Experiments." Thesis, Linköpings universitet, Kvalitetsteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-81789.
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The Master thesis has been carried out at Autoliv B.V. & Co. KG in Dachau, which is a global automotive safety corporation. The objective of the thesis was to define component characteristics, which would reduce the load on a 5th percentile female dummy in a full frontal crash to achieve a five star in the new Euro NCAP full frontal crash test. Euro NCAP (voluntary vehicle safety rating system) tests new vehicles launched on the European market with the goal to encourage manufacturers to aim for more than the legislative minimum requirements. The safety performance of the vehicles is evaluated and rated in a star rating system where a maximum of five stars can be awarded depending on the impact on the dummy. The method Design of Experiments was used in the thesis and determined as a successful method to find an optimal component setting. The system with the 5th percentile female dummy was decided to be investigated in total nine parameters with different settings and eleven measured responses. The D-optimal design was considered as the most suitable design for the experiments since it was handling input parameters with different levels on the factors. Moreover, it was significantly reducing the number of required experiments. The D-optimal design was considered as suitable for optimization of parameters, however it was found as preferable to first execute a simple screening of the parameters to ensure that an appropriate range of the parameters had been selected. In this case a screening with Plackett Burman would have required 80% less experiments to investigate the selected range of the parameters. The two software programs, Minitab and Datalysor, were used to analyze the Design of Experiments. In the analysis, the main parameters, interactions and higher terms were identified, which significantly influenced the responses. Furthermore, regressions were evaluated and the programs strengths and weaknesses were compared. It was shown that the regressions made in Datalysor were more accurate and a better model of the reality. The reason for the better regression was because Datalysor had the possibility to remove different outliers and predictors for every regression, which was not possible in Minitab. From the regression model an optimal setting was found which fulfilled the requirements from Euro NCAP and five stars could be achieved.
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Doranga, Sushil. "Nonlinear System Identification with Applications to Durability Testing of Ground Vehicle Components." springer, 2014. http://hdl.handle.net/1993/30439.
Full textAbstract:
Presently in ground vehicle industries, conducting durability tests is an essential step to predict the life of full vehicle, subsystem and component designs. The procedure of durability testing includes measuring the data in the test track, generating the accelerated loading profiles and implementing it by using the base excited shaker table. The problem associated with the implementation is the output loading profiles measured from the shaker table deviates from the desired input loading profiles. The engineering problem associated with the implementation is due to the unknown dynamics of the test structure, such as, nonlinear stiffness and damping.
A new approach for the nonlinear system identification of continuous lightly damped system from the experimental data is presented. The new approach is based on the theory of force reconstruction, base excitation and nonlinear system identification. The methodology is verified by using the simulation example and is demonstrated by using the cantilever beam as an example.
An experimental setup is designed, fabricated and installed in order to demonstrate the proposed methodology. The experimental setup is similar to that of industrial settings but with lower power range. Several experimental case studies are carried out to demonstrate the proposed methodology. The results from the experiments are the identification of viscous damping coefficient dependent upon the displacement amplitudes and the cubic stiffness nonlinearity.
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Divecha, Avinash S. "Modelling of Hybrid Electric Vehicle Components in Modelica And Comparison with Simulink." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461244804.
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Björkblad, Anders. "Fatigue Assessment of Cast Components : Influence of Cast Defects." Doctoral thesis, KTH, Lättkonstruktioner, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9133.
Full textAbstract:
This thesis is on the fatigue assessment of cast components with special attention to defects. The primary material in view is nodular cast iron, but also cast steel is considered. However, the fatigue behaviour is in principle valid for general use on other cast metals.The first two papers is about general cast material behaviour in fatigue loading. The materials considered are a high strength alloyed cast steel and a medium strength nodular cast iron. It is concluded that cast defects is the main fatigue initiation cause and it is only in exception that the fatigue life is not ruled by fracture mechanics. The third paper is a fracture mechanics evaluation of a nodular iron cast sleeve. The analysis of the component is based on crack initiation from cast defects and low-cycle fatigue. Fracture mechanics material parameters for Paris law, c and m, are extracted for the materials considered. In paper D design quality rules for nodular cast iron based on the Swedish standard SS 11 40 60 is presented. The quality rules regard cast defects in fatigue assessments and facilitate defect-based component design. In paper E, a finite element tool that is capable to predict and calculate 3D crack propagation for embedded cracks and defects is presented. The tool is an add-on for ANSYS finite element program. In paper F, closure equations for nodular cast iron are proposed in parallel to refined fracture mechanics material data. The paper includes crack propagation at different load ratios and in different microstructures.Summarized, the thesis composes a further development of the fatigue assessment of cast components. The central role of defects in fatigue is clarified and tools are provided for fracture mechanics evaluations of defects as well as for defect based design. The quality rules are also fit for application in manufacturing and for acceptance tests, hence covering the span from design to complete product.QC 20100712
Gjutdesign
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Janowski, Nils Peter. "Targeted heating of powertrain components to improve vehicle fuel economy during warm-up." Thesis, University of Nottingham, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.605156.
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When the powertrain of a vehicle is running cold, a fuel consumption penalty is incurred overcoming the higher friction losses within the engine, transmission and differential. The investigations described in this thesis concern computational studies of a vehicle powertrain to optimize the warm-up behaviour from a cold start to achieve minimum fuel consumption by reducing the cold start penalty. The newly developed vehicle model represents a premium sector, medium sized saloon based on a Jaguar S-Type with rear wheel drive and a powertrain composed of a V6 2.71 diesel engine, a six-speed ZF 6HP26 automatic transmission and a rear differential. The formulation of a powertrain model within GT-Suite, and the use of sub-models for engine friction levels, fuel flow rates and gas-side heat transfer rates, including the effect of EGR, are described. The engine's thermal behaviour is modelled using a lumped capacity approach. A 2-mass model was adequate to describe the thermal coupling between the coolant, engine oil and the engine structure. For the gas-side heat transfer a correlation is applied that is related to a commonly used form developed by Taylor and Toong. The friction model integrated is a modified version of the Patton, Nitschke and Heywood model. The descriptions of automatic transmission and differential losses and their dependence on operating state are based on empirical maps. The model validation was based on experimental data from the testbed at the University of Nottingham, and against experimental performance data from Jaguar Cars Ltd. over the NEDC. The characteristics of heat exchangers in the coolant, oil and transmission fluid circuits have been investigated through test-bed studies. The performance of the model relative to test data illustrates the accuracy of and confidence in model predictions. Following this, the application of the model was to investigate the sensitivity and enhancement of the powertrain warm-up. First, factors influencing and improving the internal heat flows of the powertrain were investigated. Different approaches were applied to establish their effectiveness. The total fuel consumption over the NEDC was used as a measure of effectiveness. Optimisation of the internal heat flows of the powertrain through the use of a transmission cooler during the warm-up showed a positive influence on the fuel consumption. A small improvement in fuel consumption was found by using a more effective transmission cooler at a later point of the warm-up, which at the same time promoted the cabin heater performance. A vailable literature lacks the knowledge of how the coolant, engine oil, automatic transmission fluid and differential oil respond to time and magnitude of heat input. This was investigated and the information was used to develop a heating strategy for an overall powel" train improvement. The lower the heat available, the greater is the relative advantage from heating the differential oil compared to the other fluids. A clear difference was found between applying a heating strategy to a powertrain with a transmission cooler or without. The heating strategy show little sensitivity to magnitude and time and were illustrated with examples of recovered exhaust gas enthalpy and regenerative braking. For the use of a transmission cooler a clear indication is given that concentrating the heat on the differential singly or in combination is the most effective way to improve fuel economy. To heat the differential in combination the ranking for the other fluids is: engine oil, coolant and then the ATF. For a gearbox without cooling equipment the benefit of heating the gearbox oil is most favourable, followed by the differential oil and then the engine oil and coolant.
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Park, Hyungjoo. "Development of a Test System to Measure Squeak Propensity of Vehicle Underbody Components." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1592135515122287.
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Baric, Marina. "The effects of accelerated aging on optical components : Application to vehicle camera systems." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-159828.
Full textAbstract:
Companies providing products have many requirements, both from standards and customers, that they need to comply with in order to be able to sell their product. Veoneer AB is a leading automotive machine vision supplier, providing mono, stereo, night vision and driver monitoring systems consisting of both electronic, mechanical and optical components. These systems have to withstand certain environmental tests in order to assure the lifetime of the totalsystems. Since the life time is usually several years accelerated tests are used that correspond to a few weeks ormonths. The tests used at Veoneer are specified for electronic equipment and what Veoneer does not know today is ifthe accelerated environmental tests stated for electronic equipment are relevant for the optical component of the visionsystem. In this master thesis project two different accelerated environmental tests, dry and damp heat, have been chosen inorder to investigate the effect of temperature and relative humidity on the adhesive in the optical component connecting the sensor and lens. The optical components where characterized by measurement of focus position and mechanicalstrength. Different combinations of temperature and relative humidity where chosen in order to compare the effect of different stress levels but also for the purpose of deriving parameters needed for accelerated testing models such as theArrhenius, Eyring, Lawson and Peck model. Amongst the results from this thesis work is the focus shift measurement which follows the same trend as seen in previous research regarding the effect of temperature and relative humidity on adhesives. With an exponentialdistribution being seen in different directions for the respective stresses. Pull tests show a greater degradation withhigher stress levels, where one test case shows the greatest degradation. Calculations regarding activation energy and constants for models match previous research where one model, combining temperature and relative humidity, showssimilar values as found in literature. Calculations also show that standard accelerated life time tests overexpose adhesives due to calculations of test times with lower activation energies.
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Hills, Esther. "Uncertainty propagation in structural dynamics with special reference to component modal models." Thesis, University of Southampton, 2006. https://eprints.soton.ac.uk/65678/.
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Altman, Aaron. "A conceptual design methodology for low speed high altitude long endurance unmanned aerial vehicles." Thesis, Cranfield University, 2000. http://hdl.handle.net/1826/3998.
Full textAbstract:
A conceptual design methodology was produced and subsequently coded into a
Visual C++ (GUI) environment to facilitate the rapid comparison of several possible
configurations to satisfy High Altitude Long Endurance (FIALE) unmanned aircraft (UAV)
missions in the Low Speed (propeller driven aircraft) regime.
Several comparative studies were performed to verify the applicability of traditional
design methods. The traditional computational design methodologies fail in several areas
such as high aspect ratio wing weight estimation and design, low Reynolds number wing
design, high altitude engine performance, low Reynolds number drag estimation, unmanned
aircraft design, and the conceptual design of unconventional configurations. The
methodology developed for this thesis was robust enough to allow not only for
consideration of these areas of inadequacy in traditional methods, but also to allow for the
inclusion of advancements in the relevant technologies as they become more widely
available.
The following configurations were evaluated for suitability to the Low Speed HALE
UAV application: conventional, canard, twin boom, multiple fuselage (conventional or
canard), tandem wing, multiple fuselage tandem wing or flying wing configuration. The
configurations were compared on the basis of aircraft endurance for takeoff weights ranging
from 2,000 to 20,000 pounds and wing loadings ranging from 5 to 25 lbs1fe.
Initial drag estimates were made using traditional parabolic drag estimation
techniques. A more refined drag buildup was performed using a vortex lattice drag
estimation for the lift induced drag (for all lifting components) and calculated skin friction
coefficients for the parasite drag. Statistically based methods were used for other
components of drag having much smaller contributions. In addition, a statistical approach
was taken to the weight estimation of the major aircraft components. However, this
approach made comparison of alternative configurations more difficult. Thus wing bending
moments trends were evaluated and utilized in the development of weight saving values for
multiple fuselage wing weight estimation.
The comparative performance of each configuration is justified with direct reference
to the terms in the Breguet Endurance equation. Validation was performed where possible
on all modules and segments associated with the methodology, as well as for the
macroscopic results. In addition, parametric studies on endurance were performed for the
conventional configuration for geometric characteristics and operating conditions directly
and indirectly effecting the calculated endurance and generalized results presented. Finally, a
case study was performed to demonstrate this capability.
A new relation was developed for aircraft empty weight prediction, a low speed
airfoil figure of merit was proposed, and new constants were offered for UAV fuselage
length prediction. In addition, horizontal and vertical tail volume coefficients were proposed
for all of the Low Speed HALE UAV configurations considered. It was determined that the
multiple fuselage configurations showed comparatively superior endurance performance
across a range of takeoff weights, with several other configurations demonstrating marginal
endurance improvements. Finally, a highly flexible and robust computer based conceptual
design methodology was developed and validated enabling the quick comparison of a greater
number of possible configurations to satisfy a given mission for Low Speed HALE UAV's
and providing detailed drag and weight breakdown data.