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Dissertations / Theses on the topic 'Weald'

Author: Grafiati

Published: 4 June 2021

Last updated: 25 January 2023

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1

Evans, Andrew Timothy. "Pollen studies on recent sediments in the western Weald." Thesis, King's College London (University of London), 1991. https://kclpure.kcl.ac.uk/portal/en/theses/pollen-studies-on-recent-sediments-in-the-western-weald(18152655-86b6-41ad-a2ba-4a28c10fed65).html.

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2

Everard, David Alexander. "Composition, structure and processes along woodland gradients in the Weald." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385319.

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3

Clark, Colin Jeremy. "The glass industry in the woodland economy of the Weald." Thesis, University of Sheffield, 2007. http://etheses.whiterose.ac.uk/15153/.

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4

Bagg, Janet. "Social relations in the Kentish Weald : a computer aided historical study." Thesis, University of Kent, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305055.

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5

Kaminski, Jaime. "The environmental implications of Romano-British iron production in the Weald." Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242399.

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6

Gardiner, Mark Francis. "Medieval settlement and society in the eastern Sussex Weald before 1420." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434871.

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7

Higgs, Karen E. "A geochemical and diagenetic study of the Lower Greensand, Weald Basin." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358174.

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8

Wilkes, Michael. "Basin plumbing dynamics : modelling fluid flow in the Weald Basin, Southern England." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357275.

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9

Adams, Marcus John. "The hydrogeology and hydrogeochemistry of the Lower Greensand in the Western Weald, U.K." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393840.

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10

Allen, Barbara Janet. "The acquisition and practice of working-class literacy in the nineteenth-century Sussex Weald." Thesis, University of Sussex, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426287.

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11

Cole, James M. "The palynology, palynofacies and palaeoenvironment of the Early Cretaceous Weald Clay of Southeast England." Thesis, London Metropolitan University, 1987. http://repository.londonmet.ac.uk/2941/.

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12

Kirk, Jayne Claudia. "The supply and utilisation of vernacular building timber in the rural Sussex Weald 1500-1800." Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368497.

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13

Bohnet, Iris Cacilia. "Exploring landscape character : a socio-ecological analysis in the High Weald Area of Outstanding Natural Beauty." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247818.

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14

Shabestari, Gholamreza Mirab. "Diagenesis and reservoir properties of the Great Oolite Formation (Middle Jurassic), Weald Basin, south of England." Thesis, University of Liverpool, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433035.

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15

Lockwood, Carol Anne. "The changing use of land in the Weald region of Kent, Surrey, and Sussex, 1919-1939." Thesis, University of Sussex, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267937.

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16

Kitzel, Mary E. "Chasing ancestors : searching for the roots of American Sign Language in the Kentish Weald, 1620-1851." Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/48877/.

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Late twentieth-century discourses regarding deaf people and sign language provide the theoretical background for investigating early modern families with hereditary deafness within the Kentish Weald. The first of its kind, this thesis described the methods used to ascertain the presence of sufficient numbers of networked deaf people to maintain natural sign language. A source-driven work, it began with two data sources - a list generated by previous American genealogical research of the first known European-American deaf families originating from seventeenth-century Kent and the 1851 Census of Great Britain, a previously unexplored resource of the first attempt to fully enumerate deaf people in Britain. This thesis was based on an analysis of primary documentation and a critical reading of previous primary and secondary sources seeking to connect the two initial sources. Its framework was predicated on a stance that acknowledges and values deaf culture and its embodied performed manifestation, sign language. Examining the discourses surrounding deaf people throughout the period, it relied upon the concepts of representation, individual identity, and group identity to query the existence of a deaf group identity predating the labels used to describe it.

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17

Chester-Kadwell, Brendan. "A sense of place in rural settlement : a locally orientated study of the Huntingdonshire Ouse Valley and the Eastern High Weald." Thesis, University of East Anglia, 2010. https://ueaeprints.uea.ac.uk/32167/.

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18

Abbott, Sunshine. "Depositional architecture and facies variability in anhydrite and polyhalite sequences : a multi-scale study of the Jurassic (Weald Basin, Brightling Mine) and Permian (Zechstein Basin, Boulby Mine) of the UK." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/45720.

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Quantifying the geometries of evaporite deposits at a <1 km scale is critical in our understanding of similar ancient depositional systems, but is challenging given evaporite mineral dissolution at surface conditions. Two high-resolution stratigraphic studies in mines provide insight into the geometries, dimensions, and spatial distributions of sedimentary bodies in 3-D at a <1-km scale in evaporites. A field mapping study was conducted in Brightling (Purbeck Group) and Boulby (Zechstein Group) mines, in southeast and northeast England, respectively. This is integrated with XRD, petrography, and δ13C and δ18O isotope analyses. The evolution and conditions of sedimentation during the Tithonian in the Weald Basin is also evaluated. A newly defined megasequence boundary at the base of the Purbeck Group is suggested to mark the onset of rifting of the Bay of Biscay and to the north of the Charlie-Gibbs Fracture Zone, which implies an earlier rifting phase than previously proposed. Basal Purbeck lateral facies changes are influenced by the position in the Weald Basin, normal fault systems, and relative sea level changes. In Brightling Mine, the basal Purbeck exhibits carbonate-evaporite shoaling upward cycles, likely controlled by localized high-frequency relative sea level changes and/or sabkha hydrology. The dynamic process of evaporite deposition led to subtle stratigraphic heterogeneities and changes in bed thicknesses, but largely continuous lateral bedding. Boulby Mine offers a unique opportunity to study early deformation structures in ancient polyhalite that formed in playa conditions. The controlling mechanism that formed these syndepositional polyhalite tepees is attributed to soft sediment deformation via polyhalite dewatering coupled with penecontemporaneous precipitation of halite during fluid escape. This study offers new insight into the types of heterogeneity observed in ancient evaporites formed in marginal playa and sabkha environments at a < 1 km-scale, which can include a variety of compositions and morphologies at a range of scales.

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19

Elliott, Simon. "Change and continuity in the exploitation of natural resources (such as stone, iron, clay and wood) in the principal areas of industrial activity in Kent (namely the Weald, Folkestone region and upper Medway Valley) during the Roman occupation." Thesis, University of Kent, 2017. https://kar.kent.ac.uk/61960/.

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Kent was a key component of Roman Britain, featuring aspects it held in common with the rest of this north-western fringe of Empire, but also elements unique to the region. With economic activity for much of the occupation concentrated in three specific areas - the industrial zone of the Weald, a region ranging from Canterbury to Folkestone on the Channel coast, and the upper Medway Valley - the area covered by the modern county was particularly important for the exploitation of natural resources. These included ferrous-ores for iron production in the Weald, greensands for quern production around Folkestone and ragstone quarrying in the upper Medway Valley (the latter providing much of the building stone used in the occupation-period South East). This study brings together a wide range of research findings to present a picture of the economic use and associated organisation of this landscape. The study shows there to have been a hitherto unrecognized depth of economic exploitation, demonstrated by the variety of evidence types assembled in these pages. These activities had an important role within the Imperial, commercial and personal agendas of the time, with the thesis aiming to address the question of how and why these enterprises were brought into being in the area of Kent, and their links to wider spheres within the Empire. Establishing the details of change and continuity regarding this exploitation provides a unique insight into the narrative of Roman Britain. It also allows some specific themes and theories to be explored, informing our wider knowledge of the occupation. These include the concept of the region as being more militarised than a 'normal' civitas, the links between elite settlement, individual agency and industry, the changing balance of importance between industry and agriculture, and what remained of Romanitas in Kent at the end of the occupation.

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20

Tsiagbe, Walter Yao. "Relaxation of weld residual stresses by post-weld heat treatment." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385842.

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21

Sharma, Saurabh. "WELD FOR ITANIUM PROCESSOR." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-11182002-120028/.

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This dissertation extends a WELD for Itanium processors. Emre Özer presented WELD architecture in his Ph.D. thesis. WELD integrates multithreading support into an Itanium processor to hide run-time latency effects that cannot be determined by the compiler. Also, it proposes a hardware technique called operation welding that merges operations from different threads to utilize the hardware resources. Hardware contexts such as program counters and the fetch units are duplicated to support for multithreading. The experimental results show that Dual-thread WELD attains a maximum of 11% speedup as compared to single-threaded Itanium architecture while still maintaining the hardware simplicity of the EPIC architecture.

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22

Sapountzakis, Dimitrios. "Weld penetration control system." Thesis, University of Liverpool, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428243.

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23

Boote, Luke B. "Weld inspection process improvement." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111485.

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Thesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management, in conjunction with the Leaders for Global Operations Program at MIT, 2017.
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, in conjunction with the Leaders for Global Operations Program at MIT, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 61-62).
This project addressed challenges within the weld inspection process in one factory at Caterpillar through the implementation of phased array ultrasonic testing. The chosen factory fabricates and machines large weldments for track-type tractors. The industry trend towards lighter weight, lower cost, higher performance structures requires greater confidence in weld quality than can currently be ensured with existing inspection methods in use at Caterpillar. Previous attempts to implement phased array technology in production factories at Caterpillar were unsuccessful due to the perceived costs of the technology, a lack of training, a lack of internal standards, and a lack of a change agent. The first step in the project began with understanding the current state of weld inspections. This was accomplished through factory visits, as well as interviews with -vendors and Caterpillar's non-destructive evaluation community. Statistical analysis of quality data was conducted to understand current welding and inspection performance. This revealed several problems with the process that led to inaccurate inspection results and unnecessary factory rework. Next, the project identified a pilot case to introduce the phased array technology. After acquiring the necessary phased array equipment, a robust, repeatable, cost effective process was developed where data is stored, and can be recalled and used to improve quality and future designs. Necessary fixtures were prototyped and tested to demonstrate the value of implementation. The implementation phase focused on training the operators to use the new equipment and procedures while still ensuring that the quality of parts released downstream was not compromised. The final phase of the implementation validated the quality of the inspection data and focused on improving the speed and safety of the phased array ultrasonic inspections. This project integrated phased array ultrasonic testing into a factory and provided a framework for Caterpillar to continue to develop and deploy this technology across the enterprise. By identifying and solving gaps in the technology rollout process in collaboration with Caterpillar's non-destructive evaluation community, this project created positive change in the culture and execution of how improvements are made to weld inspection processes.
by Luke B. Boote.
M.B.A.
S.M.

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24

Andersson, Filip, and Rhodel Bengtsson. "Spot-Weld Fatigue Optimization." Thesis, KTH, Hållfasthetslära (Avd.), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232529.

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The purpose of this thesis project is to develop a methodology that can be used to minimize the number of spot-welds in a mechanical structure, this is done in a reliable manner via optimization methods. The optimization considers fatigue life in spot-welds and also stiffness and eigenfrequency values. The ﬁrst chapter of this thesis presents a spot-weld fatigue model proposed by Rupp (1995), common FEmodels of spot-welds and also important aspects about structural optimization in general. The second chapter further describes how topology optimization and size (parameter) optimization are applied on a simple multi-weld model with respect to the aforementioned structural constraints. The topology optimization is later used on a full-size car model, while the size optimization is used to optimize the multiweld model by adding an non-linear structural constraint - a crash indentation constraint. The spot-weld fatigue model proposed by Rupp (1995), is also veriﬁed by comparing FE results using different FE-models of spot-welds compared to fatigue data by Long and Khanna (2007). Both optimization methods successfully minimize the total amount of spot-welds on the multi-weld model. The topology optimization,accompanied with thegradient based MFD algorithm,minimizes th etotal spot-welds with around 15% and 3% on the multi-weld model and car body respectively. The size optimization, using design of experiments and response surfaces, manage storeduce the number of welds in the multi-weldmodel by 25%. However, with the size optimization the computational time is several orders of magnitude longer-even without the formulation of the crash constraint. The fatiguespot-weld model fares reasonably well compared to the experimental fatigue data, regardless of the FE model of the spot-weld. It is concluded that the ACM model would be recommended based on its compatibility with fatigue and optimization methods, mesh-independence and also other studies have shown its ability to represent stiffness and eigenfrequency correctly.

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25

Cavanough, Gary L. "Automated weld quality monitoring." Thesis, Queensland University of Technology, 1994.

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26

Cool, Tracey. "Design of steel weld deposits." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248809.

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27

Bruce, N. B. "Computer prediction of weld performance." Thesis, Swansea University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636165.

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The aim of the current PhD project was to develop a user friendly PC based software system (SNAP, Simplex based Numerical Analysis Package), to aid in the prediction of weld performance from process variables, utilising experimental data and mathematical expressions inputted by the user. The modelling and quantification of materials data using numerically optimized mathematical functions is an important and widespread practice. In this thesis the development of robust and exploratory data analysis strategies based on exploratory data analysis procedures and robust statistics is described. Application of this new PC based data analysis system to four sets of established data which relate materials information to process variables demonstrates the advantages of a comprehensive and robust approach to analysis. The advantages of techniques that use both goodness of fit and also predictive statistical criteria for mathematical/statistical models are described.

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28

Deekhunthod, Rujira Ninni. "Weld Quality in Aluminium Alloys." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-226136.

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The aims of this project are to present an understanding in what happens when aluminium-(Al) alloys are welded, and to investigate how the Mg-, Si- and Cr-contents in AA6005A influence the weld strength and cracking susceptibility. It is known that heat from welding affects the mechanical properties (strength) of the material. Different heat cycles during welding are one of the main reasons that the strength varies. Welding can cause various phenomena such as decreased strength, porosity, deformation, cracks and corrosion. To minimize these phenomena one has to have a balance between the welding parameters, alloy composition and welding fixture setup. Al alloys are sensitive to heat from welding because they have high heat conductivity and high thermal expansion coefficient. They also deform easily when the material is heated locally. If the material is deformed too much then cracking easily occurs. This project has examined how the Mg-, Si- and Cr-contents in AA6005A, affect the welded material. A V-joint with MIG welding is used for producing weld samples. For evaluation Vickers micro-hardness, tensile testing, radiography (X-ray), LOM and SEM with EBSD and EDS was used. The evaluation focuses on mechanical properties and microstructure. The results show that small variations of Mg-, Si- and Cr-content do not have any clear effects on the welded material. The results from tensile testing show that all samples have failed in the heat affected zone (HAZ). The tensile strength of all samples are higher than standard but the yield strength are lower than standard (EN ISO 10042:2005). The lowering in hardness and tensile strength in the HAZ are believed to be a result from beta-phase (AlFeSi), lead to transformation and coarsening of the strengthening and metastable precipitate. The HAZ is wide, ranging about 20 mm from the fusion line in 5 mm thick plate. The microstructure evaluation has shown that the grain size in the HAZ has been influenced while welding. The EDS analysis shows that a small amount of AlFeSi particles occur in the base material and HAZ but not in the weld seam. Future research is suggested to focus on understanding more about ageing, coarsening of beta-phase and precipitation of intermetallic phases.

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29

Stone, David Andrew. "Frontface monitoring of weld penetration." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329510.

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30

Ainscough, D. M. "Automatic control of weld penetration." Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234822.

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31

Hultgren, Gustav. "Assessment of fatigue for laser-scanned weld surfaces : Correlation between weld geometry and fatigue initiation." Thesis, KTH, Hållfasthetslära (Avd.), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-259518.

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The work conducted in this project proposes a method to determine the location of fracture initiation for non-load carrying fillet welds based on continuous geometry measurements. Measurements were carried out on welded specimens using a laser line triangluator together with the weld quality evaluation software qWeld from Winteria®. The 119 specimens produced were after scanning fatigue tested until failure. The fracture surfaces have been investigated in order to find the most probable location(s) of fracture initiation. This data was then used to fit the proposed model parameters used to analytically predict the point(s) of fracture initiation. Local weld geometry measurements were extracted from the predicted fracture initiation location(s) in an effort to analyse the correlation between local weld geometry and fatigue life. This showed that fatigue life and leg length were positively correlated and that strong correlations exists between the individual geometrical parameters. New specimens were produced to test the fitted data of the proposed model, this data was however inconclusive as the new specimens had a high ratio of weld defects.
Arbetet i detta projekt föreslår en metod för att bestämma punkten/punkterna för sprickinitiering för icke-lastbärande kälsvetsar baserat på kontinuerliga mätmetoder. Mätningar utfördes på svetsade prover med hjälp av en laserlinjetriangluator tillsammans med utvärderingsprogrammet qWeld från Winteria®. De 119 provstavar som producerades testades efter mätningarna med en cyklisk belastning till de gick till brott. Brottytorna undersöktes sedan för att hitta platsen/platserna för de mest sannolika startpunkterna. Dessa punkter användes sedan för att passa de föreslagna modellparametrarna som användes för att förutsäga startpunkten. Lokal svetsgeometri extraherades från de förutsagda sprickinitieringsplatserna i ett försök att analysera korrelationen mellan lokal svetsgeometri och antalet cykler till brott. Detta visade att antalet cykler och katetlängden var positivt korrelerade och att det finns starka korrelationer mellan de enskilda geometriska parametrarna. Nya provbitar framställdes för att testa de anpassade parametrarna i den framtagna metoden, dessa gav dock inga tydliga resultat då en hög andel svetsdefekter upptäcktes efter att de provats.

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32

Norton, Seth Jason. "Ferrous friction stir weld physical simulation." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1143252009.

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33

Mitchell, K. C. "Weld repair of steam turbine rotors." Thesis, Swansea University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638208.

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Turbine rotors are among the most critical and highly stressed components in steam power plants. Although relatively few instances of catastrophic rotor bursts have occurred, they have resulted in lengthy forced outages and severe economic penalties to the affected utilities. To forestall the possibility of a catastrophic burst, utilities will retire the rotors affected, generally to the original equipment manufacturer's (OEM's) recommendations. The criteria and methodology for determining which rotors should be retired are proprietary and vary among manufacturers. If utilities could extend the life of these rotors by 10-20 years, then substantial savings would be made. The principal method for extending their life is weld repair and over the last 20 years, there has been a substantial increase in the number of repairs combined with the complexity of repair adopted. This project was designed to evaluate the relationship between microstructure and properties of welds on ex-service steam turbine rotor steels, after applying appropriate welding parameters and weld bead deposition sequence to minimise heat input and produce acceptable microstructures. From the project work, it is clear that the LP, IP and HP ex-service rotor forgings selected were representative of UK manufactured rotor forgings. Although never intended for weld repair, NP have demonstrated their ability to repair these steels successfully and produce weldments with acceptable microstructures and mechanical properties.

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34

Terry, P. B. "An optical automated weld profile monitor." Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233828.

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35

Berg, Michael C. Ph D. Massachusetts Institute of Technology. "Biological applications of weal polyelectrolyte multilayers." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33599.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2005.
Includes bibliographical references.
This thesis research focused on biological applications of ultra-thin weak polyelectrolyte multilayers with specific emphasis on cell patterning, drug delivery, and antibacterial coatings. All of these very different applications were studied using three different polymers - polyacrylic acid (PAA), poly(allylamine hydrochloride) (PAH), polyacrylamide (PAAm). The first part of this thesis focuses on patterning polyelectrolyte multilayers found to resist mammalian cell adhesion, with ligands that promote specific interactions for adhesion. It was found that by patterning PAH on polyelectrolyte multilayers, the patterned functional group density and thickness could be tuned through ink pH adjustment. By changing the surface density of amine groups in the PAH patterns, the ligand density could also be altered using specific chemistry to attach peptides containing the tri-peptide sequence, RGD, which is known to promote cell adhesion in a number of cell types. The RGD density in the patterned regions determined the number of cells attached and the amount of cytoskeletal protein organization. The second part is an evaluation of porous polyelectrolyte multilayers as a delivery system for controlled release of small molecule drugs. The loading and releasing properties of porous PAH/PAA multilayers were investigated using the two drugs, ketoprofen and cytochalasin D. It was determined that the amount of drug released was proportional to the number of porous layers. Nanoporous films showed zero-order release, whereas microporous films displayed Fickian diffusion. The efficacy of the released drugs was checked by monitoring the effect of released cytochalasin D on fibroblasts' division.
(cont.) In the final part of this thesis, the antibacterial properties of both silver-loaded polyelectrolyte multilayers and superhydrophobic multilayers are examined. It was found that silver loaded multilayers killed bacteria to an extent greater than 99.99% for both airborne and waterborne models. Superhydrophobic films showed excellent anti-fouling properties for proteins, mammalian cells, and bacteria.
by Michael C. Berg.
Ph.D.

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36

Farson, Dave F. "Control of arc weld thermal cycles." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1387446228.

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37

Gu, Maoshi Carleton University Dissertation Engineering Mechanical. "Computational weld analysis for long welds." Ottawa, 1992.

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38

Eriksson, Inger. "Methods for automatic inspection of weld geometry." Thesis, University West, Department of Engineering Science, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-720.

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The earlier in the production chain discontinuities in the weld area are discovered the better and less expensive it is to modify the weld. If the weld is bigger than necessary the cost and the weight grow, and if the weld is undersized the strength is put at risk. This report contains a summary of a literature survey for finding means for optical measurements of weld geometry. Some of the articles are about existing devices that can measure welds. One is hand-held and is applied on the weld afterwards and compares the data with pre set parameters. Experiments were performed with two different systems to evaluate their capability to capture the weld geometry. The first system is an in - house built system with a laser line diode and a CMOS - camera, the other system is scanCONTROL, and is a device with integrated camera and laser line. Matlab was used to process and analyse data from both systems. Experiments with the first system ended when it was quite obvious that it did not meet the expected result. The laser line projection was too short to cover enough of the weld area and it was hard to process the image to find defects in the weld area. The data from the scanCONTROL system was ready to use and it was quite easy to find different defects and discontinuities in the weld area. It is possible to find the geometry of the weld and it is possible to find defects like spatter, undercut and sharp edges, with laser line projection and camera. The equipment is important in order to extract data useful for analysis.

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39

Lindén, Mattias J. "Optimization of Weld Nut Geometry by Simulation." Thesis, KTH, Industriell produktion, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-49776.

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This project covers resistance projectionwelding of HP weld nuts and simulationsof these weld nuts welded to Dogal(350YP, 600DP, 800DP) and HyTens1000. When the simulation results werecompared to results in the previous report,Resistance Nut Welding of High StrengthSteel, it showed that the simulations ofHPM8 weld nuts were more accurate thenthe HPM6 simulations.Comparison HPM8 weld nut welded againstDogal 600DPTherefore projection geometry of theHPM8 weld nuts was selected foroptimisation in this project. Most of thesimulation results were insufficient but insome of the evaluated cases a satisfactoryweld zone was developed.These geometries were manufactured byturning (modifying) existing weld nuts andthen welded with an MFDC weldingmachine. Cross-sections of these weld nutswere compared to the simulation results.These results showed differences in thefusion zone between simulated results andwelding results. The differences were moreconnected to which base material that wasindicates problems in the material modelsComparisons optimized weld nuts of HPM8 typewelded against Dogal 600DP and HyTens 1000Mechanical testing in terms of pull-out andtorsion tests were also carried out. Themaximum pull-out loads were notsignificantly changed compared to theoriginal design. The torsion test methodthat was used was insufficient. The HPweld nuts joint were too strong to be testedwith manual tools and must be tested withmachine testing as a report done by RezaKhezri suggests.The simulation programme that wasevaluated, SORPAS version 9.0 and 9.8,showed to be an insufficient tool forevaluating and optimisation of nutwelding.

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Sugden, Alastair Allen Brockbank. "Towards the prediction of weld metal properties." Thesis, University of Cambridge, 1989. https://www.repository.cam.ac.uk/handle/1810/221892.

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Kaur, Aman P. "Electron beam diagnosis for weld quality assurance." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/13436.

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Electron beam welding is used for fabricating critical components for the aerospace and nuclear industries which demand high quality. The cost of materials and associated processes of fabrication is also very high. Therefore, manufacturing processes in these industries are highly controlled. However, it has been found that even minor changes in the electron beam gun itself can produce large variations in beam characteristics, leading to unpredictable welding performance. Hence, it is very important to ensure the beam quality prior to carrying out welds. This requires some kind of device and process to characterise the electron beam to indicate variations. A detailed review of different technologies used to develop devices to characterise electron beams has been carried out. At this time, it is uncommon for beam measurement to be carried out on production EBW equipment. Research carried out for this thesis is focused on development of a novel approach to characterise the electron beams using a slit-probe to maintain the quality of the welds. The challenge lies in deriving relevant features from the acquired probe signal which can effectively differentiate between the beams of different quality. Wavelet transformation, with its advantages over other methods for simultaneous time and frequency localization of signals, has found its application to feature extraction in many pattern based classifications. This technique has been used to analyse probe signals considering that different quality beams will possess unique signal profiles in the form of their distribution of energies with respect to frequency and time. To achieve the aim of the thesis, an experimental approach was used by carrying out melt runs on Ti-6Al-4V plates focusing on aerospace requirements, and varying beam properties and acquiring probe signals for all beam settings. Extracted features from the probe signals have been used in classification of the electron beams to ensure these will produce welds within the tolerance limits specified by aerospace standards for quality assurance. The features vector was compiled following statistical analysis to find the significant beam characteristics. By analysing the performance of classifier for different combination of parameters of the features vector, the optimum classification rate of 89.8% was achieved by using the parameters derived from wavelet coefficients for different decomposition levels. This work showed that the use of wavelet analysis and classification using features vectors enabled identification of beams that would produce welds out-of-tolerance. Keywords: Electron beam welding, probe devices, electron beam characterisation, quality assurance, wavelet transform, features vector, linear discriminant classifier, weld profiles, weld defects.

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Roberts, D. R. "Ultrasonic spot weld testing with automatic classification." Thesis, Swansea University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638690.

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Spot welds are used to join sheet steel in automobile bodies. To ensure vehicle integrity, these welds, must be tested. Ideally, non-destructive testing would be employed. However, spot weld quality in the automotive industry is currently assessed using destructive methods. Spot welds can be tested non-destructively with ultrasound. Operators place a single crystal ultrasonic probe on a weld and interpret the returning signal to estimate the quality of the weld. However, this ultrasonic method has not been widely accepted in the past, possibly due to difficulties in manually quantifying the information contained in the signals. In an attempt to make ultrasonic testing viable for automotive use, a system has been created which automatically interprets the ultrasonic signals and classifies welds as good or bad. There are two main aspects to the systems. Firstly, echoes occurring within the signal are identified by an algorithm. This was developed after discovering the sequence in which the critical intermediate echoes occur. The second aspect of the system is classification of the spot weld based upon certain features of the identified echoes. The strength of the intermediate echoes was found to be primary source of information on weld size. Extensive experimental studies were designed and conducted to identify other potential information sources. Notably, the attenuation rate of the back-wall echoes in the signal was investigated. Most published papers in the field report that signal attenuation may be used to estimate weld size. It has been generally believed that the grain structure of the welded steel significantly increases ultrasound scattering, leading to higher attenuation is not caused by weld grain structure. The evidence gathered strongly favours weld surface irregularities as the primary cause of ultrasound attenuation in spot welds.

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Birrell, L. "Mathematical modelling of flash butt weld failure." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596660.

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The work described in this thesis details the investigation into flash butt weld failure at Corus, Port Talbot, where the process is used to join coils of steel, permitting cold rolling without interruption. The aim of this work was to examine the factors which constitute weld failure and to determine whether failure could be eliminated. It was shown that weld failure cannot be predicted with appreciable levels of confidence with the use of neural networks based on inputs such as steel composition and the thickness and width of the coils to be joined. 817 weld breaks were recorded during 2006, of which all but two were observed during cold rolling. Analysis of the samples provided indicate that in some case the term weld break was incorrectly used to describe what was in fact failure in the base material, away from the joint. Prior to this work there were no reported data on the residual stress levels generated after flash butt welding of sheet steel with a thickness of 2.5 mm. It is now clear that in addition to the expected tensile stress in the weld, there is also a compressive stress of up to 200 MPa in the base material which extends far beyond the heat-affected zone. This result may go someway to explain why failure in the base material is observed outside the heat-affected zone during cold rolling. Finally, a post-weld heat treatment for a high hardening boron-steel was examined. The heat treatment was intended to supersede previous attempts to reduce the post-weld cooling rate by applying a voltage across the weld to locally heat the region to a desired temperature.

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Espinosa, Daniel C. "Visualization of gas tungsten arc weld pools." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/28643.

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McRobie, D. E. "Cleavage fracture in C-Mn weld metals." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355272.

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Henwood, Cynthia E. (Cynthia Elsie) Carleton University Dissertation Engineering Mechanical. "An analytical model for computing weld microstructures." Ottawa, 1987.

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Dettmering, Dennis L. "Wausau/Mosinee Papers weld training Rhinelander, Wisconsin." Online version, 2001. http://www.uwstout.edu/lib/thesis/2001/2001dettmeringd.pdf.

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Ohlsson, Simon. "IGSCC in weld with high ferrite content." Thesis, KTH, Fysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-252691.

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Krakovský, Andrej. "Analýza způsobů modelování procesu svařování metodou konečných prvků." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-400469.

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Presented master thesis deals with computational modelling (simulation) of welding process. Its main goal is to determine the residual stresses and deformations arising after welding. SYSWELD and ANSYS are used for simulation, both based on the finite element method. Specifically, the processes of welding fillet and butt welds are solved. Results from both software are compared with each other and verified by experimental results.

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rudow, matthew. "Effect of Oxidation on Weld Strengthof Dissimilar Resistance Weld Interface Between 304 Stainless Steeland Near Equiatomic Austenitic Nitinol Guide Wire." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/855.

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Abbott Vascular encountered strength and variability issues when attempting to resistively weld 304 Stainless Steel to equiatomic Nitinol. Initial observations suggested that passivation layer (Cr2O3, TiO2) formation affected the weld interface. One hundred 304 Stainless Steel/Nitinol pairs were allowed to oxidize in air at room temperature for allowed periods of time (.1, 1, 3, 5, 7, 12, 16, 24, 168, and 336 hours). Each pair was welded resistively with constant current. A Miyachi/Unitek Advanced Data Analysis Monitor (ADAM) recorded the peak resistance at the instance the weld was made. Resistances were compared to Instron 5900 tensile maximum break load (KgF). Use of optical microscopy and Scanning Electron Microscopy (SEM) revealed microstructural reduction of void size at the sample fracture surface (1-.5 µm). Literature suggested the existence of metastable precipitate forms at near equiatomic compositions within the theoretical temperature range (261.9-1425.2 0C). The Instron 5900 mechanically validated presence of precipitates, while Electron Dispersive X-Ray Spectroscopy (EDS) confirmed the existence compositionally. Literature confirms B19’ precipitates size increases with temperature. This suggests higher resistance samples will promote growth of precipitates due to increased heat input. Increased average particle size was observed with increased resistance (0-.3 µm). Crystal lattice inconsistencies between Nitinol parent phase (B2) and B19’ promote premature fracture due to increased misfit dislocation density. Therefore increased weld resistance promotes the growth of incoherent Ti3Ni4 precipitates which inhibit load bearing capabilities, causing premature failure.

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