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1
Eagles, Graeme. « Modelling plate kinematics in the Scotia Sea ». Thesis, University of Leeds, 2000. http://etheses.whiterose.ac.uk/258/.
Texte intégralRésumé :
A new model of plate kinematics in the Scotia Sea region is presented in which continental crustal blocks and the signatures of seafloor spreading are defined semi-automatically using gravity and total field magnetic anomalies and some of their residuals, transformations and derivatives. This study is the first of the region to integrate gridded magnetic and gravity data in order to make reconstructions, and one of the first anywhere to make full use of gridded magnetic data in an inverse procedure. The context provided by the quantitative reconstructions allows qualitative assessment of visually-derived reconstructions of small movements in the region. The Scotia Sea floor consists of three large oceanic magnetic provinces: the west,central and east Scotia seas, and four smaller sub-basins, all enclosed within the elevated submarine and emergent Scotia Arc. The Scotia Arc consists of Mesozoic continental and Cenozoic island-arc fragments. Only the east Scotia Sea remains active; the west and central parts are the products of extinct spreading centres. West Scotia sea spreading is reasonably well described by tectonic flowlines expressed in satellite free-air gravity anomalies and magnetic reversal isochrons in total field anomalies. These data are combined in an inversion to reconstruct the west Scotia Sea's margins between its inception at thron C8 (- 26.5 Ma) and extinction at chron C3a (- 6 Ma). The results suggest strongly, and for the first time, that the west Scotia Sea formed as a small ocean basin whose passive margins were Tierra del Fuego and the central Scotia Sea, and not as a back-arc basin in the strict sense. During its growth the kinematics of the west Scotia Sea's margins approximated those of the South American and Antarctic plates. The small kinematic differences are suggested to be due to convergence at the `proto-South Sandwich-Discovery' subduction zone, to the east of the central Scotia Sea, and to dextral strike-slip (pre-C6 (N 20 Ma)) and oblique convergence (post-C6) at the North Scotia Ridge, the Mesozoic northern arm of the Scotia Arc. The most widely-accepted interpretations of the central Scotia Sea hold that it is a back-arc basin, but model flowlines about published reconstruction poles in the region show that instead it could have originated by accretion to the South American plate at the ancestral South American-Antarctic Ridge in the Weddell Sea, later to move eastwards as the eastern passive margin to the west Scotia Sea. Magnetic reversal anomalies in the central Scotia Sea are consistent with its accretion in this way during the Cretaceous, probably between chrons M4 and M20 (- 126-149 Ma). All of this material was hitherto thought to have been destroyed completely by subduction at the ancestors of the South Sandwich subduction zone. The central Scotia Sea is thus also re-assigned in the model to have an oceanic, rather than back-arc basin, origin. Hence, the bulk of the Scotia Sea floor formed as a consequence of the predictable movements of major plates following the break-up of Gondwana, with back-arc basins in the strict sense only forming small subbasins until the inception of the east Scotia Sea at or soon after C5c. The development of this much larger, oceanic, back-arc basin occurred following a change in the direction of relative motion at the West Scotia and South American-Antarctic Ridges at C6. This new model of Scotia Sea kinematics, presented as a series of reconstructions of total field and Bouguer anomalies, is the first to be both self-consistent and consistent within the context of known major plate motions. The new interpretation of the central Scotia Sea is at odds with previous reconstructions which place South Georgia in the heart of a reconstructed compact connection between Tierra del Fuego and the Antarctic Peninsula. The altered position of South Georgia, south of Maurice Ewing Bank (Falkland Plateau) helps explain the puzzling provenance of its turbidites and suggests, as previous workers have done, that it may be appropriate to redefine the genesis of at least the eastern part of the Rocas Verdes Basin as an oceanic basin formed by accretion at a propagating rift, rather than (as before) a rare example of a back-arc basin formed behind an east-directed subduction zone. Although the new model is self-consistent, it is not uniquely so for two of the small basins in the Scotia Sea (Protector and Dove Basins) whose age remains poorly defined.It can be speculated that either or both of these basins may have opened deep-water gateways in the Drake Passage region prior to spreading in the west Scotia Sea, possibly in the Middle Eocene. A very tentative correlation between such events and initial cooling prior to the onset of Antarctic glaciation, via the cooling effect of establishing an efficient Antarctic Circumpolar Current, is suggested.
2
Le, Thi Huyen Cham. « Robust variable kinematics plate finite elements for composite structures ». Thesis, Paris 10, 2019. http://faraway.parisnanterre.fr/login?url=http://bdr.parisnanterre.fr/theses/intranet/2019/2019PA100053/2019PA100053.pdf.
Texte intégralRésumé :
Le but de ce travail est de développer deux nouveaux éléments finis quadrilatéraux à quatre et à huit nœuds implantés dans le code commercial de calcul par Eléments Finis (EF) Abaqus pour plaques composites. Les modèles plaques à cinématique variable sont formulés dans le cadre de la formulation unifiée de Carrera (CUF), qui regroupent des descriptions de type: couche équivalente (ESL) et couches discrètes (LW), avec les variables définies par des polynômes jusqu’au 4ème ordre suivant épaisseur z. Les deux formulations variationnelles sont utilisées pour dériver les matrices des éléments finis: le Principe des Déplacements Virtuels (PVD) et le Théorème Variationnel Mixte de Reissner (RMVT). Grâce à la technique de condensation statique, une formulation hybride basée sur le RMVT est introduite. Afin d’éliminer la pathologie de verrouillage en cisaillement transverse, deux approximations compatibles pour le champ de déformations de cisaillement transverse indépendantes en z, notée QC4 et CL8, sont étendues aux éléments plaques à cinématique variable basés sur CUF. De plus, les QC4S et CL8S interpolations sont également introduites pour les contraintes de cisaillement transverse dans les éléments mixtes et les éléments hybrides. Les résultats numériques comparés à ceux disponibles dans la littérature montrent que les FE proposés sont efficaces pour modéliser des éléments finis robustesThe aim of this work is the development of two classes of new four-node and eightnode quadrilateral finite elements implemented into the commercial finite element (FE) code Abaqus for composite plates. Variable kinematics plate models are formulated in the framework of Carrera’s Unified Formulation (CUF), which encompasses Equivalent Single Layer (ESL) as well as Layer-Wise (LW) models, with the variables that are defined by polynomials up to 4th order along the thickness direction z. The two classes refer to two variational formulations that are employed to derive the finite elements matrices, namely the Principle of Virtual Displacement (PVD) and Reissner’s Mixed Variational Theorem (RMVT). Thanks to the static condensation technique, a Hybrid formulation based on the RMVT is derived. For the purpose of eliminating the shear locking pathology, two field compatible approximations for only the z−constant transverse shear strain terms, referred to as QC4 and CL8 interpolations, are extended to all variable kinematics CUF plate elements. Moreover, the QC4S and CL8S interpolations, are also introduced for the transverse shear stress field within RMVT-based and Hybrid mixed-based elements. Numerical results in comparison with those available in literature show that the proposed FEs are efficient for modeling a robust finite elements
3
Huggins, Paul. « Relay zones in intra-continental normal faults : geometry, mechanics and kinematics ». Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309975.
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4
Zahirovic, Sabin. « Post-Pangea global plate kinematics and geodynamic implications for Southeast Asia ». Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/13327.
Texte intégralRésumé :
Modern plate reconstructions, with evolving plate boundaries that document the breakup of Pangea hold vital clues for the factors affecting plate motions. Previous studies have evaluated the present-day plate arrangements and velocities, and therefore cannot capture the inherent plate behaviour over deep geological time. A handful of studies have used plate reconstructions to alleviate these temporal shortcomings, but have been limited by the small number of plate reconstruction timesteps, leading to conflicting suggestions that continents may both inhibit or promote fast plate motions. This thesis demonstrates that increasing portions of continental plate area significantly reduces plate velocities when using a post-Pangea plate reconstruction framework. However, plates with large continents exhibit short-lived (~5-10 Myr) but high-amplitude anomalous accelerations that are often related to plume head arrivals. The breakup of Pangea opened the vast Atlantic, Indian and Southern Oceans at the expense of the equatorial oceanic gateway that linked the Tethys and (proto-) Pacific. Refined reconstructions of this lost oceanic gateway, in the absence of preserved oceanic crust, required a synthesis of geological data from the continents that travelled on these now-subducted plates. By coupling the refined plate reconstructions to numerical mantle flow simulations, this thesis demonstrates that the short-lived (~10-15 Myr) subduction hiatus from the accretion of continental blocks at ~80 Ma along southern Sundaland resulted in ~200 m of dynamic uplift of the continental promontory, which was likely responsible for the enigmatic Late Cretaceous to Paleocene regional unconformity. The approaches presented in this thesis highlight the need for data-driven global plate reconstructions, coupled to geodynamic simulations of mantle flow in a global spherical mantle shell, to study both the global plate-mantle system but also address regional geological enigmas.
5
Magnavita, Luciano Portugal. « Geometry and kinematics of the Reconcavo-Tucano-Jatoba Rift, NE Brazil ». Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305625.
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6
Fay, Noah Patrick. « Kinematics and dynamics of the Pacific-North American plate boundary in the western United States / ». view abstract or download file of text, 2006. http://proquest.umi.com/pqdweb?did=1280144291&sid=2&Fmt=2&clientId=11238&RQT=309&VName=PQD.
Texte intégralRésumé :
Thesis (Ph. D.)--University of Oregon, 2006.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 118-140). Also available for download via the World Wide Web; free to University of Oregon users.
7
Thomas, David William. « Tectonic evolution and kinematics of the Mesozoic Rift System, U.K. northern North Sea ». Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338697.
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8
Powell, Ceri M. « Positive and negative inversion tectonics : the geometries and kinematics of reactivated fault systems ». Thesis, Cardiff University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306111.
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9
Dooley, Timothy Paul. « Geometries and kinematics of strike-slip fault systems : insights from physical modelling and field studies ». Thesis, Royal Holloway, University of London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296655.
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10
Di, Giuseppe Erika. « Dynamics of subduction and implications for plate kinematics : insights from numerical and laboratory models / ». Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17833.
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11
Cembrano, José. « Kinematics and timing of intra-arc deformation at the southern Andes plate boundary zone ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0017/NQ49249.pdf.
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12
Cole, Gregory Lawrence. « Models of plate kinematics along the western margin of the Americas : Cretaceous to present ». Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185048.
Texte intégralRésumé :
We provide a realistic assessment of the uncertainties associated with plate reconstructions by creating empirical probability density functions (PDFs) for rotations between plate pairs based upon uncertainties in the positions of observed fracture zone and magnetic anomaly crossings. We determine the PDF for a sequence of rotations through Monte Carlo sampling of the PDFs for these plate pairs. We assign confidence limits within PDFs and find that worst-case uncertainty regions for global reconstruction poles can be twice as large as 95% confidence regions. We illustrate our technique with the anomaly 6 rotation between the Pacific and North American plates and demonstrate that realistic uncertainties for summations of rotations are apt to be significantly smaller than those previously predicted by earlier techniques. We develop revised apparent polar wander paths for the North American and Pacific plates through paleomagnetic Euler pole analysis. We determine motions of the Pacific plate within the hotspot reference frame for the past 80 Ma through a similar analysis and extend the model back to 145 Ma through study of anomalous basement depths and application of the paleomagnetic constraints. The match between the paleomagnetic and hotspot reference frames within uncertainty limits imposed by the available data, contradicts the notion of true polar wander during the late Cretaceous and/or motion between distinct Pacific plates. Applying realistic limits on the expected error in global plate reconstructions, we determine that either the South Atlantic hotspot track is improperly defined, or that there has been more than 1,000 kilometers of relative motion between the Pacific and South Atlantic hotspots since 80 Ma. Our model of plate interactions for the western Americas indicates subduction perpendicular to the margins from 78 Ma to 33 Ma. Northward transpression and transport of allochthonous terranes is limited to regions north of the evolving Pacific-Izanagi (Kula) ridge. We present a series of reconstructions which allows quantification of subduction and lateral transport along the margins. We model the generation of possible oceanic plateaus by known hotspots in the Pacific region and find little evidence to indicate that their subduction had an impact on the magmatic history of North America.
13
Plattner, Christina. « Dynamic implications of Baja California microplate kinematics on the North America - Pacific plate boundary region ». Diss., kostenfrei, 2009. http://edoc.ub.uni-muenchen.de/10275/.
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14
Viñas, Gaza Marina. « Tectonic structure and formation kinematics of the Western Mediterranean basins ». Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/401563.
Texte intégralRésumé :
In this work we present a geophysical study of three Western Mediterranean basins: Valencia Trough, Gulf of Lions and Algero-Balearic Basin. The work aims to define the tectonic structure, nature of the basement, and to discuss the age, kinematics and mechanisms involved in basin formation. To study the basins we have gathered all deep penetrating seismic data available in the region consisting on several academic and industry data reprocessed and interpreted for this work.
To study the Valencia Trough Basin structure, we reprocessed from field data the 400 km-long multichannel seismic line ESCI-Valencia acquired in 1992 by Geco-Prakla’s survey vessel M.V. Bin Hai supported by the Spanish “Plan Nacional de I+D” with reference projects GEO89-0858 and GEO90-0733. We reprocessed the stack of the 170 km-long VALSIS-819 multichannel seismic line acquired in 1988 by the Lamont- Doherty Earth Observatory Research Vessel (R/V) Robert D. Conrad. We have also interpreted an industry seismic grid SGV01 acquired in 2001 by the Fugro-Geoteam vessel R.V. Geo Baltic.
To study the Gulf of Lions Basin formation we interpreted an industry dataset SPBAL01 acquired in 2001 by Spectrum Energy with the Polar Princes vessel. Some amount of post-migration cosmetic processing was done on some of the lines of this data set for presentation purposes.
To study the tectonic structure of the Algero-Balearic Basin we processed a 97 km- long multichannel seismic line TOPOMED-26 acquired by our group and with my participation in 2011 on-board the Spanish R/V Sarmiento de Gamboa. In order to discuss the nature of the basement of the Algero-Balearic Basin, we also used the Vp model of the wide-angle seismic profile P03 from the WESTMED project. Moreover we have done “mirror imaging” with Ocean Bottom Seismometers along line P04 of WESTMED, and integrated the results of line ESCI-Valencia across the south-Balearic margin.
The analysis, processing and interpretation of all this dataset allows us to a novel interpretation of a series of aspects regarding the structure and nature of the crust, and to discuss some new proposals for the tectonic processes that have led to the current configuration of the main Western Mediterranean basins.
Seismic interpretation of the Valencia Trough reveals that this basin is possibly floored by continental crust and it is possibly the oldest Western Mediterranean basin. Contrary
to what it is typically interpreted; we propose that the present day configuration of the Valencia Trough is strongly dominated by the tectonic activity of Mesozoic structures. During Mesozoic times occurred the greatest thinning of the crust yielding a minimum crustal thickness of ~4.5 km under the Columbretes Basin (SW Valencia Trough). Multichannel seismic sections show that the main tectonic structures are Mesozoic in age and reveal that the Neogene extensional event is very limited comparatively and has had a minor influence in the formation of the current crustal structure of the Valencia Trough. We also found no evidence of any relevant crustal thickening during Paleogene times. Thus our interpretation supports that the extension leading to the crustal configuration of the Valencia Trough was largely formed during Mesozoic times.
Interpretation of a grid of multichannel seismic profiles in the Gulf of Lions supports the existence of three geological domains that are: 1) a continental domain formed by normal faults that tilted the continental basement with syn-rift sediment infill. 2) a ~100 km wide transition domain between continental and clear oceanic domain, characterized by a thin anomalous layer with high velocity (7.5 km s-1) that has been debated in the literature and that we interpret as exhumed and serpentinized mantle peridotite and 3) an oceanic domain characterized by thin oceanic crust (~5 km) with little evidence of important faulting.
Multichannel seismic results from Algero-Balearic Basin have been complemented with information provided by a Vp wide-angle tomographic model coincident with one of the seismic reflection lines. A comparison of depth-velocity profiles of the tomographic model with existing 1D velocity-depth compilations of continental and oceanic crust (e.g. White et al., 1992; Christensen and Mooney, 1995) gives clues on the nature of the basement. The results reveal the existence of three main geological and geophysical domains: 1) a continental domain, with little evidence of faulted and tilted blocks (which are common features on extensional margins), although the vertical velocity structure matches well the Vp compilation for continental crust (Christensen and Mooney, 1995). The Vp data, seismic images and previous works on the region available in literature support abundant magmatism (with volcanism) during extension of soon after. 2) A narrow continent-ocean domain with vertical velocities neither typically continental crust nor oceanic crust and 3) a clear oceanic domain characterized by 6 km thick oceanic crust, with a vertical velocity gradient of oceanic layer 2 and 3, even though in this case formed in a back-arc context.
A new kinematic model for the opening of the Western Mediterranean basins is beyond the scope of our work, and requires integration with other datasets from
Tyrrhenian and Alboran Basins, and an extended study of the West Sardinia and Corsica margins. Also, to advance in such model, it requires a detailed reconstruction of submarine volcanic activity, imaged in the seismic data in all three basins but inadequately studied in available literature. Nonetheless, the results of this work should be considered in the future for new reconstructions that we propose need to be reviewed.Aquesta tesi té com a objectiu descriure l’estructura tectònica i la naturalesa del basament de les principals conques de la Mediterrània occidental: Solc de València, Golf de Lleó i conca algerina-balear i discutir l’edat i els mecanismes de formació que han donat lloc a la configuració actual. Per això, s’han utilitzat tot un seguit de dades geofísiques tant d’indústria com acadèmiques. S’ha dut a terme el processat i la interpretació de diversos perfils de sísmica multicanal situats a l’àrea d’estudi i la interpretació de dos perfils de sísmica de gran angle de la conca algerina-balear. A més a més, en aquest cas s’ha utilitzat una nova tècnica coneguda com “Mirror Imaging” per a processar el senyal dels múltiples en sísmica de gran angle i que dona uns resultats equiparables als de sísmica multicanal. La interpretació sísmica dels diferents perfils mostra com el Solc de València presenta un basament de naturalesa continental al llarg de tota la conca i com la seva configuració està lligada als processos i les estructures que van tenir lloc durant el Mesozoic. Per altre banda, la interpretació sísmica dels perfils situats al Golf de Lleó han permès definir el límit entre 3 dominis amb un tipus de naturalesa del basament diferent: 1) Domini continental, 2) domini de transició entre escorça continental i oceànica i 3) Domini oceànic. Finalment, la interpretació dels resultats de sísmica multicanal de la conca algerina-balear juntament amb un estudi exhaustiu de les velocitats obtingudes a través de la tomografia de gran angle a permès comparar el model de velocitats obtingut per aquets zona amb els models de referència per escorça continental (Christensen and Mooney, 1995) i escorça oceànica (White et al., 1992), definint així 3 dominis diferents: 1) Domini continental, 2) domini de transició entre escorça continental i escorça oceànica i 3) domini oceànic. Els resultats obtinguts en aquesta tesi intenten donar resposta a diverses qüestions encara obertes avui en dia, com son l’edat d’obertura de les diferents conques i la cinemàtica que ha donat lloc a llur formació, així com discutir la validesa dels diferents models establerts per a la formació de les conques de rere arc a la Mediterrània occidental.
15
Sturmer, Daniel Murray. « Geometry and kinematics of the Olinghouse fault zone : role of left-lateral faulting in the right-lateral Walker Lane, western Nevada / ». abstract and full text PDF (free order & ; download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1447806.
Texte intégralRésumé :
Thesis (M.S.)--University of Nevada, Reno, 2007."May, 2007." One colored map on folded leaf in pocket. Includes bibliographical references (leaves 103-117). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2007]. 1 microfilm reel ; 35 mm.
16
Oral, M. Burc. « Global Positioning System (GPS) measurements in Turkey (1988-1992) : kinematics of the African-Arabia-Eurasia plate collision zone ». Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/58251.
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Nicol, Andrew. « Structural styles and kinematics of deformation on the edge of the New Zealand plate boundary zone, mid-Waipara region, North Canterbury ». Thesis, University of Canterbury. Geology, 1991. http://hdl.handle.net/10092/4971.
Texte intégralRésumé :
In North Canterbury, on the SE edge of the New Zealand plate boundary zone, deformation in late Cretaceous and younger cover rocks is complex. Detailed mapping of the cover sequence (which is about 1 km. thick), has revealed a pattern of synchronous faulting and folding about orthogonal
E-ESE and N-NNE orientations younger than early Pleistocene.
Complex and irregular basin and dome fold interference patterns are defined by distinctive limestone marker horizons, and partial star, triangular and corrugated hose fold surface geometries (defined by structure contours) are common. These geometries are often associated with folds that vary in shape along their hinge line and secondary folds developed oblique to the main interfering fold sets. Fold interference geometries are also characterised by composite conical geometries, composed of several distinct cone segments.
Folding in the cover sequence has developed in response to: (1) fault propagation and displacement in the basement; and, (2) shortening within the fault bounded blocks. The folds related to faulting are asymmetric and parallel the major faults. Fold amplitudes of 0.5-1.6 km. are proportional to vertical fault displacements, and wavelengths of 5-20 km. are approximately equal to the strike-normal distances between the major faults. Fold interference patterns are indicative of the styles and levels of activity of the orthogonal faulting.
Analysis of fault and slickenside striation geometries suggests that faulting is dominated by oblique-reverse faults and thrusts, which verge north, south, east and west. Interspersed with the regional contractional faulting are, local areas of E-ESE oblique-normal faults, inferred to be reactivated late Cretaceous structures. Computed stress tensors derived from minor fault motion data suggest that the principal stress axes most commonly plunge at shallow to moderate angles. Locally they have variable orientations but regionally these data imply a predominant NW-SE compression, comparable to local geodetic shortening and focal mechanism compression directions.
Geometric and spatial analysis of large numbers of sets of small scale, mainly brittle structures, documents the local history of deformation. Multiple joint, pressure solution seam and stylolite, macrofracture and mesofault sets record only two periods of deformation since the mid-Cenozoic. The first was a weak regional mid-late Oligocene compression; the second involving a NW-SE compression since the Pliocene. Post Pliocene deformation is characterised by initial NW-SE shortening, followed by approximate N-S and E-W shortening associated with folding. The sequence of structural development during the late Pliocene and Pleistocene implies a progressive increase in the intensity of deformation and a rapid widening of the plate boundary zone during the last 2-3 ma.
The mainly contractional deformation in North Canterbury, commonly associated with thrusting to the NW, is distinct from the major right-lateral and eastward directed thrust tectonics in Marlborough. This not only reflects a difference between inner and outer plate boundary deformation, but also the diminishing influence of subduction related tectonics.
18
Hochmuth, Katharina [Verfasser], Karsten [Akademischer Betreuer] Gohl, Wilfried [Gutachter] Jokat et Wolfgang [Gutachter] Bach. « From crustal structure to plate kinematics : the role of Large Igneous Provinces in the Pacific Ocean / Katharina Hochmuth. Betreuer : Karsten Gohl. Gutachter : Wilfried Jokat ; Wolfgang Bach ». Bremen : Staats- und Universitätsbibliothek Bremen, 2016. http://d-nb.info/1106374487/34.
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Cuffaro, Marco. « Plate Kinematic Models ». Doctoral thesis, La Sapienza, 2007. http://hdl.handle.net/11573/917380.
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Merdith, Andrew. « Kinematic Plate Models of the Neoproterozoic ». Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/17715.
Texte intégralRésumé :
Plate tectonic reconstructions traditionally use a combination of palaeomagnetic and geological data to model the changing positions of continents throughout Earth history. Plate reconstructions are particularly useful because they provide a framework for testing a range of hypotheses pertaining to climate, seawater chemistry, evolutionary patterns and the relationship between mantle and surface. During the Mesozoic and Cenozoic these are underpinned by data from the ocean basins that preserve relative plate motions, and data from hotspot chains and tomographic imaging of subducted slabs within the mantle to constrain absolute plate motions. For earlier times, neither ocean basins nor subducted slabs are preserved to assist with constructing plate models. Previously published plate models are usually built around times that have high quality palaeomagnetic data and between these times, the motion of continental crust is usually interpolated. Alternatively, regional tectonic models are developed predominantly from using geological data but without integrating the model into a global context. Additionally, until now all global plate models for the Neoproterozoic model only describe the configurations of continental blocks and do not explicitly consider the spatial and temporal evolution of plate boundaries. In this thesis, I present the first topological plate model of the Neoproterozoic that traces the dynamic evolution and interaction of tectonic plates, which encompass the entire earth. This model synthesises new geological and palaeomagnetic data, along with conclusions drawn from kinematic data to help discriminate competing continental configurations of the western area of the Neoproterozoic supercontinent, Rodinia. The thesis concludes by analysing the supercontinent cycle from 1000 to 0 Ma, by extracting the rift length, subduction zone length and perimeter-to-area ratio of continental crust to better understand the long-term evolution of our planet.
21
Pandit, Hemant Govind. « Sagittal plane kinematics after knee arthroplasty ». Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510203.
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Agresta, Cristine. « THE INFLUENCE OF THE BACK FUNCTIONAL LINE ON LOWER EXTREMITY FRONTAL PLANE KINEMATICS AND KINEMATIC PREDICTORS OF LOADING DURING RUNNING ». Diss., Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/309569.
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Physical TherapyPh.D.
Running injuries have been linked to poor lower extremity dynamic alignment, increased whole body and joint loading, and insufficient modulation of stiffness throughout stance phase. Upper body muscle activity and movement have a relationship to lower body dynamics; however, the literature has largely neglected their role during running. To date, biomechanical gait analysis has primarily focused on lower extremity mechanics and muscle activation patterns with no studies investigating the role of functional muscle synergies on stability and loading during running. Therefore, the primary objective of this project is to determine the role of the Back Functional Line (BFL), via measure of latissimus dorsi (LD), gluteus maximus (GM), and vastus lateralis (VL) muscle activity, during running and to determine their influence on lower extremity kinematics and kinematic predictors of loading that are linked to running-related injuries (RRI). We used conditions of arm swing constraint to manipulate the action of the LD and investigate the response in GM and VL muscles. Our main variables of interest include: 1) BFL muscle activity, specifically mean and peak amplitude, onset, and co-activation of the LD and GM 2) frontal plane lower extremity kinematics, and 3) kinematic predictors of kinetics, specifically foot inclination angle at initial contact and vertical COM displacement. Twenty healthy recreational runners (10 M; 10 F) participated in this study. Male runners tended to be slighter older with a higher weekly running mileage and longer running history. All participants were between the ages of 18 and 55 years old and consistently ran at least once per week. Participants ran under three arm conditions - free arm swing, unilateral arm swing constraint, and bilateral arm swing constraint. During the running trials, surface EMG and lower extremity kinematics were collected over the gait cycle. We operationally defined the primary BFL as the muscle synergy composed of the non-dominant upper extremity (i.e., constrained side during unilateral condition) LD muscle, the dominant GM muscle, and the dominant VL muscle. The secondary BFL was defined as the dominant upper extremity (i.e., unconstrained during unilateral condition) LD muscle, the non-dominant GM muscle, and the non-dominant VL muscle. Primary and secondary BFL muscle synergy activity were analyzed during two specific phases of gait - the pre-activation (PA) phase and the loading response (LR) phase. In support of the hypothesis, the primary BFL LD mean amplitude decreased during both the PA and LR phases of gait. GM and VL muscle mean amplitude demonstrated a varied response. During the PA phase, both the GM and VL muscles increased during the unilateral condition and decreased during the bilateral condition. During LR phase, GM and VL muscles increased during both arm swing constraint conditions. The highest increase in amplitude was seen during the unilateral condition. Peak amplitudes for each muscle did not change dramatically across conditions for either the PA or LR phases of gait. Secondary BFL LD and GM mean and peak amplitude increased during both the PA and LR phases of gait, with changes during the LR phase reaching significance for both muscles. Secondary BFL VL also increased in mean and peak amplitude during the bilateral constraint condition. GM and VL mean and peak muscle amplitude were significantly correlated during the LR phase, but not for the PA phase. This indicates that the lower extremity muscles of the BFL (GM and VL) may not be preparing for impact similarly but are adjusting muscle activity in a similar fashion as the lower limb is loaded. The increase in muscle amplitude for secondary BFL muscles, particularly during the LR phase of gait, may have resulted from a difference between lower limb strength or lower extremity single leg stability. Onset of muscle activity during loading response did not significantly differ across conditions for the LD, GM, or VL muscles, however, analysis of co-activation demonstrated that LD and GM were in-phase throughout the gait cycle. This suggests that this portion of the BFL may be acting together to stabilize the lumbopelvic-hip complex (LPHC) during running. LD and GM appeared to be co-activated throughout the gait cycle regardless of arm swing variation. Instability, either from asymmetrical movement patterns or poor single leg stability may contribute to the activation of the BFL muscle synergy. GM increased during the unilateral arm swing constraint during both phase and for both BFL synergies, indicating that asymmetrical movement patterns may induce a potential instability or an unstable state requiring the need for greater stability around the LPHC. Knee frontal plane kinematics changed significantly across conditions. Knee abduction angle showed the greatest increase during the unilateral arm swing constraint condition suggesting that asymmetrical movement patterns effect lower extremity mechanics more so than symmetrical patterns (i.e., bilateral arm swing restriction or free arm swing). Hip adduction and contralateral pelvic drop angles did not differ significantly across conditions. Our study did not find a significant relationship between BFL muscle activity and knee abduction angles. Participants demonstrated larger knee abduction angles on their non-dominant limb at midstance. The corresponding (secondary) BFL LD and GM demonstrated a significant increase during the LR phase. This may indicate that BFL muscle activity is engaged when the need for lower limb stability is greater, either due to poor single leg dynamic control or abnormal frontal plane mechanics. Kinematic predictors of joint and whole-body loading differed across conditions. Vertical COM displacement was significantly decreased during the bilateral arm swing constraint condition. Foot inclination angle at initial contact did not significantly change with arm swing constraint. Differences were found between right and left lower extremity foot strikes (i.e., foot inclination angle) across all conditions; the non-dominant limb demonstrated greater plantarflexion during initial contact. Knee flexion angle at initial contact and peak knee flexion during stance did not demonstrate a significant change. Muscle activity was not significantly correlated to kinematic predictors. Spatiotemporal measures altered with arm swing suppression. Stride length decreased and step rate increased significantly. Taken together, these results suggest that runners alter spatiotemporal measures more so than sagittal plane kinematics when adjusting to arm swing suppression. The role of the BFL muscle synergy during running remains unclear. Asymmetrical movement patterns and arm swing restriction appear to influence BFL muscle activity and lower extremity kinematics. Single leg stability, particularly during the LR phase, may alter BFL muscle activity due to the need for increased stabilization of the loaded limb and the LPHC. Future research is needed to determine how these variables impact BFL muscle activation and whether injured runners respond differently to arm swing constraint during running.
Temple University--Theses
23
Matthews, Kara Jane. « Geologic and Kinematic consequences of major plate boundary reorganisations ». Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/9805.
Texte intégralRésumé :
Tectonic structures on the seafloor preserve a wealth of information on seafloor spreading and plate boundary evolution, and reveal that long intervals of uniform plate motions are punctuated by episodes of relatively rapid change. These plate reorganisation events are recurrent in Earth’s history and form an integral component of plate tectonics, yet the driving mechanisms and effects of major events are insufficiently understood. In this thesis I undertake global and regional-scale investigations of plate boundary reorganisation events to better understand their geologic and kinematic consequences. I create a near-global digital tectonic fabric map of the ocean basins using satellite altimetry-derived vertical gravity gradient data, and identify intervals of widespread changes in plate motions. Kinematic observations from seafloor fabric are combined with onshore and offshore geology to investigate a postulated major plate reorganisation event at ~100 Ma and the plate boundary evolution in the southwest Pacific following this reorganisation, focusing on the Late Cretaceous to mid Eocene timeframe. I show that fracture zone indicators of plate motion changes are common in seafloor that formed during the middle of the Cretaceous Normal Superchron interval, ranging from about 120 to 83 Ma. I combine constraints from fracture zones with a detailed global compilation of oceanic and continental, tectonic and volcanic events that occurred at 110-90 Ma, and show that a major plate reorganisation event initiated between ~105-100 Ma. This event is recorded in both the oceanic and continental domains and was global in scale. In each ocean basin that preserves seafloor of mid Cretaceous age, I find evidence for changes in spreading between ~105-100 Ma. Slab pull is known to be a dominant driver of plate motion and I speculate that cessation of long-lived eastern Gondwanaland subduction is a potential driving mechanism for the event. This subduction zone constituted approximately 1/6 of the total estimated length of circum-Pacific subduction zones at this time, and I suggest that its termination had the propensity to modify the motion of plates along the margin and subsequently neighbouring plates. However, eruption of the Bouvet plume at the South American-African-Antarctic spreading ridge triple junction may have had at least a regional-scale influence on plate motions and continental tectonics. The 105-100 Ma global plate reorganisation profoundly influenced the tectonic evolution of the southwest Pacific; however due to sparse and ambiguous data there is much debate over where and when plate boundaries were active following cessation of eastern Gondwanaland subduction at this time, particularly before 45 Ma. Kinematic analyses of plate motions in the southwest Pacific using revised relative motion histories at the Australian-East Antarctic ridge and in the West Antarctic Rift System suggest the presence of a plate boundary between of the Pacific and Lord Howe Rise before 55 Ma, accommodating minor convergence (<20 km) with a possible strike-slip component. This scenario precludes subduction and slab rollback driven by strong convergence during this time, as has previously been suggested. Geologic evidence for the opening of the South Loyalty Basin to the east of New Caledonia during the mid Cretaceous-Palaeocene implies that a plate boundary must have existed in this area at this time. The results of my kinematic analysis are consistent with an existing model of trench retreat driven by collapse of the East Gondwanaland Cordillera and associated widespread extension, as this scenario can account for basin opening and slab rollback in the absence of convergence. At ~55 Ma a subduction initiation event occurred to the east of New Caledonia as supported by dyke emplacement and metamorphism in New Caledonia, and arc-type rocks dredged from the Tonga forearc. An important implication of my work on the tectonic development of the southwest Pacific and my analysis of the seafloor fabric globally relates to major plate motion changes centred at ~55 Ma. Subduction inception in the southwest Pacific at 55 Ma is coeval with other plate motion changes in the Pacific and Atlantic ocean basins and southeast Indian Ocean. This plate reorganisation in the southwest Pacific at 55 Ma may therefore form part of a much larger early Eocene Pacific-wide event. I provide observational constraints for mid Cretaceous and early Eocene reorganisations, and in order to resolve what ultimately drove these events fully dynamic numerical models are needed to quantitatively assess plate driving forces.
24
Howard, Colin Bryan. « Kinematic and dynamic modelling of foreland basin development ». Thesis, University of Liverpool, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333687.
Texte intégral
25
Jagirdar, Saurabh. « Kinematics of curved flexible beam ». [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001853.
Texte intégral
26
Brocklehurst, Anne M. « Kinematic modelling of ridge-trench interactions with application to the Antarctic Peninsula ». Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366726.
Texte intégral
27
Shepley, Martin Gerard. « The kinematic and structural evolution of the Embrunais-Ubaye nappe system (southern French Alps) ». Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314922.
Texte intégral
28
Wallis, S. R. « The kinematic and structural development of the Austroalpine-Pennine Boundary in the S.E. Tauern, Eastern Alps ». Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233592.
Texte intégral
29
Newman, Patrick S. Garner Brian Alan. « The influence of load on kinematics of computer-simulated sagittal-plane lifting ». Waco, Tex. : Baylor University, 2005. http://hdl.handle.net/2104/2888.
Texte intégral
30
Rahman, Haseeb Ahmad. « Accurate measurement of three-dimensional natural knee kinematics using single-plane fluoroscopy ». [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0002640.
Texte intégral
31
Simões, Eduardo Tenório. « Linear and nonlinear hirarchical plate models and a posteriori kinematical error estimator ». Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-26072016-151855/.
Texte intégralRésumé :
This study explores the use of hierarchical models to represent three-dimensional solids in a computationally inexpensive way. First, it is investigated the choice of the finite element spaces and how it affects the convergence in relation to the thickness parameter. It was studied three different models. It was shown that the best lowest order suitable combination of spaces grows in all fields as the model order is enriched. After, it is presented a theory to evaluate the error in the discretization and the kinematical hypothesis. It is shown that the implemented error in discretization technique is capable of capturing the boundary layer in automated way for any model. It is also given a posteriori error procedure for kinematical hypothesis. The method is based on the equilibrium error of higher order models. Good results are shown. In the end, it is presented a geometrical nonlinear hierarchical shell model and its discretization. It is shown that the model succeeds in representing the three-dimensional solution when compared with solid elements in a commercial code.Este estudo explora o uso de modelos hierárquicos para representar sólidos tridimensionais de forma computacionalmente barata. Em primeiro lugar, é explorada a escolha dos espaços de elementos finitos e como isso afeta a convergência em relação ao parâmetro da espessura. Foram estudados três modelos diferentes. Mostrou-se que a menor ordem adequada do espaço de discretização cresce para todos os campos conforme a ordem do modelo é enriquecida . Isso impõe um problema, já que um maior polinômio exige maior custo computacional e modelos de alta ordem só são necessários perto do contorno. Depois, são usados estimadores de erro na discretização e na hipótese cinemática. Mostra-se que o erro implementado na discretização é capaz de capiturar a camada limite de forma automatizada para qualquer modelo. Também é apresentada uma técnica de erro a posteriri na hipótese cinemática com base no erro no equilíbrio de modelos de ordem superior. No final, é apresentado um modelo hierárquico de casca geométricamente não linear e sua discretização. Mostra-se que o modelo consegue representar a solução tridimensional quando comparado com o um software comercial.
32
Devivier, Cédric. « Damage identification in layered composite plates using kinematic full-field measurements ». Troyes, 2012. http://www.theses.fr/2012TROY0017.
Texte intégralRésumé :
Ce travail porte sur le développement d'une technique expérimentale qui peut aider à définir les paramètres clefs du comportement après impact de panneaux composites stratifiés. Pour cela, des modèles éléments finis ont été construits pour inclure des délaminages à partir d'observations de CT-scans d'échantillons impactés. Les résultats de ces modèles ont été comparés à des mesures expérimentales obtenues par une technique de mesure de champs de pentes : la déflectométrie. Ce travail présente aussi un nouvel indicateur d'endommagement basé sur l'application de la méthode des champs virtuels à l'évaluation d'écarts locaux à l'équilibre. Cette procédure d'abord détaillée est ensuite appliquée à des échantillons de types poutres et plaques. Les résultats expérimentaux illustrent la remarquable sensibilité de cette technique de mesure : elle permet de capturer les effets de très faibles endommagements. Aussi, cette technique montre que les modèles numériques assez simples présentés dans ce travail nécessitent des améliorations pour se rapprocher des données expérimentales. L'indicateur d'écart à l'équilibre a détecté correctement le contour des zones endommagées quand suffisamment d'information spatiale était disponible. Poursuivre ce travail permettrait de créer un outil précieux aidant la conception de pièces en compositesThis work focuses on the development of an experimental technique which can help to define the key parameters for post-impact behaviour of laminated composite panels. To address this issue, finite element models were built to represent delaminations based on the observations of CT-scans of impacted samples. The results of these models have been correlated to experimental data obtained using a slope fullfield measurement technique: deflectometry. This work also develops a new damage indicator based on the application of the virtual fields method to compute a local equilibrium gap. The procedure is first presened and then applied to beam and plate samples. The experimental results illustrate the remarkable sensitivity of this measurement method as it captures the effect of very small amount of damage and shows that the simple numerical models need to be refined to present a better correlation to experimental results. The damage indicator successfully detects contours of damaged areas when sufficient spatial information is available. It is believed that pursuing the present work could lead to an invaluable tool to help design engineers
33
McElderry, Susie. « Contrasting deformation styles in the Domeyko Fault System, northern Chile ». Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366424.
Texte intégralRésumé :
Subduction of an oceanic plate under the Pacific margin of South America has heen prevalent since Jurassic times. Magmatic and deformation centres have migrated eastward since suhduction began. Northern Chile houses two north-south trench linked strike-slip fault systems, the Atacama Fault Zone and the Domeyko Fault System (DFS). The DFS lies within the Chilean Precordillera from 2 10 to 28°S. Lateral movement began on the DFS in the Eocene. The DFS can be divided into three segments which have apparently undergone differing deformation histories. This study has focused on the central segment of the DFS, to determine fault kinematics and to establish a relative chronology of deformation. Observations have been made in more detail than previous investigations and have heen used to infer the deformation history . Shallow level faulting has resulted in heavily fractured zones with occasional slickenline surfaces. It is difficult to infer kinematics of faulting from these. Much effort has been expended in developing techniques to analyse fracture patterns associated with brittle faulting under conditions of plane strain, simple shear. A novel approach of analysing the shapes of clasts of rock defined by secondary fractures within a fault zone has been used. The clasts approximate ellipses when viewed in 2 dimensions. Combining ellipse orientation and aspect ratio from mutually perpendicular sections through the fault zone allowed calculation of an ellipsoid representative of the clasts of rock in 3 dimensions. Independent determination of the fault kinematics using stratigraphic relationships across the fault, fracture distribution, incremental strain axes and palaeomagnetic analysis has all owed evaluation of the new technique. The shapes of rock clasts are found to be related to the kinematics of the fault system. Up to a critical stage of development of the fault zone the axes of the rock clasts parallel the slip direction, intermediate strain axis and pole to the boundary faults. Which rock clast axis parallels which structural feature depends upon the spacing and curvature of fractures and stage of development of the fault zone. Analysis of the shapcs or rock clasts defined by fractures can avoid bias of the data set towards thicker fractures or against irregular fractures, which can occur when measuring fracture orientations directly. The degree of development of the fault zone varies laterally along the fault over short distances. This causes the shape.: fabric of the rock clasts to change, so predictions of connectivity within a fault zone are limited. The history of the central segment of the DFS determined from this study is found to occur with earlier workers. The complementary deformation histories produced from two scales of ohservation verifies the reliability of the chronology. Lateral movements along the DFS are thought to begin in the Eocene with a sinistral transpressive event which occurred along all three segments of the DFS. En echelon folds, east and west verging thrusts and clockwise rotations associated with sinistral faulting along the master fault of the segment are documented. Later, in the Oligocene, dextral faulting occurred. large clockwise palaeomagnetic rotations, determined from Palaeozoic samples beside the master fault, indicate sinistral displacements have been larger than dextral disp acements. It is inferred that only one episode of large lateral transport occurred. This is the Eocene sinistral event. Normal faulting associated with sinistral displ acements along the western side of the system are documented. This later sinistral faulting has not been documented before in the central segment of the DFS. After Oligocene age dextral faulting, the three segments of the DFS underwent separate deformation histories, as the main Andean deformation foci had moved eastward.
34
Worcester, Katherine Sara. « EFFECTS OF INERTIAL LOAD ON SAGITTAL PLANE KINEMATICS DURING FLYWHEEL-BASED RESISTANCE TRAINING SQUATS ». UKnowledge, 2018. https://uknowledge.uky.edu/khp_etds/57.
Texte intégralRésumé :
Background: Training to increase muscular power is essential for improving athletic performance in most sports. Weight training (WT) is a common means for training muscular power. Another modality, flywheel resistance training (FRT), may be superior for improving muscular power. However, few studies have examined if FRT is kinematically similar to WT, or if FRT kinematics change with increasing inertial load. The purposes of this study were to determine how sagittal plane joint kinematics are affected by increasing inertial load during FRT squats, and to determine how FRT squat joint kinematics compare to WT squat joint kinematics.
Methods: Subjects (n=9) completed three visits for this study. On the first visit subjects completed squat 1 repetition maximum (1RM) testing. The second visit served as a full FRT familiarization session in which subjects performed one set of 5 maximal effort FRT squats at each inertial load (0.050, 0.075, and 0.100 kgm2). On the third visit, subjects were videoed in the sagittal plane while performing the FRT squat protocol. Subjects then completed 5 maximal velocity repetitions of WT squats with the barbell loaded according to the Kansas Squat Test (KST) protocol. Kinematic differences between inertial loads were determined via 1-way repeated measures ANOVAS while differences between FRT and WT were determined with paired T-tests.
Results: There were no differences in peak sagittal plane knee, trunk-hip, trunk (absolute) or ankle angles between inertial loads. Peak and mean joint angular velocities decreased with increasing inertial loads at the knee and trunk-hip. Mean joint angular velocities decreased at the ankle with increasing inertial loads, while peak and mean trunk (absolute) angular velocities were unaffected. No statistical analyses were conducted for FRT and WT comparison as not enough subjects met the criteria (n=3).
Conclusions: Sagittal plane joint kinematics are largely maintained despite increasing inertial load during FRT squats. Lower extremity joint angular velocities decreased with increasing inertial load. If training for muscular power and knee extensor velocity is the goal, then the inertia of 0.050 kgm2 is most suitable.
35
Wenzel, Christian. « Local FEM Analysis of Composite Beams and Plates : free-Edge effect and Incompatible Kinematics Coupling ». Thesis, Paris 10, 2014. http://www.theses.fr/2014PA100107/document.
Texte intégralRésumé :
Cette thèse traite des problèmes des concentrations de contraintes locales, en particularité des effets des bords libres dans des structures stratifiés. À l'interface entre deux couches avec des propriétés élastiques différentes, les contraintes ont un comportement singulier dans le voisinage du bord libre en supposant un comportement de matériau élastique linéaire. Par conséquent, ils sont essentiels pour promouvoir le délaminage. Via Formulation unifiée de la Carrera (CUF) différents modèles cinématiques sont testés dans le but de capter les concentrations de contraintes. Dans la première partie de ce travail, les approches de modélisation dimensionnelle réduits sont comparées. Deux classe principale sont présentés: la couche équivalent (ESL) et l'approche par couche, LW. Par la suite leurs capacités à capter les singularités sont comparées. En utilisant une fonction a priori singulière, via une expression exponentielle, une mesure des contraintes singulières est introduite. Seulement deux paramètres décrivent pleinement les composantes des contraintes singulières au voisinage du bord libre. Sur la base des paramètres obtenus les modèles sont comparés et aussi les effets sous des charges d'extension et de flexion et pour différents stratifiés. Les résultats montrent une nécessité des modèles complexes dans le voisinage du bord libre. Cependant loin des bords libres, dans le centre de plaques composite, aucune différence significative ne peut être noté pour les modèles plutôt simples. La deuxième partie de ce travail est donc dédiée au couplage de modèles cinématique incompatibles. Modèles complexes et coûteux sont utilisés seulement dans des domaines locaux d'intérêt, tandis que les modèles économiques simples seront modéliser le domaine global. La eXtended Variational Formulation (XVF) est utilisé pour coupler les modèles de dimensionnalité homogènes mais de cinématique hétérogènes. Ici pas de recouvrement de domaine est présent. En outre, le XVF offre la possibilité d'adapter les conditions imposées à l'interface en utilisant un paramètre scalaire unique. On montre que, pour le problème de dimensionnalité homogène, que deux conditions différentes peuvent être imposées par ce paramètre. Un correspondant à des conditions fortes des Multi Point Constraints (MPC) et un second fournir des conditions faibles. La dernière offre la possibilité de réduire extrêmement le domaine qui utilise le modèle cinématique complexe, sans perte de précision locale. Comme il s'agit de la première application de la XVF vers les structures composites, le besoin d'un nouvel opérateur de couplage a été identifié. Un nouveau formulaire est proposé, testé et sa robustesse sera évaluéeThis work considers local stress concentrations, especially the free-Edge effects of multilayered structures. At the interface of two adjacent layers with different elastic properties, the stresses can become singular in the intermediate vicinity of the free edge. This is valid while assuming a linear elastic material behaviour. As a consequence this zones are an essential delamination trigger. Via the Carrera Unified Formulation (CUF), different kinematical models are testes in order to obtain the correct local stress concentration. In the first part of this work, the reduced dimensional modelling approaches are compared. Two main class are presented: Equivalent Single Layer (ESL) models treating the layered structure like one homogenous plate of equal mechanical proper- ties, and the Layer Wise approach, treating each layer independently. Subsequently their capabilities to capture the appearing singularities are compared. In order to have a comparable measurement of those singularities, the obtained stress distributions will be expressed via a power law function, which has a priori a singular behaviour. Only two parameters fully describe therefore the singular stress components in the vicinity of the free edge. With the help of these two parameters not only the different models capabilities will be compared, but also the free edge effect itself will be measured and compared for different symmetrical laminates and the case of extensional and uniform bending load. The results for all laminates under both load cases confirm the before stated need for rather complex models in the vicinity of the free edge. However far from the free edges, in the composite plates centre, no significant difference can be noted for rather simple models. The second part of this work is therefore dedicated to the coupling of kinematically incompatible models. The use of costly expensive complex models is restricted to local domains of interest, while economic simple models will model the global do- main. The Extended Variational Formulation (XVF) is identified as the most suitable way to couple the kinematically heterogenous but dimensional homogenous models. As it uses a configuration with one common interface without domain overlap, the additional efforts for establishing the coupling are limited. Further the XVF offers the possibility to adapt the conditions imposed at the interface using a single scalar parameter. It will be shown that for the homogenous dimensional problem under consideration only two different conditions can be imposed by this parameter. One matching the strong conditions imposed by the classical Multi Point Constrains (MPC) and a second one providing a weak condition. The last one is shown to provide the possibility to reduce further the domain using the complex kinematical model, without the loss of local precision. As this is the first application of the XVF towards composite structures, the need for a new coupling operator was identified. A new form is proposed, tested and its robustness will be evaluated
36
Armijo, Rolando. « Mecanismes des deformations quaternaires au tibet : cinematique de la collision inde-asie ». Paris 7, 1986. http://www.theses.fr/1986PA077217.
Texte intégralRésumé :
Etude neotectonique du tibet realisee dans le cadre de la cooperation scientifique franco-chinoise entre 1980 et 1982. Cartographie detaillee des feuilles actives, des decalages de la morphologie specialement glaciaire et l'analyse microtectonique: cinematique des mouvements combines de failles normales et decrochantes. L'extension au tibet est orientee de facon uniforme; elle est recente et rapide
37
Foss, Kari D. « Kinetic and kinematic gait analysis in Doberman Pinschers with and without cervical spondylomyelopathy ». The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337003842.
Texte intégral
38
Wyngaardt, Shaun Metzler. « Relativistic plane wave description of spin transfer observables for proton knockout reactions ». Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52429.
Texte intégralRésumé :
Thesis (PhD)--Stellenbosch University, 2001.ENGLISH ABSTRACT: In this dissertation we set out to develop the first relativistic model for calculating complete sets of (p, 2p) spin transfer observables. In addition to this a new technique has been developed which allows us to evaluate the transition amplitude, which is used to calculate the scattering observables for the reaction directly. The influence of various modiuin-modificd parameters ()1I the scattered wave functions anr] NN interact ion lH-IVC' })('('11 invest igatcd DlIC t,C) (I,llIlJigllitic's surrounding the nNN coupling we have included both pseudosoalar and pseudovector coupling into the nucleon-nucleon interaction model. Furthermore we have included two different kinematic prescriptions to obtain the effective NN laboratory kinetic energy and center of mass scattering angle, which are used to obtain the NN scattering amplitudes. The aim of this study is to investigate the effects of the various model parameters on complete sets of scattering observables. Our investigation has shown that although the analyzing power is not very sensitive to nuclear medium effects, and the various other spin transfer observables such as Dnn should provide valuable insight. Further refinements of the model would be to include nuclear distortions as well as the IA2 model of the NN interaction.
AFRIKAANSE OPSOMMING: In hierdie tesis ontwikkel ons die eerste relatiwistiese model vir die berekening van 'n volledige stel (p, 2p) spin waarneembares. Verder word 'n nuwe tegniek ingevoer wat ons toelaat om die oorgangsamplitude, wat gebruik word in berekening van die verstrooings waarneembares vir die reaksie, direk te evalueer. Die invloed van verskeie medium-gemodifiseerde parameters op die verstrooide golffunksies en die NN wisselwerking word bestudeer. As gevolg van onsekerhede betreffende die лNN koppeling word beide die pseudoskalaar en pseudovektor koppeling in die nukleon-nukleon interaksie model ingesluit. Ons sluit ook twee verskillende kinematiese preskripsies in om die effektiewe NN laboratorium kinetiese energie en die massa middelpunt verstrooiings hoek, wat gebruik word vir die berekening van die NN verstrooiings amplitude, te bereken. Die doel van hierdie studie is om die effek van verskeie model parameters op 'n volledige stel spin waarneembares te ondersoek. Die studie toon dat alhoewel die analiseervermoë nie baie sensitief is vir medium effekte nie, die ander spin waarneembares soos byvoorbeeld Dnn waardevolle insig lewer. Daar word voorgestel dat die model verfyn word deur kerndistorsies as ook die meer algemele IA2 model vir die NN interaksie in te sluit.
39
Ioppolo, James. « Kinematic joint measurements using radiostereometric analysis (RSA) and single-plane x-ray video fluoroscopy ». University of Western Australia. Orthopaedics Unit, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0090.
Texte intégralRésumé :
[Truncated abstract] Measuring the kinematics of joints and implants following orthopaedic surgery is important since joint motion directly influences the functional outcome of the patient and the longevity of the implant. Radiostereometric Analysis (RSA) has been used to assess the motion over time of various joints and implant designs following corrective orthopaedic and joint replacement surgery for more than 20 years in more than 10,000 patients around the world. While the use of RSA reduces the risk of implanting potentially inferior prostheses on a large scale, conventional methodological procedures are based on the acquisition of static, stereographic x-ray images that are not suitable for measuring skeletal kinematics in a dynamic manner. The purpose of this thesis was to design, validate and test a novel technique for dynamically assessing the skeletal motion of human subjects using RSA and single-plane digital x-ray video fluoroscopy. The validation procedure utilised two in-vitro phantom models of human joints capable of simulating normal kinematic motion. These phantom models were supplied with realistic spatial displacement protocols derived from cadaveric specimens. The spatial positions of a series of tantalum markers that were implanted in each skeletal segment were measured using RSA. Skeletal motion was determined in x-ray fluoroscopy images by minimising the difference between the markers measured and projected in the single image plane. Accuracy was determined in terms of bias and precision by analysing the deviation between the applied displacement protocol and measured pose estimates. ... The RSA and low dose single-plane fluoroscopy technique developed, validated and tested in this thesis is capable of dynamically measuring the kinematics of any joint in the human body, following the implantation of small metallic markers in the surrounding bone during corrective orthopaedic surgery. The kinematics of joints with replacement prostheses, such as the total knee replacement (TKR), can be analysed in addition to the kinematics of joints without replacement prostheses, such as the sacroiliac joint. The technique may be used in the future on groups of human subjects enrolled in controlled trials that are designed to analyse the kinematics of the shoulder, spine, hip, knee, patella or ankle joints for the purposes of quantitatively comparing the kinematics of different prosthesis designs and various corrective orthopaedic procedures.
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Robbins, Donald H. « Hierarchical modeling of laminated composite plates using variable kinematic finite elements and mesh superposition ». Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/40117.
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Fan, Xiaozhou. « Canonical Decomposition of Wing Kinematics for a Straight Flying Insectivorous Bat ». Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/91469.
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Bats are some of the most agile flyers in nature. Their wings are highly articulated which affords them very fine control over shape and form. This thesis investigates the flight of Hipposideros Pratti. The flight pattern studied is nominally level and straight. Measured wing kinematics are used to describe the wing motion. It is shown that Proper Orthogonal Decomposition (POD) can be used to effectively to filter the measured kinematics to eliminate outliers which usually manifest as low energy higher POD modes, but which can impact the stability of aerodynamic simulations. Through aerodynamic simulations it is established that the first two modes from the POD analysis recover 62% of the lift, and reflect a drag force instead of thrust, whereas the first three modes recover 77% of the thrust and even more lift than the native kinematics. This demonstrates that mode 2, which features a combination of spanwise twisting (pitching) and chordwise cambering, is critical for the generation of lift, and more so for thrust. Based on these inferences, it is concluded that the first 7 modes are sufficient to represent the full native kinematics.
The aerodynamic simulations are conducted using the immersed boundary method on 128 processors. They utilize a grid of 31 million cells and the bat wing is represented by about 50000 surface elements. The movement of the immersed wing surface is defined by piecewise cubic splines that describe the time evolution of each control point on the wing.
The major contribution of this work is the decomposition of the native kinematics into canonical flapping wing physical descriptors comprising of the flapping motion, stroke-plane deviation, pitching motion, chordwise, and spanwise cambering. It is shown that the pitching mode harvests a Leading Edge Vortex (LEV) during the upstroke to produce thrust. It also stabilizes the LEV during downstroke, as a result, larger lift and thrust production is observed. Chordwise cambering mode allows the LEV to glide over and cover a large portion of the wing thus contributing to more lift while the spanwise cambering mode mitigates the intensification of LEV during the upstroke by relative rotation of outer part of the wing ( hand wing ) with respect to the inner part of the wing ( arm wing).
While this thesis concerns itself with near straight-level flight, the proposed decomposition can be applied to any complex flight maneuver and provide a basis for unified comparison not only over different bat flight regimes but also across other flying insects and birds.MS
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Bini, Cosimo. « A pick-and-place robot for coffee capsules : virtualization and trajectory design ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
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Even if Virtual Commissioning is not widely spread among industries yet, it offers plenty of advantages for the manufacturing of productive plants, that consist of reduced commissioning time, optimization of the code, better synergy between mechanical and software design. However, due to the cost of the requested investments, only big firms employ it in their production processes. This work aims at providing an example of how Virtual Commissioning can be applied to an automatic machine and how it can be used to improve the kinematic behaviour of two degrees of freedom manipulator, that moves coffee capsules into carton boxes. In particular, the simulations deal with the modifications of the parameters of the current trajectory and the test of a different kind of path for the robot, paying attention to collisions with the other parts of the machine.
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Feng, Huijuan. « Kinematics of spatial linkages and its applications to rigid origami ». Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC014/document.
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La thèse conduit une analyse cinématique des mécanismes spatiaux allant de mécanismes sphériques aux mécanismes spatiaux sur-contraints basés sur la méthode matricielle D-H et l’applique pour explorer le comportement rigide de pliabilité et de mouvement des modèles d’origami. Dans ce processus, la pliabilité rigide du motif origami en torsion triangulaire est d’abord examinée sur la base de la cinématique du réseau de mécanismes 4 R sphériques et de nouveaux mécanismes 6 R sur-contraints dérivés par la technique du kirigami. Ensuite, la cinématique du mécanisme de Bricard 6 R plan-symétrique est analysée et ses variations de bifurcation sont discutées. Après cela, les résultats sont appliqués pour étudier le pliage symétrique de l’origami de la waterbomb à six plis à panneau épais, qui est modélisé sous laforme d’un réseau de mécanismes de Bricard 6 R plan-symétriques. Le comportement de mouvement de sa tessellation correspondante de feuille de zéro-épaisseur est démontré par unréseau de mécanismes 6 R sphériques. Enfin, le comportement de mouvement de la forme cylindrique fermée de l’origami de la waterbomb est analysé à travers une étude paramétrique, en le modélisant comme un réseau fermé de mécanismes 6 R sphériques. Ces études aident à approfondir la compréhension de la cinématique des mécanismes spatiaux et du mouvement rigide de l’origami, et à jeter les bases des applications techniques des mécanismes spatiaux et des motifs d’origami rigidesThis dissertation conducts kinematic analysis of spatial linkages ranging from spherical linkages to overconstrained linkages based on the D-H matrix method, and applies it to explore the rigid foldability and motion behaviour of origami patterns. In this process, the rigid foldability of triangle twist origami pattern is firstly examined based on the kinematics of spherical 4 R linkage network and new overconstrained 6 R linkages are derived by kirigami technique. Then the kinematics of the plane-symmetric Bricard 6 R linkage is analyzed and its bifurcation variations are discussed. After that, the results are applied to study the symmetric folding of six-crease thick-panel waterbomb origami, which is modelled as a network of planesymmetric Bricard 6 R linkages. The motion behaviour of its corresponding tessellation of zerothickness sheet is demonstrated by a network of spherical 6 R linkages. Finally, the motion behaviour of the closed cylindrical form of waterbomb origami is investigated through a parametric study, by means of modelling it as a closed network of spherical 6 R linkages. These studies help to deepen the understanding of spatial linkage kinematics and rigid origami motion, and lay the foundation for engineering applications of spatial linkages and rigid origami patterns
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León, Alejandro. « A pseudo-rigid-body model for spherical mechanisms : The kinematics and elasticity of a curved compliant beam ». Scholar Commons, 2007. http://scholarcommons.usf.edu/etd/2259.
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This thesis improves a previous kinematic analysis and develops the elastic portion of the analysis of a curved compliant beam. This analysis is used to develop a Pseudo-Rigid-Body Model for the curved compliant beam. The Pseudo-Rigid-Body Model consist of kinematic and elastic parameters which can be used to simplify the computation of the large deflections of the beam as it undergoes spherical motion. The kinematic parameters that are developed are the characteristic radius, Gamma*length, the parametric angle coefficient, c_theta, and the kinematic parametrization limit, Capital_theta_max(Gamma). The elastic parameters developed are the stiffness coefficient, K_theta, and the elastic parameterization limit, Capital_theta_max(K). Additionally, curve fit parameters are developed which enable the calculation of the stress in curved beam as it deflects.
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Baggaley, Michael William Robinson. « Is There A Relationship Between Hip Structure, Hip Muscle Strength, and Lower Extremity Frontal Plane Kinematics During Treadmill Running ? » UKnowledge, 2014. http://uknowledge.uky.edu/khp_etds/18.
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INTRODUCTION: Excessive hip adduction (HADD) has been associated with a number of lower extremity overuse injuries, and it has been suggested that it may be the result of reduced strength of the hip abduction musculature. Hip structure has been postulated to influence both hip abduction (HABD) strength and HADD. The purpose of this study was to investigate the relationship between hip structure, HABD strength, and frontal plane kinematics during running. METHODS: Peak isometric HABD strength, lower extremity kinematics, femoral neck-shaft angle (NSA), and pelvis width-femur length (pw-fl) ratio were recorded for 25 female subjects. Pearson correlations (P < .05) were performed between variables. RESULTS: A fair relationship was observed between femoral NSA and HABD strength (r = -.472 P = .017) where an increased NSA was associated with reduced HABD strength. No relationship was observed between HABD strength and frontal plane kinematics or between NSA/pw-fl and frontal plane kinematics. CONCLUSION: Alterations in the femoral NSA have the ability to influence peak isometric hip abduction strength. However, alterations in strength did not result in changes in lower extremity kinematics. Structural deviations at the hip do not appear to influence hip kinematics during running.
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Durusu, Deniz. « Camera Controlled Pick And Place Application With Puma 760 Robot ». Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606759/index.pdf.
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This thesis analyzes the kinematical structure of Puma 760 arm and introduces the implementation of image based pick and place application by taking care of the obstacles in the environment. Forward and inverse kinematical solutions of PUMA 760 are carried out. A control software has been developed to calculate both the forward and inverse kinematics solution of this manipulator. The control program enables user to perform both offline programming and real time realization by transmitting the VAL commands (Variable Assembly Language) to the control computer.
Using the proposed inverse kinematics solutions, an interactive application is generated on PUMA 760 arm. The picture of the workspace is taken using a fixed camera attached above the robot workspace. The captured image is then processed to find the position and the distribution of all objects in the workspace. The target is differentiated from the obstacles by analyzing some specific properties of all objects, i.e. roundness. After determining the configuration of the workspace, a clustering based search algorithm is executed to find a path to pick the target object and places it to the desired place. The trajectory points in pixel coordinates, are mapped into the robot workspace coordinates by using the camera calibration matrix obtained in the calibration procedure of the robot arm with respect to the attached camera. The required joint angles, to get the end effector of the robot arm to the desired location, are calculated using the Jacobian type inverse kinematics algorithm. The VAL commands are generated and sent to the control computer of PUMA 760 to pick the object and places it to a user defined location.
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Darin, Michael Harrison. « Late Miocene Extensional Deformation in the Sierra Bacha, Coastal Sonora, Mexico : Implications for the Kinematic Evolution of the Proto-Gulf of California ». Thesis, University of Oregon, 2011. http://hdl.handle.net/1794/12189.
Texte intégralRésumé :
xv, 95 p. : ill. (some col.), maps (some col.) Plate 1. Geologic Map of the Sierra Bacha, Coastal Sonora, Mexico (1:30,000 scale) attached as a separate file.The Gulf of California is an active rift basin formed by late Cenozoic dextral-oblique extension along the Pacific-North America plate boundary. Well exposed volcanic and sedimentary rocks in the Sierra Bacha, coastal Sonora, Mexico, preserve a history of proto-Gulf (late Miocene) deformation and offer insight into the structures and kinematics responsible for localization of the plate boundary and inception of the Gulf at about 6 Ma. Geologic mapping, fault kinematic analysis, and paleomagnetic data suggest that proto-Gulf deformation in the Sierra Bacha occurred primarily by ENE-WSW extension and that vertical-axis rotation related to dextral strain was minor. Lack of significant dextral shear supports an emerging model for proto-Gulf deformation in which dextral strain was not ubiquitous across Sonora but instead became localized during latest Miocene time in a narrow coastal shear zone that mechanically weakened the lithosphere and helped facilitate continental rupture. This thesis includes the "Geologic Map of the Sierra Bacha, Coastal Sonora, Mexico" as supplemental material.
Committee in charge: Dr. Rebecca J. Dorsey, Chairperson; Dr. Marli B. Miller, Member; Dr. Ray J. Weldon II, Member
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Drakos, Peter S. « Tertiary stratigraphy and structure of the southern Lake Range northwest Nevada assessment of kinematic links between strike-slip and normal faults in the northern Walker Lane / ». abstract and full text PDF (free order & ; download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1442868.
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Wittwer, Ara. « The Effect of Chronic Ankle Instability on Lower Extremity Frontal-plane Kinematics and Plantar Pressure During a Dynamic Postural Control Task ». University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1333379147.
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Breen, Alexander C. « A quantitative fluoroscopic study of the relationship between lumbar inter-vertebral and residual limb/socket kinematics in the coronal plane in adult male unilateral amputees : exploring the spine and lower limb kinematics of trans-tibial amputees ». Thesis, Bournemouth University, 2016. http://eprints.bournemouth.ac.uk/24293/.
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Introduction: Much of lower back pain (LBP) is thought to be mechanical in origin and lower limb amputees have an increased prevalence. There is also evidence that a large proportion of them also have altered spinal posture and it is commonly thought that the movement between the vertebrae (kinematics) may be affected. The current study was designed to explore the kinematics of the lumbar spine segments in trans-tibial amputees and compare it to a similar population with intact lower limbs using quantitative fluoroscopy (QF). The study also investigated possible relationships between lumbar spine stability and the motion between the prosthetic socket and residual limb. It is hoped that these investigations will improve understanding of the importance of limb-socket fit to the functional integrity of the lumbar spine in lower limb amputees. Methods: A literature review and three preliminary QF studies were carried out; one to the determine the best plane of motion and orientation of participants during QF imaging of the spine, a second to inform the optimal imaging protocol for the limb-socket interface and the third to validate a QF measurement of inter-vertebral stability. This phase determined the measurement parameters and investigative protocols. Given the complexity of the technique, 12 male below knee amputees and 12 healthy male controls of similar age and body mass index were recruited and received passive recumbent coronal QF imaging of their lumbar spines. This was followed immediately by anterior-posterior QF imaging of their limb-socket interfaces during three different forms of simulated gait. Differences between amputee and control spine kinematics and relationships between limb-socket motion and inter-vertebral kinematics in amputees were investigated. Results: Passive recumbent coronal plane QF appears to be a valid method for measuring inter-vertebral stability. Although there were no systematic differences between the magnitude of inter-vertebral kinematics variables of amputees and controls, there was a trend towards greater variability in both inter-vertebral range and symmetry of motion in amputees and a significantly higher proportion of correlations in attainment rate between levels among amputees than controls (2-sided p < 0.04). There was also a substantial, statistically significant inverse linear relationship between passive inter-vertebral motion symmetry and limb-socket telescoping in amputees. Conclusions: This thesis provides evidence that the kinematics of the lumbar spine may be affected by lower limb amputation – particularly in respect of socket fit. The importance of consistency and symmetry of restraint by the intrinsic spinal holding elements in trans-tibial amputees has been highlighted. An indication of a relationship between limb socket telescoping and spine kinematics was identified, suggesting the need for replication of this part of the study in a larger amputee population. The variables of interest and the basis for this have been identified. Finally, inter-vertebral motion pattern variation has been associated with chronic low back pain in the literature. It was discovered that there was more interdependence in passive inter-vertebral motion between and across levels in below knee amputees than controls in terms of laxity, but not range of motion. The apparent relationship between this and socket fit in amputees suggests a possible mechanism and diagnostic subgroup in this population.