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Scanning Laser Registration And Structural Energy Density Based Active Structural Acoustic Control, Daniel Alan Manwill
Scanning Laser Registration And Structural Energy Density Based Active Structural Acoustic Control, Daniel Alan Manwill
Theses and Dissertations
To simplify the measurement of energy-based structural metrics, a general registration process for the scanning laser doppler vibrometer (SLDV) has been developed. Existing registration techniques, also known as pose estimation or position registration, suffer from mathematical complexity, instrument specificity, and the need for correct optimization initialization. These difficulties have been addressed through development of a general linear laser model and hybrid registration algorithm. These are applicable to any SLDV and allow the registration problem to be solved using straightforward mathematics. Additionally, the hybrid registration algorithm eliminates the need for correct optimization initialization by separating the optimization process from solution selection. …
Active Noise Control Of A Two-Fan Exhaust-Mounted Array Using Near-Field Control Sources And Error Sensors, Ryan Leonard Rust
Active Noise Control Of A Two-Fan Exhaust-Mounted Array Using Near-Field Control Sources And Error Sensors, Ryan Leonard Rust
Theses and Dissertations
Multiple fans are sometimes used in an array configuration to cool various types of electronic equipment. In addition to adding another noise source, using two fans with closely spaced blade passage frequencies (BPF) can create an annoying beat frequency. A two fan array with each fan having a different BPF was considered. The fans were theoretically modeled at the BPF and first harmonics. Each fan has two acoustic paths to the far field. Thus, each fan was modeled as a two source array. The first control configuration consisted of one control filter using six control sources and six error sensors …
Joining Polycrystalline Cubic Boron Nitride And Tungsten Carbide By Partial Transient Liquid Phase Bonding, Grant O. Cook Iii
Joining Polycrystalline Cubic Boron Nitride And Tungsten Carbide By Partial Transient Liquid Phase Bonding, Grant O. Cook Iii
Theses and Dissertations
Friction stir welding (FSW) of steel is often performed with an insert made of polycrystalline cubic boron nitride (PCBN). Specifically, MS80 is a grade of PCBN made by Smith MegaDiamond that has been optimized for the FSW process. The PCBN insert is attached to a tungsten carbide (WC) shank by a compression fitting. However, FSW tools manufactured by this method inevitably fail by fracture in the PCBN. Permanently bonding PCBN to WC would likely solve the fracturing problem and increase the life of PCBN FSW tools to be economically viable. Partial transient liquid phase (PTLP) bonding, a process used to …
Modeling And Testing Of Dna Motion For Nanoinjection, Regis Agenor David
Modeling And Testing Of Dna Motion For Nanoinjection, Regis Agenor David
Theses and Dissertations
A new technique, called nanoinjection, is being developed to insert foreign DNA into a living cell. Such DNA transfection is commonly used to create transgenic organisms vital to the study of genetics, immunology, and many other biological sciences. In nanoinjection, DNA, which has a net negative charge, is electrically attracted to a micromachined lance. The lance then pierces the cell membranes, and the voltage on the lance is reversed, repelling the DNA into the cell. It is shown that DNA motion is strongly correlated to ion transport through a process called electrophoresis. Gel electrophoresis is used to move DNA using …
Identifying Potential Applications For Lamina Emergent Mechanisms And Evaluating Their Suitability For Credit-Card-Sized Products, Nathan Bryce Albrechtsen
Identifying Potential Applications For Lamina Emergent Mechanisms And Evaluating Their Suitability For Credit-Card-Sized Products, Nathan Bryce Albrechtsen
Theses and Dissertations
Lamina emergent mechanisms (LEMs) are a maturing technology that is prepared for commercial implementation into new products. LEMs are defined by three functional characteristics; they (1) are compliant, (2) are fabricated from planar materials, and (3) emerge from a flat initial state. Advantages, design challenges, and design tools are described for each of the functional characteristics. Opportunities for LEMs are discussed, namely disposable LEMs, novel arrays of LEMs, scaled LEMs, LEMs with surprising motion, shock absorbing LEMs, and deployable LEMs. Technology push product development processes were employed to select applications for LEMs. LEM technology was characterized. In a LEM workshop, …
Automated Tool Design For Complex Free-Form Components, Kevin G. Foster
Automated Tool Design For Complex Free-Form Components, Kevin G. Foster
Theses and Dissertations
In today's competitive manufacturing industries, companies strive to reduce manufacturing development costs and lead times in hopes of reducing costs and capturing more market share from early release of their new or redesigned products. Tooling lead time constraints are some of the more significant challenges facing product development of advanced free-form components. This is especially true for complex designs in which large dies, molds or other large forming tools are required. The lead time for tooling, in general, consists of three main components; material acquisition, tool design and engineering, and tool manufacturing. Lead times for material acquisition and tool manufacture …
Investigation Of Mechanical Differentials As Continuously Variable Transmissions, Dax B. Wells
Investigation Of Mechanical Differentials As Continuously Variable Transmissions, Dax B. Wells
Theses and Dissertations
In recent years the increasing demand for fuel efficient and less pollutant vehicles has stimulated the development of hybrid and electric vehicles. These vehicle platforms often incorporate drivetrains which utilize multiple power sources for vehicle propulsion in an effort to increase fuel mileage and reduce emissions. Coupling multiple power sources, such as an internal combustion engine and electric motor(s), has new challenges in drivetrain design. Understanding the torque and rpm relationships within the power transmission device used to combine power sources is fundamental to overcoming the design challenges associated with hybrid and electric vehicle platforms. Results from this research include …
A Flexible Context Architecture For A Multi-User Gui, Yue Xu
A Flexible Context Architecture For A Multi-User Gui, Yue Xu
Theses and Dissertations
This thesis focuses on the design and development of a flexible context architecture for a multi-user GUI that serves several users engaged in collaborative computer-aided applications (CAx). The objective of this thesis is to extend previous research into multi-user GUI's by providing multiple users with a flexible context interface for interaction with other users working on the same part at distributed locations. The investigation will consider how distributed users, through user interfaces, interact to simultaneously build models and how interaction context might be presented to regulate the way they wish to interact. The implementation integrates a Multi-User GUI (MUG) with …
Lean Manufacturing As A Source Of Competitive Advantage, Ryan Scott Williams
Lean Manufacturing As A Source Of Competitive Advantage, Ryan Scott Williams
Theses and Dissertations
The productivity advances generated from lean manufacturing are self-evident. Plants that adopt lean are more capable of achieving high levels of quality, shorter lead times, and less waste in the system. While it seems logical that higher levels of productivity and quality, as is common in lean companies, should result in positive financial performance, the research community has failed to establish the financial profitability of lean. Those researchers who have studied the financial returns issue report varying results. The goal of this research was to determine if a connection exists between lean and financial success and to discover why so …
Improved Measurement And Separation Techniques For Interior Near-Field Acoustical Holography, Zachary A. Collins
Improved Measurement And Separation Techniques For Interior Near-Field Acoustical Holography, Zachary A. Collins
Theses and Dissertations
Recent advances in near-field acoustical holography (NAH) have expanded the theory to interior spaces where multiple sources and/or reflections are present. In 1990, Tamura presented the spatial Fourier transform separation method to measure the reflection coefficient at oblique angles using two measurement planes in the wave number domain. This paper adapts the spatial Fourier transform separation method for application in interior NAH. A practical exploration of important experimental parameters is performed, which include the relative amplitudes of primary and disturbing sources, the measurement plane separation distance, and an acceptable noise floor. This technique is successfully applied in a reverberant environment …
Straightness Of Growth For Carbon Nanotube Microelectromechanical Systems, Kellen S. Moulton
Straightness Of Growth For Carbon Nanotube Microelectromechanical Systems, Kellen S. Moulton
Theses and Dissertations
The purpose of this research is to examine the effect of iron catalyst thickness on the straightness of growth of carbon nanotube microelectromechanical systems (CNT-MEMS). One of the key benefits of CNT-MEMS is that they can potentially have very high aspect ratios. One of the challenges in attaining these high aspect ratios is maintaining device straightness; as these devices get taller, the edges tend to curve rather than grow straight vertically. Scanning electron mi- croscope images of samples grown using various iron catalyst thicknesses show that both straight growth and relatively good edge definition can be achieved using iron thicknesses …
Design Principles And Preliminary Actuation Approaches For Novel Multiple-Layer Lamina Emergent Mechanisms, Paul Shumway Gollnick
Design Principles And Preliminary Actuation Approaches For Novel Multiple-Layer Lamina Emergent Mechanisms, Paul Shumway Gollnick
Theses and Dissertations
Multiple-layer Lamina Emergent Mechanisms (MLEMs) are mechanisms made from multiple sheets (lamina) of material with motion that emerges out of the fabrication plane. This study has shown that understanding how layers are used in existing products and in nature provides insight into how MLEMs can also use layers to achieve certain tasks. The multi-layered nature of MLEMs and the interactions between these layers are what enhance the capabilities of MLEMs and allow them to better meet design objectives. Layer separation is one objective for which MLEMs are well-suited. Layer separation can have a variety of applications and there are a …
Search Pattern Generation And Path Management For Search Over Rough Terrain With A Small Uav, Jacob L. Bishop
Search Pattern Generation And Path Management For Search Over Rough Terrain With A Small Uav, Jacob L. Bishop
Theses and Dissertations
Search operations can be described by the interaction between three entities: the target, the sensor, and the environment. Past treatments of the search problem have focused primarily on the interaction between the sensor and the target. The effects that the environment has on the target and sensor have been greatly simplified or ignored completely. The wilderness search and rescue scenario is one case in which these interactions cannot be safely ignored. Using the wilderness search and rescue problem as our motivating example, we develop an algorithm for planning search paths for a small unmanned aerial vehicle (UAV) over rough terrain …
Developing Intelligent Engineering Collaboration Tools Through The Use Of Design Rationale, Jordan David Ryskamp
Developing Intelligent Engineering Collaboration Tools Through The Use Of Design Rationale, Jordan David Ryskamp
Theses and Dissertations
This thesis presents a new method that improves upon the existing approaches to developing collaborative tools. The new method uses automatically inferred and manually recorded design rationale to intelligently filter the information that is shared by a collaborative tool. This represents an improvement upon the existing state of the art in collaborative engineering tools. To demonstrate the viability of the method three collaborative tools were created. The first is a multi-user collaborative design environment tool named SimulPart and built upon the NX CAD package. SimulPart uses the new method to limit the amount of communication required to keep every user …
Defect Detection Microscopy, Stuart Craig Rogers
Defect Detection Microscopy, Stuart Craig Rogers
Theses and Dissertations
The automotive industry's search for stronger lighter materials has been hampered in its desire to make greater use of Magnesium alloys by their poor formability below 150°C. One current challenge is to identify the complex structure and deformation mechanisms at work and determine which of these are primary contributors to the nucleation of defects. Orientation Imaging Microscopy has been the most accessible tool for microstructural analysis over the past 15 years. However, using OIM to analyze defect nucleation sites requires prior knowledge of where the defects will occur because once the defects nucleate the majority of microstructural information is destroyed. …
Development Of A Pseudo-Uniform Structural Velocity Metric For Use In Active Structural Acoustic Control, Jeffery M. Fisher
Development Of A Pseudo-Uniform Structural Velocity Metric For Use In Active Structural Acoustic Control, Jeffery M. Fisher
Theses and Dissertations
Active control of sound and vibration fields has become an strong area of research over the past few decades. In regards to the active control of acoustic radiation from vibration fields, known as active structural acoustic control (ASAC), there have been many different methods employed to understand structural and acoustic relationships and to control vibrations to limit the acoustic radiation. With active sound field control, sensors, usually microphones, need to be dispersed in the sound field, or an array of microphones must be placed directly in the sound field which, in many cases, uses up too much space for practical …
Quantitative And Qualitative Results From Droplet Impingement Experiments On Superhydrophobic Surfaces With Micro-Ribs For Three Liquid Types, John T. Pearson
Quantitative And Qualitative Results From Droplet Impingement Experiments On Superhydrophobic Surfaces With Micro-Ribs For Three Liquid Types, John T. Pearson
Theses and Dissertations
Experiments were performed in which liquid droplets were videographically recorded impacting horizontal superhydrophobic surfaces. The superhydrophobic surfaces were micropatterned with alternating ribs and cavities and coated with a hydrophobic coating. The following surface types were also tested for comparison: smooth uncoated, micropatterned uncoated, and smooth coated surfaces. Three liquid types were used: pure water, ethanol, and a 50/50 water/glycerine mixture. Acquired data demonstrated that the maximum droplet spread diameter exhibited a greater Weber number dependence than that previously reported in the literature. The time delays between impact and maximum spread and between impact and ejection of a vertical jet were …
Using Design Of Experiments And Electron Backscatter Diffraction To Model Extended Plasticity Mechanisms In Friction Stir Welded Aisi 304l Stainless Steel, Benjamin D. Nelson
Using Design Of Experiments And Electron Backscatter Diffraction To Model Extended Plasticity Mechanisms In Friction Stir Welded Aisi 304l Stainless Steel, Benjamin D. Nelson
Theses and Dissertations
Extended plasticity mechanisms (EPM) allow a metal to undergo extended plastic deformation without failure. These mechanisms are responsible for the extended plastic deformation characteristic of hot working processes. In this thesis it is shown that electron backscatter diffraction (EBSD) is capable of detecting EPM artifacts in the final microstructure of AISI 304L stainless steel (304L). Results also indicate that dislocation cells form in hot worked AISI 304L stainless steel. Additionally, in this study EBSD data collection and analysis is used with a design of experiments approach to model the presence of EPM artifacts in the final microstructure of friction stir …
Numerical Simulation Of Atmospheric Internal Waves With Time-Dependent Critical Levels And Turning Points, Brian Patrick Casaday
Numerical Simulation Of Atmospheric Internal Waves With Time-Dependent Critical Levels And Turning Points, Brian Patrick Casaday
Theses and Dissertations
Just as water surface waves are found everywhere on the ocean's surface, internal waves are ubiquitous throughout the atmosphere. These waves constantly propagate and interact with other flows, but these interactions are difficult to observe due to inadequate current technology. Numerical simulations are often utilized in the study of internal waves. In this work, ray theory is used to numerically simulate the interaction of atmospheric internal waves with time-dependent and time-independent background flows, specifically the interaction of small-scale internal waves and large-scale inertial waves. Parameters such as initial wavenumbers and amplitudes of both small internal waves and inertial waves are …
An Experimental Investigation Of Friction Bit Joining In Az31 Magnesium And Advanced High-Strength Automotive Sheet Steel, Rebecca Gardner
An Experimental Investigation Of Friction Bit Joining In Az31 Magnesium And Advanced High-Strength Automotive Sheet Steel, Rebecca Gardner
Theses and Dissertations
Friction Bit Joining (FBJ) is a recently developed spot joining technology capable of joining dissimilar metals. A consumable bit cuts through the upper layer of metal to be joined, then friction welds to the lower layer. The bit then snaps off, leaving a flange. This research focuses on FBJ using DP980 or DP590 steel as the lower layer, AZ31 magnesium alloy as the top layer, and 4140 or 4130 steel as the bit material. In order to determine optimal settings for the magnesium/steel joints, experimentation was performed using a purpose-built computer controlled welding machine, varying factors such as rotational speeds, …
Influence Of Material And Geometric Parameters On The Flow-Induced Vibration Of Vocal Folds Models, Brian A. Pickup
Influence Of Material And Geometric Parameters On The Flow-Induced Vibration Of Vocal Folds Models, Brian A. Pickup
Theses and Dissertations
The vocal folds are an essential component of human speech production and communication. Advancements in voice research allow for improved voice disorder treatments. Since in vivo analysis of vocal fold function is limited, models have been developed to simulate vocal fold motion. In this research, synthetic and computational vocal fold models were used to investigate various aspects of vocal fold vibratory characteristics. A series of tests were performed to quantify the effect of varying material and geometric parameters on the models' flow-induced responses. First, the influence of asymmetric vocal fold stiffness on voice production was evaluated using life-sized, self-oscillating vocal …
A New Eulerian-Based Double Continuity Model For Predicting The Evolution Of Pair Correlation Statistics Under Large Plastic Deformations, Sadegh Ahmadi
Theses and Dissertations
A new model using a double-continuity relation for predicting the evolution of pair-correlation functions (PCFs) is presented. The proposed model was developed using statistical continuum theory and is employed to predict the viscoplastic behavior of polycrystalline materials. This model was built based upon the continuity relations and a double divergence law that guarantees the conservation of both orientation and mass; and also satisfies the field equations (equilibrium, constitutive, and compatibility) at every point of the polycrystalline material throughout the deformation process. In the presented model, motion of particles in the real space and rotation of crystallographic orientations in the Euler …
Modeling, Design, And Testing Of Contact-Aided Compliant Mechanisms In Spinal Arthroplasty, Peter Andrew Halverson
Modeling, Design, And Testing Of Contact-Aided Compliant Mechanisms In Spinal Arthroplasty, Peter Andrew Halverson
Theses and Dissertations
Injury, instrumentation, or surgery may change the functional biomechanics of the spine. Spinal fusion, the current surgical treatment of choice, stabilizes the spine by rigid fixation, reducing spinal mobility at the cost of increased stress at adjacent levels. Recently, alternatives to spinal fusion have been investigated. One such alternative is total disc replacements. The current generation of total disc replacements (TDRs) focuses on restoring the quantity of motion. Recent studies indicate that the moment-rotation response and axis of rotation, or quality of motion (QOM), may have important implications in the health of adjacent segments as well as the health of …
A Computational Fluid Dynamics Feature Extraction Method Using Subjective Logic, Clifton H. Mortensen
A Computational Fluid Dynamics Feature Extraction Method Using Subjective Logic, Clifton H. Mortensen
Theses and Dissertations
Computational fluid dynamics simulations are advancing to correctly simulate highly complex fluid flow problems that can require weeks of computation on expensive high performance clusters. These simulations can generate terabytes of data and pose a severe challenge to a researcher analyzing the data. Presented in this document is a general method to extract computational fluid dynamics flow features concurrent with a simulation and as a post-processing step to drastically reduce researcher post-processing time. This general method uses software agents governed by subjective logic to make decisions about extracted features in converging and converged data sets. The software agents are designed …
A Computationally-Assisted Methodology For Rapid Exploration Of Design Possibilities In Conceptual Design, Garrett J. Barnum
A Computationally-Assisted Methodology For Rapid Exploration Of Design Possibilities In Conceptual Design, Garrett J. Barnum
Theses and Dissertations
One of the most important decisions in the product development process is the selection of a promising design concept because of the large influence it has on the final product. A thorough search for the best design is a significant challenge to designers, who are trying to balance the objective and subjective performance of the designs they create. In this thesis, a computationally-assisted design methodology is developed and used in the early stages of design to more thoroughly search for designs that perform well according to objective physics-based models and subjective designer-specific preference-based models. The method presented herein uses an …
Corrosion-Related Gas Measurements And Analysis For A Suite Of Coals In Staged Pulverized Coal Combustion, Todd A. Reeder
Corrosion-Related Gas Measurements And Analysis For A Suite Of Coals In Staged Pulverized Coal Combustion, Todd A. Reeder
Theses and Dissertations
Eleven gas species, including CO, CO2, H2, H2O, H2S, HCl, NOX, O2, SO2, COS and SO3, were measured in a 150 kWth, staged, pulverized coal, down-fired combustor using a Fourier transform infrared (FTIR) spectrometer, gas chromatograph (GC), and a Horiba PG-250 5-gas analyzer. Additional gases such as HCN, NH3, CH4, and other hydrocarbons were also measured. Seven coals of varying rank and composition were investigated. Measurements were obtained in reducing (S.R. = 0.85) and oxidizing (S.R. = 1.15) conditions. In particular, sulfur- and chlorine-containing species including H2S, SO2, COS, SO3, and HCl are discussed. In the reducing zone, all four …
Piezoresistive Nano-Composites: Characterization And Applications, Thomas B. Hyatt
Piezoresistive Nano-Composites: Characterization And Applications, Thomas B. Hyatt
Theses and Dissertations
Innovative multifunctional materials are essential to many new sensor applications. Piezoresistive nano-composites make up a promising class of such materials that have the potential to provide a measurable response to strain over a much wider range than typical strain gages. Commercial strain gages are currently dominated by metallic sensors with a useable range of a few percent strain at most. There are, however, many applications that would benefit from a reliable wide-range sensor. These might include the study of explosive behavior, instrumentation of flexible components, motion detection for compliant mechanisms and hinges, human-technology interfaces, and a wide variety of bio-mechanical …
Natural Fibers And Fiberglass: A Technical And Economic Comparison, Justin Andrew Zsiros
Natural Fibers And Fiberglass: A Technical And Economic Comparison, Justin Andrew Zsiros
Theses and Dissertations
Natural fibers have received attention in recent years because of their minimal environmental impact, reasonably good properties, and low cost. There is a wide variety of natural fibers suitable for composite applications, the most common of which is flax. Flax has advantages in tensile strength, light weight, and low cost over other natural fibers. As with other natural and synthetic fibers, flax is used to reinforce both thermoset and thermoplastic matrices. When flax is used in thermoplastic matrices, polypropylene and polyethylene are the main resins used. Although at first glance flax may seem to be a cheaper alternative to fiberglass, …
Testing Guidelines For New Product Development, Derek W. Egbert
Testing Guidelines For New Product Development, Derek W. Egbert
Theses and Dissertations
While many literary sources outline the product development process, few make mention of the prototyping and testing stage. This thesis suggests that because of its importance in the product development process, "Testing" should be documented as a major step and not just listed as a side note. As part of the testing step, it is suggested that standardized, in-use, and market tests be used to properly evaluate a product. While many rely solely on standardized tests to validate their products, effective in-use tests can be another vital tool that can prove the performance of the product in more specific and …
Optimization And Correlation Of The Penn State Model Of Friction Stir Welding To Experimental Welds In 304l Stainless Steel, Devin Donaldson Furse
Optimization And Correlation Of The Penn State Model Of Friction Stir Welding To Experimental Welds In 304l Stainless Steel, Devin Donaldson Furse
Theses and Dissertations
A numerical model of friction stir welding developed by T. DebRoy, R. Nandan, and others has been optimized to fit experimental data of eleven welds of 304L stainless steel at various weld feed rates and spindle speeds. Optimization was used to determine the values of five difficult-to-measure model parameters. The optimal parameter values were then correlated to the weld machine inputs. The mechanical efficiency and the coefficient of friction were not correlated with feed rate, spindle speed, or axial pressure. Tool slip was positively correlated with feed rate, negatively correlated with spindle speed, and not correlated with axial pressure. The …