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Articles 1 - 30 of 254

Full-Text Articles in Mechanical Engineering

Rapid Prediction Of Low-Boom And Aerodynamic Performance Of Supersonic Transport Aircraft Using Panel Methods, Ted N. Giblette Dec 2019

Rapid Prediction Of Low-Boom And Aerodynamic Performance Of Supersonic Transport Aircraft Using Panel Methods, Ted N. Giblette

All Graduate Theses and Dissertations

The Utah State University Aerolab developed and tested a set of tools for rapid prediction of the loudness of a sonic boom generated by supersonic transport aircraft. This work supported a larger effort led by Texas A&M to investigate the use of adaptive aerostructures in lowering sonic boom loudness at off design conditions. Successful completion of this effort will improve the feasibility of supersonic commercial transport over land.

Funding was provided by a NASA University Leadership Initiative grant to several universities, including Utah State University, as well as industry partners to complete this work over a five year period ...


Calibration Of Hot-Film X-Probes For High Accuracy Angle Alignment In Wind Tunnels, Dallin L. Jackson Aug 2019

Calibration Of Hot-Film X-Probes For High Accuracy Angle Alignment In Wind Tunnels, Dallin L. Jackson

All Graduate Theses and Dissertations

This thesis investigates the use of hot-film thermal anemometers to align a plate on a wind tunnel at Hill Air Force Base that is used to calibrate Angle of Attack Transmitters on F-16s. A reoccuring problem with this wind tunnel is that no two instruments can verify an angle reading of the the mounting plate for the Angle of Attack Transmitters to the air stream in the wind tunnel. Multiple thermal anemometer calibration methods, such as Jorgensen’s equation and a look-up table are implemented to attemp to achieve consistent measurements between multiple probes. The results show that it is ...


Isentropic Efficiency And Theoretical Analysis Of The Planetary Rotor Expander, Joseph L. James Aug 2019

Isentropic Efficiency And Theoretical Analysis Of The Planetary Rotor Expander, Joseph L. James

All Graduate Theses and Dissertations

Expanders allow pressurized fluids to undergo a pressure decrease in a controlled environment via volumetric growth to extract fluid energy. There are many types of expanders, and the objective of this thesis is to model the efficiencies of the planetary rotor expander (PRE), a century-old design undeveloped due to insufficient manufacturing capabilities (until recently). Geometric relationships are derived and mathematical models are generated to determine the efficiency of the PRE as a function of design variables. Two industrially relevant case studies show that, to maximize isentropic efficiency, the planetary rotor expander (PRE) rotational frequency is maximized and rotor geometry optimized.


How Vision Governs The Collective Behaviour Of Dense Cycling Pelotons, J. Belden, Mohammad M. Mansoor, A. Hellum, S. R. Rahman, A. Meyer, C. Pease, J. Pacheco, S. Koziol, Tadd T. Truscott Jul 2019

How Vision Governs The Collective Behaviour Of Dense Cycling Pelotons, J. Belden, Mohammad M. Mansoor, A. Hellum, S. R. Rahman, A. Meyer, C. Pease, J. Pacheco, S. Koziol, Tadd T. Truscott

Mechanical and Aerospace Engineering Faculty Publications

In densely packed groups demonstrating collective behaviour, such as bird flocks, fish schools or packs of bicycle racers (cycling pelotons), information propagates over a network, with individuals sensing and reacting to stimuli over relatively short space and time scales. What remains elusive is a robust, mechanistic understanding of how sensory system properties affect interactions, information propagation and emergent behaviour. Here, we show through direct observation how the spatio-temporal limits of the human visual sensory system govern local interactions and set the network structure in large, dense collections of cyclists. We found that cyclists align in patterns within a ± 30° arc ...


Water Walking As A New Mode Of Free Surface Skipping, Randy C. Hurd, Jesse Belden, Allan F. Bower, Sean Holekamp, Michael A. Jandron, Tadd T. Truscott Apr 2019

Water Walking As A New Mode Of Free Surface Skipping, Randy C. Hurd, Jesse Belden, Allan F. Bower, Sean Holekamp, Michael A. Jandron, Tadd T. Truscott

Mechanical and Aerospace Engineering Faculty Publications

Deformable elastomeric spheres are evaluated experimentally as they skip multiple times over a lake surface. Some spheres are embedded with small inertial measurement units to measure the acceleration experienced during water surface impact. A model for multiple impact events shows good agreement between measured acceleration, number of skipping events and distanced traveled. The experiment reveals a new mode of skipping, “water walking”, which is observed for relatively soft spheres impacting at low impact angles. The mode occurs when the sphere gains significant angular velocity over the first several impacts, causing the sphere to maintain a deformed, oblong shape. The behavior ...


Developing Silent Unmanned Aerial Vehicles, Glen Wright Mar 2019

Developing Silent Unmanned Aerial Vehicles, Glen Wright

Research on Capitol Hill

The optimization of a drone propeller’s acoustic signature can play an important role in the Department of Defense, observation of nature, commercial operations, and marine propulsion.

The aim of this research is to optimize the acoustic signature of propellers by isolating and modifying specific propeller characteristics. Propeller variations being researched in this project include:

  • Leading-edge serrations: break up incoming fluid and evenly disperse it along airfoil
  • Trailing-edge serrations: minimize vortex occurrences along the trailing edge of airfoil
  • Airfoil ribs: force fluid through tangential channels along airfoil
  • Winglets: disrupt turbulence and vortices at the tips of the propeller

Successful drone ...


Study Of The 3w Measurement Of The In-Plane And The Cross-Plane Thermal Properties On Anisotropic Thin Film Materials, Daxi Zhang Dec 2018

Study Of The 3w Measurement Of The In-Plane And The Cross-Plane Thermal Properties On Anisotropic Thin Film Materials, Daxi Zhang

All Graduate Theses and Dissertations

Due to the size of the nano-scale and micro-scale materials, traditional method for measuring the thermal properties of the bulk materials cannot be applied. The 3 OmegaMethod was developed by D. G. Cahill in the early 90s. It was used extensively to measure the thermal properties of thin film dielectric materials. Compare with other simulations or experimental methods, the 3 Omega Method has many advantages. Previous research has indicate that the 3 Omega method is capable of measuring the cross-plane thermal conductivity of thin film materials. In extension, an alternative improvement for measurement of the in-plane thermal conductivity and calculating ...


Inter-Laminar Fracture Of 3d-Printed Plastics - Development Of Methods, Christopher Stolinski Dec 2018

Inter-Laminar Fracture Of 3d-Printed Plastics - Development Of Methods, Christopher Stolinski

All Graduate Plan B and other Reports

Due to the increased use of 3D printed acrylonitrile butadiene styrene (ABS) plastic parts, a way to quantify the failure energy (energy needed to initiate cracking) is needed. Impact tests at high rates of loading are performed to determine failure energy. Throughout testing, specimens are monitored with high speed cameras to perform camera-based deformation measurements. Data acquisition and processing methods to calculate failure energy using crack opening displacement, and loading rates are developed to enable further use by Dr. Ryan Berke’s lab at Utah State University.


Development Of An Improved Low-Order Model For Propeller-Wing Interactions, Joshua Taylor Goates Dec 2018

Development Of An Improved Low-Order Model For Propeller-Wing Interactions, Joshua Taylor Goates

All Graduate Theses and Dissertations

For aircraft that have propellers mounted in front of the wings or tail, the prop wash produced by the propellers can have a strong influence on the aerodynamics of the aircraft. As the accelerated air from the propeller flows over the wings and tail, it can cause an alteration in the aerodynamic forces produced by those surfaces. Thus, an understanding of propeller-wing interactions is essential for the design and analysis of many aircraft.

There are multiple existing methods for analyzing the propeller-wing interactions. High order methods, such as wind tunnel testing or computational fluid dynamics, provide very accurate results but ...


Droplet Impact Onto Super-Hydrophobic Surfaces And Determining The Response To Heat And Light Of Terrestrial Cyanobacteria, Benjamin B. Lovett Dec 2018

Droplet Impact Onto Super-Hydrophobic Surfaces And Determining The Response To Heat And Light Of Terrestrial Cyanobacteria, Benjamin B. Lovett

All Graduate Theses and Dissertations

This thesis examines droplets striking water repelling surfaces as well as the movement of a soil based bacteria under various light and heat conditions. Droplet impact studies have shown that introducing a macroscopic feature to a water repelling surface can reduce the amount of time that droplet is in contact with the surface. By manipulating water droplets to impact different sized needles at varying speeds, we present how a needle can induce a similar reduction in the residence time of the droplet to more widely studied features. Results show the spreading and lift-off characteristics of the droplet are dependent on ...


Fluted Films, Nathan B. Speirs, Mohammad M. Mansoor, Jesse Belden, Randy C. Hurd, Zhao Pan, Tadd T. Truscott Oct 2018

Fluted Films, Nathan B. Speirs, Mohammad M. Mansoor, Jesse Belden, Randy C. Hurd, Zhao Pan, Tadd T. Truscott

Mechanical and Aerospace Engineering Faculty Publications

This paper is associated with a poster winner of a 2017 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original poster is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2017.GFM.P0030


The Effects Of Geometric And Stoichometric Change In Nanoparticles And Materials On Lattice Thermal Conductivity, W. Tanner Yorgason Aug 2018

The Effects Of Geometric And Stoichometric Change In Nanoparticles And Materials On Lattice Thermal Conductivity, W. Tanner Yorgason

All Graduate Theses and Dissertations

Thermal transport properties are critical for applications ranging from thermal management to energy conversion. Passive thermal management has been an area of study for over a century and has only grown as technology has advanced because it requires no additional energy to remove heat. Changing the nanostructure of the materials involved in passive heat transfer methods, either by geometric changes or stoichiometric changes, can greatly improve the effectiveness of this heat transfer method. In order to explore this further, this work employs LAMMPS molecular dynamics (MD) simulation software to calculate the lattice thermal conductivity (λp) of a nanoparticle (NP ...


A Non-Equilibrium Molecular Dynamics Study Of The Effects Of Helium Bubbles On The Thermal Conductivity Of Zrc, Tate Shorthill Aug 2018

A Non-Equilibrium Molecular Dynamics Study Of The Effects Of Helium Bubbles On The Thermal Conductivity Of Zrc, Tate Shorthill

All Graduate Plan B and other Reports

Zirconium carbide (ZrC) has been proposed as a potential improvement to nuclear fuel cladding. As such, it is important to characterize its physical properties, particularly those relating to thermal energy transport. Reactor conditions are known to damage fuel microstructure over time. While research has been conducted on undamaged and damaged ZrC, some areas of interest remain. Fission products, such as helium, can accumulate in pores within the fuel microstructure. Such a case has yet to be characterized in ZrC fuel cladding.

A non-equilibrium molecular dynamics model was developed to characterize the thermal properties of ZrC. Fourier’s Law allows the ...


Design Survey Of Laminated Composite I-Beam, Mrinmoy Saha Aug 2018

Design Survey Of Laminated Composite I-Beam, Mrinmoy Saha

All Graduate Plan B and other Reports

Composite I-beams are popular for high-strength low-weight applications. Learning the macro-mechanics and designing the composite I-beam properly are necessary. In this report, a design overview of the composite I-beam is discussed which is based on classical lamination theory where it includes the homogenization approach, the plane stress assumption and the Kirchhoff hypothesis. Using these assumptions, a method was developed to come up with the effective material properties of a beam. Formulas to calculate maximum deflection and maximum bending stress and shear stress and the stress concentration at the connection of web-flange are discussed which describe ways for designing and manufacturing ...


Thermal And Stress Analysis Of Nasa X-57 Maxwell Battery Pack, Bhumika Nautiyal Aug 2018

Thermal And Stress Analysis Of Nasa X-57 Maxwell Battery Pack, Bhumika Nautiyal

All Graduate Plan B and other Reports

Air travel has long been an established way of life for millions around the world, but innovation continues to push the boundaries of what is possible in the skies. While aviation has made it easy to travel long distances, the need to lower emissions from flights is pressing. The European Commission has described aviation as “one of the fastest-growing sources of greenhouse gas emissions.”

Airplanes release around 500 million tons of carbon dioxide into the atmosphere each year, representing a significant contribution to global warming. The very concept of a fossil-fuel-powered airplane needs to evolve to fully mitigate the impacts ...


Ultraviolet Diffraction Assisted Image Correlation (Uv-Daic) For Single-Camera 3d Strain Measurement At Extreme Temperatures, Ethan K. Nickerson Aug 2018

Ultraviolet Diffraction Assisted Image Correlation (Uv-Daic) For Single-Camera 3d Strain Measurement At Extreme Temperatures, Ethan K. Nickerson

All Graduate Theses and Dissertations

Digital Image Correlation (DIC) is a technique which uses images taken before and after deformation to determine displacement and strain data over the surface of the sample. In order to obtain this data for both in-plane as well as out-of-plane direction, multiple views of the sample are required. Typically, this is accomplished using multiple cameras, but it is possible to use diffraction gratings to bend the light coming from the specimen in order to allow a single camera to capture multiple views. This technique is referred to as Diffraction Assisted Image Correlation (DAIC) and has been previously demonstrated at room ...


Uncertainty Quantification And Sensitivity Analysis Of Multiphysics Environments For Application In Pressurized Water Reactor Design, Cole David Blakely Aug 2018

Uncertainty Quantification And Sensitivity Analysis Of Multiphysics Environments For Application In Pressurized Water Reactor Design, Cole David Blakely

All Graduate Theses and Dissertations

The most common design among U.S. nuclear power plants is the pressurized water reactor (PWR). The three primary design disciplines of these plants are system analysis (which includes thermal hydraulics), neutronics, and fuel performance. The nuclear industry has developed a variety of codes over the course of forty years, each with an emphasis within a specific discipline. Perhaps the greatest difficulty in mathematically modeling a nuclear reactor, is choosing which specific phenomena need to be modeled, and to what detail.

A multiphysics computational environment provides a means of advancing simulations of nuclear plants. Put simply, users are able to ...


Water Entry Cavity Dynamics, Nathan B. Speirs Aug 2018

Water Entry Cavity Dynamics, Nathan B. Speirs

All Graduate Theses and Dissertations

When a sphere or a stream of water hits the surface of a pool of water and enters a crater or air cavity often forms. This topic has been studied, both formally and informally, for a long time. This dissertation investigates four areas of water impact that are still poorly understood using high-speed photography. First, it examines a stream of droplets impacting on a pool of water, similar to a faucet drizzling into a full bucket. For these types of impacts we predict the depth, diameter, velocity, and shape of the cavities that the droplet stream forms. Second, it examines ...


Catalytic Augmentation Of An Arc-Ignited Hydrogen Peroxide/Abs Hybrid Rocket System, Stephen Whitmore, Christopher J. Martinez Jul 2018

Catalytic Augmentation Of An Arc-Ignited Hydrogen Peroxide/Abs Hybrid Rocket System, Stephen Whitmore, Christopher J. Martinez

Mechanical and Aerospace Engineering Faculty Publications

The authors have collaborated with an industry partner to develop a prototype upper stage for a dedicated nano-launch vehicle. In addition to providing sufficient impulse for orbit insertion, the unique motor system also provides capability for multiple restarts; allowing operation as an orbital maneuvering thruster. The hybrid motor design uses 85%-90% hydrogen peroxide solution and 3-D printed ABS as propellants. In the original system design the peroxide catalyst bed was completely removed and a patented arc-ignition system thermally ignited the propellants. The thermal ignition system was effective but resulted in a combustion latency of approximately 1-second, reducing overall performance ...


Numerical Evaluation Of Energy Release Rate At Material Interfaces For Fatigue Life Predictions, Robert L. Hendrickson May 2018

Numerical Evaluation Of Energy Release Rate At Material Interfaces For Fatigue Life Predictions, Robert L. Hendrickson

All Graduate Theses and Dissertations

Composite materials are becoming popular in almost all industries. Carbon-fiber and glass-fiber composites are used in aircraft, sports equipment, boats, prosthetics, and wind turbine blades. In all these applications, the composites are subjected to different loads. Loads can take the form of impact or cyclic/fatigue loading, both of which decrease the strength of composites as micro-cracks grow through the composite. Composite laminates are made up of fiber plies (thin layers of fiber) and the fibers are surrounded by a resin like epoxy. It is common for laminates to fail because of delamination growth (plies peeling apart). Small delaminations do ...


Methods For The Aerostructural Design And Optimization Of Wings With Arbitrary Planform And Payload Distribution, Jeffrey D. Taylor May 2018

Methods For The Aerostructural Design And Optimization Of Wings With Arbitrary Planform And Payload Distribution, Jeffrey D. Taylor

All Graduate Theses and Dissertations

The design of an aircraft wing often involves the use of mathematical methods for simultaneous aerodynamic and structural design. The goal of many of these methods is to minimize the drag on the wing. A variety of computer models exist for this purpose, but some require the use of expensive time and computational resources to give meaningful results. As an alternative, some mathematical methods have been developed that give reason ably accurate results without the need for a computer. However, most of these methods can only be used for wings with specific shapes and payload distributions. In this thesis, a ...


A High-Magnification Uv Lens For High-Temperature Optical Strain Measurements, Robert S. Hansen May 2018

A High-Magnification Uv Lens For High-Temperature Optical Strain Measurements, Robert S. Hansen

All Graduate Plan B and other Reports

Digital Image Correlation (DIC) is an experimental method used to produce full-field strain maps of specimens undergoing deformation. In this measurement, images of a specimen are taken before and after mechanical and thermal loading, then software is used to track deformation and compute strains. DIC has been recently adapted for high-temperature tests by using ultraviolet (UV) range cameras, lenses, and filters to produce the images.

Application of DIC to small length scales and at high temperatures can be performed with proper equipment. However, for these measurements, there is no commercially available high-magnification lens that will allow images to be taken ...


Importance Of Exposure Time On Digital Image Correlation (Dic) At Extreme Temperatures, Thinh Quang Thai May 2018

Importance Of Exposure Time On Digital Image Correlation (Dic) At Extreme Temperatures, Thinh Quang Thai

All Graduate Theses and Dissertations

Extreme temperatures have increasingly played an important role in engineering applications, including leading edges during hypersonic flight, spacecraft re-entry, and propulsion systems. In order to design for such thermo-mechanical conditions, materials must be characterized using suitable measurement methods. DIC is a popular and versatile method in full-field measurement. In brief, DIC compares images of a sample between its undeformed and deformed state in order to get displacement and strain field maps. Since the images are acquired from digital cameras, it is important to have high contrast images for meaningful correlation. Exposure time is a pivotal camera setting relating to camera ...


A Propeller Model Based On A Modern Numerical Lifting-Line Algorithm With An Iterativesemi-Free Wake Solver, Zachary S. Montgomery May 2018

A Propeller Model Based On A Modern Numerical Lifting-Line Algorithm With An Iterativesemi-Free Wake Solver, Zachary S. Montgomery

All Graduate Theses and Dissertations

A fundamental aerodynamic analysis technique for a single straight fixed wing has been expounded upon and turned into a modern technique that can analyze multiple wings of more realistic shapes common on aircraft. This modern technique is extended further to apply towards propellers. A method to overcome propeller analysis problems at low airspeeds is presented. This method is compared to more traditional propeller analysis techniques.


Characterization Of Carbon Nanostructured Composite Film Using Photothermal Measurement Technique, Kurt E. Harris May 2018

Characterization Of Carbon Nanostructured Composite Film Using Photothermal Measurement Technique, Kurt E. Harris

All Graduate Theses and Dissertations

Graphene is a form of carbon with unique thermal and structural properties, giving it high potential in many applications, from electronics to driveway heating. Advanced fabrication techniques putting small, graphene-like structures in a polymer matrix could allow for incorporation of some of the benefits of graphene into very lightweight materials, and allow for broader commercialization. Measuring the thermal properties of these thin-film samples is a technical capability in need of development for use with the specific specimens used in this study. Relating those thermal properties to the microstructural composition was the focus of this work.

Several conclusions could be drawn ...


Distribution Of Particle Image Velocimetry (Piv) Errors In A Planar Jet, Jaron A. Howell May 2018

Distribution Of Particle Image Velocimetry (Piv) Errors In A Planar Jet, Jaron A. Howell

All Graduate Theses and Dissertations

Particle Image Velocimetry (PIV) is an optical fluid measurement technique used to obtain velocity measurements. Two PIV systems were used to capture data simultaneously and measurement error for the MS PIV system is calculated. An investigation of error distribution is performed to determine when uncertainty estimations fail for the CS PIV-UQ method. Investigation of when results from multi pass PIV processing are achieve were performed so that reliable uncertainty estimations are produced with the CS method. An investigation was also performed which determined that error distributions in PIV systems are correlated with flow shear and particle seeding density. Correlation of ...


The Water Entry Of Multi-Droplet Streams And Jets, Nathan B. Speirs, Zhao Pan, Jesse Belden, Tadd T. Truscott Apr 2018

The Water Entry Of Multi-Droplet Streams And Jets, Nathan B. Speirs, Zhao Pan, Jesse Belden, Tadd T. Truscott

Mechanical and Aerospace Engineering Faculty Publications

Water entry has been studied for over a century, but few studies have focused on multiple droplets impacting on a liquid bath sequentially. We connect multi-droplet streams, jets and solid objects with physical-based scaling arguments that emphasize the intrinsically similar cavities. In particular, the cavities created by the initial impact of both droplet streams and jets on an initially quiescent liquid pool exhibit the same types of cavity seal as hydrophobic spheres at low Bond number, some of which were previously unseen for jets and droplet streams. Low-frequency droplet streams exhibit an additional three new cavity seal types unseen for ...


Water Main Break Rates In The Usa And Canada: A Comprehensive Study, Steven Folkman Mar 2018

Water Main Break Rates In The Usa And Canada: A Comprehensive Study, Steven Folkman

Mechanical and Aerospace Engineering Faculty Publications

The economic prosperity of modern cities is based on a complex infrastructure network located both above and below ground. A critical component to public health and economic well-being is our drinking water which is brought to the tap through an elaborate network of underground pipe distribution systems. Since most of this infrastructure is underground, it is out of sight and often neglected. Empirical data on water main breaks helps utilities in their repair and replacement decision making processes in order to deliver clean drinking water to their customers at an affordable price. This report documents the survey results of water ...


Les Taux De Rupture De Conduites D’Eau Aux États-Unis Et Au Canada : Une Étude Complète, Steven Folkman Mar 2018

Les Taux De Rupture De Conduites D’Eau Aux États-Unis Et Au Canada : Une Étude Complète, Steven Folkman

Mechanical and Aerospace Engineering Faculty Publications

La prospérité économique des villes modernes est basée sur un réseau d’infrastructures complexe à la fois en surface et sous la terre. Un élément essentiel pour la santé publique et le bien-être économique est notre eau potable, qui est acheminée jusqu’à notre robinet à travers un réseau complexe de conduites de distribution d’eau souterraines. Étant donné que la plus grande partie de cette infrastructure se trouve sous terre, elle est hors de vue et souvent négligée. Disposer de données empiriques sur des ruptures de conduites d’eau aide les services publics avec leurs processus de prises de ...


A Comparison Of The Aerodynamic Centers For Panel Code Compressible Corrections And Openfoam 5 For Mach 0.1 To 0.8, Dustin Weaver Dec 2017

A Comparison Of The Aerodynamic Centers For Panel Code Compressible Corrections And Openfoam 5 For Mach 0.1 To 0.8, Dustin Weaver

All Graduate Plan B and other Reports

It is known that the aerodynamic center changes from quarter chord to half chord from incompressible to compressible flows on airfoils. Compressible corrections are derived and implemented in a vortex panel code. These results will be used to find the aerodynamic centers for the specified Mach range of 0.1 to 0.8 in 0.1 increments within - 6 to 6 degrees angle of attack. OpenFOAM 5 cases will be created with specific meshes and settings. The results calculated from OpenFOAM 5 will be compared to the results obtained from the compressible corrections.