Teses / dissertações sobre o tema "Freeformer"
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Le, Boterff Julien. "Compréhension des phénomènes physico-chimiques impliqués dans la réalisation de pièces polyoléfines par fabrication additive". Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Lille Douai, 2019. http://www.theses.fr/2019MTLD0012.
Additive Manufacturing (AM) concerns are growing the last years due to the capabilities brought by the technology. Indeed, the AM processes offer the possibility to simply and rapidly create 3D parts with specific geometries, difficult or impossible to obtain with conventional processes. A new technology called Freeformer supplied by ARBURG (Germany) allows to manufacture high quality 3D parts using standard-commercial pellets. Contrary to the standard FDM processes, feedstock materials are cheap and any thermoplastic polymer can be theoretically employed. The Freeformer technology is based on two injection molding units that enables to melt the standard pellets and to feed the printing head. The discharge unit featuring a pulsed nozzle closure generates small (down to 200 μm) molten polymer droplets to build, layer-by-layer, three-dimensional parts in a thermoregulated chamber. Even if 3D parts are easily fabricated by using standard materials (ABS, TPU, …), the process parameters have to be optimized before getting good-quality parts with all other polymers, which consumes times and materials. In the same way than for a conventional polymer processing technology the choice of appropriate grades and the optimization of the associated processing parameters are needed. Hence, the different phenomenon which occur during a part realisation have to be examined in the case of a non-standard material in AM: polypropylene (PP). To optimize the structure and the mechanical properties of the parts, a common approach is to practice a parametric study. This time-consuming approach is not always efficient. Thus, the aim of this work, cofounded by the Région Hauts de France, is to understand the correlations between materials properties and process parameters
Wheelwright, Brian. "Freeform Solar Concentrating Optics". Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/577087.
Guo, Jing. "Freeform Rammed Earth Shell Construction". University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1491312964445038.
Wang, Yu. "Efficient modeling methods for freeform objects /". View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?MECH%202006%20WANG.
Sachlos, Eleftheherios. "Tissue engineering with solid freeform fabrication". Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418645.
Wedowski, Raphael David. "Dynamic inspection of specular freeform surfaces". Thesis, University of the West of England, Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572902.
Fournier, Florian. "FREEFORM REFLECTOR DESIGN WITH EXTENDED SOURCES". Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3146.
Ph.D.
Optics and Photonics
Optics and Photonics
Optics PhD
Kim, David. "Freeform 3D interactions in everyday environments". Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2575.
Dharmaraj, Karthick. "Automated freeform assembly of threaded fasteners". Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/19624.
Uthoff, Ross D., Rachel N. Ulanch, Kaitlyn E. Williams, Diaz Liliana Ruiz, Page King e R. John Koshel. "Designing a freeform optic for oblique illumination". SPIE-INT SOC OPTICAL ENGINEERING, 2017. http://hdl.handle.net/10150/627186.
Rice, Christopher S. (Christopher Scott). "Solid freeform fabrication using semi-solid processing". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/32166.
Hong, Zhihan, e Rongguang Liang. "IR-laser assisted additive freeform optics manufacturing". NATURE PUBLISHING GROUP, 2017. http://hdl.handle.net/10150/625522.
Park, Seok-min. "Advanced data exchange for solid freeform fabrication /". Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p3004352.
Blumberg, LottaGili(LottaGili G. ). "Exploring fabrication principles for making freeform breadBoards". Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/123005.
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019
Cataloged from student-submitted PDF version of thesis. "June 2019."
Includes bibliographical references (pages 53-55).
CurveBoards are 3D breadboards integrated into the surface of physical prototypes. CurveBoards offer both the flexibility of breadboards, i.e., the ability to add or remove components, while also integrating well with the shape of the prototype. Thus, designers can use CurveBoards to test function directly in context of the actual physical form. We demonstrate our method for fabricating the CurveBoard in which designers only have to 3D print the housing and then fill the wire channels with conductive silicone. We also discuss limitations to this approach and alternative fabrication methods. We display a range of different application scenarios and report on a user study with six participants that showed that prototypes created as CurveBoards looked and felt closer to the final design.
by LottaGili Blumberg.
M. Eng.
M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
Dutta, Anirban. "Study and enhancement of electrophotographic solid freeform fabrication". [Gainesville, Fla.]: University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE0000527.
Sasian, Jose, e Yufeng Yan. "Miniature camera lens design with a freeform surface". SPIE-INT SOC OPTICAL ENGINEERING, 2017. http://hdl.handle.net/10150/627187.
Moghimi, Mahdi. "Formex configuration processing of compound and freeform structures". Thesis, University of Surrey, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435092.
Stevens, Adam G. "A robotic system for photopatteming of freeform surfaces". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101485.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 79-88).
Additive manufacturing by photopolymerization (e.g., stereolithography) is attractive due to its high resolution and its compatibility with soft and hard polymers, composites, and biomaterials. While traditional stereolithography machines are designed to build on planar substrates, patterning of non-planar surfaces would enable integration of new functionality onto existing objects for applications such as structurally integrated sensors, conformal electronics, and customized medical implants. This thesis presents the design, construction, and initial performance evaluation of a robotic system capable of maskless photopatterning on objects having complex curvature and dimensions ranging from centimeters to meters. The system incorporates a six-axis serial robot arm, a high-precision rotary stage, a custom-built DLPbased end effector, and custom software that coordinates and controls the system. The workpiece is patterned by first digitally triangulating the surface with a 3D scanner and associating the location of each triangle in the digital space with the corresponding location on the workpiece surface in real space. Subsequently, the area enclosed by each triangle is associated with a user-specified texture photomask. The large-area photopattern is then fabricated by sequentially exposing each individual textured triangle in the photomask as the robot steps to each corresponding location on the workpiece surface, which is coated with a photocurable polymer. By measuring patterning results on a test object, the system was determined to have a positioning accuracy over a subsection of the working volume of 330tm and a repeatability of 20pm was measured by a motion test. The system positioning accuracy is limited by performance of the actuators and the kinematics of the manipulator. System patterning rate is limited by the power output of the light source. The system's performance is demonstrated by patterning a 21cm diameter sphere with a map of the Earth and performing a preliminary test on the patellar surface of an anatomical femur model. Future work will focus on improving the system accuracy by mapping the workspace using a coordinate measuring machine and increasing throughput by a combination of increased optical power and more efficient use of the projection field of view. The system will also be investigated as an enabling technology for deterministically patterning cartilage cells onto joint surfaces or three-dimensional anatomical models.
by Adam G. Stevens.
S.M.
Kim, Dae Wook, Chang-jin Oh, Andrew Lowman, Greg A. Smith, Maham Aftab e James H. Burge. "Manufacturing of super-polished large aspheric/freeform optics". SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622422.
Kasichainula, Sridhar. "Multilayered ceramic/metal composites by extrusion freeform fabrication". Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/280308.
Souvignier, Chad William. "Solid freeform fabrication of highly loaded composite materials". Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/284190.
Schoech, Alexander. "Quality control of freeform parts at elevated temperature". Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424502.
Le moderne industrie manifatturiere si trovano ad operare in una condizione di forte stress economico, ma allo stesso tempo con richieste dal mercato sempre più complesse. Ad esempio, se da un lato i processi produttivi aumentano la proprio complessità, dall’altro, le tolleranze richieste, le dimensioni dei lotti e il “time-to-market” si riducono sempre più. Questo andamento, per certi versi contradditorio, richiede l’adozione di processi produttivi sempre più sofisticati e tecniche avanzate per il controllo della qualità e del processo. L’obbiettivo di questo lavoro è di analizzare, in un processo produttivo complesso come quello delle palette per turbina, il controllo qualità e l’ottimizzazione di processo per lotti ridotti col fine di abbassare i costi legati alla produzione. Nel processo in analisi, le palette per turbina vengono forgiate a caldo e poi raffreddate in aria calma fino al raggiungimento della temperatura ambiente in modo da poter essere successivamente lavorate tramite macchine a controllo numerico. Le attuali tecnologie di misura rendono possibile il primo controllo dimensionale solo a valle del completo raffreddamento, che può richiedere fino a diverse ore. Date le dimensioni dei lotti tipicamente ridotte, spesso, la forgiatura di un intero lotto viene completata prima che sia stato possibile verificare la geometria del primo pezzo; ciò implica che potenzialmente può essere prodotto un intero lotto fuori tolleranza. Dopo la fase di forgiatura, il controllo dimensionale viene focalizzato alla ricerca dei sovrametalli, che, nel caso siano superiori al valore imposto in fase di progetto comporteranno un aumento dei costi di lavorazione a macchina, diversamente, qualora siano inferiori, porteranno a scartare il pezzo appena prodotto. A seguito di queste considerazioni si comprende l’importanza di anticipare la fase di controllo qualità, ma per fare ciò, non solo è importante essere in grado di misura ad elevate temperature occorre anche sviluppare dei modelli per la comprensione degli effetti distorsivi indotti dal raffreddamento così da prevedere la geometria finale. Ciò diventa un punto cruciale per le geometrie sottili e "freeform" che caratterizzano la foglia di una paletta per turbina. Inoltre, per ottimizzare il processo in base ai risultati delle misurazioni, è necessario comprendere le tolleranze e i costi legati all’ottimizzazione. Infatti, l’ottimizzazione dei parametri di processo durante le fasi iniziali di produzione di un lotto, essenziali per la corretta lavorazione di un componente, comportano rallentamenti e conseguenti costi. Lotti di ridotte dimensioni ne vengono maggiormente penalizzati. Di conseguenza è necessario sviluppare una procedura per determinare quando valga la pena fermare il processo di ottimizzazione. In questo lavoro, un sistema di misura basato sulla triangolazione laser per misura dimensionale di pezzi ad elevata temperatura viene presentato e discusso. Per ragioni di visualizzazione e misurazione, un algoritmo euristico, per la ricostruzione di superfici a partire da nuvole di punti, è stato adattato per superfici libere e concave come quelle che caratterizzano le palette per turbina. Data la rapidità dell’algoritmo è possibile visualizzare la geometria in contemporanea alla misura, permettendo all’operatore di monitorare qualitativamente l’andamento della misura. Le cause di incertezza principali del sistema di misura sono state identificate, quantificate e, se necessario, corrette. In particolare, nel caso di geometrie tipo "freeform", è stata dimostrata l’importanza di una miglior procedura di settaggio dei sensori. Un nuovo metodo per la taratura di sistemi multisensore è stato sviluppato ed è in grado di garantire tempi di settaggio cinque volte inferiori rispetto ai metodi manuali. Grazie alle correzioni proposte, l’ottimizzazione di processo per piccoli lotti di palette per turbina diventa possibile. Un metodo per la valutazione del numero ottimale di iterazioni durante il processo di ottimizzazione è disponibile in letteratura per una specifica combinazione di cosi asimmetrici e variabilità del processo tramite la valutazione del costo atteso ("expected cost"). Una nuova formulazione e un appropriato approccio numerico sono proposti per valutare i costi attesi con variabilità di processo e modello di costo arbitrari. A partire da queste considerazioni, due criteri generalizzati per decidere quando fermare l’ottimizzazione sono proposti, ognuno con particolari vantaggi in specifiche applicazioni. Le prestazioni di queste procedure sono comparate ad un esistente modello allo stato dell’arte, portando una riduzione dei costi pari al 90% quando le misurazioni vengono effettuate solamente durante la fase di ottimizzazione. Infine, una procedura complessiva per l’ottimizzazione di processo, incorporando i metodi proposti, verrà discussa.
Chen, Tiebing. "Analysis and modeling of direct selective laser sintering of two-component metal powders". Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/5818.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (November 15, 2006) Vita. Includes bibliographical references.
Kaya, Ilhan. "Mathematical and Computational Methods for Freeform Optical Shape Description". Doctoral diss., University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5959.
Ph.D.
Doctorate
Electrical Engineering and Computing
Engineering and Computer Science
Computer Engineering
Smyth, Evan P. (Evan Patrick) 1967. "Designing aesthetically pleasing freeform surfaces in a computer environment". Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/70339.
Includes bibliographical references (p. 151-160).
Statement: If computational tools are to be employed in the aesthetic design of freeform surfaces, these tools must better reflect the ways in which creative designers conceive of and develop such shapes. In this thesis, I studied the design of aesthetically constrained freeform surfaces in architecture and industrial design, formulated a requirements list for a computational system that would aid in the creative design of such surfaces, and implemented a subset of the tools that would comprise such a system. This work documents the clay modeling process at BMW AG., Munich. The study of that process has led to a list of tools that would make freeform surface modeling possible in a computer environment. And finally, three tools from this system specification have been developed into a proof-of-concept system. Two of these tools are sweep modification tools and the third allows a user to modify a surface by sketching a shading pattern desired for the surface. The proof-of-concept tools were necessary in order to test the validity of the tools being presented and they have been used to create a number of example objects. The underlying surface representation is a variational expression which is minimized using the finite element method over an irregular triangulated mesh.
by Evan P. Smyth.
Ph.D.
Nace, John G. (John Gregory) 1955. "A surface texture modeling system for solid freeform fabrication". Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43605.
Includes bibliographical references (leaves 83-84).
Solid Freeform Fabrication, SFF, is a set of manufacturing processes that fabricates parts as a bonded stack of individual layers. The Three Dimensional Printing process, 3DPTM process, is an SFF technology developed at MIT. It builds layers by ink jet printing binder onto the surface of a bed of powder. The bed of powder is lowered and fresh powder is spread onto the bed. As subsequent cross sections of the part are printed, the part exists, submerged in the powder bed. Access to the individual layers as they are fabricated gives access to the interior structure of the part. This approach allows the part to have high geometric complexity. In this work a designer centric Computer Aided Design system is proposed to allow the interactive creation of functional surface texture on mechanical parts. This system is structured to behave like a VLSI CAD system, which offers substantial process capabilities. The requirements for a Mechanical CAD, MCAD, system to behave like VLSI CAD are determined to be: 1. That the informational model of the unit cell of texture be separable into distinct logical subsets.2. That manipulations on either subset not violate the logical consistency of the other subset. This thesis shows that geometric dimensions and tolerances carry the essential information of the model of a unit cell of functional texture. A variety of Unit Cell editors are evaluated according to their ability to meet the desired system criteria. A tool, Swiss Solid Geometry, SSG, for the design of unit cells of functional texture is developed, that fulfills requirement #1. SSG is an approach to MCAD modeling that combines geometric primitives in the manner of Constructive Solid Geometry, however the primitives of SSG, are different. They consist of simple objects such as lines, but includes the spatial envelope around them of a fixed offset. Also, they are used to represent both positive and negative regions of space. The placement of the individual replications is established by a mesh, that covers the intended 3D surface region. A meshing algorithm is developed that regularizes the mesh by directly utilizing the dimensional tolerances specified in the process of Unit Cell design. The geometric dimensions are instantiated as standalone geometric entities that push and pull on the nodes of the mesh in order to bring their length into dimensional tolerance. This method fulfills requirement #2, and it is implemented into a CAM software called Vari 4. The modularity of the CAM software, Vari 4, is described in detail.
by John G. Nace.
S.M.
Bristow, Kelly H. "Freeform Cursive Handwriting Recognition Using a Clustered Neural Network". Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc804845/.
Gannon, Caleb, e Rongguang Liang. "Ray mapping with surface information for freeform illumination design". OPTICAL SOC AMER, 2017. http://hdl.handle.net/10150/624040.
Yarkinoglu, Onur. "Computer Aided Manufacturing (cam) Data Generation For Solid Freeform Fabrication". Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608834/index.pdf.
Simpson, Leon. "Geometric algebra as applied to freeform motion design and improvement". Thesis, University of Bath, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558894.
Li, Likai. "Design, Fabrication and Metrology of Precision Molded Freeform Plastic Optics". The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1412162892.
Fay, James Edward. "Electrostatic analysis of and improvements to electrophotographic solid freeform fabrication". [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001397.
Jowers, Iestyn. "Computation with curved shapes : towards freeform shape generation in design". Thesis, Open University, 2007. http://oro.open.ac.uk/43671/.
Wang, Changling. "Sketch based 3D freeform object modeling with non-manifold data structure /". View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?MECH%202002%20WANGC.
Includes bibliographical references (leaves 143-152). Also available in electronic version. Access restricted to campus users.
Xu, Jinye, e 徐金叶. "Two-photon photochemical crosslinking-based fabrication of protein microstructures". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47179223.
published_or_final_version
Mechanical Engineering
Master
Master of Philosophy
Ma, Jiaoni, e 馬姣妮. "Multiphoton based biofabrication of 3D protein micro-structures and micro-patterns : voxel and cell matrix niche studies". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208048.
Zhao, Wenchuan, Logan R. Graves, Run Huang, Weihong Song e DaeWook Kim. "Iterative surface construction for blind deflectometry". SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622001.
Williams, Kaitlyn Elizabeth, e Kaitlyn Elizabeth Williams. "Parametrizing Freeform Optical Surfaces for the Optimized Design of Imaging and Illumination Systems". Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/624141.
Zhu, Zhengbo, Donglin Ma, Qiaomu Hu, Yongqian Tang e Rongguang Liang. "Catadioptric freeform optical system design for LED off-axis road illumination applications". OPTICAL SOC AMER, 2017. http://hdl.handle.net/10150/626573.
Reshidko, Dmitry, e Jose Sasian. "A method for the design of unsymmetrical optical systems using freeform surfaces". SPIE-INT SOC OPTICAL ENGINEERING, 2017. http://hdl.handle.net/10150/627183.
Lu, Lin Zhou Jack. "Biomimetic porogen freeform fabrication and biopolymer injection methods for bone tissue scaffolds /". Philadelphia, Pa. : Drexel University, 2007. http://hdl.handle.net/1860/2714.
Heard, David. "Rapid solidification of an aluminum-lithium alloy for solid freeform fabrication applications". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117033.
Le comportement de solidification d'un alliage aluminium-lithium (Al-Li), AA2199, et la morphologie microstructurale des distributions de soluté de trois techniques rapides de traitement de solidification ont été étudiés. Contrôle de court-circuit métallique de gaz inerte (CSC-MIG), Re-fondrement au Laser (LRM), et dépôt d'électro-érosion (ESD), ont été étudiés. La morphologie microstructurale du matériel solidifié rapidement a ensuite été comparée au modèle Kurz-Giovanola-Trivedi (KGT) qui décrit le développement microstructurale lors de la solidification rapide afin de permettre l'estimation de la vitesse du front de solidification (SFV) apparaissant au cours du traitement. Cet SFV a ensuite été comparé à celui des partitions de soluté non-équilibrés prédit par le modèle de croissance continue d'Aziz. Les distributions de soluté ont ensuite été mesurées et comparées à celles prédites pour l'éffet de partage à l'équilibre et hors d'équilibre afin de déterminer si le phénomène de piégeage de soluté a été incité au cours du solidification.Le matériel déposé par CSC-MIG affiche une structure cellulaire très fine(4,3 ± 1 micron) et comparable à celle rapportée antérieurement pour le soudage par faisceau d'électrons. L'estimation de l'SFD est d'environ 2-4.5x10-4m / s. Ceci est inférieure à celle requise pour causer une déviation de partition à l'équilibre comme prévu par le CGM. L'analyse chimique par EDS et TOF-SIMS a révélé une ségrégation latérale de cuivre sur les parois cellulaires et un profil de ségrégation semblable à celui prédit par le modèle Clyne-Kurz. Time-Of-Flight-secondary-Ion Mass Spectroscopy-(TOF-SIMS) a révélé une distribution latérale homogène de lithium. Cependant, le profile en profondeur affiche une certaine quantité d'enrichissement de lithium à la surface du matériel déposé.Au sein du matériel LRM, il a été déterminé que les énergies de pulsation au laser à l'ordre de 0,125 à 0,5 Joules causent une structure cellulaire de solidification fine. Il a ensuite été estimé que des vitesses de front de solidification (SFV) entre 3 et 25 cm / s ont été atteints au cours de la solidification. Le CGM pour le piégeage des solutés a prédit une déviation des partitions à l'équilibre lors de la solidification pour tous niveaux d'énergie de pulsation employés. Ce phénomène a été appuyé par le profile chimique de lithium dans les échantillons refondus et mesurés à l'aide du spectroscopie de photoélectrons au rayons X (XPS). Les mesures du paramètre du réseau crystalline par diffraction de rayons X (XRD) ont révélé que le phénomène de piégeage de soluté donne lieu à la formation d'une solution saturée super-solide, ce qui est démontré par une réduction du paramètre du réseau de 4,0485 Å pour le matériel de départ comparé à 4,0399 Å pour le matériel refondu avec une énergie de pulsation de 0,125 joule.L'analyse de la matière solidifiée par ESD a révélé la désintégration de l'interface planaire solide-liquide en une morphologie cellulaire qui entraîne la présence de cellules fines riches en cuivre à l'intérieure de la microstructure (~ 30-60nm de largeur). Le modèle déduit par KGT prédit que ceci se produit à un SFV d'environ 1m / s. Le CGM prédit une piégeage significatif de lithium à une SFV de 1 m / s, ce qui a été soutenu par les données TOF-SIMS qui ont révélé une distribution homogène de lithium dans le matériel solidifié. Ensuite, la tomographie par sonde d'atoms a révélé la présence de la phase Al3Li sur les parois des cellules riches en cuivre. De plus, il a été déterminé que le Al3Li n'a pas été formé lors de la solidification. Ceci est prédit par un modèle temporel de nucléation qui sert à la prédiction de la suppression de phases au cours de la solidification rapide, et donc le résultat est un processus de vieillissement antérieur.
Khan, Usman M. "An investigation of freeform surface induction from freehand sketches using neural networks". Thesis, Brunel University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439792.
Reis, Nuno. "Solid freeform fabrication of ceramics by controlled droplet deposition of particulate suspensions". Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249617.
Samji, Isaac Chandra Annie Shalom [Verfasser]. "Intelligent Freeform Deformation for LED Illumination Optics / Annie Shalom Samji Isaac Chandra". Karlsruhe : KIT Scientific Publishing, 2018. http://www.ksp.kit.edu.
Somthong, Thammarat. "3D freeform surface measurement on coordinate measuring machine using photometric stereo method". Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/15270.
Jiang, Caigui. "Geometric Rationalization for Freeform Architecture". Diss., 2016. http://hdl.handle.net/10754/615127.
Liu, Yen-Liang, e 劉彥良. "Freeform Design: Progressive Addition Lens". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/65787346340106589815.
臺灣大學
光電工程學研究所
98
Optical systems are composed by various of optical elements, such as lenses and mirrors. In order to achieve different purpose, positions, materials, and surface shapes of the optical elements can be regulated. Among these specifications, regulating surface shapes of the optical elements is an issue that is worth researching. In early age, the surface shapes of lens or mirrors are spherical. For the sake of decreasing optical aberrations or other purpose, aspherical or freeform surfaces may be adapted. Although it is more difficult to design or manufacture, progress of computer power and manufacture technology have made the applications of aspherical and freeform elements more and more various. In order to achieve better performance of optical systems, designing aspherical and freeform surfaces are worth more concerns. In the thesis, freeform surfaces are applied to progressive Addition lenses (PAL), A PAL can combine different requirements of diopter on one lens, avoiding the necessity of a presbyopic changing different pairs of spetacles while viewing far side and near side. B-spline surfaces are used to describe the freeform surfaces applied on PALs in the thesis. The designs are achieved by optimization. Sample PALs are also produced and measured to show the feasibility. The simulation and measurement result shows that the performance of view zone area and cylinder are equal or even better to modern products.
"Intuitive freeform modeling using subdivision surfaces". 2005. http://library.cuhk.edu.hk/record=b5892524.
Thesis submitted in: November 2004.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references (leaves 100-102).
Abstracts in English and Chinese.
Abstract --- p.i
摘要 --- p.ii
Acknowledgment --- p.iii
List of Figures --- p.iv
Table of Content --- p.vii
Chapter 1. --- Introduction --- p.1
Chapter 1.1. --- Problem Definition --- p.1
Chapter 1.2. --- Proposed Solution --- p.2
Chapter 1.3. --- Thesis Contributions --- p.2
Chapter 2. --- Modeling Approaches --- p.4
Chapter 2.1. --- Polygon Modeling --- p.4
Chapter 2.2. --- Patch Modeling --- p.6
Chapter 2.3. --- Freehand Sketch-based Modeling --- p.7
Chapter 2.4. --- Template Based Modeling --- p.8
Chapter 2.5. --- Curve Interpolation Method --- p.9
Chapter 3. --- Surface Operations --- p.11
Chapter 3.1. --- Surface Blending --- p.11
Chapter 3.2. --- Surface Trimming --- p.13
Chapter 3.3. --- Boolean Operations --- p.14
Chapter 4. --- Subdivision Surface --- p.16
Chapter 4.1. --- Basic Principle --- p.16
Chapter 4.2. --- Catmull-Clark Surface --- p.17
Chapter 5. --- Modeling Algorithm Overview --- p.21
Chapter 6. --- Subdivision Surface Generation --- p.23
Chapter 6.1. --- Input Curves --- p.23
Chapter 6.2. --- Surface Sweeping --- p.24
Chapter 6.3. --- Subdivision Surface Fitting --- p.29
Chapter 7. --- Surface Blending --- p.32
Chapter 7.1. --- Introduction --- p.32
Chapter 7.2. --- Problem Definition --- p.32
Chapter 7.3. --- Algorithm Overview --- p.36
Chapter 7.4. --- Blend Region Detection --- p.39
Chapter 7.4.1. --- Collision Detection --- p.40
Chapter 7.4.2. --- Result and Analysis --- p.42
Chapter 7.5. --- "Mesh Refinement, Surface Fitting and Region Removal" --- p.46
Chapter 7.5.1. --- Mesh Refinement --- p.46
Chapter 7.5.1.1. --- Adaptive Subdivision --- p.46
Chapter 7.5.1.2. --- Additional Subdivision Constraint --- p.47
Chapter 7.5.2. --- Surface Fitting --- p.49
Chapter 7.5.2.1. --- General Approach --- p.49
Chapter 7.5.2.2. --- Surface Point Correspondence --- p.50
Chapter 7.5.2.3. --- Numerical Fitting Method --- p.51
Chapter 7.5.3. --- Unwanted Region Removal --- p.55
Chapter 7.5.4. --- Result and Analysis --- p.56
Chapter 7.6. --- Boundary Smoothing --- p.58
Chapter 7.6.1. --- General Approach --- p.59
Chapter 7.6.2. --- Constraint on Deformation Direction of Vertex --- p.61
Chapter 7.6.3. --- Result and Analysis --- p.63
Chapter 7.7. --- Blend Curves --- p.65
Chapter 7.7.1. --- Problem Definition --- p.65
Chapter 7.7.2. --- Proposed Solution Overview --- p.66
Chapter 7.7.3. --- Maintenance of Regular Vertex Valence along Blend Curve --- p.67
Chapter 7.7.3.1. --- Pairing Up Blend Boundary Vertices --- p.70
Chapter 7.7.4. --- Minimization of Distortion Caused by Extraordinary Vertices --- p.72
Chapter 7.7.5. --- Blend Vertex Position Optimization Function --- p.74
Chapter 7.7.5.1. --- Face Normal Expression --- p.74
Chapter 7.7.5.2. --- Face Normal Difference Energy Function --- p.77
Chapter 7.7.5.3. --- Midpoint Distance Energy Function --- p.78
Chapter 7.7.5.4. --- Weighted Least Square Energy Minimization --- p.78
Chapter 8. --- Implementation --- p.81
Chapter 8.1. --- Data Structure --- p.81
Chapter 8.2. --- User Interface --- p.82
Chapter 9. --- Results --- p.83
Chapter 9.1. --- Surface Generation --- p.83
Chapter 9.2. --- Surface Blending --- p.86
Chapter 9.2.1. --- Ideal Case --- p.86
Chapter 9.2.2. --- Angle of Insertion --- p.87
Chapter 9.2.3. --- Surface Feature Near Intersection --- p.88
Chapter 9.2.4. --- Comparison --- p.89
Chapter 9.2.5. --- Other Examples --- p.92
Chapter 9.3. --- Overall Performance --- p.94
Chapter 9.4. --- Limitations --- p.97
Chapter 9.4.1. --- Limitation on Generated Shape --- p.97
Chapter 9.4.2. --- Limitation on Input Surfaces --- p.98
Chapter 10. --- Conclusion and Future Work --- p.99
References --- p.100
Tsai, Yu-Lin, e 蔡玉麟. "Freeform Surface for Non-image Optics". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/64076648144291730806.
國立交通大學
光電工程研究所
104
In this thesis, we propose freeform design model for constructing a single refractor (or reflector) surface under a predefined geometry. The freeform model based on energy conservation and ray propagation law can be characterized by a nonlinear partial differential equation (PDE) under the small planar approximation. The nonlinear PDE can be solved by finite element method with high order element to satisfy the condition of continuity (1st -order) and smoothness (2nd - order). To validate the proposed methodology, we use commercial software LightTools® , to evaluate the illumaninance performance via designed freeform engine in realization of uniform and non-uniform illuminance distribution on the planar.