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- AZ31 magnesium alloy (1)
Articles 31 - 58 of 58
Full-Text Articles in Engineering
Multi-User Methods For Fea Pre-Processing, Prasad Weerakoon
Multi-User Methods For Fea Pre-Processing, Prasad Weerakoon
Theses and Dissertations
Collaboration in engineering product development leads to shorter product development times and better products. In product development, considerable time is spent preparing the CAD model or assembly for Finite Element Analysis (FEA). In general Computer-Aided Applications (CAx) such as FEA deter collaboration because they allow only a single user to check out and make changes to the model at a given time. Though most of these software applications come with some collaborative tools, they are limited to simple tasks such as screen sharing and instant messaging. This thesis discusses methods to convert a current commercial FEA pre-processing program into a …
Evaluation Of Advanced Conductive Nickel Materials For Strain Sensing In Carbon Fiber Reinforced Polymers, Michael Christian Koecher
Evaluation Of Advanced Conductive Nickel Materials For Strain Sensing In Carbon Fiber Reinforced Polymers, Michael Christian Koecher
Theses and Dissertations
Due to their unique properties, carbon fiber reinforced polymers (CFRP) are becoming ever more prevalent in today's society. Unfortunately, CFRP suffer from a wide range of failure modes and structural health monitoring methods are currently insufficient to predict these failures. It is apparent that self-sensing structural health monitoring could be advantageous to protect consumers from catastrophic failure in CFRP structures. Previous research has shown that embedded nickel nanostrand nanocomposites can be used to instantaneously measure strain in carbon fiber composites, but these methods have been severely limited and can induce high stress concentrations that compromise the structural integrity of the …
Microscopic Light Field Particle Image Velocimetry, Bryce Adam Mcewen
Microscopic Light Field Particle Image Velocimetry, Bryce Adam Mcewen
Theses and Dissertations
This work presents the development and analysis of a system that combines the concepts of light field microscopy and particle image velocimetry (PIV) to measure three-dimensional velocities within a microvolume. Rectanglar microchannels were fabricated with dimensions on the order of 350-950 micrometers using a photolithographic process and polydimethylsiloxane (PDMS). The flow was seeded with fluorescent particles and pumped through microchannels at Reynolds numbers ranging from 0.016 to 0.028. Flow at Reynolds numbers in the range of 0.02 to 0.03 was seeded with fluorescent particles and pumped through microchannels. A light field microscope with a lateral resolution of 6.25 micrometers and …
The Composition And Morphology Of Coal Ash Deposits Collected In An Oxy-Fuel, Pulverized Coal Reactor, Curtis K. Stimpson
The Composition And Morphology Of Coal Ash Deposits Collected In An Oxy-Fuel, Pulverized Coal Reactor, Curtis K. Stimpson
Theses and Dissertations
Coal ash deposits were collected in a 160 kWth, down-fired oxy-coal reactor under staged and unstaged conditions for four different coals (PRB, Gatling, Illinois #6, and Mahoning). Concentration measurements of carbon, oxygen, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, titanium, chromium, manganese, iron, nickel, strontium, and barium were gathered from each deposit sample using scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS). Backscattered electron micrographs for each deposit sample were analyzed to gather morphological data. Particle size and shape were studied for each deposit collected. The average particle sizes of the particles in upstream deposits were much larger …
Mechanical Properties And Mems Applications Of Carbon-Infiltrated Carbon Nanotube Forests, Walter C. Fazio
Mechanical Properties And Mems Applications Of Carbon-Infiltrated Carbon Nanotube Forests, Walter C. Fazio
Theses and Dissertations
This work explores the use of carbon-infiltrated carbon nanotube (CI-CNT) forests as a material for fabricating compliant MEMS devices. The impacts of iron catalyst layer thickness and carbon infiltration time are examined. An iron layer of 7nm or 10nm with an infiltration time of 30 minutes produces CI-CNT best suited for compliant applications. Average maximum strains of 2% and 2.48% were observed for these parameters. The corresponding elastic moduli were 5.4 GPa and 4.1 GPa, respectively. A direct comparison of similar geometry suggested CI-CNT is 80% more flexible than single-crystal silicon. A torsional testing procedure provided an initial shear modulus …
No, Burnout, Flame Temperature, Emissivity, And Radiation Intensity From Oxycombustion Flames, Darrel Patrick Zeltner
No, Burnout, Flame Temperature, Emissivity, And Radiation Intensity From Oxycombustion Flames, Darrel Patrick Zeltner
Theses and Dissertations
This work produced the retrofit of an air-fired, 150 kW reactor for oxy-combustion which was then used in three oxy-combustion studies: strategic oxy-combustion design, oxy-combustion of petroleum coke, and air versus oxy-combustion radiative heat flux measurements. The oxy-combustion retrofit was accomplished using a system of mass flow controllers and automated pressure switches which allowed safe and convenient operation. The system was used successfully in the three studies reported here and was also used in an unrelated study. A study was completed where a novel high oxygen participation burner was investigated for performance while burning coal related to flame stability, NO, …
A Method For Exploring Optimization Formulation Space In Conceptual Design, Shane Keawe Curtis
A Method For Exploring Optimization Formulation Space In Conceptual Design, Shane Keawe Curtis
Theses and Dissertations
Formulation space exploration is a new strategy for multiobjective optimization that facilitates both divergent searching and convergent optimization during the early stages of design. The formulation space is the union of all variable and design objective spaces identified by the designer as being valid and pragmatic problem formulations. By extending a computational search into the formulation space, the solution to an optimization problem is no longer predefined by any single problem formulation, as it is with traditional optimization methods. Instead, a designer is free to change, modify, and update design objectives, variables, and constraints and explore design alternatives without requiring …
The Application Of Origami To The Design Of Lamina Emergent Mechanisms (Lems) With Extensions To Collapsible, Compliant And Flat-Folding Mechanisms, Holly Greenberg
The Application Of Origami To The Design Of Lamina Emergent Mechanisms (Lems) With Extensions To Collapsible, Compliant And Flat-Folding Mechanisms, Holly Greenberg
Theses and Dissertations
Lamina emergent mechanisms (LEMs) are a subset of compliant mechanisms which are fabricated from planar materials; use compliance, or flexibility of the material, to transfer energy; and have motion that emerges out of the fabrication plane. LEMs provide potential design advantages by reducing the number of parts, reducing cost, reducing weight, improving recyclability, increasing precision, and eliminating assembly, to name a few. However, there are inherent design and modeling challenges including complexities in large, non-linear deflections, singularities that exist when leaving the planar state, and the coupling of material properties and geometry in predicting mechanism behavior. This thesis examines the …
Evaluation And Development Of Actuators For Lamina Emergent Mechanisms With Emphasis On Flat Solenoids, Justin Durant Black
Evaluation And Development Of Actuators For Lamina Emergent Mechanisms With Emphasis On Flat Solenoids, Justin Durant Black
Theses and Dissertations
Lamina emergent mechanisms (LEMs) can provide a way to meet the demand for more compact and inexpensive mechanisms. Previous research has developed LEM designs and identified applications for them, but many applications would benefit from suitable actuation techniques. This thesis presents the design considerations and a variety of applicable methods for internal and external LEM actuation in the macro scale. Integrated LEM actuator possibilities have been identified, each with its advantages and disadvantages depending on the application. Shape memory alloys are especially compatible with LEMs. Traditional actuators have also been discussed as a way of actuating a LEM from the …
Application Of Two-Color Pyrometry To Characterize The Two-Dimensional Temperature And Emissivity Of Pulverized-Coal Oxy-Flames, Teri Snow Draper
Application Of Two-Color Pyrometry To Characterize The Two-Dimensional Temperature And Emissivity Of Pulverized-Coal Oxy-Flames, Teri Snow Draper
Theses and Dissertations
Oxy-combustion is a developing technology that enables carbon dioxide (CO2) capture. Flame temperature and emissivity data were taken on a 150 kWth, pulverized-coal, burner flow reactor (BFR) that has been modified to run oxy-combustion with pure CO2 as simulated recycled flue gas. Data were taken at 78 conditions in which three parameters were varied, namely: the swirl angle of the fuel stream, the location of the oxidizer as it exited the burner, and the flow rate of diluent (pure CO2) added to the outer, secondary stream. At each condition, digital color images were obtained using a calibrated RGB camera. The …
An Investigation Of The Ward Leonard System For Use In A Hybrid Or Electric Passenger Vehicle, Cody L. Telford
An Investigation Of The Ward Leonard System For Use In A Hybrid Or Electric Passenger Vehicle, Cody L. Telford
Theses and Dissertations
Since the early 1900's demand for fuel efficient vehicles has motivated the development of electric and hybrid electric vehicles. Unfortunately, some components used in these vehicles are expensive and complex. Today's consumer electric vehicles use dangerously high voltage,expensive electronic controllers, complex battery management systems and AC motors. The goal of this research at BYU is to increase safety by lowering the operating voltage and decrease cost by eliminating expensive controllers and decrease the number of battery cells. This paper specifically examines the use of a Ward Leonard Motor Control system for use in a passenger vehicle. The theory of the …
Cavitation Of A Water Jet In Water, Michael Marshall Wright
Cavitation Of A Water Jet In Water, Michael Marshall Wright
Theses and Dissertations
Cavitation is a phenomenon that occurs in liquids when the pressure drops below the vapor pressure of the liquid. Previous research has verified that cavitation bubble collapse is a dynamic and destructive process. An understanding of the behavior of cavitation is necessary to implement this destructive mechanism from an axisymmetric jet for underwater material removal. This work investigates the influence of jet pressure and nozzle diameter on the behavior of a cloud of cavitation bubbles generated by a submerged high-pressure water jet. First, this investigation is put into context with a condensed historical background of cavitation research. Second, a description …
Application Of Parametric Nurbs Geometry To Mode Shape Identification And The Modal Assurance Criterion, Evan D. Selin
Application Of Parametric Nurbs Geometry To Mode Shape Identification And The Modal Assurance Criterion, Evan D. Selin
Theses and Dissertations
The dynamic characteristics of a part are highly dependent on geometric and material properties of the part. The identification and tracking of vibrational mode shapes within an iterative design process becomes difficult and time consuming due to the frequently changing part definition. Currently, visual inspection of analysis results is used as the means to identify the shape of each vibrational mode determined by the modal analysis. This thesis investigates the automation of the mode shape identification process through the use of parametric geometry and the Modal Assurance Criterion. Displacement results from finite element modal analysis are used to create parametric …
Method For The Simulated Layup Of Composite Fabrics, David M. Christensen
Method For The Simulated Layup Of Composite Fabrics, David M. Christensen
Theses and Dissertations
Due to the complexity of designing advanced composite parts, many software tools have been developed to aid the designer and reduce design cycle time. Draping is one of those tools and is used to predict the fiber angles throughout the part. This application of draping is to simulate the actual hand layup process that a technician would go through while creating a multi-layered laminate composite part. This method is the first to use plies as an underlying surface for draping instead of just using an offset mold surface. This method can visualize full 3D ply geometry taking into account the …
Failure Mechanisms And Texture Evolution Of Wrought Az31b Magnesium At Temperatures Ranging From 25 C To 125 C, Jonathan Michael Scott
Failure Mechanisms And Texture Evolution Of Wrought Az31b Magnesium At Temperatures Ranging From 25 C To 125 C, Jonathan Michael Scott
Theses and Dissertations
Failure mechanisms were studied in wrought AZ31B magnesium alloy under different strain paths and various temperatures. Optical micrographs were used to observe the formation of shear bands and regions of high twin density in samples strained under uniaxial, biaxial and plane strain conditions. Interrupted testing at 4% effective strain increments until failure was used to observe the evolution of the microstructure. Results showed that shear bands with a high percentage of twinned grains appeared early in the samples strained under biaxial or plane strain tension. These bands are similar to the failure region in uniaxial tension specimens. A forming limit …
Application Of High Resolution Electron Backscatter Diffraction(Hr-Ebsd) Techniques To Twinning Deformation Mechanism In Az31 Magnesium Alloy, Ali Khosravani
Application Of High Resolution Electron Backscatter Diffraction(Hr-Ebsd) Techniques To Twinning Deformation Mechanism In Az31 Magnesium Alloy, Ali Khosravani
Theses and Dissertations
The application of high resolution electron backscatter diffraction (HR-EBSD) techniques has been used in order to study the evolution of geometrically necessary dislocation (GND). The tested materials were taken from AZ31 magnesium sheet which had strong basal texture. Because of low symmetry of the magnesium crystal lattice, the von Mises criteria cannot be satisfied by the three independent, easily activated, basal slips. The strain along the c-axis of the crystal must be accommodated by either twinning and/or slip systems. HR-EBSD data was taken in order to investigate these phenomena. The HR-EBSD results were post processed in order to resolve total …
Buckling Failure Boundary For Cylindrical Tubes In Pure Bending, Daniel Peter Miller
Buckling Failure Boundary For Cylindrical Tubes In Pure Bending, Daniel Peter Miller
Theses and Dissertations
Bending of thin-walled tubing to a prescribed bend radius is typically performed by bending it around a mandrel of the desired bend radius, corrected for spring back. By eliminating the mandrel, costly setup time would be reduced, permitting multiple change of radius during a production run, and even intermixing different products on the same line. The principal challenge is to avoid buckling, as the mandrel and shoe are generally shaped to enclose the tube while bending. Without the shaped mandrel, buckling will likely occur sooner, that is, at larger bend radii. A test apparatus has been built for arborless bending. …
Estimated Instability And Breaking Of Internal Waves Due To Time-Dependent Shear, Leonardo A. Latorre
Estimated Instability And Breaking Of Internal Waves Due To Time-Dependent Shear, Leonardo A. Latorre
Theses and Dissertations
The effects of propagation of a short internal gravity wave through an inertia wave on internal wave stability is analyzed and parameterized. The interactions are specifically between a short wave packet and a large inertia wave packet. The short wave packet is a wave bounded with a Gaussian envelope with high frequencies and scales in the hundreds of meters horizontally and tens of meters vertically. The inertia wave packet is also an enveloped wave but with frequencies close to the rotation of the earth and scales in the thousands of meters in the horizontal and hundreds of meters in the …
Numerical Investigation Of Internal Wave-Vortex Dipole Interactions, Tyler D. Blackhurst
Numerical Investigation Of Internal Wave-Vortex Dipole Interactions, Tyler D. Blackhurst
Theses and Dissertations
Three-dimensional linear ray theory is used to investigate internal waves interacting with a Lamb-Chaplygin pancake vortex dipole. These interactions involve waves propagating in the same (co-propagating) and opposite (counter-propagating) horizontal directions as the dipole translation. Co-propagating internal waves in the vertical symmetry plane between the vortices of the dipole can approach critical levels where the wave energy is absorbed by the dipole or where the waves are overturned and possibly break. As wave breaking cannot be simulated with this linear model, changes in wave steepness are calculated to aid in estimating the onset of breaking. Counter-propagating internal waves in the …
A Methodology For Strategically Designing Physical Products That Are Naturally Resistant To Reverse Engineering, Stephen P. Harston
A Methodology For Strategically Designing Physical Products That Are Naturally Resistant To Reverse Engineering, Stephen P. Harston
Theses and Dissertations
Reverse engineering - defined as extracting information about a product from the product itself - is a design tactic commonly used in industry from competitive benchmarking to product imitation. While reverse engineering is a legitimate practice - as long as the product was legally obtained - innovative products are often reverse engineered at the expense of the pioneering company. However, by designing products with built-in barriers to reverse engineering, competitors are no longer able to effectively extract critical information from the product of interest. Enabling the quantification of barriers to reverse engineering, this dissertation presents a set of metrics and …
High Speed Friction Stir Spot Welding On Dp 980 Steel:Joint Properties And Tool Wear, Nathan David Saunders
High Speed Friction Stir Spot Welding On Dp 980 Steel:Joint Properties And Tool Wear, Nathan David Saunders
Theses and Dissertations
With the desire to improve passenger safety and fuel efficiency, Ultra High Strength Steels (UHSS) have been developed for use in the automotive industry. UHSS are high strength steels with high ductility and strength. DP 980 is one of these UHSS being applied in automobile manufacturing. DP 980 is difficult to join with Resistance Spot Welding (RSW) because of the high carbon content and alloying in this material. The weld becomes brittle when it solidifies during the welding process. With the desire and motivation of widely using UHSS, new welding processes are needed to be developed in order to effectively …
Mathematical Framework For Early System Design Validation Using Multidisciplinary System Models, Bradley Jared Larson
Mathematical Framework For Early System Design Validation Using Multidisciplinary System Models, Bradley Jared Larson
Theses and Dissertations
A significant challenge in the design of multidisciplinary systems (e.g., airplanes, robots, cell phones) is to predict the effects of design decisions at the time these decisions are being made early in the design process. These predictions are used to choose among design options and to validate design decisions. System behavioral models, which predict a system's response to stimulus, provide an analytical method for evaluating a system's behavior. Because multidisciplinary systems contain many different types of components that have diverse interactions, system behavioral models are difficult to develop early in system design and are challenging to maintain as designs are …
Application Of Subjective Logic To Vortex Core Line Extraction And Tracking From Unsteady Computational Fluid Dynamics Simulations, Ryan Phillip Shaw
Application Of Subjective Logic To Vortex Core Line Extraction And Tracking From Unsteady Computational Fluid Dynamics Simulations, Ryan Phillip Shaw
Theses and Dissertations
Presented here is a novel tool to extract and track believable vortex core lines from unsteady Computational Fluid Dynamics data sets using multiple feature extraction algorithms. Existing work explored the possibility of extracting features concurrent with a running simulation using intelligent software agents, combining multiple algorithms' capabilities using subjective logic. This work modifies the steady-state approach to work with unsteady fluid dynamics and is designed to work within the Concurrent Agent-enabled Feature Extraction concept. Each agent's belief tuple is quantified using a predefined set of information. The information and functions necessary to set each component in each agent's belief tuple …
Investigation And Implementation Of A Robust Temperature Control Algorithm For Friction Stir Welding, Kenneth A. Ross
Investigation And Implementation Of A Robust Temperature Control Algorithm For Friction Stir Welding, Kenneth A. Ross
Theses and Dissertations
In friction stir welding, the temperature of the process zone affects the properties of the resulting weld and has a dramatic effect on tool life in PCBN (polycrystalline cubic boron nitride) tools. Therefore an active control system that changes process parameters to control weld temperature is desirable. Mayfield and Sorensen proposed a two-stage control model that contains an inner loop that controls the spindle speed to keep power constant and an outer loop for setting the desired power based on weld temperature. This work contains the analysis and implementation of a temperature control method based on their work. This research …
Integration Of Massive Multiplayer Online Role-Playing Games Client-Server Architectures With Collaborative Multi-User Engineering Cax Tools, Joshua D. Winn
Integration Of Massive Multiplayer Online Role-Playing Games Client-Server Architectures With Collaborative Multi-User Engineering Cax Tools, Joshua D. Winn
Theses and Dissertations
This research presents a new method for integrating client server architectures that are used for the development of Massive Online Role Playing Games (MMORPG) into multi-user engineering software tools. The new method creates a new architecture named CAx Connect by changing the client-pull-server communication pipeline to a server-push-client communication pipeline, effectively reducing the amount of bandwidth consumed and allowing these tools to utilize multiple server processors for complex calculations. This method was used on the new NX Connect multi-user CAx prototype developed at BYU. The new method provides a road map to further implement this architecture and its services into …
The Influence Of Nozzle Spacing And Diameter On The Acoustic Emissions Of Closely Spaced Supersonic Jet Arrays, Ian S. Coltrin
The Influence Of Nozzle Spacing And Diameter On The Acoustic Emissions Of Closely Spaced Supersonic Jet Arrays, Ian S. Coltrin
Theses and Dissertations
The acoustic emissions from supersonic jets represent an area of significant research needs; not only in the field of aero-acoustics, but in industry as well where high pressure let down processes have been known to cause acoustically induced vibrations. A common method to reduce the acoustic emissions of such processes involves dividing the single larger supersonic flow into several smaller ones. Though this is common practice, there is not yet a current model which describes the reduction of acoustic emissions from an array of smaller supersonic jets. Current research which studies supersonic jet arrays are mainly focused on the effects …
Characterization And Biomechanical Analysis Of The Human Lumbar Spine With In Vitro Testing Conditions, Dean K. Stolworthy
Characterization And Biomechanical Analysis Of The Human Lumbar Spine With In Vitro Testing Conditions, Dean K. Stolworthy
Theses and Dissertations
Biomechanical testing of cadaveric spinal segments forms the basis for our current understanding of healthy, pathological, and surgically treated spinal function. Over the past 40 years there has been a substantial amount of data published based on a spinal biomechanical testing regimen known as the flexibility method. This data has provided valuable clinical insights that have shaped our understanding of low back pain and its treatments. Virtually all previous lumbar spinal flexibility testing has been performed at room temperature, under very low motion rates, without the presence of a compressive follower-load to simulate upper body weight and the action of …
Biomechanical Implications Of Lumbar Spinal Ligament Transectiona Finite Element Study, Gregory Allen Von Forell
Biomechanical Implications Of Lumbar Spinal Ligament Transectiona Finite Element Study, Gregory Allen Von Forell
Theses and Dissertations
The purpose of this work was to determine the possible effects of isolated spinal ligament transection on the biomechanics of the lumbar spine. A finite element model of a lumbar spine was developed and validated against experimental data. The model was tested in the primary modes of spinal motion in the intact condition, followed by comparative analysis of isolated removal of each spinal ligament. Results showed that stress increased in the remaining ligaments once a ligament was removed, potentially leading to ligament damage. Results also showed changes in bone remodeling "stimulus" which could lead to changes in bone density. Isolated …