Manufacturing Commons^™

Investigating The Effect Of Bead Geometry On Fiber Orientation And Thermomechanical Properties For Large-Format Extrusion-Based Additive Manufacturing, Joanna F. Keaton

Electronic Theses and Dissertations

In large-format extrusion-based additive manufacturing of polymer composites, the relationship between material properties and processing parameters requires further investigation. This thesis focuses on the relationship between fiber orientation and thermomechanical properties for short fiber-filled thermoplastic polymer systems manufactured by extrusion-based additive manufacturing. Fiber orientation is particularly important in determining the thermomechanical properties of the composite material as properties in the direction of deposition are expected to be higher for highly aligned fibers than randomly aligned fibers. Fiber orientation distribution, which is related to processing parameters and deposition conditions, can be efficiently represented by the orientation tensor. The orientation tensor can …

Development Of Thermoplastic Composite External Reinforcing Of Concrete Decking System, Jackman A. Mickiewicz

Electronic Theses and Dissertations

The use of reinforced concrete is very common in the construction of a wide variety of structures. In buildings it is used for floors, beams, columns, and walls. It can also be used in infrastructure as parts of bridges, dams, pavements, etc. Typically, concrete is reinforced with steel, primarily rebar, to carry tensile stresses.

Like every other industry, construction is always looking at ways to advance its technology. The work outlined in this thesis looks to assist in that goal, primarily by looking at options for using a different material than the traditional steel reinforcements to create a reinforced concrete …

Thermal And Mechanical Numerical Modeling Of Extrusion-Based 3d Printed Reinforced Polymers For Selecting Manufacturing Process Parameters, Sunil Bhandari

Electronic Theses and Dissertations

Extrusion-based 3D printing of thermoplastic polymer composites manufactures parts that have nonhomogenous, orthotropic, and process-dependent macro-scale material properties. As a part of the dissertation, research works were carried out to: • improve the interlayer mechanical properties and reduce the orthotropy, • use experimentally homogenized orthotropic material properties to numerically model the mechanical behavior of the non-homogenous orthotropic 3D printed parts, • create an efficient numerical thermal model to predict the process-dependent thermal history of the 3D printed part, and • aid the manufacturing process by selecting a suitable set of processing parameters based on a simplified sequentially coupled thermomechanical model. …

Feasibility Of Using 3d Printed Molds For Thermoforming Thermoplastic Composites, Sunil Bhandari

Electronic Theses and Dissertations

This thesis presents a novel combined experimental and numerical mechanics approach for characterizing 3D printed thermoplastic materials by the fused deposition modeling process for thermoforming thermoplastic composites. The implications of this work are:

1. a methodology for model-based performance evaluation of 3D printed structural parts, and
2. an improved design of 3D printed molds for composites manufacturing, which has potential for material innovations and scaled-up applications in additive manufacturing.

The thesis formulates basic criteria for selection of thermoplastic polymer used for the 3D printed mold based on forming temperatures. The thesis creates a lattice and shell finite element model of the 3D …

Color Removal From Pulp Mill Effluent Using Coal Ash Produced From Georgia Power Coal Combustion Plants, Christopher B. Willett

Electronic Theses and Dissertations

Two environmental concerns currently face Georgia: coal fly ash (CFA) waste from coal power plants, and the effluent generated by pulp mills. Pulp mill effluent discolors surface waters into which it is discharged, and has been proven to negatively impact the dissolved oxygen and carbon necessary for aquatic life. The proposed solution is a cost-effective adsorption treatment using an inexpensive but abundantly available waste material: CFA. CFA possesses beneficial properties that allow it to effectively remove contaminants, and is available at significantly reduced cost. The primary research objective was to define treatment parameters that would result in the maximum removal …