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Full-Text Articles in Engineering

Nanoenhanced Additive Manufacturing: Additive Introduction Onto Halloysite Nanotubes And Into 3d Printing Filament For Tailored Material Characteristics, James Connor Nicholson Jul 2015

Nanoenhanced Additive Manufacturing: Additive Introduction Onto Halloysite Nanotubes And Into 3d Printing Filament For Tailored Material Characteristics, James Connor Nicholson

Doctoral Dissertations

With the rapid advancement of additive manufacturing technologies in recent years on both the microscale and the macroscale, research must be done to test the limits of currently available technologies. On the microscale, halloysite nanotubes have proven to be a viable platform for reinforcement of polymers and time release of loaded chemicals, as well as a substrate material for the deposition of nanoparticles. The range of materials are limited due to polarity conflicts, and often lead to wet chemical processes that use more toxic alternatives. Three-dimensional (3D) printing and macroscale additive manufacturing techniques can be used to generate custom structures, …


Process Monitoring In Additive Manufacturing Aimed Toward Part Qualification, Shakerur Ridwan Jan 2015

Process Monitoring In Additive Manufacturing Aimed Toward Part Qualification, Shakerur Ridwan

Open Access Theses & Dissertations

Additive Manufacturing (AM), or layer-by-layer part fabrication, has played a tremendous role in the maker culture by allowing ideas to be materialized with limited resources or knowledge in manufacturing. Various cutting edge AM technologies exist today that are used to create end-use parts; however, these technologies are still new and the processes have not gone through the rigorous evaluation process that traditional manufacturing (i.e. milling, stamping, casting) methods have been through. As a result, several important questions arise when looking to adapt AM technology, including control of the manufacturing process, effect of manufacturing process on part properties, level of variance …


Freeze-Form Extrusion Fabrication Of Boron Carbide, Aaron Scott Thornton Jan 2015

Freeze-Form Extrusion Fabrication Of Boron Carbide, Aaron Scott Thornton

Masters Theses

"Boron carbide is a safe, alternative to beryllium as a material for aerospace structures since it is also light-weight and exhibits high strength. This paper discusses a study of the Freeze-form Extrusion Fabrication (FEF) process to fabricate parts from boron carbide. Process parameters and hardware were modified to fabricate boron carbide specimens free of printed defects. Four-point bending tests were performed to measure the flexural strength of fabricated specimens. Observations of the presence of voids caused by ice crystals in fabricated parts led to further development and characterization of the boron carbide paste used with the FEF process. Additives were …


A Framework For Uncertainty Quantification In Microstructural Characterization With Application To Additive Manufacturing Of Ti-6al-4v, Gregory Thomas Loughnane Jan 2015

A Framework For Uncertainty Quantification In Microstructural Characterization With Application To Additive Manufacturing Of Ti-6al-4v, Gregory Thomas Loughnane

Browse all Theses and Dissertations

The sampling of three dimensional (3D) mesoscale microstructural data is typically prescribed using simple rules, likely resulting in data under- or oversampling depending on the measurement(s) of interest. The first part of this work investigates one approach for determining a minimally sufficient sampling scheme for 3D microstructural data, using computer-generated phantoms of polycrystalline grain microstructures. Sources of error that are observed experimentally are modeled using phantoms, in order to determine the effect that errors have on the microstructural statistic(s)-of-interest. Minimally-sufficient sampling schemes are then established based on a required accuracy in the microstructural statistic(s). The characterization error modeling framework is …


Performance Metrics For Powder Feeder Systems In Additive Manufacturing, Venkata Sivaram Bitragunta Jan 2015

Performance Metrics For Powder Feeder Systems In Additive Manufacturing, Venkata Sivaram Bitragunta

Masters Theses

"In blown powder Direct Metal Deposition (DMD) process, parts are built by adding metal powder on the melt pool created by the laser system. At low feed rates powder feeder systems have perturbations. The study focused on relationship between the perturbation frequencies by inherent powder feeder designs and its impact on deposition quality. Performance metric determine the relation between perturbations in the powder flow and quality of the deposit. To determine performance metric, various powder feeder designs were analyzed. Perturbation frequencies were introduced to the disk feeder design. The quality of the deposit was determined by the surface roughness of …