<p>  </p> <p>This thesis is motivated by the author’s observation that no systematic methodology is available to characterize and model mechanical behaviors of 3D printed parts in terms of their elastic modulus and critical loading capacities. Note that the more controlled and steadier printing process is, the easier the mechanical properties parts can be predicted. This research focuses on the methods for the prediction and validation of mechanical properties of 3D printed parts, and the focus is the responses of the printed parts subjected to tensile loads. The mathematic models are derived to characterize the mechanical properties of a part along three principal directions, and the models are validated experimentally by following the American Society for Testing and Materials (ASTM) D638 testing standards. It is assumed that a unidirectional plane stress occurs to each lamina to (1) simplify a compliance matrix with a size 3 by 3 and (2) characterize the mechanical properties by the elastic modules and strengths in three principal directions. Two mathematical models are developed using the experimental data from the classical laminate theory and finite element analysis (FEA) by the SolidWorks. Both of the developed models are used to predict the ultimate tensile strength and Young’s modulus of the specimens that are printed by setting different raster angles on different layers. This thesis work aims to (1) gain a better understanding of the impact of printing parameters on the strengths of printed parts and (2) explore the feasibility of using the classical laminate theory to predict the mechanical properties of the parts printed with different raster angles and patterns. To validate the proposed mathematic models, parts by FDM are tested by following the ASTM testing standards; moreover, it testifies if the selected ASTM-D638 is suitable to test 3D printed parts by FDM. </p>

To better manage deteriorating infrastructure, quantitative data about the performance of infrastructure assets is required. Rayleigh based distributed fibre optic strain sensing (FOS) is a technology that has the potential to offer this type of data and unlike traditional strain sensors it can measure the strain along the full length of the structure. A series of experiments were undertaken to develop installation techniques and evaluate sensor accuracy for typical civil engineering materials: steel, concrete and reinforced concrete. The results of these experiments showed that the choice of sensing fibre and adhesive was dependent on the material being monitored. When the sensing fibre and adhesive are chosen correctly, the Rayleigh system can provide the same accuracy as a strain gauge for steel and concrete, and useful measurements can be obtained even in areas of concrete cracking. The FOS technique was utilized to determine whether distributed strain measurements could be used to detect and quantify localized deterioration of the steel reinforcement (localized area reductions of 0-30%) at service loads. A series of specimens was tested, the sensing system was able to detect the presence of localized deterioration with embedded nylon and polyimide fibres, but the nylon fibre cannot quantify large strain gradients due to slip within the sensing fibre. The strain profiles gave insights to the failure mechanism occurring in the reinforced concrete specimens. The strain profiles for both test series indicated that the tension reinforcement was acting as a tension tie and the strain profiles suggested the presence of compressive struts indicative of an arching mechanism in the specimens. The Black River bridge in Madoc, Ontario was instrumented with fibre optics sensors to determine whether the use of FOS is both practical and beneficial for reinforced concrete bridge assessment when compared to conventional instrumentation. The FOS showed reasonably good agreement with conventional sensors. The fibre optic strain results are used to calculate curvature, slope and displacement but careful consideration of the boundary conditions is required. The results from the fibre optic sensors can be used to show the bridge load distribution and give insights into the support conditions of the beams. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-08-21 11:56:53.276

Die Schriftenreihe „Werkstoffe und werkstofftechnische Anwendungen“ behandelt Themengebiete der Werkstoffwissenschaft und -technik, der Oberflächentechnik sowie deren industriellen Anwendungen. Es werden aktuelle Forschungsergebnisse aus den vier Professuren des Instituts für Werkstoffwissenschaft und Werkstofftechnik der TU Chemnitz vorgestellt: Professur Elektronenmikroskopie und Mikrostrukturanalytik, Professur Verbundwerkstoffe und Werkstoffverbunde, Professur Werkstoff- und Oberflächentechnik, Professur Werkstoffwissenschaft. Weiterhin sind in der Schriftenreihe die Tagungsbände des jährlich am Institut stattfindenden „Werkstofftechnischen Kolloquium“ enthalten. Die einzelnen Bände beschäftigen sich mit den Forschungsgebieten Galvanische Metallabscheidung, Anodisieren, Thermisches und Kaltgas-Spritzen, Löten, Verbundwerkstoffe, Werkstoffverbunde, Wärmebehandlung, CVD-Beschichtungen/PVD-Beschichtungen, Simulation in der Beschichtungstechnik, Organisches Beschichten (Pulverbeschichten, Lackieren, Sol-Gel-Verfahren), Elektrochemisches Strukturieren, Thermomechanische Behandlung und Mechanische Werkstoffeigenschaften. / The book series „Werkstoffe und werkstofftechnische Anwendungen“ outlines up-to-date topics of material science and engineering, surface engineering as well as resulting industrial applications. Mainly, recent research results of the departments Composite Materials and Surface Engineering/Functional Materials of the Institute of Material Science and Engineering of Chemnitz University of Technology are presented. In addition, the book series includes the proceedings of the annual in-house conference “Werkstofftechnisches Kolloquium”. The separate volumes concentrate on the following fields of scientific research: Galvanised Coating, Anodising, Thermal and Cold Spraying, Soldering and Brazing, Composite Materials, Composite Structures, Thermal and Thermomechanical Treatment, CVD and PVD Coating, Simulation of Coating Processes, Organic coating (Powder Coating, Varnishing, Sol-Gel Processes), Electrochemical Structuring and Mechanical Material Properties.

Die dielektrischen Eigenschaften, also die Interaktion mit elektrischen Feldern, sind ein wichtiger Qualitätsparameter der Matrix in Faserverbundmaterialien und allgemein in Harzen. Sie werden bisher mit Hilfe von kapazitiven Verfahren oder Hochfrequenzverfahren wie z. B. der Mikrowellentechnik gemessen. Allerdings können beide Verfahren nicht an elektrisch leitfähigen Materialien wie Kohlenstofffaserverstärkten Kunststoffen (CFK) eingesetzt werden und auch bei der Anwendung der Methoden an Kunststoffen oder elektrisch isolierenden Faserverbundmaterialien gibt es Nachteile. So benötigt die kapazitive Messtechnik meist eine spezielle Probenpräparation für quantitative Messungen und erreicht eine vergleichsweise schlechte Ortsauflösung beim Permittivitätsmapping. Die vorliegende Arbeit widmet sich daher der Untersuchung einer alternativen, in diesem Kontext neuen Methode zur Charakterisierung dielektrischer Eigenschaften: Die Hochfrequenzwirbelstrommesstechnik, welche bisher zur Messung der elektrischen Leitfähigkeit und magnetischen Permeabilität genutzt wird, wird theoretisch und praktisch hinsichtlich ihres Anwendungspotentials zur Permittivitätsmessung an Epoxidharzen und Faserverbundwerkstoffen diskutiert. Dabei werden zuerst Grundlagen wie Anwendungsfelder für die Nutzung dielektrischer Eigenschaften von Harzen und Verbundwerkstoffen zur Qualitätssicherung bzw. gängige Messverfahren erläutert. Anschließend wird theoretisch gezeigt, warum dielektrische Eigenschaften auf das Hochfrequenzwirbelstrom (HFWS)-Signal wirken. Dabei werden sowohl die Maxwell-Gleichungen genutzt, als auch Finite Elemente (FE)-Simulationen. Der Schwerpunkt der Forschungsarbeit liegt dann auf der experimentellen Untersuchung der Permittivitätsmessung mittels HFWS. Es werden verschiedene Anwendungsfälle betrachtet: von zeitlich kontinuierlichen Permittitivitätsänderungen (am Beispiel der Aushärtung von Epoxidharzen), über lokale Permittivitätsabweichungen (in Folge von Defekten, Textureigenschaften oder thermischen Überlasten) bis hin zu quantitativen Permittivitätsmessungen (zur Materialcharakterisierung bzw. Alterungsuntersuchung). Dabei kann gezeigt werden, dass es möglich ist, die Permittivität von Faserverbundwerkstoffen und Epoxidharzen mittels HFWS zu charakterisieren, selbst wenn das zu prüfende Material elektrisch nicht leitfähig ist.

В данной работе были рассмотрены различные испытательные машины, изучен принцип и особенности работы разрывной машины для статических испытаний металлов Р-10. Проведены расчеты геометрических параметров гидроцилиндров (основного рабочего и захватов), прочностной и расчет на устойчивость. Также, исходя из перечисленных расчетов подобран рабочий насос и среда – масло. Смоделированы детали модели в пакете программ SolidWorks, а в пакете MATLAB Simscape составлена сборка разрывной машины и добавлена система с гидроприводом. В результате исследования была получена имитационная модель статической разрывной машины для металлов, при помощи которой было проведено моделирование испытания на растяжение. Для этого был выбран образец стали известной марки с заранее определенными геометрическими параметрами. После чего к образцу были приложены различные усилия, и сняты показания удлинения образца. На основе этого был получен график. Затем с помощью данных усилие/перемещение и начальных геометрических параметров были рассчитаны пределы пропорциональности, текучести, прочности на основании которых и был определен материал образца. Данный пример демонстрирует правильность разработки подобных моделей в системе MATLAB, которые могут позволить провести детальные исследования процессов работы механизмов машины во время испытаний, в том числе оценить характеристики гидравлической системы разрывной испытательной машины. / In this dissertation, various testing machines were considered, the principle and features of the operation of a tensile testing machine for static testing of metals R-10 were studied. Calculations of the geometrical parameters of hydraulic cylinders (main working and grippers), strength and stability calculations were carried out. Also, based on the above calculations, a working pump and a medium - oil were selected. The details of the model were modeled in SolidWorks, and the tensile testing machine assembly was assembled in MATLAB Simscape and the hydraulic actuator system was added. As a result of the study, a simulation model of a static tensile testing machine for metals was obtained, with the help of which a simulation of a tensile test was carried out. For this, a sample of well-known brand steel with predetermined geometric parameters was selected. After that, various forces were applied to the sample, and indications of the elongation of the sample were taken. Based on this, a graph was obtained. Then, using the force / displacement data and the initial geometric parameters, the limits of proportionality, yield, strength were calculated, on the basis of which the sample material was determined. This example demonstrates the correctness of developing such models in MATLAB. They can make it possible to conduct detailed studies of the operation of the machine mechanisms during testing, including the evaluation of the characteristics of the hydraulic system of the tensile testing machine.

<p>Uobičajeni pristup i testiranju biolo&scaron;kog pona&scaron;anja materijala je da se počne sa jednostavnim in vitro testovima baziranim na ćelijskim kulturama. In vitro testovi citotoksičnosti su danas jedan od osnovnih načina za procenu biolo&scaron;kog odgovora na materijal jer su brži, lak&scaron;i za ponavljanje, ocenjivanje i jeftiniji u odnosu na eksperimente koji se izvode na životinjama i ljudima. Koriste se kao neka vrsta skrining testova za procenu biolo&scaron;ke sigurnosti materijala. Za razliku od ćelijskih kultura, istraživanja koja uključuju eksperimentalne životinje pružaju bolji uvid u biokompatibilnost materijala, zbog mogućnosti praćenja kompleksnog imunolo&scaron;kog odgovora živog organizma. Smatraju se neophodnim za ocenu bilo&scaron;kih odgovora na novi materijal, pre nego &scaron;to se on upotrebi na ljudima. Mnogi aspekti biolo&scaron;kog odgovora ne mogu biti reprodukovani in vitro testovima uključujući krvne interakcije, zarastanje rana, reakcije preosetljivosti, karcinogenezu, hroničnu inflamaciju. Eksperimenti na životinjama pružaju informacije o ovim tipovima efekata bez izlaganja ljudi riziku. Cilj ovog istraživanja bio je da se oceni biokompatibilnost objekata od polimera na bazi epoksi smole Accura&reg; ClearVue&trade; (hemijski sastav: 4,4&rsquo;- izopropilidendicikloheksanol, produkti oligomerne reakcije sa 1-hlor-2,3- epoksipropanom(40-65%), sme&scaron;а triaril-sulfonijum soli (50% propilen-karbonata i 50% triaril-sulfonijum heksafluoroantimonatnih soli) (1-10%) i 3-etil-3hidroksimetil-oksetan(10-20%). U oceni citotoksičnosti materijala Accura&reg; ClearVue&trade; kori&scaron;ćeni su agar diguzioni i MTT test. Oba testa rađena sun a ćelijskim kulturama L929 (mi&scaron;iji fibroblasti) i MRC-5 (humani fibroblasti). Ocena biokompatibilnosti testiranog materijala vr&scaron;ena je na osnovu urađenog testa iritacije oralne mukoze na modelu bukalne kesice hrčka, &scaron;to je definisano standardom ISO 10993-10:2010. Biokompatibilnost materijala ispitana je i implantacijom uzoraka u potkožno tkivo dorzuma pacova soja Wistar.</p> / <p>Uobičajeni pristup i testiranju biolo&scaron;kog pona&scaron;anja materijala je da se počne sa jednostavnim in vitro testovima baziranim na ćelijskim kulturama. In vitro testovi citotoksičnosti su danas jedan od osnovnih načina za procenu biolo&scaron;kog odgovora na materijal jer su brži, lak&scaron;i za ponavljanje, ocenjivanje i jeftiniji u odnosu na eksperimente koji se izvode na životinjama i ljudima. Koriste se kao neka vrsta skrining testova za procenu biolo&scaron;ke sigurnosti materijala. Za razliku od ćelijskih kultura, istraživanja koja uključuju eksperimentalne životinje pružaju bolji uvid u biokompatibilnost materijala, zbog mogućnosti praćenja kompleksnog imunolo&scaron;kog odgovora živog organizma. Smatraju se neophodnim za ocenu bilo&scaron;kih odgovora na novi materijal, pre nego &scaron;to se on upotrebi na ljudima. Mnogi aspekti biolo&scaron;kog odgovora ne mogu biti reprodukovani in vitro testovima uključujući krvne interakcije, zarastanje rana, reakcije preosetljivosti, karcinogenezu, hroničnu inflamaciju. Eksperimenti na životinjama pružaju informacije o ovim tipovima efekata bez izlaganja ljudi riziku. Cilj ovog istraživanja bio je da se oceni biokompatibilnost objekata od polimera na bazi epoksi smole Accura&reg; ClearVue&trade; (hemijski sastav: 4,4&rsquo;- izopropilidendicikloheksanol, produkti oligomerne reakcije sa 1-hlor-2,3- epoksipropanom(40-65%), sme&scaron;a triaril-sulfonijum soli (50% propilen-karbonata i 50% triaril-sulfonijum heksafluoroantimonatnih soli) (1-10%) i 3-etil-3hidroksimetil-oksetan(10-20%). U oceni citotoksičnosti materijala Accura&reg; ClearVue&trade; kori&scaron;ćeni su agar diguzioni i MTT test. Oba testa rađena sun a ćelijskim kulturama L929 (mi&scaron;iji fibroblasti) i MRC-5 (humani fibroblasti). Ocena biokompatibilnosti testiranog materijala vr&scaron;ena je na osnovu urađenog testa iritacije oralne mukoze na modelu bukalne kesice hrčka, &scaron;to je definisano standardom ISO 10993-10:2010. Biokompatibilnost materijala ispitana je i implantacijom uzoraka u potkožno tkivo dorzuma pacova soja Wistar.</p> / <p>The usual approach in testing biological behavior of materials is to start with simple in vitro tests based on cell cultures. In vitro cytotoxicity tests are one of the basic methods of assessing the biological response to material because they are faster, cheaper, easier for repeating and evaluating compared to experiments carried out on animals and humans. They are used as a kind of screening test for evaluating the biosafety of materials. Unlike cell culture, studies involving experimental animals provide better insight into the biocompatibility of materials due to the possibility of monitoring the complex immune response of a living organism. They are considered necessary for assessing the biological response to new material before it is used on humans. Many aspects of a biological response cannot be reproduced with in vitro tests, including blood interaction, wound healing, hypersensitivity reactions, carcinogenesis, chronic inflammation. Animal experiments provide information about these types of effects without exposing humans to risk.&nbsp; The aim of this study was to evaluate the biocompatibility of polymer objects on the basis of epoxy resins Accura&reg; ClearVue &trade; (chemical composition: 4.4&#39; Isopropylidenedicyclohexanol, oligomeric reaction products with 1-chloro-2.3-epoxypropane (40-65%), a mixture of triaryl sulfonium salt (50% propylene carbonate and 50% of a triarylsulfonium hexafluoroantimonate salt) (1- 10%) and 3-ethyl-3-hydroxymethyl-oxetane (10-20%). In the assessment of the cytotoxicity of materials Accura&reg; ClearVue &trade; agar diffusion and MTT tests were used. Both tests were conducted on cell cultures L929 (mouse fibroblasts) and MRC-5 (human fibroblasts). An assessment of the biocompatibility of the tested material was done on the basis of an oral mucosa irritation test on a hamster cheek pouch as defined by ISO 10993-10: 2010. The biocompatibility of the material was also tested with the implantation of a samples into the dorsal subcutaneous tissue of a Wistar rats. The subcutaneous implantation test, as one of the most reliable methods for assessing the biocompatibility of dental materials, is defined by ISO 10993-6: 2010. The study was conducted on 30 rats which were sacrificed in groups</p>