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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Maintenance program developmentandImport /Export of Aircraft in USA

Takele, Teklu January 2009 (has links)
AbstractThis thesis discuss how United Parcel Service (UPS) develop its aircraft maintenanceprogram after import of McDonnell Douglas MD-11aircraft and the process of exporting newMD-11 aircraft from manufacturer in USA to European operator as passenger aircraft. It alsodiscusses the process of importing the same types of aircraft as freight carrier. The aircraftundergo, through different modifications at Singapore Technologies Aerospace (STA)conversion from passenger to freight carrier, a program specially designed for UPS airlinesbefore import to USA.The thesis work was carried out in close communication with the maintenance department atUPS in California and Kentucky, McDonnell Douglas manufacturing plant in Missouri and atBoeing in Washington.The aim of this thesis was to examine and discuss the rules and regulation of import andexports of aircraft in U.S. based on UPS import of MD-11 aircraft. Furthermore, to discussthe transformation of maintenance program from one airline to another, with emphasis onhow U.S. operator develop their maintenance program.McDonnell Douglas manufactures MD-11 aircraft, and as aircraft manufacturing companythey must comply with the United States of America Federal aviation regulation part 21requirements. Besides that, the company has bilateral agreement with the buying countrySwitzerland, facilitating the reciprocal airworthiness certification of civil aeronauticalproducts exported between the two parties. Bilateral airworthiness agreement or aviationsafety agreement with implementation procedure for airworthiness facilitate the airworthinesstechnical cooperation between the Federal Aviation Administration (FAA) and its counterpartSwitzerland Civil Aviation Authorities (SCAA).UPS buy MD-11 aircraft after being modified as freight carriers. In order to obtainairworthiness certification from FAA UPS and Boeing secures that the aircraft is airworthyand have got appropriate overall maintenance service through a careful investigation processof the technical history and background of the aircraft. After receiving the FAA certificateUPS in cooperation with Boeing develop the maintenance program, before the aircraft isassigned for service in the UPS fleet.During my work it has been difficult to find information about the technical history of theaircraft, mainly because the first operator Swissair became bankrupt and all documentationwas transferred to Boeing and then to UPS. There were also many companies involved in theprocess of converting passenger aircraft to freight carrier, like ST Aero Subsidiary, Sasco inSingapore and Boeing.The work can be used as a reference to check what part of FAA deals and documents areneeded for import and export of aircraft, and what should be done to start the import andexport process. It guides the reader to an immediate understanding of regulatory organizationand their particular departments or part numbers.
22

Non-linear finite element dynamic analysis of tapered hollow steel poles for passive base isolation

Le, Tri. January 2008 (has links)
Thesis (Ph.D.) -- University of Texas at Arlington, 2008.
23

The intrinsic stress field near a crack tip

Yaksh, Michael Clifton 05 1900 (has links)
No description available.
24

Topology and dimensional synthesis of linkage mechanism based on the constrained superposition method

Chen, Wei-Ju. January 2008 (has links)
Thesis (M.S.)--Rutgers University, 2008. / "Graduate Program in Mechanical and Aerospace Engineering." Includes bibliographical references (p. 80-81).
25

Stress paths for compacted soil during collapse due to wetting

Maswoswe, Justice January 1985 (has links)
No description available.
26

Micromechanics of deformation in short fiber or whisker-reinforced metal matrix composites

Kim, Hong Gun 01 January 1992 (has links)
The objective of this dissertation is to provide, for a fiber reinforced MMC, an understanding of the evolution of strains as a result of thermo-mechanical loadings and the relationship of the deformation evolution to microstructural factors. Both analytical and finite element approaches were used to predict global and local properties. The analytical approach involved rigorous modifications to the shear-lag model to account for fiber end effects. It was demonstrated that the modification not only results in a correct prediction of the modulus increases in the small aspect ratio regime, but is also able to correctly predict the values of local stress variations in the matrix and whisker. The elasto-plastic behavior of the composite including fiber/fiber interactions was investigated in detail. Cyclic stress-strain hysteresis and Bauschinger effect due to the presence of fibers was also analyzed. It was found that plastic constraint generates a triaxiality in the matrix and so gives a substantial increase of fiber axial stress and an elevation of composite flow stress. Detailed deformation evolution was evaluated both under monotonic and fatigue conditions. Role of thermal residual stresses due to thermal mismatch in MMCs were investigated using the thermo-elasto-plastic FEA with temperature dependent matrix properties. It was found that the spatial distribution of the residual stresses during cooling is sensitive to constraint effects. The evolution of the "caging" plasticity surrounding fibers during cooling including the shape and size of the plastic zones were determined. While FEA solutions give good results, the application of FEA to composites requires careful attention to the geometry of the optimum mesh used in the analysis. The optimization strategy was based on an error energy norm calculation for global convergence and traction differential approach for local convergence at the fiber/matrix interface. It was shown that this optimization approach provides the optimum mesh with a much more rapid convergence than conventional automatic codes. The mesh patterns generated are also shown to be significantly different from using this approach. A converged local property values can be obtained using a significantly lower degree of freedom than by conventional methods.
27

Response of liquid storage tanks with soil-structure interaction and uplift effect

Ma, Lun 01 January 1990 (has links)
This dissertation presents the analytical and numerical investigation of the response of a slab-supported liquid storage tank taking into account soil-structure interaction and nonlinear uplift effect. The dissertation consists of two parts. In the first part, a generalized approach based on the variational principle is developed to analyze the dynamic response of liquid storage tanks taking into account soil-structure interaction. Two types of tank movements are studied: (i) a liquid storage tank on a deformable soil undergoing lateral and rocking motion; (ii) a liquid storage tank on a deformable soil subjected to a vertical excitation. Also in this part of the analysis, governing equations for the liquid sloshing motion in a flexible tank are derived in a concise form. Examples with various properties are presented for the two types of tank movements to illustrate the significant effects of soil-structure interaction. Comprehensive numerical data are also presented which may be used readily in design applications. The second part studies the nonlinear uplift behavior of a liquid storage tank from its rigid supporting slab under static loadings. In this part of the study, the nonlinear large deflexion plate theory is used to model the tank bottom plate while, for simplicity, the linear shell theory is used for describing the tank shell. To describe the uplift behavior of the bottom plate, a set of nonlinear differential equations and the corresponding boundary conditions for the plate are derived using the variational principle. According to the interface conditions between the tank shell and the bottom plate, a complete nonlinear boundary value problem is defined for the uplifting tank system. An approximate solution procedure based on the Ritz method is developed for such an uplifting tank system. An example is also provided to show the tank performance during its uplifting.
28

Design av snöskoter

Reldin, Marcus, Lenninger, Thomas January 2007 (has links)
<p>Detta examensarbete på C-nivå behandlar design av en snöskoter. Uppdragsgivaren är företaget SnoWolverine som vill utveckla en snöskoter med tre drivband varav två placerade i fronten.</p><p>Den omfattande informationsinsamling som har skett under arbetets gång har visat att en trebandad skoter, som har utmärkt framkomlighet, har en stor marknad. De lösningar som finns på marknaden, främst fyrhjuling med bandsats, har alla kompromisser.</p><p>Produktutvecklingsverktyg som funktionsanalys och QFD har använts i processen. Stort fokus har legat på utveckling av formspråket för snöskoter och utvecklingen av smarta funktioner som efterfrågas av målgruppen.</p><p>Resultatet är en kraftfull snöskoter med ett kompakt utseende. Främre boggin är gjord så utrymmessparande som möjligt och designad för att vara robust. Unika funktioner är bland annat en vindtunnel som fungerar som vindruta, frontbåge med vinschfäste, utfällbar sadel och förvaringslösningar.</p>
29

Norrman, Christian January 2008 (has links)
<p>Examensarbetet är utfört i samarbete med företaget Mil Tech i Västerås. Arbetet har gått ut på att konvertera en redan existerande turbojetmotor med dragkraft på 110 Newton till en turboaxelmotor där effekten tas ut via en axel. Konverteringen av turbojetmotorn till en turboaxelmotor sker genom att konstruera en modul bestående av ett friturbinsteg som fästes på turbojetmotorn. Arbetets fokus har legat på att få en lättillverkad och enkel moduluppbyggt friturbinsteg som med få medel kan fästas direkt på turbojetmotorns utloppsdel utan att behöva modifiera turbojetmotorn. Det moduluppbyggda friturbinsteget innehåller alla de mekaniska detaljer som gör en konvertering från turbojetdrift till turboaxeldrift möjlig. Arbetet har inletts med att ta fram termodynamiska beräkningar för att avgöra motorns prestanda och motorns fysikaliska krav på design, konstruktion, material och hållfasthet. Examensarbetet innehåller solidmodeller samt konstruktionsritningar som gör det möjligt att utifrån detta bygga en fungerande friturbinmodul.</p>
30

Tillämpning av FRTP Heater

Ngo, Nhu Phuc, Matevossian, David January 2010 (has links)
<p>Detta examensarbete som är på avancerad nivå handlar om ett samarbete med företaget Calesco Foil AB. Målet med arbetet är att ta fram nya användningsområden för deras befintliga produkt FRTP Heater (Fiber Reinforced Thermoplastic Heater). Det är en patenterad produkt som är ett värmegivande folie laminerat med glasfibrer. Det vi gjort är en produktframtagning med företagets FRTP Heater integrerad med en lampa som tillsammans bildar ett innovativt värmeelement. Detta har gjorts med fokus på företagets produkt egenskaper.Vi har använt oss av olika produktutvecklingsverktyg för att sammanställa och utveckla arbetet. En marknadsundersökning har utförts för att kollat vilka konkurrenter det finns ute på marknaden. Vi har använt oss av CAD programmet SolidWorks för att kunna visualisera våra modeller i 3D och samtidigt ta fram tekniskt ritunderlag för dessa. Det har dokumenterats och förklarats utförligt i denna tekniska rapport. Vi har tagit fram två olika koncept och valt att utveckla en av dem till en fungerande prototyp modell.</p>

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