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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Multi-Material 3D-Printed Silicone Vocal Fold Models

Young, Clayton Adam 23 May 2022 (has links)
Self-oscillating synthetic vocal fold (VF) models are often used to study human voice production. In this thesis, a method for fabricating multi-layer self-oscillating synthetic VF models using silicone 3D printing is presented. Multi-material 3D printing enables faster fabrication times with more complex geometries than traditional casting methods and builds a foundation for producing VF models with potentially more life-like geometries, materials, and vibratory characteristics. The printing method in this study used a custom dual extruder and slicing software to print UV-curable liquid silicone into a gel-like support matrix. The extruder was fabricated using high-torque stepper motors with high resolution leadscrews for precise extrusion and retraction. The custom slicing software accounted for challenges with printing a low-viscosity uncured silicone and was capable of allowing the user to visually observe the effects of print settings on print paths before finalizing the g-code. Three validation tests were conducted to demonstrate the 3D printer’s ability to print ultra-soft silicone with the desired range of stiffness, change between materials quickly, and print a material stiffness gradient. Two types of VF models were printed in this study, a previously-designed model with multiple distinct layers (“EPI” model), and the same model but with a vertical stiffness gradient (VSG) in the superficial lamina propria layer. The EPI model was chosen to demonstrate the ability to 3D print a multi-layer model, and the VSG model was chosen to demonstrate the ability to print multi-material VFs with geometric and material properties that are difficult to fabricate using traditional casting methods. Sixteen VFs (i.e., eight pairs) of each model type were printed, and their vibratory responses were recorded, including onset pressure, frequency, and glottal width. A micro-CT scanner was used to evaluate the external geometric accuracy of the models. One-centimeter cubes were 3D printed and tensile tested to characterize the material properties of each set of VF models. The material and phonatory properties of both the EPI and VSG VF models were found to be comparable to human data and to previous data acquired using synthetic VF models fabricated via other methods. In this thesis, the 3D printing methodology is summarized, the setup and results of the validation and VF model tests are reported and discussed, and recommendations for future work are provided.
2

3D-Multimaterialdruck für die Fertigung von Komponenten elektromagnetischer Energiewandler

Rudolph, Johannes, Lorenz, Fabian, Werner, Ralf 19 November 2019 (has links)
Bei dem 3D-Multimaterialdruck handelt es sich um ein Verfahren, mit dem es erstmals möglich ist, mehrere Materialien mit unterschiedlichen Eigenschaften in einem Arbeitsgang zu verdrucken. Um die geometrischen und physikalischen Beschränkungen aufzubrechen, wurde an der Professur Elektrischen Energiewandlungssysteme und Antriebe ein Verfahren entwickelt, mit dem es möglich wird, ganze elektromagnetische Energiewandler in einem Arbeitsgang herzustellen. Gleichzeitig lassen sich völlig neue Bauformen von Maschinen realisieren. Durch den Austausch von konventionellen Isolationsmaterialien durch Keramikisolation, werden die thermischen Eigenschaften von Elektromotoren signifikant verbessert.

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