Mechanical Engineering Commons^™

A Generalisable Bottom-Up Methodology For Deriving A Residential Stock Model From Large Empirical Databases., Ciara Ahern, Brian Norton

Articles

Average reference dwellings representing a predominant housing typology are defined in this work. Specifying such reference buildings is a prerequisite for (i) calculating cost-optimal energy performance requirements for buildings and building elements and (ii) ensuring valid calculations of national building energy consumption. In the EU, an Energy Performance Certificate (EPC) rating is an assessment of the energy consumption of a dwelling. The use of inappropriate default-values for the building envelope thermal transmittance coefficients (U-values) and standardised thermal bridging transmittance coefficients (Y-values) in the production of EPCs leads to an over-estimation of potential energy savings from interventions in the existing dwelling …

Heat Transfer Measurements And Enhancement For Materials And Processes In Polymer Extrusion Based Additive Manufacturing, Hardikkumar Mangaldas Prajapati

Mechanical and Aerospace Engineering Dissertations - Archive

Additive manufacturing (AM) is a burgeoning method for manufacturing over the subtractive manufacturing methodologies. Among the various method of polymer additive manufacturing the fused deposition modeling (FDM) also known as 3D printing is the most popular technique. In this technique, a rastering extruder dispenses a thermoplastic material on to a bed at a temperature greater than its glass transition temperature to build the part. Due to the additive nature of the process, AM introduces several challenges related to functional properties such as strength, thermal conductivity, etc of the eventual part. Measurement of thermal conductivity of additively manufactured polymer samples in …

Reinitiation Mode Study Of Highly Irregular Detonation, Nandakumar Vijayakumar

Mechanical and Aerospace Engineering Dissertations - Archive

The propagation of detonation waves is governed by their stability characteristics. Interest in highly unstable detonation grew when early experiments revealed limits of operation to be directly proportional to the stability of detonation. This research focuses on reinitiation pathways of highly irregular self-sustaining detonation. This is an important aspect of stability which is not yet fully understood, while many possible mechanisms have been proposed in the literature. First, a one-dimensional instability model simulation was performed using a global one-step chemistry mechanism to understand the different unstable modes by increasing the activation energy of a mixture of hydrogen and oxygen. The …

Measurement And Optimization Of Thermal Transport Phenomena For Weld Strength Improvement In Polymer Extrusion Based Additive Manufacturing, Darshan Babu Ravoori

Mechanical and Aerospace Engineering Dissertations - Archive

Additive manufacturing (AM) processes involve layer-by-layer addition of material to fabricate a 3-dimensional part. AM offers significant design and manufacturing flexibility compared to traditional manufacturing approaches. The major challenge in polymer-based additive manufacturing (AM) is that printed parts often have poor thermal/structural properties. These properties depend on weld strength of filaments and which intern depends on the degree of healing/neck growth between deposited polymers. The major contribution of this dissertation is understanding the importance of heat transfer during the printing process on the polymer neck growth and presented with techniques to improve the thermal and structural strength of finished part. …

Design And Optimization Of Thermal Management Approaches In Data Center Applications, Rajesh Kasukurthy

Mechanical and Aerospace Engineering Dissertations - Archive

In the present day to day life, Internet of Things (IOT) is everything, i.e., Internet and telecommunication is needed for almost every task of our life, which require data centers. These data centers provide various facilities such as, data processing, storage, transmission, maintenance, operations etc., To perform these tasks, a huge amount of power is consumed, which in turn generates large amount of heat. As these data centers are to be made operational throughout the year, cooling of data centers is of utmost importance. The continued increase in heat flux at the chip level due to new and robust technology …

Computational Study Of Air-Cooled Servers With Improved Ducting And Chassis Re-Design, Himanshu Girishchandra Modi

Mechanical and Aerospace Engineering Theses - Archive

In recent years there has been a phenomenal increase in cloud computing, net-working, virtualization, and storage which has led to an increase in demand for data centers. To meet this demand, there is a need for the latest computing nodes which causes an increase in power consumption. The cooling system occupy almost 40% portion of total energy consumption. Per ASHRAE TC 9.9, IT equipment needs to operate within recommended and allowable temperatures and humidity zone based on the circumstances. As the inlet air temperature increases, fan power consumption increases too and the Central Processing Units (CPUs) and high heat-generating components …

Experimental Study Of Dynamic Cooling Of Racks Using Flow Control Devices, Fnu Akash

Mechanical and Aerospace Engineering Theses - Archive

A data center is a cluster of multiple servers that a company uses to store and process large amounts of data. Due to never-ending demands, the processor densities are increasing every day. A higher processor density would result in the servers heating up more than it would normally creating a need for an efficient cooling system. On an average a water-cooled system would consume up to 40% of the total power required by a data center. Studies are being conducted on improving the overall efficiency of the system by either improving the thermal properties of the system or by improving …

Modeling, Fabrication, And Characterization Of Porous Inconel 718 Structures Using Selective Laser Melting Process, Srihari Srivathsan

Mechanical and Aerospace Engineering Theses - Archive

Bio-inspired cellular structures are of great interest these days for many applications, from engineering research to industries. Honeycomb, Body-Centered Cubic with/without Z-struts (BCC-Z/ BCC), Face Centered Cubic with/without Z-struts (FCC-Z/ FCC), and Triply Periodic Minimal Surface (TPMS) such as Gyroid, Diamond, and Schwartz lattices are the most common bio-inspired lattice structures. These structures can be tailored based on their structural organization resulting in superior materials with lightweight properties, adequate strength, and low stiffness. Thankfully, additive manufacturing (AM) has made the fabrication of these complex cellular materials realistic. However, the use of AM could lead to several defects, such as damaged …

Cfd Analysis On Liquid Cooled Cold Plate Using Copper Nanoparticles, Sarthak Agarwal

Mechanical and Aerospace Engineering Theses - Archive

In today’s world, most data centres have multiple racks with numerous servers in each of them. The high amount of heat dissipation has become the largest server-level cooling problem for the data centres. The higher dissipation required, the higher is the total energy required to run the data centre. Although still the most widely used cooling methodology, air cooling has reached its cooling capabilities especially for High-Performance Computing data centres. Liquid-cooled servers have several advantages over their air-cooled counterparts, primarily of which are high thermal mass, lower maintenance and eventually lower costs by maintenance by labour. Nano-fluids have been used …

Prediction And Validation Of Continuous Fiber Stiffened Plates Manufactured With Continuous Fiber Fabrication, Nabeel Ahmed Khan

Mechanical and Aerospace Engineering Theses - Archive

The purpose of this thesis was to develop an analytical method for predicting the structural properties of continuous fiber stiffened plates, which was then validated both experimentally and via finite element analysis. The MarkForged Mark Two 3D printer enables parts to be printed with continuous carbon fibers embedded within them. A manufacturing process was developed for printing stiffened grids with our without skins, with continuous fiber reinforcement on the top and bottom of the stiffening ribs, which allows bending stiffness can be maximized. An orthotropic grid was printed using Continues Filament Fabrication (CFF), an additive manufacturing process that embeds reinforcing …

Experimental And Numerical Study Of Process Parameters Effects Towards Part Quality And Porosity During Powder Bed Additive Manufacturing Processes., Subin Shrestha

Electronic Theses and Dissertations

Powder bed additive manufacturing (PB-AM) process utilizes an electron beam or a laser as a heat source to melt the metallic powder particles. These processes have the capability of freeform fabrication, however certain defects such as porosity, high surface roughness, etc. would hinder its application. It is important to understand the effect of the process parameters and the underlying physical phenomena, which lead to the formation of such defects. In this regard, a three-dimensional (3D) thermo-fluid model is developed to study the effect of beam speed on the surface morphology during powder bed electron beam additive fabrication (PB-EBAF). Besides, the …

Impact Of Viscoelastic Properties Of Low Loss Printed Circuit Boards (Pcbs) On Reliability Of Wcsp Packages Under Drop Test, Akshay Boovanahally Lakshminarayana

Mechanical and Aerospace Engineering Theses - Archive

Reliability of electronic packages is a major concern as different failure modes are induced due to factors such as temperature loads, mechanical stresses, humidity, corrosion and so on. Finite element analysis (FEA) is often performed to assess reliability under different loading conditions such as thermal cycling, drop testing, power cycling and vibrational loads. Having accurate material property data is one of the key requirements to perform successful FEA study, and a significant amount of time and money is spent to perform accurate material characterizations. Lump modeling approach, where components are represented by a block and assigned effective properties, is commonly …

Measurement Of Change In Cte Of Pcbs Due To Single Phase Immersion Cooling And Impact Of Changed Properties Of Pcbs On Solder Joint Reliability Of Bga Package, Sameer Hemant Dhandarphale

Mechanical and Aerospace Engineering Theses - Archive

Oil immersion cooling in high-density data centers is emerging as an alternative for traditional air cooling because of the less power consumption, capacity to handle high power density and less space requirement. To adopt this technique extensively, effect of immersion on reliability of server components in dielectric coolant needs to be evaluated. One of the major reliability concerns in BGA package is 2nd level solder joint failure. The primary reason of solder joint failure is CTE mismatch between the PCB and the package. Also, difference in stiffness of the PCB and the package affects the solder joint reliability. As properties …

Impact Of Magnetocaloric Material Properties On Performance Of A Magnetocaloric Heat Pump., Michael G. Schroeder

Electronic Theses and Dissertations

In the field of magnetocaloric heat pumps much research has been performed around machine design and theoretical machines, but little has been researched around practical problems such as variability in material properties. The present work defines a simulation tool that has been proven with experimental data. Magnetocaloric material cascades were statistically analyzed and parameterized, such that they could be recreated parametrically using a split Lorentz function with normally distributed parameters. Correlated curve-defining values with standard deviations were used as input into the simulation tool to determine the effect of variation on cooling heat pump performance for a household refrigerator application. …

Improvement Of Ultraviolet Digital Image Correlation (Uv-Dic) At Extreme Temperatures, Thinh Quang Thai

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Extreme temperature has increasingly played an essential role in design and operation of various engineering applications including spacecraft re-entry, hypersonic flight, next-generation nuclear reactors, and hot-fire rocket testing. To protect instruments against the harsh environments, it is preferable to use non-contacting measurements when monitoring the integrity of those mechanical structures. Digital Image Correlation (DIC) is a popular method which uses digital cameras in order to track motion thanks to images acquired before and after deformation. Displacements and strains are plotted over a full-field region which is conducive to identify highly risky zones. At high temperature, objects emit light which interferes …

Aerodynamic Interactions Of Synchronized Propellers, Nathan Welker, Samuel Johnson

Utah Space Grant Consortium

Emerging advances in electric-propulsion technology are enabling aircraft to use distributed electric propulsion (DEP) to increase efficiency and maneuverability. Distributed electric propulsion can also provide unique take-off and landing abilities which are not commonly found on traditional aircraft. The implementation of DEP effectively decreases the spacing between propellers, introducing complex aerodynamic interactions that are not well understood. This study aims to obtain experimental measurements of the flow fields of synchronized propellers at close-proximity in a side-by-side configuration using particle image velocimetry (PIV) in a wind tunnel. The results of this work will be focused on identifying the impact closely-spaced propellers …

Comparison Of Wake Expansion Methods For Use In Wake Expansion Continuation Optimization, Jared J. Thomas

Utah Space Grant Consortium

This paper presents a comparison of three methods for expanding the wake for use with wake expansion continuation (WEC) optimization. A process related to continuation optimization methods for reducing multi-modality in the wind farm layout optimization problem. A reduction in multi-modality is achieved by starting with an increased wake spread, while maintaining normal velocity deficits at the center of the wakes, and then reducing the wake spread for each of a series of optimization runs until the standard wake spread is used. Three wake expansion methods were tested: (1) increasing the wake expansion angle, (2) multiplying the wake diameter, and …

Monte-Carlo Methods And The Step-Back Kalman Filter For Orbital State Estimation, Louis Tonc

Utah Space Grant Consortium

This research assesses the performance of filtering schemes for tracking uncooperative satellites through space-based optical measurements, and identifies a simple and numerically stable methodology that ameliorates the poor performance of standard filtering schemes at a substantially reduced cost in comparison to nonlinear particle filter-based remedies. Traditional filtering schemes, such as the extended Kalman filter (EKF) and unscented Kalman filter (UKF), both diverge when tracking a resident space object (RSO) in geosynchronous orbit (GEO) when there is a long time duration between measurements. This divergence is identified as a consequence of nonlinearity in the dynamics and nonlinearity in the optical measurements, …

An Examination Into The Defining Characteristics Of Flexible Solar Aircraft Configurations Through Optimization, Taylor Mcdonnell

Utah Space Grant Consortium

This paper examines the defining characteristics of various solar aircraft configurations through gradient-based multidisciplinary design optimization. We first present a general gradient-based solar aircraft optimization framework which accounts for nonlinear aeroelastic effects resulting from structural flexibility. We then apply this framework to several discrete SR-HALE aircraft geometric, structural, and propulsion system configuration choices to determine the defining characteristics of each configuration choice.

Model Reference Predictive Adaptive Control For Large Scale Soft Robots, Phillip Hyatt, Curtis Johnson

Utah Space Grant Consortium

Past work has shown Model Predictive Control (MPC) to be an effective strategy for controlling continuum joint soft robots using rudimentary models, however the in-accuracies of these models often mean that an integration scheme must be combined with MPC. Presented in this work is a novel dynamic model formulation for continuum joint soft robots which is more accurate than the authors’ previous models yet remains fast enough for MPC. This model is based on the Piecewise Constant Curvature (PCC) assumption and a relatively new configuration representation and allows for computationally efficient simulation. Due to the difficulty in determining model parameters …

Ensuring Extramobile And Intramobile Motion On Cylindrical Developable Mechanisms, Jared Butler

Utah Space Grant Consortium

Developable mechanisms offer the ability to deploy to perform tasks then return to a hidden position along or interior to a predetermined developable surface. It is often advantageous for these mechanisms to not penetrate the surface along which they conform. This paper presents the limits of extramobile and intramobile motion (motion exterior to and interior to a developable surface). Three conditions are identified that determine a limit of extramobile and intramobile behavior. It is shown that the more difficult of these conditions to predict is never reached prior to the more simple cases. This is demonstrated for all possible Grashof …

Influence Of Electrode Height On Carbon Nanotube Electrochemical Biosensors, Benjamin J. Brownlee

Utah Space Grant Consortium

High sensitivity of electrochemical sensors enables the detection of low concentrations of target analyte. Being able to quickly and accurately detect low concentrations of proteins at point-of-care allows for results to be analyzed more easily and effectively. Having high surface area allows for more analyte to be detected, possibly leading to increased sensitivity. Vertically-aligned carbon nanotubes (VACNTs) were patterned into interdigitated electrodes (IDEs) and then functionalized with the representative protein streptavidin to demonstrate sensing of biotin. Three electrode heights were investigated to determine the influence of electrode height on sensor sensitivity. Cyclic voltammetry and electrochemical impedance spectroscopy were used to …

Evolutionary Nonlinear Model Predictive Control On A Fixed-Wing And Multirotor, Jaron Ellingson, Matthew Haskell

Utah Space Grant Consortium

Real-time model predictive control (MPC) is limited to short time horizons and linear systems because the optimization complexity is too large with long time horizons and nonlinear systems. For this reason, MPC is typically accomplished using linearized models and convex optimization solvers. We seek to explore evolutionary algorithms allowing for nonlinear models and constraints, non-convex costs, and extended time horizons.

Our contributions include extending nonlinear evolutionary MPC to flight vehicles, fixed-wing and multirotor UAVs, as well as enhancing the evolutionary algorithm. We also intend to parameterize the design space of the optimization to reduce solve times. These contributions validate the …

Comprehensive Second-Order Adjoint Sensitivity Analysis Methodology (2nd-Asam) Applied To A Subcritical Experimental Reactor Physics Benchmark: V. Computation Of Mixed 2nd-Order Sensitivities Involving Isotopic Number Densities, Ruixian Fang, Dan Gabriel Cacuci

Faculty Publications

This work applies the Second-Order Adjoint Sensitivity Analysis Methodology (2nd-ASAM) to compute the mixed 2nd-order sensitivities of a polyethylene-reflected plutonium (PERP) benchmark's leakage response with respect to the benchmark's imprecisely known isotopic number densities and the other benchmark imprecisely known parameters, including: (i) the 6 × 180 mixed 2nd-order sensitivities involving the total microscopic cross sections; (ii) the 6 × 21,600 mixed 2nd-order sensitivities involving the scattering microscopic cross sections; (iii) the 6 × 60 mixed 2nd-order sensitivities involving the fission microscopic cross sections; and (iv) the 6 × 60 mixed 2nd-order sensitivities involving the average number of neutrons produced …

Portable Calorimeter For Fire Experiments, Kayla Collins, Kara Hewson, Christopher Chen, Joel Keddie

Mechanical Engineering

Executive Summary

An oxygen consumption calorimeter works by measuring the heat release rate of a burning substance. This value is calculated by measuring the oxygen and byproducts in smoke from afire.In order to get these values two types of sensors were used. A non-dispersive infrared sensor (NDIR) that measured CO and CO2 and a zirconium O2 sensor were used to find their respective gas concentrations.The design to calculate the heat release rate is focused on maximizing sensor accuracy and portability while simplifying the manufacturing by using off-the-shelf components. The goal included making the system simple to recreate and package in …

Flash Lab: A High-Speed Imaging Laboratory, Cody D. Hatch

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

To help students become better acquainted with high-speed instrumentation and measurement techniques, a high-speed imaging laboratory for the College of Engineering is equipped with a high-speed camera and schlieren imaging device. The laboratory will be used for labs in classes, such as Instrumentation, Thermal/Fluids Lab, Experimental Solids, and Mechanical Experiments. In addition, graduate students will use it for research purposes. The laboratory also has the potential to have a course associated with it that would include the image processing techniques for a variety of applications (e.g., a course on high-speed imaging). The scope of this project will be to create …

Static Pressure Recovery Effects Of Conical Diffusers With Swirling Inlet Flow, James Ray Wright Iii

All Theses

Conical diffusers are used in hundreds of engineering applications in various industries. Some of the operating conditions that they operate under cause swirling flow to enter the diffuser. It is generally well documented that the addition of swirl to the flow of a diffuser allows for greater divergence angles without wall separation, resulting in better overall performance of the diffuser and the machine it’s attached to. It is also known that as swirl strength is increased, the flow will eventually breakdown, resulting in internal flow recirculation and decreased diffuser performance. However, the relationship between the diffuser geometry and its performance …

Delineating The Relationship Between Cardiovascular Physiology And Subject Characteristics Using Computational Modeling And Systemic Review, Aseem Pradhan

All Theses

Lumped Parameter Networks (LPN) are computational models that can capture the systemic responses of the cardiovascular system. An LPN describes the systemic behavior by providing outputs such as the blood pressure, flowrate, and heart chamber volume at the points defined in the network. To use the LPN for medical applications, it needs to provide output values that represent the physiology of realistic subjects. The cardiovascular system exhibits short-term and long-term adaptations to factors such as aging, weight gain, exercise, etc. Therefore, subject characteristics such as age, height, weight, etc. affect the output values of the LPN. Current literature reports the …

Additive Manufacturing And How 3d Printing Is Fighting Covid-19, Raghavan Srinivasan, Ahsan Mian, Joy Gockel, Laura M. Luehrmann

Mechanical and Materials Engineering Faculty Publications

This is the fourth installment in the Shelter in Place (SiP) Lecture series. This installment covers the creative ways that 3D printing has supported efforts to combat the pandemic. It covers the basics of what 3D printing is, some of the various creative projects that have used 3D printing to combat the pandemic, among other topics and questions by the pandemic.

Experimental Evaluation Of Heat Leak And Convective Heat Transfer In A Household Freezer., Catherine E. Berghuis

Electronic Theses and Dissertations

Heat leak into household refrigerated cabinets is a key driver affecting energy consumption and efficiency of the cooling system. Additionally, knowledge of heat transfer coefficients of internal surfaces is valuable in the development of cabinet and system level performance simulations. Several studies have examined heat leak of refrigeration units using heat flux sensors (HFS); however, no such studies have used heat flux measurements to derive convective heat transfer coefficients of the refrigerated unit walls. The goal of this study is to evaluate the use of HFS to quantify heat leak into a 490-liter freezer and determine the wall convective heat …