To see the other types of publications on this topic, follow the link: Deformation Processing.
Dissertations / Theses on the topic 'Deformation Processing'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Deformation Processing.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Wang, Jianye. "Processing and deformation of ZrB2." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/11179.
Full textAbstract:
Zirconium diboride, ZrB2, based materials have been proposed for structural applications at ultra-high temperatures (>2000 [degrees] C). However, their mechanical behaviour at such temperatures is only poorly documented. In this work, the processing and the deformation behaviour of ZrB2 at temperatures up to 2000 [degrees] C is investigated. Densification of zirconium diboride based materials is difficult and most reported routes use a combination of high pressures and high temperatures to obtain a high density. However, it had been reported that with the aid of carbon, boron carbide and silicon carbide, pressureless sintering of ZrB2 is possible. Further work in this thesis shows that the key factor to obtain successful sintering is to limit the oxidation of the raw materials. It is shown also that dense materials can be obtained from relatively coarse powders with only carbon as the sintering additive. Adding silicon carbide or boron carbide does allow the grain growth at the sintering temperature to be limited. Mechanical characterisation of these materials was performed firstly using small-scale hardness measurements by nano-indentation at moderate temperatures (25-300 [degrees] C). The indentations were carried out at strain rates in the range 10-4 and 10-1 s-1. An analysis to extract the Peierls stress (6.6 ± 0.7 GPa) and activation energy (2.56 ± 1:6 x 10-19 J) for lattice resistance controlled plastic flow is presented. Additional mechanical characterisation consisted in measuring the self-contact hardness at temperatures from 900-2000 [degrees] C. These measurements clarify that the initial rapid decrease in hardness at room temperature is followed by a region of more or less constant hardness before further decreases in hardness become apparent at the highest temperatures. A TEM investigation of the deformation mechanisms shows that near room temperature, extensive dislocation flow occurs underneath indentations, whereas at the highest temperatures measured in this work, dislocations either anneal out or do not partake in the deformation. The available data was then summarised through proposing a deformation mechanism map for ZrB2.
2
Kalidindi, Surya R. (Surya Raju). "Polycrystal plasticity : constitutive modeling and deformation processing." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/13146.
Full text
3
Brown, Rebecca A. (Rebecca Ann) 1976. "Large strain deformation of PETG as processing temperatures." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/88847.
Full text
4
Balasubramanian, Srihari 1971. "Polycrystalline plasticity and its applications to deformation processing." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36056.
Full text
5
Ahmed, Shatil S. "Study of deformation processing of Structural Porous Metals." Ohio University / OhioLINK, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1178817532.
Full text
6
McLaren, Andrew John. "Modelling of thermomechanical processing of metals." Thesis, University of Sheffield, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361091.
Full text
7
Balasubramanian, Srihari 1971. "Polycrystalline plasticity : application to deformation processing of lightweight metals." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/29878.
Full text
8
Zhang, Nianxian. "Processing of a two-phase alloy by severe plastic deformation." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/388051/.
Full textAbstract:
This thesis presents a systematic study on evolutions of microstructure, microhardness and superplasticity of a Pb-62% Sn alloy processed by both equal-channel angler pressing (ECAP) and high-pressure torsion (HPT) and the subsequent self-annealing process at room temperature (RT). The Pb-Sn alloy exhibits characteristics with significant grain refinement after processing by ECAP and HPT but with a reduction in the hardness values by comparison with the initial as-cast condition. For HPT processing, it is shown that there are generally smaller grains at the edges of the discs by comparison with the disc centres. The hardness results are different from those generally reported for conventional single-phase materials where a hardening trend was commonly observed after HPT processing. The significance of this difference is examined. The microstructures of the alloy after HPT were repeatedly investigated during the course of self-annealing by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and scanning electron microscopy (TEM). A significant grain growth combined with increase of microhardness was observed. It was demonstrated that there was a large fraction of twin boundaries with a twin relationship of 62.8°<100> in the microstructure for the as-cast condition. Owing to the presence of high pressure, the mobility of Ʃ21 boundaries at 71° was greatly favoured during processing by HPT. But the mobility of the dislocation-twin boundary near 62.8°<100> was favoured during self-annealing at RT once the high pressure was removed. The HPT processing significantly increased the solubility of Sn in Pb phase. This supersaturated state of Sn in Pb is, however, not stable at RT during self-annealing and therefore a decomposition of Sn from Pb-rich phase was observed after 16 days of storage. Lattice diffusion should be considerable as the main mechanism for the decomposition. Moreover, abnormal grain growth was observed to be greatly favoured during self-annealing when the introduced strain was relatively low, i.e. 2 passes by ECAP and the centre region of a HPT-processed disc after one turn. Consequently, a series of HPT-processed samples with different storage time was tested in tension at RT and at 1.0 × 10-4 - 1.0 × 10-1 s-1. The results demonstrated that, despite the storage time, all processed alloy exhibited excellent RT superplasticity at 1.0 × 10-4 s-1 and the highest elongation of 630% was recorded in the processed alloy after storage for 4 days at RT. The detailed investigation showed, due to the high strain rate sensitivity of the processed alloy, a transition strain rate of ~1.0 × 10-2 s-1 was observed in which stain softening with ductile behaviour is apparent due to active GBS below the transition point but high strength is observed because of grain boundary strengthening above the transition during plastic deformation at RT in the Pb-Sn alloy after HPT. Nanoindentation tests were then performed applying both indentation depth-time (h-t) relationship at holding stage and the hardness, H, at various loading rates to explore the evolution of strain rate sensitivity (SRS), m. The results obtained by both tensile test and nanoindentation show that the relatively fast self-annealing of the HPT-processed Pb-62% Sn eutectic alloy is occupying by an unambiguous changing-tendency of strain rate sensitivity. The results confirm the validity of using nanoindentation for measuring strain rate sensitivity.
9
Alhajeri, Saleh N. "Processing of aluminium and titanium alloys by severe plastic deformation." Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/185107/.
Full text
10
Agrawal, Chandra Prakash. "Full-field deformation measurement in wood using digital image processing." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/43078.
Full textAbstract:
<p>A digital image processing system was used to non-destructively measure the full-field
deformation on aluminum and wood specimens loaded in compression and
bending. The measurement technique consisted of creating a random speckle pattern
on the specimen surface, recording images before deformation and after deformation,
and computing the relative displacements of small image subsets. Two methods for producing speckle patterns on the specimens were studied: spray paint and adhesive-backed photographic film.</p>
<p>Baseline tests were conducted to evaluate the influence of signal noise on the measurement system. Uniform translation tests were conducted to evaluate the capability
of the system for measuring finite motion. the technique was used to monitor
the full-field deformation response of aluminum and wood specimens tested in
bending and static compression. Moderate duration compression creep tests were
conducted, on the wood specimens to investigate the suitability of the system for
monitoring the creep response of materials. The results obtained from the two
speckle techniques were also. compared. The results showed that for the magnification
and speckle patterns tested displacement measurements smaller than 3.29x10-4 inch may be unreliable due to signal noise.</p><br>Master of Science
11
Jungner, Andreas. "Ground-Based Synthetic Aperture Radar Data processing for Deformation Measurement." Thesis, KTH, Geodesi och satellitpositionering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199677.
Full textAbstract:
This thesis describes a first hands-on experience working with a Ground-Based Synthetic Aperture Radar (GB-SAR) at the Institute of Geomatics in Castelldefels (Barcelona, Spain), used to exploit radar interferometry usually employed on space borne platforms. We describe the key concepts of a GB-SAR as well as the data processing procedure to obtain deformation measurements. A large part of the thesis work have been devoted to development of GB-SAR processing tools such as coherence and interferogram generation, automating the co-registration process, geocoding of GB-SAR data and the adaption of existing satellite SAR tools to GB-SAR data. Finally a series of field campaigns have been conducted to test the instrument in different environments to collect data necessary to develop GB-SAR processing tools as well as to discover capabilities and limitations of the instrument. The key outcome of the field campaigns is that high coherence necessary to conduct interferometric measurements can be obtained with a long temporal baseline. Several factors that affect the result are discussed, such as the reflectivity of the observed scene, the image co-registration and the illuminating geometry.<br>Det här examensarbetet bygger på erfarenheter av arbete med en mark-baserad syntetisk apertur radar (GB-SAR) vid Geomatiska Institutet i Castelldefels (Barcelona, Spanien). SAR tekniken tillåter radar interferometri som är en vanligt förekommande teknik både på satellit och flygburna platformar. Det här arbetet beskriver instrumentets tekniska egenskaper samt behandlingen av data for att uppmäta deformationer. En stor del av arbetet har ägnats åt utveckling av GB-SAR data applikationer som koherens och interferogram beräkning, automatisering av bild matchning med skript, geokodning av GB-SAR data samt anpassning av befintliga SAR program till GB-SAR data. Slutligen har mätningar gjorts i fält for att samla in data nödvändiga for GB-SAR applikations utvecklingen samt få erfarenhet av instrumentets egenskaper och begränsningar. Huvudresultatet av fältmätningarna är att hög koherens nödvändig för interferometriska mätningar går att uppnå med relativ lång tid mellan mätepokerna. Flera faktorer som påverkar resultatet diskuteras, som det observerade områdets reflektivitet, radar bild matchningen och den illuminerande geometrin.
12
Paloumbi, Vassia Vasiliki. "Monitoring large strain deformation in the processing of polyethylene pipes." Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497537.
Full text
13
Swaroop, N. R. Sathya. "Processing And High Temperature Deformation Of Pure And Magnesia Doped Alumina." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/180.
Full textAbstract:
Creep resistance is an important design criterion at high temperatures especially when continuous attempts are made to increase the efficiencies by increasing the operating temperatures. Alumina is an important high temperature material and in addition to that it is used in wide variety of applications such as substrates for electronic packaging, spark plugs, envelopes for sodium vapour lamps, cutting tools (when reinforced with silicon carbide) and in artificial joint prostheses.
Studies on creep in alumina. have started as early as 1961. There are differing mechanisms proposed to explain the creep behaviour of alumina in the literature, but until now there is no any unanimous decision as to what the rate controlling mechanism is. Magnesia doped at ppm levels can produce significant changes in the microstructure of alumina, the most important consequence of that being the grain growth inhibition, which renders alumina superplastic. However, in a stoichiometric oxide like alumina, small impurities can create extrinsic defects which would change the diffusivities and creep rates. Therefore the background impurities in alumina should be kept to a minimum, if small dopant effects have to be studied. The present study was undertaken making use of high purity alumina powder and comparing the grain growth and creep properties of pure and magnesia doped alumina, especially since no such investigation was carried out in the recent past with high purity alumina.
Pure alumina was processed by cold compaction followed by cold isostatic pressing (CIP) and pressureless sintering in air at 1773 K for 1 hour. Magnesia doped alumina was prepared by calcining a mixture of alumina and magnesium nitrate at 973 K for 2 hours followed by cold compaction, CIPing and pressureless sintering in air at 1773 K. Both pure and magnesia doped alumina were further annealed at 1873 K for various times to get grain sizes in the ranges of 1-5 μm.
Grain growth kinetics of pure and magnesia doped alumina were studied at 1823 and 1873 K. The parameter Kg which quantifies the mobility of the grain boundary was got. It was found that Kg had decreased in the magnesia doped alumina (in comparison with pure alumina) by a factor of about 3 to 4 which was marginal and insignificant. The grain sizes followed a log normal distribution in both the cases, indicative of normal grain growth.
Creep studies were conducted on pure and magnesia doped alumina in three modes, namely, constant stress, temperature jump and stress jump test. The temperature range used was 1673 to 1773 K and the stress range used was 10 to 100 MPa. The creep parameters were found to be n~1.6, p~3.7 and Q-545 kJ mol"1 for pure alumina and n~l .3, p~3.0 and Q~460 kJ mol-1 for magnesia doped alumina. The creep rates in the case of magnesia doped alumina were found to have increased by a factor of 2 to 3, in comparison with pure alumina. The increase in creep rates were found to be insignificant. The creep data were analyzed and the possibility of the dislocation and interface reaction controlled creep mechanisms were ruled out since they were inconsistent with the data. It was found, from creep parameters and the comparison of theoretical Coble and Nabarro-Herring creep rates with the experimental rates, that Coble creep might be rate controlling. The activation energy values suggested that aluminium ion diffusing along grain boundary might be the rate controlling species. However, when the theoretical creep rates considering various species were compared, the rate controlling species turned out to be oxygen ion diffusing along the grain boundary.
14
Janssen, Volker Surveying & Spatial Information Systems Faculty of Engineering UNSW. "A mixed-mode GPS network processing approach for volcano deformation monitoring." Awarded by:University of New South Wales. School of Surveying and Spatial Information Systems, 2003. http://handle.unsw.edu.au/1959.4/20771.
Full textAbstract:
Ground deformation due to volcanic magma intrusion is recognised as an important precursor of eruptive activity at a volcano. The Global Positioning System (GPS) is ideally suited for this application by being able to measure three-dimensional coordinate changes of the monitoring points over time. Due to the highly disturbed ionosphere in equatorial regions, particularly during times of maximum solar activity, a deformation monitoring network consisting entirely of single-frequency GPS receivers cannot deliver baseline solutions at the desired accuracy level. In this thesis, a mixed-mode GPS network approach is proposed in order to optimise the existing continuous single-frequency deformation monitoring system on the Papandayan volcano in West Java, Indonesia. A sparse network of dual-frequency GPS receivers surrounding the deformation zone is used to generate empirical 'correction terms' in order to model the regional ionosphere. These corrections are then applied to the single-frequency data of the inner network to improve the accuracy of the results by modelling the residual atmospheric biases that would otherwise be neglected. This thesis reviews the characteristics of existing continuously operating GPS deformation monitoring networks. The UNSW-designed mixed-mode GPS-based volcano deformation monitoring system and the adopted data processing strategy are described, and details of the system's deployment in an inhospitable volcanic environment are given. A method to optimise the number of observations for deformation monitoring networks where the deforming body itself blocks out part of the sky, and thereby significantly reduces the number of GPS satellites being tracked, is presented. The ionosphere and its effects on GPS signals, with special consideration for the situation in equatorial regions, are characterised. The nature of the empirically-derived 'correction terms' is investigated by using several data sets collected over different baseline lengths, at various geographical locations, and under different ionospheric conditions. Data from a range of GPS networks of various sizes, located at different geomagnetic latitudes, including data collected on Gunung Papandayan, were processed to test the feasibility of the proposed mixed-mode deformation monitoring network approach. It was found that GPS baseline results can be improved by up to 50% in the midlatitude region when the 'correction terms' are applied, although the performance of the system degrades in close proximity to the geomagnetic equator during a solar maximum.
15
Janssen, V. "A mixed-mode GPS network processing approach for volcano deformation monitoring." School of Surveying and Spatial Information Systems, The University of New South Wales, 2003. http://eprints.utas.edu.au/510.
Full textAbstract:
Ground deformation due to volcanic magma intrusion is recognised as an important precursor of eruptive activity at a volcano. The Global Positioning System (GPS) is ideally suited for this application by being able to measure three-dimensional coordinate changes of the monitoring points over time. Due to the highly disturbed ionosphere in equatorial regions, particularly during times of maximum solar activity, a deformation monitoring network consisting entirely of single-frequency GPS receivers cannot deliver baseline solutions at the desired accuracy level. In this thesis, a mixed-mode GPS network approach is proposed in order to optimise the existing continuous single-frequency deformation monitoring system on the Papandayan volcano in West Java, Indonesia. A sparse network of dual-frequency GPS receivers surrounding the deformation zone is used to generate empirical 'correction terms' in order to model the regional ionosphere. These corrections are then applied to the single-frequency data of the inner network to improve the accuracy of the results by modelling the residual atmospheric biases that would otherwise be neglected. This thesis reviews the characteristics of existing continuously operating GPS deformation monitoring networks. The UNSW-designed mixed-mode GPS-based volcano deformation monitoring system and the adopted data processing strategy are described, and details of the system's deployment in an inhospitable volcanic environment are given. A method to optimise the number of observations for deformation monitoring networks where the deforming body itself blocks out part of the sky, and thereby significantly reduces the number of GPS satellites being tracked, is presented. The ionosphere and its effects on GPS signals, with special consideration for the situation in equatorial regions, are characterised. The nature of the empirically-derived 'correction terms' is investigated by using several data sets collected over different baseline lengths, at various geographical locations, and under different ionospheric conditions. Data from a range of GPS networks of various sizes, located at different geomagnetic latitudes, including data collected on Gunung Papandayan, were processed to test the feasibility of the proposed mixed-mode deformation monitoring network approach. It was found that GPS baseline results can be improved by up to 50% in the mid-latitude region when the 'correction terms' are applied, although the performance of the system degrades in close proximity to the geomagnetic equator during a solar maximum.
16
Kamil, Ridha. "Processing improvement of moiré interferometry for accurate crack-tip deformation measurement." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=1962.
Full textAbstract:
Thesis (M.S.)--West Virginia University, 2001.<br>Title from document title page. Document formatted into pages; contains v, 81 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 80-81).
17
Begg, Henry S. "Processing, structure and properties of Al-matrix composites." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:6b825394-f5a0-4087-a89a-1ec6ca091426.
Full textAbstract:
Three classes of Al-matrix composite were manufactured to combine dissimilar metals and incorporate structural hierarchy, in an attempt to develop unusual combinations of mechanical properties. The first class combined a brittle, nano-quasicrystalline forming Al-3Fe-2Cr-2Ti phase with a ductile Al-4Cu phase into a layered structure using low pressure plasma spraying (LPPS). By using a substrate with multi-scale topological features, an ultra-thick (>2mm) deposit was successfully sprayed, which was subsequently consolidated by hot rolling to reduce residual porosity. The microstructure comprised a 'brick-wall' structure consisting of a convoluted arrangement of inter-leaved discreet droplet splats. Structure-property relationships were studied for four volume fractions of ductile additions and in-situ electron microscopy of beams subjected to 3-point bending suggested the ductile additions were providing additional toughening to the composite by a crack-bridging mechanism. The second class of composite investigated highly deformed microstructures of Al with 20vol% additions of either Sn or Ti. Nano-scale fibrous structures of the minority additions were achieved via an accumulative extrusion method, where extruded rod was abraded, degreased, bundled and re-extruded. This process was repeated to create refined microstructures while retaining a large material section. Fracture properties were studied in three point bending and crack growth monitored using Digital Image Correlation (DIC) to produce strain fields of the deforming beam surface. Modest changes were observed in mechanical properties with weak interfaces between poorly bonded extruded rods dominating fracture behaviour. Whiskers formed on polished surfaces of extruded Al-20vol%Sn and were monitored in real time by electron microscopy. Growth rates of up to 2.8nm/s were measured, which exceeds re- ported values in the literature on electroplated coatings by at least one order of magnitude. This may provide a convenient new means of studying whisker formation and calls into question current growth models. The third class of composite combined heavily rolled sheets of Al-20vol%Sn and Al-20vol%Ti with glass fibre/epoxy sheets to produce a laminate with multi-scale architecture. This laminate was designed as a proof-of-concept hierarchical material with structures ranging from the near millimetre scale of the metal-polymer layers, to the micro-sized glass fibre reinforcement of the epoxy and the nano-scale filamentary/lamellar microstructure of the highly deformed metal sheets. Fracture of such laminates was investigated in 3-point bending with continuous optical monitoring.
18
Tam, Ming Sin. "Some surface deformation algorithms with applications in footwear design /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?IEEM%202003%20TAM.
Full textAbstract:
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.<br>Includes bibliographical references (leaves 93-95). Also available in electronic version. Access restricted to campus users.
19
Mohammed, Peshawa. "Deformation monitoring using GNSS:A study on a local network with preset displacements." Thesis, Högskolan i Gävle, Samhällsbyggnad, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-30153.
Full textAbstract:
In the past two decades, the number of observations and the accuracy of satellite-basedgeodetic measurements like Global Navigation satellite systems (GNSS) greatly increased,providing measured values of displacements and velocities of permanent geodetic stations.Establishment of the geodetic control networks and collecting geodetic observations, indifferent epochs, are a commonly used method for detection of displacements andconsequently disaster management. Selecting proper processing parameters for differenttypes of monitoring networks are critical factors of the deformation monitoring analysisusing GNSS, which is the main aim of this research. In this study, a simulation study and acontrolled survey were performed using simultaneous GNSS measurements of 5 geodeticpillars, established by Lantmäteriet at Gävle airport. Sensitivity analyses were performed ondifferent types of monitoring networks using different set of processing paarameters . Thesescenarios consider different sets of parameters, different types of monitoring networks, andvarious number of monitoring stations to evaluate the detectable displacements andcompare with the known millimeter displacements (simulated one). The results showed thatthe selection of processing parameters depends on the type and size of the monitoringnetwork and the location of the monitoring stations. Analyses also show that onlineprocessing services can provide mm-cm level accuracy for displacement detection ifsufficient observation time is available. Finally, checks were performed on the two ofsample scenarios to find the minimum observation time required for reaching to the mostaccurate simulated (preset) displacements.
20
Pierce, Frank Allen. "The isothermal deformation of nickel aluminum bronze in relation to friction stir processing." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://handle.dtic.mil/100.2/ADA430658.
Full textAbstract:
Thesis (M.S. in Mechanical Engineering) Naval Postgreaduate School, June 2004.<br>Thesis Advisor (s): Terry R. McNelley. "June 2004." Includes bibliographic references (p. 53-54). Also available in print.
21
Duvvuru, Hari Kishore Kalidindi Surya. "Spectral methods for modeling microstructure evolution in deformation processing of cubic polycrystalline metals /." Philadelphia, Pa. : Drexel University, 2007. http://hdl.handle.net/1860/2711.
Full text
22
Chen, Pei. "Volumetric reconstruction and real-time deformation modeling of biomedical images." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 6.09 Mb., p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3220796.
Full textAbstract:
Thesis (Ph.D.)--University of Delaware, 2006.<br>Principal faculty advisors: Kenneth E. Barner, Dept. of Electrical and Computer Engineering; and Karl V. Steiner, Delaware Biotechnology Institute. Includes bibliographical references.
23
Boldetti, Carlo. "Multi-scale measurement and modelling of large deformation of structural metals during thermomechanical processing." Thesis, University of Sheffield, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434486.
Full text
24
Orsetti, Rossi Pedro Luis. "Effects of multipass deformation on the recrystallisation behaviour of commercial aluminium alloys during thermomechanical processing." Thesis, University of Sheffield, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307946.
Full text
25
Donoghue, Jack. "Hybrid additive manufacture and deformation processing for large scale near-net shape manufacture of titanium aerospace components." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/hybrid-additive-manufacture-and-deformation-processing-for-large-scale-nearnet-shape-manufacture-of-titanium-aerospace-components(5bb9e7db-824e-46e2-a832-c2780e15d6b8).html.
Full textAbstract:
The titanium alloy Ti-6Al-4V has been favoured by the aerospace industry for the past several decades due to its good combination of specific mechanical properties, alongside corrosion and fatigue resistance. Titanium alloys are naturally suited to the near net shape processing technique of Additive Manufacture (AM) due to both the inherent high cost of the raw materials, and the difficulties associated with machining the alloys. Unfortunately, the combination of Ti-6Al-4V with AM has been found to lead to undesirable microstructures with respect to large columnar prior β grains being found to grow potentially across the entire height of builds. This microstructure has been shown to lead to property anisotropy and poor fatigue resistance. However, it has recently been found that the integration of an additional process step that lightly deforms the deposited material between added layers leads to the refinement of this undesirable microstructure. This work characterises the effect that two different deformation processing techniques have on two different additive manufacturing processes; the effect of peening on a laser-powder AM technique, and the effect of rolling on an electric arc-wire AM technique. In both cases far more randomly textured prior β grains were found with an average grain size of > 100 µm rather than mm long columnar grains with a common growth direction formed in the non-deformed builds. The refined β microstructure was found to lead to a reduction in texture of the room temperature alpha phase. The low stains involved (>10%) indicated that the refined grain structures did not form by traditional recrystallisation mechanisms. In-situ EBSD measurements at temperatures spanning the alpha → β phase transformation have been used to observe the growth of new β orientations from crystallographic twins in the deformed microstructure that may explain the origin of the refined grains. New β orientations were observed to grow from twinned alpha colonies and from between alpha laths, where the new β is found to grow sharing a twinning relationship with the residual β. Simulation of both of the individual processing steps under laboratory conditions has been found to successfully replicate the refinement observed in process. Orientation analysis suggests that twinning of the residual β could lead to the texture observed in the refined grains. It is therefore suggested that the refined grains are formed from β twinned regions in the deformed material growing under the alpha → β phase transformation, as the material is heated by the next added layer during AM.
26
Peng, Xuan. "Co-deformation and bonding of multi-component billets with application to Nb-Sn based superconductor processing." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1127096847.
Full textAbstract:
Thesis (Ph. D.)--Ohio State University, 2005.<br>Title from first page of PDF file. Document formatted into pages; contains xix, 182 p.; also includes graphics (some col.). Includes bibliographical references (p. 177-182). Available online via OhioLINK's ETD Center
27
Johnston, Andrew A. "An integrated model of the development of process-induced deformation in autoclave processing of composite structures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0030/NQ27172.pdf.
Full text
28
Kyriazis, Panagiotis A. "Analysis and processing of mechanically stimulated electrical signals for the identification of deformation in brittle materials." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/4604.
Full textAbstract:
The fracture of brittle materials is of utmost importance for civil engineering and seismology applications. A different approach towards the aim of early identification of fracture and the prediction of failure before it occurs is attempted in this work. Laboratory experiments were conducted in a variety of rock and cement based material specimens of various shapes and sizes. The applied loading schemes were cyclic or increasing and the specimens were tested to compression and bending type loading of various levels. The techniques of Pressure Stimulated Current and Bending Stimulated Current were used for the detection of electric signal emissions during the various deformation stages of the specimens. The detected signals were analysed macroscopically and microscopically so as to find suitable criteria for fracture prediction and correlation between the electrical and mechanical parameters. The macroscopic proportionality of the mechanically stimulated electric signal and the strain was experimentally verified, the macroscopic trends of the PSC and BSC electric signals were modelled and the effects of material memory to the electric signals were examined. The current of a time-varying RLC electric circuit was tested against experimental data with satisfactory results and it was proposed as an electrical equivalent model. Wavelet based analysis of the signal revealed the correlation between the frequency components of the electric signal and the deformation stages of the material samples. Especially the increase of the high frequency component of the electric signal seems to be a good precursor of macrocracking initiation point. The additional electric stimulus of a dc voltage application seems to boost the frequency content of the signal and reveals better the stages of cracking process. The microscopic analysis method is scale-free and thus it can confront with the problems of size effects and material properties effects. The AC conductivity time series of fractured and pristine specimens were also analysed by means of wavelet transform and the spectral analysis was used to differentiate between the specimens. A non-destructive technique may be based on these results. Analysis has shown that the electric signal perturbation is an indicator of the forthcoming fracture, as well as of the fracture that has already occurred in specimens.
29
Neilson, Henry Jathuren. "Mechanical Behavior and Microstructural Evolution during Hot Deformation of Aluminum 2070." Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case152302739582634.
Full text
30
Page, Gavin S. "An investigation of techniques in deformable object recognition /." Link to online version, 2005. https://ritdml.rit.edu/dspace/handle/1850/1184.
Full text
31
Griffiths, Robert Joseph. "Dynamic and Post-Dynamic Microstructure Evolution in Additive Friction Stir Deposition." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/104664.
Full textAbstract:
Metal additive manufacturing stands poised to disrupt multiple industries with high material use efficiency and complex part production capabilities, however many technologies deposit material with sub-optimal properties, limiting their use. This decrease in performance largely stems from porosity laden parts, and asymmetric solidification-based microstructures. Solid-state additive manufacturing techniques bypass these flaws, using deformation and diffusion phenomena to bond material together layer by layer. Among these techniques, Additive Friction Stir Deposition (AFSD), stands out as unique for its freeform nature, and thermomechanical conditions during material processing. Leveraging its solid-state behavior, optimized microstructures produced by AFSD can reach performance levels near, at, or even above traditionally prepared metals. A strong understanding of the material conditions during AFSD and the phenomena responsible for microstructure evolution. Here we discuss two works aimed at improving the state of knowledge surrounding AFSD, promoting future microstructure optimization. First, a parametric study is performed, finding a wide array of producible microstructures across two material systems. In the second work, a stop-action type experiment is employed to observe the dynamic microstructure evolution across the AFSD material flow pathway, finding specific thermomechanical regimes that occur within. Finally, multiple conventional alloy systems are discussed as their microstructure evolution pertains to AFSD, as well as some more unique systems previously limited to small lab scale techniques, but now producible in bulk due to the additive nature of AFSD.<br>Doctor of Philosophy<br>The microstructure of a material describes the atomic behavior at multiple length scales. In metals this microstructure generally revolves around the behavior of millions of individual crystals of metal combined to form the bulk material. The state and behavior of these crystals and the atoms that make them up influence the strength and usability of the material and can be observed using various high fidelity characterization techniques. In metal additive manufacturing (i.e. 3D printing) the microstructure experiences rapid and severe changes which can alter the final properties of the material, typical to a detrimental effect. Given the other benefits of additive manufacturing such as reduced costs and complex part creation, there is desire to predict and control the microstructure evolution to maximize the usability of printed material. Here, the microstructure evolution in a solid-state metal additive manufacturing, Additive Friction Stir Deposition (AFSD), is investigated for different metal material systems. The solid-state nature of AFSD means no melting of the metal occurs during processing, with deformation forcing material together layer by layer. The conditions experienced by the material during printing are in a thermomechanical regime, with both heating and deformation applied, akin to common blacksmithing. In this work specific microstructure evolution phenomena are discussed for multiple materials, highlighting how AFSD processing can be adjusted to change the resulting microstructure and properties. Additionally, specific AFSD process interactions are studied and described to provide better insight into cumulative microstructure evolution throughout the process. This work provides the groundwork for investigating microstructure evolution in AFSD, as well as evidence and results for a number of popular metal systems.
32
RAJESHWAR, REDDY ELETI. "Deformation Mechanisms and Microstructure Evolution in HfNbTaTiZr High Entropy Alloy during Thermo-mechanical Processing at Elevated Temperatures." Doctoral thesis, Kyoto University, 2019. http://hdl.handle.net/2433/242505.
Full textAbstract:
京都大学<br>0048<br>新制・課程博士<br>博士(工学)<br>甲第21767号<br>工博第4584号<br>新制||工||1714(附属図書館)<br>京都大学大学院工学研究科材料工学専攻<br>(主査)教授 辻 伸泰, 教授 乾 晴行, 教授 安田 秀幸<br>学位規則第4条第1項該当<br>Doctor of Philosophy (Engineering)<br>Kyoto University<br>DFAM
33
vechalapu, uday bhaskar. "Real-Time 2D Digital Image Correlation to Measure Surface Deformation on Graphics Processing Unit using CUDA C." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1522108261138081.
Full text
34
Gong, Peng. "The precipitation behaviour and the formation of deformation induced ferrite during a new type of thermomechanical processing." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/12677/.
Full textAbstract:
A new type of thermomechanical processing with rough rolling below the recrystallisation-stop temperature (T5%), followed by a rapid reheat to 1200 °C for 10 s, and then finish rolling at the same temperature as the rough rolling, was investigated to better understand the kinetics of strain-induced precipitates (SIP). In addition, the deformation-induced ferrite transformation (DIFT) during the finishing passes was investigated as an efficient method to achieve the ultrafine ferrite grains. For comparative purposes, two experimental 0.06 wt% C steels were studied; one with 0.03 wt% Nb (Nb steel), and another one with both 0.03 wt% Nb and 0.02 wt% Ti (Nb-Ti steel). To understand SIP behaviour and its effect on the recrystallisation, six different rough rolling temperatures were used in the range of 850-1100°C. The full recrystallisation temperature (Tl) and recrystallisation stop temperature (Ts) contributions of the precipitates start temperature were determined using the Dutta and Sellars’s model approach on the basis of optical microscopy (OM) and transmission electron microscopy (TEM) characterization. It was found that there were mixed structures after rolling at 950 °C in Nb and Nb-Ti steels, which is consistent with the Tl (960 °C in Nb steel) and Ts (950 °C) by Dutta and Sellars’s model. The number density and volume fraction of SIP increased as the rolling temperature was decreased, consistent with the prediction that the nose of the precipitates-time-temperature diagrams (PTT) is at 840 °C in both steels. The orientation relationship (OR) between precipitates and ferrite matrix has been identified by analysis of selection area electron diffraction patterns. While obeying OR, the nanoscale particles precipitated in the austenite region during deformation. After the roughing schedule, with the final roughing pass taking place at 850 °C, the steels were rapidly reheated at a rate of 10 °C/sec to a temperature of 1200 °C, held at temperature for various times, and water quenched to room temperature. Then, both the precipitate dissolution kinetics, together with the austenite grain coarsening kinetics was established as a function of the holding time at 1200 °C. The importance to subsequent finish rolling was then used for the final part of the project. Finally, processing these steels consisted of a simulated roughing rolling schedule with the final roughing pass taking place at 850 °C, followed by rapidly reheating at a rate of 10°C/sec to a temperature of 1200 °C, held at temperature for 10 s and 100 s, and then air cooled to the final rolling temperature of 850 °C followed by deformation using different parameters. The effect of different rolling and reheating parameters on the microstructures and the SIP was fully analysed using various techniques. This thermomechanical process route resulted in DIFT, with ferrite nucleated primarily on the prior-austenite grain boundaries. The ferrite/martensite phase transformation temperature was increased by the heat treatment at 1200 °C. The volume fraction of SIP after finish rolling was influenced by the supersaturation of microalloyed elements in solution during heat treatment. The variation of micro-hardness correlated well with the change of volume fraction of SIP and DIFT, as well as the refinement of prior-austenite grain size.
35
Cakmak, Gulhan. "The Processing Of Mg-ti Powder For Hydrogen Storage." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613102/index.pdf.
Full textAbstract:
A study was carried out on the selection of processing condition that would yield Mg-Ti with most favourable hydrogenation properties. Processing routes under consideration were<br>mechanical milling under inert atmosphere, reactive milling i.e. milling under hydrogen atmosphere, ECAP (equal channel angular pressing) and thermal plasma synthesis. Structure resulting from each of these processing routes was characterized with respect to size reduction, coherently diffracting volume and the distribution of Ti catalyst.
Mechanical milling yielded a particulate structure made up of large Mg agglomerates with embedded Ti fragments with a uniform distribution. Mg agglomerates have sizes larger than 100 µ<br>m which arises as a result of a balance between cold welding process and ductile fracture. Repeated folding of Mg particles entraps Ti fragments inside the Mg agglomerates resulting in a very uniform distribution. Coherently diffracting volumes measured by X-ray Rietveld analysis have small sizes ca. 26 nm which implies that the agglomerates typically comprise 1011 crystallites. Mechanical milling under hydrogen, i.e. reactive milling, led to drastic reduction in particle size. Mg and Ti convert to MgH2 and TiH2 which are milled efficiently due to their brittleness resulting in particle sizes of sub-micron range. Hydrogenation experiments carried out on Mg-10 vol % Ti milled under argon yields enthalpy and entropy values of -76.74 kJ/mol-H2 and -138.64 J/K.mol-H2 for absorption and 66.54 kJ/mol H2 and 120.12 J/K.mol H2 for desorption, respectively. For 1 bar of hydrogen pressure, this corresponds to a hydrogen release temperature of 280 °<br>C. This value is not far off the lowest desorption temperature reported for powder processed Mg based alloys.
ECAP processing is a bulk process where the powders, consolidated in the first pass, have limited contact with atmosphere. This process which can be repeated many times lead to structural evolution similar to that of milling, but for efficient mixing of phases it was necessary to employ multi-pass deformation. An advantage of ECAP deformation is strain hardening of the consolidated powders which has improved milling ability. Based on this, a new route was proposed for the processing of ductile hydrogen storage alloys. This involves several passes of ECAP deformation carried out in open atmosphere and a final milling operation of short duration under inert atmosphere.
The plasma processing yields Mg particles of extremely small size. Evaporation of Mg-Ti powder mixture and the subsequent condensation process yield Mg particles which are less than 100 nm. Ti particles, under the current experimental condition used, have irregular size distribution but some could be quite small, i.e. in the order of a few tens of nanometers.
Of the four processing routes, it was concluded that both reactive milling and thermal plasma processing are well suited for the production of hydrogen storage alloys. Reactive milling yield particles in submicron range and plasma processing seems to be capable of yielding nanosize Mg particles which, potentially, could be decorated with even smaller Ti particles.
36
Paradinas, Salsón Teresa. "Simplification, approximation and deformation of large models." Doctoral thesis, Universitat de Girona, 2011. http://hdl.handle.net/10803/51293.
Full textAbstract:
The high level of realism and interaction in many computer graphic applications requires techniques for processing complex geometric models. First, we present a method that provides an accurate low-resolution approximation from a multi-chart textured model that guarantees geometric fidelity and correct preservation of the appearance attributes. Then, we introduce a mesh structure called Compact Model that approximates dense triangular meshes while preserving sharp features, allowing adaptive reconstructions and supporting textured models. Next, we design a new space deformation technique called *Cages based on a multi-level system of cages that preserves the smoothness of the mesh between neighbouring cages and is extremely versatile, allowing the use of heterogeneous sets of coordinates and different levels of deformation. Finally, we propose a hybrid method that allows to apply any deformation technique on large models obtaining high quality results with a reduced memory footprint and a high performance.<br>L’elevat nivell de realisme i d’interacció requerit en múltiples aplicacions gràfiques fa que siguin necessàries tècniques pel processament de models geomètrics complexes. En primer lloc, presentem un mètode de simplificació que proporciona una aproximació precisa de baixa resolució d'un model texturat que garanteix fidelitat geomètrica i una correcta preservació de l’aparença. A continuació, introduïm el Compact Model, una nova estructura de dades que permet aproximar malles triangulars denses preservant els trets més distintius del model, permetent reconstruccions adaptatives i suportant models texturats. Seguidament, hem dissenyat *Cages, un esquema de deformació basat en un sistema de caixes multi-nivell que conserva la suavitat de la malla entre caixes veïnes i és extremadament versàtil, permetent l'ús de conjunts heterogenis de coordenades i diferents nivells de deformació. Finalment, proposem un mètode híbrid que permet aplicar qualsevol tècnica de deformació sobre models complexes obtenint resultats d’alta qualitat amb una memòria reduïda i un alt rendiment.
37
McCracken, Leahanne. "The Thermo-Mechanical processing of commercially pure aluminium through the application of simple shear deformation and heat treatment." Thesis, University of Ulster, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489975.
Full textAbstract:
In an attempt to achieve the high strength requirements for modem applications, today's advanced metallic materials are enhanced through strengthening mechanisms such as solid solution strengthening or cold workmg. The disadvantage associated with these mechanisms is the subsequent loss in ductility. This reduction also has a significant effect on the formability of materials. For example this is a particular disadvantage in the aerospace industry were the curvature of sheet components are limited by their formability. This project investigates an alternative strengthening mechanism in an attempt to maintain ductility.
38
Azary, Sherif. "Detection of deformable objects in a non-stationary scene /." Link to online version, 2005. https://ritdml.rit.edu/dspace/handle/1850/1178.
Full text
39
Popov, Mikhail [Verfasser]. "Enhancement of mechanical properties of different magnesium alloys due to grain refinement by severe plastic deformation processing / Mikhail Popov." Clausthal : [Univ.-Bibliothek], 2007. http://d-nb.info/988801175/34.
Full text
40
Philipp, Katrin, Angelos Filippatos, Nektarios Koukourakis, et al. "In-process deformation measurements of translucent high speed fibre-reinforced disc rotors." SPIE, 2015. https://tud.qucosa.de/id/qucosa%3A35189.
Full textAbstract:
The high stiffness to weight ratio of glass fibre-reinforced polymers (GFRP) makes them an attractive material for rotors e.g. in the aerospace industry. We report on recent developments towards non-contact, in-situ deformation measurements with temporal resolution up to 200 µs and micron measurement uncertainty. We determine the starting point of damage evolution inside the rotor material through radial expansion measurements. This leads to a better understanding of dynamic material behaviour regarding damage evolution and the prediction of damage initiation and propagation. The measurements are conducted using a novel multi-sensor system consisting of four laser Doppler distance (LDD) sensors. The LDD sensor, a two-wavelength Mach-Zehnder interferometer was already successfully applied for dynamic deformation measurements at metallic rotors. While translucency of the GFRP rotor material limits the applicability of most optical measurement techniques due to speckles from both surface and volume of the rotor, the LDD profits from speckles and is not disturbed by backscattered laser light from the rotor volume. The LDD sensor evaluates only signals from the rotor surface. The anisotropic glass fibre-reinforcement results in a rotationally asymmetric dynamic deformation. A novel signal processing algorithm is applied for the combination of the single sensor signals to obtain the shape of the investigated rotors. In conclusion, the applied multi-sensor system allows high temporal resolution dynamic deformation measurements. First investigations regarding damage evolution inside GFRP are presented as an
important step towards a fundamental understanding of the material behaviour and the prediction of damage initiation and propagation.
41
Plumeri, John Edward. "Development and Application of a Numerical Model for the Prediction of Hot Deformation Processing of a Novel ZE20 Magnesium Alloy." Thesis, Lehigh University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10815301.
Full textAbstract:
<p> A numerical model was developed for the prediction of flow stress evolution and high temperature extrusion formability for a new high ductility magnesium alloy with primary alloying elements of 2.4 %wt. Zn and 0.2 %wt. Ce, designated as ZE20. The ultimate goal for the implementation of the model is for the prediction of extrusion properties of this new alloy; the study presented herein proved to successfully simulate the flow stress evolution and extrusion behavior of the ZE20 magnesium alloy in a range of conditions verified by physical experiments. Hot compression flow stress experiments were carried out for the determination of the plastic deformation characteristics of the new alloy at strain rates and temperatures typically encountered in industrial extrusion forming of magnesium alloys. Additionally, indirect and direct extrusion experiments were designed, simulated, and carried out for development of, and comparison with, the numerical model for simulation in DEFORM-3D™. Ultimately, it was shown that the numerical model accurately predicted high-strain plastic flow stress values as compared with experiments for the new alloy as well as strain, strain rate, and temperature values within the formed extrudate, which are consistent with previous studies and microsctructural findings for this material having undergone high temperature extrusion processing. Specifically, a uniform, equiaxed, fully recrystallized microstructure was observed across longitudinal weld seams in a hollow experimental automotive beam extrudate. It was shown that the temperatures developed within the billet in the weld chamber reach sufficiently high enough levels to drive full recrystallization and, thus, superior seam weld quality. It was also predicted by the model, and verified by physical results, that there is a threshold for extrusion speed for this particular alloy, at fixed tooling conditions. It has thus been demonstrated that the numerical flow stress model package developed for implementation in deformation software simulation packages such as, but not limited to, DEFORM-3D™ accurately predicts strain, strain rate, and temperature conditions for high temperature forming operations of the new magnesium alloy ZE20, allowing for the design of industrial processes which can produce high quality microstructure and mechanical properties in extruded solid or hollow profiles.</p><p>
42
Stellmar, Justin. "Predicting the Deformation of 3D Printed ABS Plastic Using Machine Learning Regressions." Youngstown State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1587462911261523.
Full text
43
Yapici, Guney Guven. "Investigation and modeling of processing-microstructure-property relations in ultra-fine grained hexagonal close packed materials under strain path changes." Thesis, [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1578.
Full text
44
Lipscomb, Celena Andrea. "Modeling of Fracture Toughness of Magnesium Alloy WE43 Before and After Friction Stir Processing." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc955106/.
Full textAbstract:
Magnesium alloys are a popular research topic for structural applications because they have a lower density than conventional structural materials, including steel, titanium, and aluminum; however, the reliability and safety of their mechanical properties must be further proven. An important mechanical property for this purpose is fracture toughness, which is the measure of the material's resistance to crack propagation. In this study, a model of an experiment to investigate the fracture toughness of a magnesium alloy WE43 before and after friction stir processing (FSP) is developed, and the results are compared to those produced by a digital image correlation (DIC) system during an experiment from another paper. The model results of the material before FSP matched well with the DIC results, but the model of the material after FSP only partially matches the DIC results. In addition, a theoretical approach to calculating the standard fracture toughness value, KIc, from the modeling results is proposed, and is found to be a conservative approach.
45
Lorenzi, Marco. "Deformation-based morphometry of the brain for the development of surrogate markers in Alzheimer's disease." Phd thesis, Université de Nice Sophia-Antipolis, 2012. http://tel.archives-ouvertes.fr/tel-00844577.
Full textAbstract:
The aim of the present thesis is to provide an e ffective computational framework for the analysis and quantifi cation of the longitudinal structural changes in Alzheimer's disease (AD). The framework is based on the diffeomorphic non-rigid registration parameterized by stationary velocity fields (SVFs), and is hierachically developed to account for the diff erent levels of variability which characterize the longitudinal observations of T1 brain magnetic resonance images (MRIs). We developed an effi cient and robust method for the quantifi cation of the structural changes observed between pairs of MRIs. For this purpose, we propose the LCC-Demons registration framework which implements the local correlation coeffi cient as similarity metric, and we derived consistent and numerically stable measures of volume change and boundary shift for the regional assessment of the brain atrophy. In order to consistently analyze group-wise longitudinal evolutions, we then investigated the parallel transport of subject-specifi c deformation trajectories across di fferent anatomical references. Based on the SVF parametrization of diffeomorphisms, we relied on the Lie group theory to propose new and effective strategies for the parallel transport of SVFs, with particular interest into the practical application to the registration setting. These contributions are the basis for the defi nition of qualitative and quantitative analysis for the pathological evolution of AD. We proposed several analysis frameworks which addressed the di fferentiation of pathological evolutions between clinical populations, the statistically powered evaluation of regional volume changes, and the clinical diagnosis at the early/prodromal disease stages.
46
Fei, Xiao Lei. "Hybrid segmentation on slant & skewed deformation text in natural scene images." Thesis, University of Macau, 2010. http://umaclib3.umac.mo/record=b2182857.
Full text
47
Yingsheng, Xing. "Finite Element Analysis of Drop Deformation in the Entrance Region of a Cylindrical Tube." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1302535388.
Full text
48
Hammes, Daniel Markus [Verfasser]. "Data processing, 3D grain boundary modelling and analysis of in-situ deformation experiments using an automated fabric analyser microscope / Daniel Markus Hammes." Mainz : Universitätsbibliothek Mainz, 2017. http://d-nb.info/114906577X/34.
Full text
49
Fujiyama-Novak, Jane Hitomi. "The Role of Nanoclay on the Deformation Behavior of Polypropylene/Maleic Anhydride Modified Polypropylene Films and Fibers in Full and Partially Molten State Processing." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1247696958.
Full text
50
Karatza, Zeynep. "A study of temporal and spatial evolution of deformation and breakage of dry granular materials using x-ray computed tomography and the discrete element method." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/28722.
Full textAbstract:
Particles exist in great abundance in nature, such as in sands and clays, and they also constitute 75% of the materials used in industry (e.g., mineral ores, formulated pharmaceuticals, dyes, detergent powders). When a load is applied to a bulk assembly of soil particles, the response of a geomaterial at the bulk (macro) scale, originates from the changes that take place at the particle scale. If particle breakage occurs, the shape and size of the particles comprising the bulk are changed; this induces changes in the contact network through which applied loads are transmitted. As a result, changes at the micro-scale can significantly affect the mechanical behaviour of a geomaterial at a macro-scale. It is therefore unsurprising that the mechanisms leading to particle breakage are a subject of intense research interest in several fields, including geomechanics. In this thesis, particle breakage of two dry granular materials is studied, both experimentally and numerically. The response of the materials is investigated under different stress paths and in all the tests grain breakage occurs. High resolution x-ray computed micro-tomography (XCT) is used to obtain 3D images of entire specimens during high confinement triaxial compression tests and strain controlled oedometric compression tests. The acquired images are processed and measurements are made of the temporal and spatial evolution of breakage, local variations of porosity, volumetric and shear strain and grading. The evolution and spatial distribution of quantified breakage including the resulting particle size distribution for the whole specimen and for specific areas, are presented and further related to the localised shear and volumetric strains that developed in the specimens. In addition, the discrete element method (DEM) was used to provide further micro-mechanical insight of the underlying mechanisms leading to particle breakage. Classical DEM simulations, using a Hertz-Mindlin contact model and non-breakable spheres, was first deployed to study the initiation and likelihood of particle breakage under oedometric compression. Moreover, a bonded DEM model was used to create clumps that represent each particle and simulate breakage of particles under single particle compression. The DEM model parameters were obtained from results of single particle compression test and the models were validated against the quantitative 3D information of the micro-scale, acquired from the XCT analysis.