Engineering Commons^™

Guided Wave Based Integrated Structural Health Monitoring And Nondestructive Evaluation, Zhenhua Tian

Theses and Dissertations

Damage detection and health monitoring are critical for ensuring the structural safety in various fields, such as aerospace, civil and nuclear engineering. Structural health monitoring (SHM) performs online nondestructive evaluation (NDE) and can predict the structural remaining life through appropriate diagnosis and prognosis technologies. Among various SHM/NDE technologies, guided ultrasonic waves have shown great potential for fast and large area SHM/NDE, due to their sensitivity to small defects and capability to propagate long distances. Recent advances in guided wave based SHM/NDE technologies have demonstrated the feasibility of detecting damage in simple structures such as metallic plates and pipes. However, there …

Wavelet Analysis Of Periodic Error In Heterodyne Interferometry, Chao Lu

Theses and Dissertations

Heterodyne displacement measuring interferometry provides important metrology for applications requiring high resolution and accuracy. Heterodyne Michelson interferometers use a two-frequency laser source and separate the two optical frequencies into one fixed length and one variable length path via polarization. Ideally these two beams are linearly polarized and orthogonal so that only one frequency is directed toward each path. An interference signal is obtained by recombining the light from the two paths; this results in a measurement signal at the heterodyne (split) frequency of the laser source. This measurement signal is compared to the optical reference signal. Motion in the measurement …

A Multiphysics Modeling Of Solid Oxide Metal-Air Redox Battery, Md Ahsan Uddin

Theses and Dissertations

Cost-effective and large scale energy storage is essential for the growth of the future’s ‘‘green energy’’ infrastructure. Among the energy storage technologies currently being used, rechargeable batteries represent a class of advanced electrical energy storage (EES) mechanisms that can be valuable for the future renewable integration and smart grid. Rechargeable batteries have innumerous advantages over the conventional pumped hydro and compressed-air energy storage system. Now days, There are various types of rechargeable batteries available to work as an energy storage device in a smart grid but it still needs many breakthroughs to become commercially viable for stationary energy storage. First …

Bio-Inspired Design Of Mechanical Band Pass Sensor With The Ability To Scavenge Energy, Md Riaz Uddin Ahmed

Theses and Dissertations

Primary objective of this work is to introduce the multi-scale computational model for the bio-inspired acousto-ultrasonic band pass sensor that are capable of mechanically sense and/or filter wide range user defined frequencies. Selecting a particular and/or a distinct band of frequencies is essential for many applications in science engineering and technologies. For example design of sensors in chemical, biomedical and biological applications; device application for acoustic modulation by breaking the acoustic reciprocity and the sensors used in precision manufacturing applications requires sensing and/or filtering of wide range of acousto-ultrasonic frequencies. Presently, electronic devices are widely employed in commercial applications for …

Pressure Field Estimation Using Particle Image Velocimetry, Jean O. Calzada

Theses and Dissertations

In recent years, scientist and engineers have shown the advantages created by using the Particle Image Velocimetry (PIV) method as flow diagnostic tool to characterize instantaneous velocity fields. One of the important benefits is found on its non-intrusive nature, this leads to accurate velocity fields. From the velocity field obtained by PIV important quantities can be derived, such as pressure and vorticity. The present study, uses PIV data of an incompressible turbulent pulsed jet to determine the pressure field associated with the flow field. The pressure is calculated by using the averaged velocity field along with three different fundamental equation: …

Modeling The Residual Useful Life Of Railroad Bearing Grease, Thania Alejandra Martinez

Theses and Dissertations

Railroad bearing performance is often constrained by the life of its lubricant. The lubricant life is determined by tribomechanical processes that are present during bearing operation. No known physical models exist to predict the railroad bearing lubricant life. This thesis summarizes the efforts undertaken in the development of empirical models that can accurately predict the residual useful life of railroad bearing grease. Modeling techniques to be employed include regression, regression trees, and split plots. The grease samples used to populate this model come from healthy and faulty bearings that were run under different loads, speeds, and ambient conditions in a …

Modeling The Feasibility Of Corn Stover Combustion As A Heat Source At Corn Ethanol Plants, Sulekha Tamvada

Theses and Dissertations

Alternative energy sources are of prime interest for most of the nations across the world. Rising fuel prices and depleting petroleum reserves are of serious national and global concern. Bio-fuels if proved feasible for larger scale implementation could become the ideal breakthrough in easing the extensive dependence on fossil fuels and retaining the current engine technology of fossil fuels. Current methods of producing bio-fuels rely heavily on the consumption of non-renewable energy in the production process. Therefore, it is desirable to find renewable alternatives to these non-renewable energy sources.

Although bio-mass based fuels have been tested and proven to be …

Multi-Level Optimal Design Using Game Theory With Model Updating By Low Discrepancy Sampling, Yanchen Xu

Theses and Dissertations

The Design of Experiment (DOE) based response surface methodology (RSM) is a commonly used technique for solving optimization problems. The traditional DOE method has some shortcomings when used to update the RSM model. This thesis aims to develop a new DOE technique to solve the model updating problems in design optimization. Toward this end, a new DOE based RSM method is proposed to solve this problem by using low-discrepancy sequence method to generate the additional data points needed to update the model to replace the traditional factor and level based DOE method.

Tested on a couple of numerical example problems, …

Effects Of Various Mobility Aids On Lower-Extremity Muscle Activity, Michael Ryan Sanders

Theses and Dissertations

Millions of people each year spend some portion of their time using mobility aids to facilitate periods of non-weight bearing ambulation. The use of these devices changes the loading conditions of the lower extremities, which may result in skeletal muscle adaptations. The purpose of this work was to evaluate the effects of 3 types of mobility aids on lower-extremity muscle activity. Evaluation was based on 1) measured muscle activation signals using electromyography (EMG), and 2) measured joint kinematics and ground reaction forces, which were used to predict muscle forces. 16 healthy subjects (7 female, 9 male), ages 18-27 participated in …

Elucidating The Mechanisms Of Rate-Dependent Deformation At Ambient Temperatures In A Model Metallic Glass, Matthew Bradley Harris

Theses and Dissertations

In this work, the Shear Transformation Zone (STZ) dynamics model is adapted to capture the transitions between different regimes of flow serration in the deformation map of metallic glass. This was accomplished by scaling the STZ volume with a log-linear fit to the strain rate, and also adjusting the activation energy of an STZ with a log-linear fit to maintain constant yield strength at differing strain rates. Twelve simulations are run at each of six different strain rates ranging from 10^-5 to 10⁰ s^-1, and statistics are collected on simulation behavior and shear band nucleation and …

Springback Force Considerations In Compliant Haptic Interfaces, Dallin R. Swiss

Theses and Dissertations

This thesis investigates the potential benefits and challenges of using compliant mechanisms in the design of haptic interfaces. The benefits and challenges are presented with an emphasis on their inherent springback behavior and an active compensation approach. Design criteria for compliant mechanism joint candidates are reviewed and several joints are surveyed. Quantitative calculations of axial stiffness and maximum stress for five candidates are presented. Generalized analytical models of springback force and compensation torque are created to simulate the implementation of each joint candidate in a two degree-of-freedom planar pantograph. We use these models in the development and discussion of an …

Springback Force Considerations In Compliant Haptic Interfaces, Dallin R. Swiss

Theses and Dissertations

This thesis investigates the potential benefits and challenges of using compliant mechanisms in the design of haptic interfaces. The benefits and challenges are presented with an emphasis on their inherent springback behavior and an active compensation approach. Design criteria for compliant mechanism joint candidates are reviewed and several joints are surveyed. Quantitative calculations of axial stiffness and maximum stress for five candidates are presented. Generalized analytical models of springback force and compensation torque are created to simulate the implementation of each joint candidate in a two degree-of-freedom planar pantograph. We use these models in the development and discussion of an …

Impact Of Constructing A Low Crested Weir In Cape Canaveral On Flushing In The Banana River, Atousa Saberi

Theses and Dissertations

The purpose of this study is to determine the extent to which constructing a low crested weir adjacent to Port Canaveral improves ushing in the Banana River. The Banana River is a 50 km long sub-basin of Indian River Lagoon (IRL), located between Cape Canaveral and Merritt Island in Brevard County. Although Port Canaveral locks connect the Banana River to the ocean, the locks remain closed when there are no passing vessels; therefore, it has limited circulation and a long ushing time. Declining water quality can be linked to recent high mortality events of di erent species living in the …

Resistance Prediction For Asymmetrical Configurations Of High-Speed Catamaran Hull Forms, Srikanth Asapana

Theses and Dissertations

Predicting the resistance of a high-speed catamaran has been of interest to naval architects for the last three decades. Even though considerable amount of research has been carried out in this area, there remains a degree of uncertainty in the accurate resistance prediction of catamaran hull forms in the early design stage. Researches carried out so far have generally ignored the resistance characteristics of unconventional and unsymmetrical catamaran hull forms. This thesis attempts to undertake a comparative analysis of resistance characteristics between newly developed unconventional catamaran hull forms of different configurations derived from existing conventional NPL series of round bilge …

Design And Manufacture Of Mesoscale Robot-Actuated Surgical Instruments, Clayton L. Grames

Theses and Dissertations

Minimally Invasive Surgery (MIS) is a growing field including both laparoscopic androbotic operations. Surgeons and engineers are making continual efforts to reduce the negative effects of procedures on patients. Reducing the size of the surgical instruments is one effective method pursued in this effort. When the instruments approach 3 mm in diameter, they reach a threshold where the entry incisions can be small enough that no scar is left on the patient. Laparoscopic instruments on this scale exist but typically lack wrist articulation and only have 1 degree of freedom (DoF). Alternatively, robotic surgical instruments can achieve high levels of …

Aerodynamic Improvement Of The Byu Supermileage Vehicle, Sayan Dobronsky

Theses and Dissertations

The purpose of this thesis work was to design a new shape for the BYU Supermileage vehicle in order to improve its fuel efficiency. Computational Fluid Dynamics (CFD) was used to obtain the coefficient of drag (CD) and drag area of the current baseline vehicle at a Reynolds number of 1.6x10^6 and 8.7x10^5. Then a new shape was developed using mesh morphing software. The new shape was imported into the CFD program and the drag figures and airflow plots from the modified design were compared with the baseline vehicle. Scale models of the vehicles were also printed using a 3D …

Design And Validation Of A Complex Loading Whole Spinal Segment Bioreactor, Amanda Marie Beatty

Theses and Dissertations

Intervertebral disc (IVD) degeneration is a prevalent health problem that is highly linked to back pain. To understand the disease and tissue response to therapies, ex-vivo whole IVD organ culture systems have recently been introduced. The goal of this study was to develop and validate a whole spinal segment culturing system that loads the disc in complex loading similar to the in-vivo condition, while preserving the adjacent endplates and vertebral bodies. The complex loading applied to the spinal segment was achieved with three pneumatic cylinders. The pneumatic cylinders were rigidly attached to two triangular alumni plates at each corner, comprising …

Using Star-Ccm+ To Evaluate Multi-User Collaboration In Cfd, Kasey Johnson Webster

Theses and Dissertations

The client-server architecture of STAR-CCM+ allows multiple users to collaborate on a simulation set-up. The effectiveness of collaboration with this architecture is tested and evaluated on five models. The testing of these models is a start to finish set-up of an entire simulation excluding computational time for generating mesh and solving the solution. The different models have distinct differences which test every operation that would be used in a general CFD simulation. These tests focus on reducing the time spent preparing the geometry to be meshed, including setting up for a conformal mesh between multiple regions in conjugate heat transfer …

An Approach For Designing Origami-Adapted Products With Aerospace Mechanism Examples, Jessica Morgan

Theses and Dissertations

The objective of this research is to develop a design process for origami-adapted products and demonstrate it using aerospace mechanism examples. Origami-adapted design is a type of origami-based design. Origami-based design ranges from abstract to concrete applications of origami to design and includes: origami-inspired design, origami-adapted design, and origami-applied design. Origami-adapted design adapts origami fold patterns into products while preserving functionality. Some of the desirable attributes of origami that are sought after in design include: 1) reduced number of parts, 2) stowability, 3) deployability, 4) transportability, 5) manufacturability from a flat sheet of material, 6) ease of miniaturization, 7) a …

Inverse Approaches For Recovery Of Distributed Loads, Aleysha Kobiske

Theses and Dissertations

Inverse load recovery is a well-researched topic which involves determining an unknown force acting on a structure from the induced strain. The methodology used to determine an unknown loading imposed on a structure begins with a finite element model of the structure. Unit loads are applied at each known load location and the strain data is collected from the model. The strain data collected from the structure during operation or from simulation is compared to the strain produced from the unit loads. The result is an estimate of the imposed load.

In order to obtain the best results possible for …

Performance Optimization And Statistical Analysis Of Basic Immune Simulator (Bis) Using The Flame Gpu Environment, Shailesh Tamrakar

Theses and Dissertations

Agent-based models (ABMs) are increasingly being used to study population dynamics in complex systems such as the human immune system. Previously, Folcik et al. developed a Basic Immune Simulator (BIS) and implemented it using the RePast ABM simulation framework. However, frameworks such as RePast are designed to execute serially on CPUs and therefore cannot efficiently handle large simulations. In this thesis, we developed a parallel implementation of immune simulator using FLAME GPU, a parallel ABM simulation framework designed to execute of Graphics Processing Units(GPUs). The parallel implementation was tested against the original RePast implementation for accuracy by running a simulation …

Dynamic Moving Load Identification Using Optimal Sensor Placement And Model Reduction, Paul Augustine

Theses and Dissertations

A structure in service can be subjected to static, dynamic or moving loads. Several situations in practice involve estimation of moving loads which induce vibrations in the structure on which they are applied. An accurate estimation of these loads will ensure product quality and reliability of the final design, and mitigate the cost of structural health monitoring systems. The moving nature of dynamic loads increases the computational difficulty of the problem. One of the types of Inverse Problems involves estimation of the applied load from measured structural response such as strain or accelerations.

Measuring response at a limited number of …

Reactive Motions In A Fully Autonomous Crs Catalyst 5 Robotic Arm Based On Rgbd Data, Arad Haselirad

Theses and Dissertations

This study proposes a method to perform velocity estimation using motion blur in a single image frame along x and y axes in the camera coordinate system and intercept a moving object with a robotic arm. It will be shown that velocity estimation in a single image frame improves the system's performance. The majority of previous studies in this area require at least two image frames to measure the target's velocity. In addition, they mostly employ specialized equipments which are able to generate high torques and accelerations.

The setup consists of a 5 degree of freedom robotic arm and a …

Neutral Parametric Canonical Form For 2d And 3d Wireframe Cad Geometry, Robert Steven Freeman

Theses and Dissertations

The challenge of interoperability is to retain model integrity when different software applications exchange and interpret model data. Transferring CAD data between heterogeneous CAD systems is a challenge because of differences in feature representation. A study by the National Institute for Standards and Technology (NIST) performed in 1999 made a conservative estimate that inadequate interoperability in the automotive industry costs them $1 billion per year. One critical part of eliminating the high costs due to poor interoperability is a neutral format between heterogeneous CAD systems. An effective neutral CAD format should include a current-state data store, be associative, include the …

Improving The Suction Performance And Stability Of An Inducer With An Integrated Inlet Cover Bleed System Known As A Stability Control Device, Ryan K. Lundgreen

Theses and Dissertations

The performance of an inducer with the integration of an inlet cover bleed system known as a stability control device (SCD) is investigated using computational fluid dynamics. Inducers are the first stage of high suction performance pumps and are designed to operate under cavitating conditions. Improvements in design have allowed inducers to operate stably with low inlet head conditions, however, cavitation instabilities ultimately lead to pump failure. It has been shown that inducers that employ an SCD fully suppress cavitation instabilities.The performance of an inducer is explored at both on- and off-design flow coefficients, where the flow coefficient is a …

Jet And Droplet Impingement On Superhydrophobic Surfaces, Jonathan Glenn Stoddard

Theses and Dissertations

The effect of superhydrophobicity on liquid water impingement on a flat horizontal surface was explored. The surfaces combined a hydrophobic surface chemistry with a patterned microstucture in order to produce high contact angles with water. Three sets of experiments were performed, one for jet impingement and two for droplet impingement, which advance previous work in characterizing the interaction of water and superhydrophobic surfaces.Jet impingement experiments were performed to characterize a transitional regime between an unsubmerged and a completely submerged superhydrophobic surface by varying an imposed downstream depth. For low downstream depths, the surface remained unsubmerged and displayed only break up …

Geometry And Material Properties Of Vocal Fold Models, Kimberly Ann Stevens

Theses and Dissertations

Voiced communication plays a fundamental role in society. Voice research seeks to improve understanding of the fundamental physics governing voice production, with the eventual goal of improving methods to diagnose and treat voice disorders. For this thesis, three different aspects of voice production research were studied. First, porcine vocal fold medial surface geometry was determined, and the three-dimensional geometric distortion induced by freezing the larynx, especially in the region of the vocal folds, was quantified. It was found that porcine vocal folds are qualitatively geometrically similar to canine and human vocal folds, as well as commonly used models, and that …

Composition Based Modaling Of Silicone Nano-Composite Strain Gauges, Daniel Alexander Baradoy

Theses and Dissertations

In this work a review of the technology surrounding high deflection strain sensing with an emphasis on that of a recently developed nickel nano-composite strain sensor is presented. A new base silicone material was identified for the nickel nano-composite strain sensor that improves its mechanical stiffness and conductive properties. A previously identified cyclic creep concern was mitigated through preconditioning and the use of adhered backing materials. Through a block design experiment the strain/resistance curves for the strain sensors were characterized over a wide range of nano-filler material compositions. An analytical model was developed based on observation that the resistance of …

Temperature Measurement Using Infrared Spectral Band Emissions From H2o, Daniel Jared Ellis

Theses and Dissertations

Currently there is no known method for accurately measuring the temperature of the gas phase of combustion products within a solid fuel flame. The industry standard is a suction pyrometer and thermocouple which is intrusive, both spatially and temporally averaging, and difficult to use. In this work a new method utilizing the spectral emission from water vapor is investigated through modeling and experimental measurements. This method was demonstrated along a 0.75m line of sight, averaged over 1 minute in the products of a natural gas flame but has the potential to produce a spatial resolution on the order of 5 …

Transport Enhancement Of Rate-Limited Chemical Reactions Via Pt-Decorated, Carbon Nanotube Microarray Membranes, Kevin M. Marr

Theses and Dissertations

Rate limited chemical reactions can be enhanced by improving the mass transport of the suspended analyte to the catalytic (or electrocatalytic) surface. While many attempts have been made to enhance this mass transport, these approaches are limited to utilizing only two enhancement methods – increasing available catalytic surface area, and increasing the flow of analyte in solution. Flow through high aspect ratio microstructures, however, would provide additional mass transport enhancement via boundary layer confinement. Platinum functionalized carbon nanotube microarray membranes (Pt-CNT-MMs) offer enhanced mass transport via all three methods, and were fabricated for demonstration in a H2O2 sample system, for …