Mechanical Engineering Commons^™

Solar Insolation Micro-Forecasts Using Longwave Infrared Sensors And Artificial Intelligence, Anthony R. Menicucci

Mechanical Engineering ETDs

Solar Insolation Micro-Forecasts (SIMF) are used by Independent Service Operators (ISOs) and other grid operators to maintain constant and stable electrical grid frequency, voltage, power factor and waveform across their transmission infrastructure. Intermittent, thick, dense and typically cumulus clouds negatively impact the electrical grid by quickly turning on and off power production from large solar photovoltaic (PV) fields, causing grid stability problems between generation and load. Forecasting insolation values over large PV fields allows operators the chance to anticipate and proactively implement mitigation strategies like engaging spinning reserve from gas turbines, deploying generators, buying power in the spot market, and …

Performance Improvements For Next Generation Falling Particle Receiver Systems, Nathan R. Schroeder

Mechanical Engineering ETDs

Falling particle receiver (FPR) systems are a rapidly developing technology for concentrating solar power applications. Solid particles are used as both the heat transfer fluid and thermal energy storage media. Through the direct solar irradiation of the solid particles, flux and temperature limitations of tube-bundle receives can be overcome leading to higher operating temperatures and energy conversion efficiencies. Particle residence time, curtain opacity, and curtain stability affect the performance of FPR designs. As the particles fall through the receiver the curtain accelerates, increasing its transmissivity thus decreasing the amount of energy absorbed. Multistage release trough structures catch and release the …

Prefilling Mylar Capacitor Edge Margins To Improve Capacitor Reliability And Size, Chase Kayser

Mechanical Engineering ETDs

Typical high-voltage, wound film-foil capacitors have large edge margins filled with air to prevent breakdown between foil electrodes. This arrangement is inefficient for energy density and leaves a volume where particulates may settle in an uncontrolled atmosphere. The reliability and size of high-voltage, wound film-foil capacitors could be improved by adding a material with higher breakdown strength into the edge margins. This will not only improve reliability and size but also act as a barrier to prevent foreign object debris (FOD), volatile organic compounds (VOCs), and water from damaging the capacitor’s performance. This paper will discuss the process of determining …

Experimental Investigation Of The Wind Energy Harvesting Potential Of A Stand-Alone Piezoelectric Strip, Phillip Christopher Scott

Mechanical Engineering ETDs

The purpose of the study was to investigate the feasibility of harvesting wind energy on a small scale in residential areas. The method investigated was the initiation of movement-induced excitation (MIE), a type of aeroelastic flutter, within samples of polyvinylidine fluoride (PVDF), a piezoelectric polymer. Single samples of PVDF were secured in a wind tunnel and sample voltage was measured over a broad range of wind speeds. Power was calculated then via the addition of ohmic resistance matched to the magnitude of the capacitive impedances of the samples. The geometry of the PVDF samples studied was maintained as a simple …

Polarity Effects Of Aluminium Nitride Thin Films And Morphological Characterization Of Molybdenum Thin Films, Aseem Poudyal

Mechanical Engineering ETDs

AlN (Aluminium Nitride) is a piezoelectric material that is often used in numerous applications as a transducer. C-axis crystal orientation control of AlN is very important as it corresponds to a high piezoelectric coefficient. Crystal orientation of sputtered AlN is strongly affected by its deposition parameters such as sputtering pressure, target to substrate distance, growth temperature, gas pressure and frequency/duty cycle in the case of pulsed DC sputtering. Crystal orientation of AlN depends on the energy of the sputtered atom and the mobility of the adatoms on the surface of the substrate. Varying the deposition parameters can alter the kinetic …

Target Control Of Networked Systems, Isaac S. Klickstein

Mechanical Engineering ETDs

The control of complex networks is an emerging field yet it has already garnered interest from across the scientific disciplines, from robotics to sociology. It has quickly been noticed that many of the classical techniques from controls engineering, while applicable, are not as illuminating as they were for single systems of relatively small dimension. Instead, properties borrowed from graph theory provide equivalent but more practical conditions to guarantee controllability, reachability, observability, and other typical properties of interest to the controls engineer when dealing with large networked systems. This manuscript covers three topics investigated in detail by the author: (i) the …

Emissivity Measurements Of Painted And Aerosol Deposited Thermographic Phosphors (Yag:Dy And Mfg:Mn), Wendy Flores-Brito

Mechanical Engineering ETDs

Combustion is one of the most difficult processes to model. Luminous flames are characteristically sooty, which creates a problem when modeling and calculating the combustion and heat transfer of the process; both of which are highly dependent on temperature and emissivity. Soot particle emissivity as well as gas contributions affect the heat transfer calculation and must be accounted for.

Thermographic phosphors (TP) are ceramic based phosphorescent materials that have a temperature dependent emission that can be exploited to obtain surface and gas temperature measurements, as well as 2D temperature maps. Emissivity knowledge is not needed to obtain temperature and is …

Qualitative Investigation Of Gaseous Hydrodynamic Mixing Model Efficacy And Associated Sensitivity, Caleb White

Mechanical Engineering ETDs

A mixing model analyzes the mixing of helium (He) and sulfur hexafluoride (SF₆) according to two classical gaseous equations of state (EOS), namely, Amagat’s Law and Dalton’s Law, undergoing planar traveling shocks in three dimensions (3D). Numerical simulations utilize the Sandia National Laboratories (SNL) shock hydrodynamic code CTH and other codes including the SNL thermochemical equilibrium code TIGER and the uncertainty qualification (UQ) and sensitivity analysis code DAKOTA. Comparison with experimental results show that none of the equations of state are able to accurately predict the properties of the shocked mixture; similar discrepancies have been observed in previous …

The Effect Of Including Pressure Within Cracks On Failure Times Of Cylinders Subjected To Internal Air Blast Loading, Molly M. Bailey

Mechanical Engineering ETDs

The importance of internal crack pressure on the extent of crack propagation is studied using both numerical and experimental results. Experimental data were obtained from shock tube testing of internally pressurized quasi-brittle hollow cylinders loaded to failure. Half of the samples were tested with an inserted membrane that transferred the shocked fluid load but prevented the fluid from entering the developing cracks. In the other cases, the membrane was removed allowing the fluid to enter the crack and assist development of fracture. A novel approach to modeling this complex structural response involving dynamic failure and fluid structure interaction is presented, …

Additively Manufactured Continuous Carbon Fiber Thermoplastic Composites For High-Performance Applications, Nekoda Van De Werken

Mechanical Engineering ETDs

The goal of this dissertation is to provide a foundation for the advancement of additive manufacturing (AM) toward production of high-performance carbon fiber reinforced polymer matrix composites (CFRPs). AM can provide valuable advantages over conventional composite manufacturing techniques, including the control over fiber orientation, capability of manufacturing complex geometries, out-of-autoclave processing, elimination of the need for composite tooling, and the ability to perform lights-out manufacturing. Currently, however, a suite of challenges related to modelling, design, manufacturing defects, and general limitations in the current understanding of the processing-structure-property relationships exist in AM of composites. To this end, this dissertation investigates novel …

Development Of Mbd Model And Analysis Methodology For Vehicle Design, Alfonso Christopher Ponce

Mechanical Engineering ETDs

This thesis is to provide a new methodology that considers the effects the chassis applies during dynamic load to the suspension and the handling characteristics of a road course vehicle. A methodology in which is described in detail as well as an applied demonstration where literature before this thesis, lacks in replication and serves to establish a basis for multi-body dynamic analysis in this area. Two models to be created, rigid and flexible, and to compare each other to study the effects the chassis torsional stiffness has during load transfer. Ultimately, to assist in the design of a vehicle that …

Mechanical Characterization Of Additively Manufactured Inconel 625 And Alsi10mg Via High-Throughput Tensile Testing, Aron Robbins

Mechanical Engineering ETDs

Additive manufacturing allows for the development of complex geometrical designs that may otherwise be impossible to fabricate through common methods. This advantage has opened the door to a new testing method capable of rapid and efficient material property characterization and qualification. The technique exhibits how 100’s of sub-size tensile bars can be tested to show an inherent statistical variation of materials produced by laser powder bed fusion. The testing technique presented is used to evaluate various heat treatments of the nickel super-alloy Inconel 625 and the aluminum alloy AlSi10Mg after stress relief annealing. Statistical analysis using 3-parameter Weibull distributions is …

Optimal Control Strategies For Complex Biological Systems, Afroza Shirin

Mechanical Engineering ETDs

To better understand and to improve therapies for complex diseases such as cancer or diabetes, it is not sufficient to identify and characterize the interactions between molecules and pathways in complex biological systems, such as cells, tissues, and the human body. It also is necessary to characterize the response of a biological system to externally supplied agents (e.g., drugs, insulin), including a proper scheduling of these drugs, and drug combinations in multi drugs therapies. This obviously becomes important in applications which involve control of physiological processes, such as controlling the number of autophagosome vesicles in a cell, or regulating the …

Post-Polymerization Modification Of Kapton Using Electron Beam Irradiation, Luis A. Hernandez

Mechanical Engineering ETDs

In the present study, the feasibility of chemical modification of electron-irradiated Kapton is investigated. Characterization techniques determined the changes between a pristine, electron irradiated, and a chemically treated, i.e., fluorinated, sample of Kapton. Kapton is a common material in space application as it serves as the exterior surface for space vehicles. Highly aged Kapton have significant material property changes, making them prone to electro-static discharge (ESD) damage. Understanding how Kapton material behaves under space conditions and the possibility of improving its structure and properties is of utmost important. To this end, changes to the physical properties of the material were …

Characterization Of Single- And Multi-Phase Shock-Accelerated Flows, Patrick John Wayne

Mechanical Engineering ETDs

Experiments conducted in the Shock Tube Facility at the University of New Mexico are focused on characterization of shock-accelerated flows. Single-phase (gaseous) initial conditions consist of a heavy gas column of sulfur hexafluoride seeded with approximately 11% acetone gas by mass. Visualization of the image plane for gaseous initial conditions is accomplished via planar laser-induced fluorescence (PLIF) with a high-powered Nd:YAG ultraviolet laser and an Apogee Alta U-42 monochrome CCD camera, with a quantum efficiency > 90%. Multi-phase (gas-solid) initial conditions consist of glass micro-beads deposited on small 1-cm diameter discs of specific surface chemistry, mounted flush with the bottom wall …

Lansce Diagnostic Robot Localization, Lucas S. Montoya

Mechanical Engineering ETDs

Los Alamos Neutron Science Center (LANSCE) operates a linear particle accelerator (LINAC) that is used for a number of scientific research projects. Due to the presence of harmful radiation, researchers are not allowed in the beam tunnel during operation. Since the beam tunnel is inaccessible, an autonomous mobile robot is to be developed and deployed in the tunnel, monitoring the accelerator during operation. The robot will present real time data for operators and scientists from sensors such as a video camera, thermal camera, microphones, and muon detectors; allowing for beam diagnostics previously unavailable.

Localization is a fundamental step in autonomous …

A Transient Thermal And Structural Analysis Of Fuel In The Annular Core Research Reactor, Elliott Pelfrey

Mechanical Engineering ETDs

The health of a nuclear reactor’s fuel is essential to the operational longevity of the reactor. The health of the fuel in the Annular Core Research Reactor (ACRR) is a topic of increased interest due to both a proposed new facility that would include the ACRR and the recent resurfacing of contradictory reports regarding thermal stresses in its fuel pellets. Unlike other reactor fuels, which are widely used and well-characterized, the fuel in the ACRR is unique. The ACRR’s fuel elements consist of UO­₂-BeO fuel pellets, fluted niobium refractory liners, and stainless-steel cladding. The purpose of this thesis …

Direct Numerical Simulation Of Incompressible Spatially Developing Turbulent Mixing Layers, Juan Diego Colmenares Fernandez

Mechanical Engineering ETDs

Turbulent mixing layers are a canonical free shear flow in which two parallel fluid streams of different velocities mix at their interface. Understanding spatial development of a turbulent mixing layer is essential for various engineering applications. However, multiple factors affect physics of this flow, making it difficult to reproduce results in experiments and simulations. The current study investigates sensitivity of direct numerical simulation (DNS) of such a flow to computational parameters. In particular, effects of the computational domain dimensions, grid refinement, thickness of the splitter plate, and the laminar boundary layer characteristics at the splitter plate trailing edge are considered. …

The Influence Of Process Variables On Physical And Mechanical Properties In Laser Powder Bed Fusion, Joshua Robert Koepke, Bradley Jared, Yu-Lin Shen

Mechanical Engineering ETDs

Laser powder bed fusion additive manufacturing consists of a process that incorporates many process variables into fabricating parts. This study investigated several of these process variables and determined their influence on part properties. The process variables investigated include laser power, velocity, focus offsets, layer thickness, and powder particle size. Physical properties will be compared including surface roughness, form, and density. Tensile testing provided mechanical properties including unloading Young’s modulus, ultimate tensile strength, yield strength, uniform elongation, and ductility. Process maps will be developed that will provide recommendations for these process settings. It will be shown that these laser settings can …

Gaussian Process Regression Applied To Marine Energy Turbulent Source Tuning Via Metamodel Machine Learning Optimization, Sterling Olson

Mechanical Engineering ETDs

Converting energy from the currents found within tidal channels, open ocean, rivers, and canals is a promising yet untapped source of renewable energy. In order to permit current energy converters for installation in the environment, the CECs must be shown to non-negatively impact the environment. While developing these model increased utility may be gained if researchers may optimize mechanical power while constraining environmental effects. Surrogate models have garnered interest as optimization tools because they maximize the utility of expensive information by building predictive models in place of computational or experimentally expensive model runs. Marine hydrokinetic current energy converters require large-domain …

Investigation Of The Coupled Nuclear, Thermal-Hydraulic, And Thermomechanical Response Of A Natural Circulation Research Reactor Under Severe Reactivity-Initiated Accident Transients, Darren G. Talley

Mechanical Engineering ETDs

Research reactors play an important role in higher education, scientific research, and medical radioisotope production around the world. It is thus important to ensure the safety of facility workers and the public. This work presents a new reactor transient analysis code, referred to as Razorback, which computes the coupled reactor kinetics, fuel element heat transfer, fuel element thermal expansion and thermal stress, and thermal-hydraulic response of a natural circulation research reactor. The code was developed for the evaluation of large rapid reactivity addition in research reactors, with an initial focus on the Annular Core Research Reactor (ACRR) at Sandia National …

Adding Semi-Structured Automated Grid Generation And The Menter-Shear Stress Turbulence Transport Model For Internal Combustion Engine Simulations To Novel Fem Lanl Combustion Codes, Brad Montgomery Philipbar

Mechanical Engineering ETDs

The addition of GridPro semi-structured, automated generation of grids for complex moving boundaries for combustion engine applications and the Menter Shear Stress Turbulent Transfer (SST) model are being developed by Los Alamos National Laboratory. The software is called Fast, Easy, Accurate, and Robust Continuum Engineering (FEARCE). In addition to improving the time and effort required to build complex grid geometry for turbulent reactive multi-phase flow in internal combustion engines, the SST turbulence model has been programmed into the Predictor Corrector Fractional-Step (PCS) Finite Element Method (FEM) for reactive flow and turbulent incompressible flow regime validation is performed. The Reynolds-Averaged Navier-Stokes …

Stability Of A Spinning Triangle Tethered Spacecraft System In A Circular Orbit, Matthew James Heitstuman

Mechanical Engineering ETDs

Equations of motion are derived for a spinning triangle tethered spacecraft system and are used to analyze the stability of such systems. Floquet theory is applied to the linearized, periodic coefficient, equations of motion to analyze spin stability as a function of triangle geometry and the average spin rate of the satellite relative to the angular velocity of the spacecraft orbiting around a central body. The results of the Floquet analysis show that spin stability is achievable for many combinations of spacecraft geometry and spin rate. Spacecraft engineers or operators for a triangle-shaped tethered spacecraft can use this information for …

Integration Of A Commercial Smart Thermostat To The Aggregated Load Control Simulation Framework, Jee Won Choi

Mechanical Engineering ETDs

As part of an effort to achieve a better balance between the power demand and supply, load (demand) control simulation framework is previously developed. In the framework, HVAC load is used as a control resource, driven by the thermostat logic modeled within the framework. However, it has not been proved, whether a com- mercial thermostat is able to perform modeled thermostat’s features. Therefore, it is desired to integrate a commercial thermostat to the framework, to verify its capabil- ity of participating and performing the Demand Response (DR) scheme developed. A ‘Nest Learning Thermostat’ is selected as a commercial thermostat. Nest …

Engineering Viscoelastic Behavior Of Carbon Fiber Reinforced Polymer Composites With Nanoparticles For Controlling Deployment Of Aerospace Structures, Mark Scherbarth

Mechanical Engineering ETDs

The United States Air Force is focused on reducing mass and power consumption of spacecraft to increase their capabilities for space missions. Low mass and power consumption can be achieved by using composites with low density and high stiffness and utilizing few satellite components. One way to achieve reduced mass is by eliminating attendant deployment mechanisms consuming valuable power and mass allocations on spacecraft with deployable structures. Secondary systems are typically used to assist deployable space structures to ensure 100% success. A passively deployed space structure would be of great value to the Department of Defense and the commercial marketplace. …

A Biomechanical Comparison Of A Low-Profile Mesh Plate Contrasted With Tension Band Wiring Treatment Of Olecranon Fractures And Osteotomies, Jasmin Regalado

Mechanical Engineering ETDs

Olecranon fractures are common upper extremity injuries caused by direct trauma to the elbow. Open reduction and internal fixation is the current standard for olecranon fractures that exceed a 2 mm fragment displacement. The tension band wire (TBW) technique is the current standard of care for treating olecranon fractures due to its positive clinical results. However, the complication rate due to prominent hardware is reported to be upwards of 50\%. This research aims to biomechanically test and compare the stiffness and fracture gap of the traditional TBW technique to a low-profile titanium mesh plate (TMP) for chevron-type fractures and osteotomies …

Reducing Stress In 3d Printed Parts Made With Laser Engineered Net Shaping, Shaun Ross Whetten

Mechanical Engineering ETDs

Thermal cycling and repeated melting/solidification cycles characteristic of 3D metal printing processes causes buildup of residual stress in 3D printed parts. Using laser engineered net shaping (LENS®), residual stresses are formed leading to deformation and possible cracking of the 3D printed metal components. The LENS process offers opportunities for rapid prototyping, alternative manufacturing processes, and repair of worn/broken components so it is important to be able to minimize the effects of residual stress. Work was performed to understand the benefit of substrate heating on reducing residual stress in metal parts made using the LENS process. Substrate deformation, and destructive methods …

Fatigue Crack Modeling Of Additively Manufactured Abs Cantilever Beam, Jason W. Booher

Mechanical Engineering ETDs

A Finite Element model was developed to model crack development in additively manufactured additively manufactured Acrylonitrile Butadiene Styrene (ABS) cantilever beams. Experiments were conducted on the beams with both shock and random vibration base excitations. The base excitations induced damage in the beam that cause crack propagation. It was observed during the cracks developmental stages that an increase in damping occurred. The proposed Finite Element model also showed similar increases in damping from the addition of Coulomb damping forces.

Co-Simulation Framework For Power Distribution System Analysis With Humans In The Loop, Victor H. Ayon

Mechanical Engineering ETDs

Recent developments in the area of power generation have led to an increased penetration of storage and distributed energy resources (DER) in power distribution systems. As a result, new and enhanced energy management systems will be necessary as the deployment of DERs, as well as the need to control loads, continues to increase in the coming years. Advanced management systems are especially important to achieve resilient power delivery during emergency situations. During a blackout for example, a section of a distribution feeder could island to operate as a microgrid to ensure critical services such as water, food, and medical care …

Investigating Scalable Manufacturing Of High-Conductivity Wires And Coatings From Ultra-Long Carbon Nanotubes, Pouria Khanbolouki

Mechanical Engineering ETDs

Carbon nanotubes (CNTs) are a promising candidate for next generation of electrical wirings and electromagnetic interference (EMI) shielding materials due to their exceptional mechanical and electrical properties. Wires and coatings from ultralong nanotubes that are highly crystalline, well-aligned and densely packed can achieve this goal. High-performance CNT conductors will be relatively lightweight and resistant to harsh conditions and therefore can potentially replace current conductors in many industries including aerospace, automotive, gas and oil.

This thesis investigates a new manufacturing approach, based on conventional solution coating and wire drawing methods, to fabricate high conductivity wires and coatings from ultra-long carbon nanotubes. …