Arizona has been rapidly expanding in both population and construction over the last 20 years, and with the hot summer climate, many homeowners experience a significant increase in their utility bills. The cost to reduce these energy bills with home renovations can become expensive. This has become increasingly apparent over the last few years with the impact that covid had on the global supply chain. Prices of materials and labor have never been higher, and with this, the price of energy continues to increase. Therefore, it is important to explore methods to make homes more energy-efficient without the price tag. In addition to benefitting the homeowner by decreasing the cost of their monthly utility bills, making homes more energy efficient will aid in the overall goal of reducing carbon emissions.

This study experimentally investigated a selected methodology of mechanical torque testing of 3D printed gears. The motivation for pursuing this topic of research stemmed from a previous experience of one of the team members that propelled inspiration to quantify how different variables associated with 3D printing affect the structural integrity of the resulting piece. With this goal in mind, the team set forward with creating an experimental set-up and the construction of a test rig. However, due to restrictions in time and other unforeseen circumstances, this thesis underwent a change in scope. The new scope focused solely on determining if the selected methodology of mechanical torque testing was valid. Following the securement of parts and construction of a test rig, the team was able to conduct mechanical testing. This testing was done multiple times on an identically printed gear. The data collected showed results similar to a stress-strain curve when the torque was plotted against the angle of twist. In the resulting graph, the point of plastic deformation is clearly visible and the maximum torque the gear could withstand is clearly identifiable. Additionally, across the tests conducted, the results show high similarity in results. From this, it is possible to conclude that if the tests were repeated multiple times the maximum possible torque could be found. From that maximum possible torque, the mechanical strength of the tested gear could be identified.

This thesis presents a comprehensive investigation into the design of roller coasters. The study includes an overview of various roller coaster types, cart design, brake design, lift hill and launch design, support design, and roller coaster safety. Utilizing No Limits 2 to design the layout and CAD software for component design, a scale model roller coaster was designed. The physics of the roller coaster and its structures were analyzed and a scale model was produced. Afterward, an accelerometer was used to collect G force data as the cart moved along the track. However, the collected data differed from the expected results, as the launch speed was higher than predicted due to more friction than anticipated. As a result, further optimization of the design and models used to design the scale model roller coasters is necessary.

This study experimentally investigated a selected methodology of mechanical torque testing of 3D printed gears. The motivation for pursuing this topic of research stemmed from a previous experience of one of the team members that propelled inspiration to quantify how different variables associated with 3D printing affect the structural integrity of the resulting piece. With this goal in mind, the team set forward with creating an experimental set-up and the construction of a test rig. However, due to restrictions in time and other unforeseen circumstances, this thesis underwent a change in scope. The new scope focused solely on determining if the selected methodology of mechanical torque testing was valid. Following the securement of parts and construction of a test rig, the team was able to conduct mechanical testing. This testing was done multiple times on an identically printed gear. The data collected showed results similar to a stress-strain curve when the torque was plotted against the angle of twist. In the resulting graph, the point of plastic deformation is clearly visible and the maximum torque the gear could withstand is clearly identifiable. Additionally, across the tests conducted, the results show high similarity in results. From this, it is possible to conclude that if the tests were repeated multiple times the maximum possible torque could be found. From that maximum possible torque, the mechanical strength of the tested gear could be identified.

A new uniaxial testing apparatus that has been proposed takes advantage of less costly methods such as 3D printing of tensile fixtures and image reference markers for accurate data acquisition. The purpose of this research is to find methods to improve the resolution, accuracy, and repeatability of this newly designed testing apparatus. The first phase of the research involved building a program that optimized the testing apparatus design depending on the sample being tested. It was found that the design program allowed for quick modifications on the apparatus in order to test a wide variety of samples. The second phase of research was conducted using Finite Elements to determine which sample geometry reduced the impact of misalignment error most. It found that a previously proposed design by Dr. Wonmo Kang when combined with the testing apparatus lead to a large reduction in misalignment errors.

The goal of this research is to couple a physics-based model with adaptive algorithms to develop a more accurate and robust technique for structural health monitoring (SHM) in composite structures. The purpose of SHM is to localize and detect damage in structures, which has broad applications to improvements in aerospace technology. This technique employs PZT transducers to actuate and collect guided Lamb wave signals. Matching pursuit decomposition (MPD) is used to decompose the signal into a cross-term free time-frequency relation. This decoupling of time and frequency facilitates the calculation of a signal's time-of-flight along a path between an actuator and sensor. Using the time-of-flights, comparisons can be made between similar composite structures to find damaged regions by examining differences in the time of flight for each path between PZTs, with respect to direction. Relatively large differences in time-of-flight indicate the presence of new or more significant damage, which can be verified using a physics-based approach. Wave propagation modeling is used to implement a physics based approach to this method, which is coupled with adaptive algorithms that take into account currently existing damage to a composite structure. Previous SHM techniques for composite structures rely on the assumption that the composite is initially free of all damage on both a macro and micro-scale, which is never the case due to the inherent introduction of material defects in its fabrication. This method provides a novel technique for investigating the presence and nature of damage in composite structures. Further investigation into the technique can be done by testing structures with different sizes of damage and investigating the effects of different operating temperatures on this SHM system.

The following is a report that will evaluate the microstructure of the nickel-based superalloy Hastelloy X and its relationship to mechanical properties in different load conditions. Hastelloy X is of interest to the company AORA because its strength and oxidation resistance at high temperatures is directly applicable to their needs in a hybrid concentrated solar module. The literature review shows that the microstructure will produce different carbides at various temperatures, which can be beneficial to the strength of the alloy. These precipitates are found along the grain boundaries and act as pins that limit dislocation flow, as well as grain boundary sliding, and improve the rupture strength of the material. Over time, harmful precipitates form which counteract the strengthening effect of the carbides and reduce rupture strength, leading to failure. A combination of indentation and microstructure mapping was used in an effort to link local mechanical behavior to microstructure variability. Electron backscatter diffraction (EBSD) and energy dispersive spectroscopy (EDS) were initially used as a means to characterize the microstructure prior to testing. Then, a series of room temperature Vickers hardness tests at 50 and 500 gram-force were used to evaluate the variation in the local response as a function of indentation size. The room temperature study concluded that both the hardness and standard deviation increased at lower loads, which is consistent with the grain size distribution seen in the microstructure scan. The material was then subjected to high temperature spherical indentation. Load-displacement curves were essential in evaluating the decrease in strength of the material with increasing temperature. Through linear regression of the unloading portion of the curve, the plastic deformation was determined and compared at different temperatures as a qualitative method to evaluate local strength.

The study of the mechanical behavior of nanocrystalline metals using microelectromechanical systems (MEMS) devices lies at the intersection of nanotechnology, mechanical engineering and material science. The extremely small grains that make up nanocrystalline metals lead to higher strength but lower ductility as compared to bulk metals. Effects of strain-rate dependence on the mechanical behavior of nanocrystalline metals are explored. Knowing the strain rate dependence of mechanical properties would enable optimization of material selection for different applications and lead to lighter structural components and enhanced sustainability.

The goal of this research is to compare the mechanical properties of CP-Ti and Ti-O and to understand the relationship between a material's microstructure and its response to fatigue. Titanium has been selected due to its desirable properties and applicability in several engineering fields. Both samples are polished and etched in order to visualize and characterize the microstructure and its features. The samples then undergo strain-controlled fatigue tests for several thousand cycles. Throughout testing, images of the samples are taken at zero and maximum load for DIC analysis. The DIC results can be used to study the local strains of the samples. The DIC analysis performed on the CP-Ti sample and presented in this study will be used to understand how the addition of oxygen in the Ti-O impacts fatigue response. The outcome of this research can be used to develop long-lasting, high strength materials.