Mechanical Engineering Commons^™

Thermoplastics 3d Printing Using Fused Deposition Modeling On Fabrics, Maxwell M. Blais

Electronic Theses and Dissertations

The creation of objects with integrated flexibility is desired and this can be achieved by additive manufacturing on fabric. We propose to use a textile fabric as a flexible joint and create to create an entire object with smaller parts called segments. Such a novel technique will bring integrated flexibility and folded assemblies using extrusion based additive manufacturing machines. The proposed process allows segments to be created flat one at a time on a continuous fabric, which will be suitable for flat to folded assemblies and eliminate size limitations of the 3D printer. Techniques considering object segmentation were used to …

Engineering The Spectrum Of Near-Field Thermal Radiation, Saman Zare

Electronic Theses and Dissertations

Thermal emission observed at sub-wavelength distances from the thermal source is referred to as near-field thermal radiation. Thermal radiation in the near-field regime can exceed Planck’s blackbody limit by orders of magnitude and be quasi-monochromatic. Due to these unique properties, near-field thermal radiation is very promising for several thermal management and energy harvesting applications. Many of these applications, such as nanogap thermophotovoltaics and thermal rectification, require near-field spectra that are not found among natural materials. Artificial metamaterials, which are engineered at the sub-wavelength scale, have been theoretically proposed for tuning the spectrum of near-field thermal radiation. However, engineering the near-field …

Computational Investigations Of The Fluid-Structure Interaction During Phonation: The Role Of Vocal Fold Elasticity And Glottal Flow Unsteadiness, Xiaojian Wang

Electronic Theses and Dissertations

Human voice production arises from the biomechanical interaction between vocal fold vibrations and airflow dynamics. Changes in vocal fold stiffness can lead to changes in vocal fold vibration patterns and further changes in voice outcomes. A good knowledge of the cause-and-effect relationship between vocal fold stiffness and voice production can not only deepen the understanding of voice production mechanisms but also benefit the treatment of voice disorders associated with vocal fold stiffness changes. This constitutes the first objective of this dissertation. The second objective of this dissertation is to further examine the range of validity of the quasi-steady assumption of …

Micro-Particle Entrainment From Density Mismatching Mixture By Dip Coating Process, S M Abu Naser Shovon

Electronic Theses and Dissertations

Solid particle transfer is a vital process for many applications such as painting, coating, materials joining, meta-surface, bio-medical applications etc. Different solid transfer techniques including welding, spray coating, roll coating etc. are available for delivering solid particles on simple structures. However, those techniques cannot effectively deliver particles to complex structures. In this thesis work, the research objective is to develop a high throughput and economical material transfer technique for complex architecture with low volumetric flux. In first part, the particle concentration of pseudo suspension was investigated in dip coating process from density mismatching mixture. The solid particles concentration was varied …

Numerical Modeling Of Localized Heating In Continuous Fiber Reinforced Thermoplastic Laminates, James T. Gayton

Electronic Theses and Dissertations

The manufacturing of continuous fiber-reinforced thermoplastic (CFRTP) laminates requires the application of heat and pressure. Standard CFRTP manufacturing methods like thermoforming take a global approach to manufacturing, where the whole part is heated and undergoes a forming process. There is an opportunity to develop advanced manufacturing methods based on localized heating and deformations of consolidated stock. This thesis provides a localized heating method via networks of resistive heating elements embedded within the laminate and a means to evaluate that method.

Typical heating methods for CFRTP laminates include infrared and convective ovens or surface contact heaters. They have the same drawbacks …

Additively Manufactured Polymer And Metal Lattice Structures With Eulerian Path, Adeeb Ibne Alam

Electronic Theses and Dissertations

Lattice structure manufacturing with polymers and metals can benefit from the use of Eulerian paths. In this research, two types of lattice fabrication methods are studied where the Eulerian path can be applicable. Polymer lattice is improved by using a new assembly design, while a new way of metal lattice fabrication is discussed.

For the fused filament fabrication process, a new interlocking design and assemble-based lattice structure building approach is investigated by increasing continuity in layers and avoiding support structures. To minimize contour plurality, Eulerian paths between the edges were enforced. Two configurations in the form of cubic and octet …

Numerical Modeling Of Vocal Control And Patient-Specific Surgical Planning Of Type 1 Thyroplasty, Mohammadreza Movahhedi

Electronic Theses and Dissertations

This study aims to develop knowledge about the roles of intrinsic laryngeal muscles on voice control in both healthy and disordered conditions through comprehensive computational models. The phonation simulator was built by combining a three-dimensional high-fidelity MRI-based model of the larynx, active muscle mechanics, and fluid-structure-acoustic interaction model, which enabled the exploration of the underlayer mechanisms of the link between individual and/or group muscles contractions under both symmetric and asymmetric activations, vocal fold posture, vocal fold vibration, and voice outcomes during voice production.

The first part of this research extensively investigated the effects of cricothyroid and thyroarytenoid muscle activations on …

Optimization Of A Lightweight Floating Offshore Wind Turbine With Water-Ballast Motion Mitigation Technology, William Ramsay

Electronic Theses and Dissertations

Floating offshore wind turbines are a promising technology to address energy needs utilizing wind resources offshore. The current state of the art is based on heavy, expensive platforms to survive the ocean environment. Typical design techniques do not involve optimization because of the computationally expensive time-domain solvers used to model motions and loads in the ocean environment. However, this project uses an efficient frequency domain solver with a genetic algorithm to rapidly optimize the design of a novel floating wind turbine concept. The concept utilizes liquid ballast mass to mitigate motions on a lightweight post-tensioned concrete platform, with a target …

Development And Characterization Of Bound Metal Deposition Including Laser Ablation, Alexander J. Watson

Electronic Theses and Dissertations

Bound Metal Deposition (BMD) is a novel metal additive manufacturing technology in which a metal powder-binder composite paste is layer-wise extruded to form a part, which is then debound and sintered into a solid metal part. Although promising, BMD suffers from shrinkage-induced warpage and an inability to produce fine length scale features. This research addresses these problems by: (1) characterizing warpage of planar parts, and (2) developing a novel laser ablated process to create fine length scale features. First, a 12-factor resolution IV fractional-factorial design of experiments (DOE) was conducted to determine the warpage of planar parts as a function …

Development Of A Structural Finite Element Modeling Approach For Hybrid Composite-Steel Shipping Containers, Jason Nagy

Electronic Theses and Dissertations

This thesis presents a summary of the development and verification of structural finite element (FE) models for predicting key responses of ISO composite-steel shipping containers. The container has a steel perimeter frame with composite corrugated panels bonded to steel tabs welded to the frame. This thesis presents the development of the FE models to predict structural behavior when the container under goes select International Standards Organization standard 1496-1 structural tests. Composite and steel mechanical properties were predicted and matched to measured data from coupon tests. Individual panels were modeled and matched to individual three-point bending tests. The individual panel models …

Development And Evaluation Of Modeling Approaches For Extrusion-Based Additive Manufacturing Of Thermoplastics, Christopher C. Bock

Electronic Theses and Dissertations

This work focuses on evaluating different modeling approaches and model parameters for thermoplastic AM, with the goal of informing more efficient and effective modeling approaches. First, different modeling approaches were tested and compared to experiments. From this it was found that all three of the modeling approaches provide comparable results and provide similar results to experiments. Then one of the modeling approaches was tested on large scale geometries, and it was found that the model results matched experiments closely. Then the effect of different material properties was evaluated, this was done by performing a fractional factorial design of experiments where …

Development And Testing Of A 1:70 Scale Model Wind Turbine Of The Iea Reference 15 Mw Floating Offshore System, Amber Parker

Electronic Theses and Dissertations

This thesis presents the development of a 1/70th scale performance-matched wind turbine intended for wind and wave basin model testing of commercially viable floating wind turbine structures based off of the International Energy Agency (IEA) Wind 15 MW design. The focus of this demonstration is to test active blade pitch response controls and to provide an experimental dataset for use by modelers and industry for future turbine improvements. Future research is planned to test the turbine in conjunction with an actively damping hull to test the interactions between the two control systems.

Outlined in this thesis are the methods of …

Joining Methods For Continuous Fiber Reinforced Thermoplastic Composites In Structural Applications, Andrew Moran

Electronic Theses and Dissertations

Continuous fiber reinforced thermoplastic (CFRTP) composites have been proposed as an alternative to metals in structural applications. CFRTP composites can be used to create structures that are lighter weight, have better resistance to environmental factors, and have the potential to be recycled. However, one of the main challenges to CFRTP composites is connections between structural members. The goal of this thesis is to investigate the feasibility of joining CFRTP composites to both similar and dissimilar materials through literature review, coupon testing, design of a structural joint, and a small scale laboratory prototype of the joint. To achieve this goal the …

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 …

The Performance Assessment Of A Small Lighter-Than-Air Vehicle For Earth Science Remote Sensing Missions, Maxwell F. Burtis

Honors College

This summer, a lighter-than-air (LTA) drone was tested in Alaska to measure glacier bedrock fracture density and orientation. Five flights were made in low wind conditions, and the directional stability of the airship made it too challenging to control in flight to realistically acquire useful image sets. The directional stability of the airship, when compared to an actively stabilized consumer-grade quadcopter was inferior. Flight logs and GPS data from the GPS on the LTA drone were analyzed and a quantitative assessment of the observed instability was made. The yaw axis and pitch were analyzed, and the yaw axis instability was …

Optimization Of Synthetic Mooring Systems For Floating Offshore Wind Turbines, William M. West

Electronic Theses and Dissertations

As the floating offshore wind industry matures it has become increasingly important for researchers to determine the next generation materials and processes that will allow platforms to be deployed in intermediate (50-85 m) water depths which challenge the feasibility of traditional catenary chain mooring systems and fixed-bottom jacket structures. One such technology, synthetic ropes, has in recent years come to the forefront of this effort. A significant challenge of designing synthetic rope moorings is capturing the complex physics of the materials which exhibit viscoelastic and nonlinear elastic properties. Currently numerical tools for modeling the dynamic behavior of floating offshore wind …