Mechanical Engineering Commons^™

Engine Sound Simulation And Generation In Driving Simulator, Shuang Wu

Masters Theses

"Simulating a driving environment that provides engine sound as auditory feedback to the driver is a challenging task due to the complexity of engine sound, a wide range of operating speeds, and repeated sound clicking during playback. This thesis describes a method of engine sound simulation and generation for a driving simulator. By analyzing sample sounds, spectral modeling synthesis was used to decompose the sound samples into deterministic and stochastic components. Then, the modeled deterministic and stochastic signals were employed to resynthesize the sounds. To represent engine sounds not available in the recorded database, sound interpolation was applied to two …

A Linear Matrix Inequality-Based Approach For The Computation Of Actuator Bandwidth Limits In Adaptive Control, Daniel Robert Wagner

Masters Theses

"Linear matrix inequalities and convex optimization techniques have become popular tools to solve nontrivial problems in the field of adaptive control. Specifically, the stability of adaptive control laws in the presence of actuator dynamics remains as an important open control problem. In this thesis, we present a linear matrix inequalities-based hedging approach and evaluate it for model reference adaptive control of an uncertain dynamical system in the presence of actuator dynamics. The ideal reference dynamics are modified such that the hedging approach allows the correct adaptation without being hindered by the presence of actuator dynamics. The hedging approach is first …

Design And Analysis Of An Axisymmetric Aerospike Supersonic Micro-Nozzle For A Refrigerant-Based Cold-Gas Propulsion System For Small Satellites, Abdalla Ali Bani

Masters Theses

"The cold-gas propulsion system being developed by M-SAT requires improvements to its original nozzle design. This study documents the research, design, and analysis of a supersonic plug nozzle concept that could be integrated to the refrigerant-based cold-gas propulsion system to possibly improve its performance. As documented in this thesis, CFD analysis showed that the outlined nozzle design method resulted in a feasible nozzle concept that has the ability to out-perform a conventional nozzle of the same area ratio. The flow-fields and thrust of the aerospike nozzle, for the full and truncated nozzles, were investigated. The purpose of this study is …

Addressing The Influence Of Carbon Monoxide On The Behavior Of An Hcci Engine, Allen Charles Ernst

Masters Theses

"Homogeneous Charge Compression Ignition (HCCI) may be the next leap of improvement to internal combustion engines due to its decreased emissions and improved engine efficiencies. However, such a jump possesses challenges owing to its strict reliance on the inherent physics that dictate start of combustion and limit the reach of stable operation. This work investigates the role and fundamental influence of carbon monoxide on the cycle-to-cycle combustion dynamics present in the region of incomplete combustion that frames the limited HCCI operating region. An improved understanding will open doors to enhanced control methodologies and an expanded stable operating envelope. A constant …

Design Of An Adaptive Force And Stiffness Controlled Compliant Device For Robotic Polishing, Mohammad Masud Parvez

Masters Theses

"Polishing is a repetitive task done in an unhealthy environment. Often more than half of the manufacturing time is required to polish a die. The manual polishing process is a tedious work actively rely on a skilled human worker. Industrial Robot has replaced the human in performing these tasks. For robotic polishing to control the polishing force, an active compliant device is used. Due to the compressibility of air, a pneumatic system is preferred as the actuator of the device. The force of the actuator is controlled by regulating air pressure in both chambers of the cylinder. However, to improve …

Design And Fabrication Of A System For The Additive Manufacturing Of Transparent Glass, Luke John Gilbert

Masters Theses

"Despite glass' prevalence in the scientific and engineering community, very little research has been conducted attempting to additively manufacture (AM) glass. Even less research has been done on optically transparent glass. Glass’ material properties make it ineligible for most AM processes if the end result is to be transparent. Even small gas inclusions can cause large amounts of scattering. Additively manufacturing transparent glass brings the advantages found in other AM processes with the added benefit of having optical properties better than those found in polymers. Additively manufacturing glass also allows the optical properties of transparent parts to vary arbitrarily. This …

Multifunctional Wearable Epidermal Device For Physiological Signal Monitoring In Sleep Study, J V M S Avinash Kankipati

Masters Theses

"Sleep is the essential part of life. Thousands of people are suffering from different kinds sleep disorders. Clinical diagnosing and treating for such disorders are costly, painful and quite sluggish. To reach the demand many commercial products are into the market to encourage home based sleep studies using portable devices. These portable devices are limited in use, cannot be handled easily and quite costly. Advancements in technology miniaturized these portable devices to wearable devices to make them convenient and economical. Elastic, soft and thin silicon membrane with physical properties well matched with that of the epidermis provides conformal and robust …

The Evaluation Of Sequential Optimization And Reliability Analysis, Guannan Liu

Masters Theses

"Sequential Optimization and Reliability Assessment (SORA) has been used for more than one decade for reliability-based design (RBD), but comprehensive theoretical studies on its performance have not been conducted. Further investigations on its performance are still needed. The objective of this thesis is to evaluate the performance of SORA for various testing problems. The performance of SORA evaluated in this thesis includes (1) accuracy, (2) efficiency, and (3) convergence behavior or robustness with numerical testing problems. SORA is evaluated with comparison with other major RBD methodologies. The testing problems are in different scales (numbers of design variables, random variables, and …

Laser Sintering And Aerosol Printing Of Conductive Nanoparticles, Mahati Guntupalli

Masters Theses

"Fabrication and printing of nanoparticles is an essential step in the manufacturing of low cost- high efficiency electronic devices. High material costs of noble metal particles necessitates the investigation for a potential substituent. Conventional methods of manufacturing are time consuming and uneconomical, thus intense research is being done to employ new methods for cost, time and space effective manufacturing process.

The first part of the thesis presents the fabrication of Copper nanoparticles. As an economical substituent for noble metal nanoparticles, Copper nanoparticles satisfy various properties as conductive inks, simultaneously suffering from the vital problem of oxidation. The acceleration effects of …

Synthesis And Photonic Sintering Of Bioresorbable Zinc Nanoparticle Ink For Transient Electronics Manufacturing, Bikram K. Mahajan

Masters Theses

"Zinc is an essential 'trace element' that supports immune systems, and is required for DNA synthesis, cell division, and protein synthesis. Zinc nanoparticles (Zn NP) has antibacterial properties and potential to be used in biodegradable printed electronics devices. The research presented here is about the synthesis of Zn NP and their potential use in transient electronics devices. In Paper 1, a technique of room temperature synthesis of Zn NP is reported using ball milling. Controlled amount of PVP was mixed in the solvent to stabilize the Zn particles and minimize cold welding during milling. The size of the produced Zn …

Output Feedback Adaptive Control With Low-Frequency Learning And Fast Adaptation, Tanmay Rajpurohit, Wassim M. Haddad, Tansel Yucelen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Although adaptive control has been used in numerous applications to achieve system performance without excessive reliance on system models, the necessity of high-gain learning rates for achieving fast adaptation can be a serious limitation of adaptive controllers. Specifically, in safety-critical systems involving large system uncertainties and abrupt changes in system dynamics, fast adaptation is required to achieve stringent tracking performance specifications. However, fast adaptation using high-gain learning rates can cause high-frequency oscillations in the control response, resulting in system instability. This paper develops an output feedback adaptive control framework for continuous-time minimum-phase multivariable dynamical systems for output stabilization and command …

A Comprehensive Model Of The Transport Phenomena In Gas Metal Arc Welding, Junling Hu, Zhenghua Rao, Hai-Lung Tsai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A comprehensive two-dimensional gas metal arc welding (GMAW) model was developed to take into account all the interactive events in the gas metal arc welding process, including the arc plasma, melting of the electrode, droplet formation, detachment, transfer, and impingement onto the workpiece, and the weld-pool dynamics and weld formation. The comprehensive GMAW model tracks the free surface using the volume of fluid method and directly modeled the coupling effects between the arc domain and the metal domain, thus eliminating the need to assign boundary conditions at the interface. A thorough investigation of the plasma arc characteristics was conducted to …

Modeling, Analysis, And Simulation For Aqueous-Based Ceramic Pastes In Freeze-Form Extrusion Fabrication Process, Mingyang Li

Doctoral Dissertations

"During the freeze-form extrusion fabrication process, both the extrusion and freezing processes are complex due to the aqueous-based ceramic pastes' non-Newtonian behavior, large latent heat of the water contained in the paste, and the small temperature difference between the ambient and the paste. In this study, the steady-state relationship between plunger velocity and extrusion force is developed based on a modified Herschel-Bulkley viscosity model and the Navier-Stokes equations, and the dynamic response of the extrusion force is described by a first-order nonlinear equation when plunger velocity is taken as an input. It is shown that the extrusion response time depends …

Hierarchical Control Of Complex Manufacturing Processes, Hesam Zomorodi Moghadam

Doctoral Dissertations

"The need for changing the control objective during the process has been reported in many systems in manufacturing, robotics, etc. However, not many works have been devoted to systematically investigating the proper strategies for these types of problems. In this dissertation, two approaches to such problems have been suggested for fast varying systems. The first approach, addresses problems where some of the objectives are statically related to the states of the systems. Hierarchical Optimal Control was proposed to simplify the nonlinearity caused by adding the statically related objectives into control problem. The proposed method was implemented for contour-position control of …

Methodology For Analysis Of Stress, Creep, And Fatigue Behavior Of Compliant Mechanisms, Joshua Allen Crews

Doctoral Dissertations

"A methodology is developed for analyzing stress within homogeneous and metallic-reinforced, fixed-free compliant segments and small-length flexural pivots. Boundary conditions related to the inclusion of metallic reinforcing components within a polymer compliant segment are investigated. The analysis method outlined herein relies on key outputs from the pseudo-rigid-body models (PRBMs). A method is presented for the redesign of compliant mechanisms to include metallic reinforcement to reduce stress while maintaining force-deflection behavior. Examples are provided in which a compliant segment is redesigned to include metallic reinforcement by using the stress equations developed from the PRBM. The effect of bonding between the polymer …

Research On Hybrid Manufacturing Using Industrial Robot, Zhiyuan Wang

Doctoral Dissertations

"The applications of using industrial robots in hybrid manufacturing overcome many restrictions of the conventional manufacturing methods, such as small part building size, long building period, and limited material choices. However, some problems such as the uneven distribution of motion accuracy within robot working volume, the acceleration impact of robot under heavy external loads, few methods and facilities for increasing the efficiency of hybrid manufacturing process are still challenging. This dissertation aims to improve the applications of using industrial robot in hybrid manufacturing by addressing following three categories research issues. The first research issue proposed a novel concept view on …

Efficient Time-Dependent System Reliability Analysis, Zhifu Zhu

Doctoral Dissertations

"Engineering systems are usually subjected to time-variant loads and operate under time-dependent uncertainty; system performances are therefore time-dependent. Accurate and efficient estimate of system reliability is crucial for decision makings on system design, lifetime cost estimate, maintenance strategy, etc. Although significant progresses have been made in time-independent reliability analysis for components and systems, time-dependent system reliability methodologies are still limited. This dissertation is motivated by the need of accurate and effective reliability prediction for engineering systems under time-dependent uncertainty. Based on the classic First and Second Order Reliability Method (FORM and SORM), a system reliability method is developed for multidisciplinary …

Modeling And Evaluation Of Moisture Diffusion In Polymer Composite Materials, Zhen Huo

Doctoral Dissertations

"Fiber-reinforced polymer composites have extensive applications due to their high specific strength, improved product performance, low maintenance and design flexibility. However, moisture absorbed by polymer composites during the service life plays a detrimental role in both the integrity and durability of composite structure. It is essential to understand the moisture diffusion behavior and induced damage in polymer matrix composites under varying hygrothermal conditions. In Part I, the moisture diffusion characteristics in hybrid composites using moisture concentration-dependent diffusion method have been investigated. Also, a multi-stage diffusion model was proposed to explain the deviation of moisture diffusion behavior for sandwich composites from …

Novel Design And Manufacturing Strategies For Portable Air-Breathing Proton Exchange Membrane Fuel Cells, Sriram Praneeth Isanaka

Doctoral Dissertations

"The purpose of this dissertation is to study the importance of design novelty and advanced manufacturing and assembly practices towards portable air-breathing proton exchange membrane fuel cells. Traditional proton exchange membrane fuel cell designs have always been based on prismatic shapes and expensive materials like graphite and steel. The novel design strategies theorized as part of this research though have led to the creation of working prototypes with unconventional form factors, materials and manufacturing methods. The benefits include improved reactant flow characteristics, superior power densities, reduced cost, and simplified manufacturing and assembly complexity as compared to conventional proton exchange membrane …

Repetitive Process Control Of Additive Manufacturing With Application To Laser Metal Deposition, Patrick M. Sammons

Doctoral Dissertations

"Additive Manufacturing (AM) is a set of manufacturing processes which has promise in the production of complex, functional structures that cannot be fabricated with conventional manufacturing and the repair of high-value parts. However, a significant challenge to the adoption of additive manufacturing processes to these applications is proper process control. In order to enable closed-loop process control compact models suitable for control design and for describing the layer-by-layer material addition process are needed. This dissertation proposes a two-dimensional modeling and control framework, with an application to a specific metal-based AM process, whereby the deposition of the current layer is affected …

Electronic Musical Instrument To Generate Musical Tones To Imitate A Stringed Instrument, Mizuki Nakagawa, Ikuo Tanaka, Shun Takai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Provided are an electronic musical instrument, computer storage device, and method for generating tone. A sound source in an electronic musical instrument generates a first tone at a first pitch in response to a first tone generation instruction received by an input device of the electronic musical instrument. A second tone generation instruction is received to generate a second tone at a second pitch while generating the first tone at the sound source. A determination is made of a pitch difference of the first and the second pitches. The sound source is controlled to generate the second tone and to …

Evaluation Of Non-Volatile Particulate Matter Emission Characteristics Of An Aircraft Auxiliary Power Unit With Varying Alternative Jet Fuel Blend Ratios, Prem Lobo, Simon Christie, Bhupendra Khandelwal, Simon G. Blakey, David W. Raper

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The aviation industry is increasingly focused on the development of sustainable alternative fuels to augment and diversify fuel supplies while simultaneously reducing its environmental impact. The impact of airport operations on local air quality and aviation-related greenhouse gas emissions on a life cycle basis have been shown to be reduced with the use of alternative fuels. However, the evaluation of incremental variations in fuel composition of a single alternative fuel on the production of non-volatile particulate matter (nvPM) emissions has not been explored. This is critical to understanding the emission profile for aircraft engines burning alternative fuels and the impact …

Materials For Programmed, Functional Transformation In Transient Electronic Systems, Suk Won Hwang, Seung Kyun Kang, Xian Huang, Mark A. Brenckle, Fiorenzo G. Omenetto

Mechanical and Aerospace Engineering Faculty Research & Creative Works

(Graph Presented). Materials and device designs are presented for electronic systems that undergo functional transformation by a controlled time sequence in the dissolution of active materials and/or encapsulation layers. Demonstration examples include various biocompatible, multifunctional systems with autonomous behavior defined by materials selection and layout.

Coalescence-Induced Jumping Of Nanoscale Droplets On Super-Hydrophobic Surfaces, Zhi Liang, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Coalescence-Induced Jumping of Tens of Microns Size Droplets on Super-Hydrophobic Surfaces Has Been Observed in Both Experiments and Simulations. However, Whether the Coalescence-Induced Jumping Would Occur for Smaller, Particularly Nanoscale Droplets, is an Open Question. using Molecular Dynamics Simulations, We Demonstrate that in Spite of the Large Internal Viscous Dissipation, Coalescence of Two Nanoscale Droplets on a Super-Hydrophobic Surface Can Result in a Jumping of the Coalesced Droplet from the Surface with a Speed of a Few M/s. Similar to the Coalescence-Induced Jumping of Microscale Droplets, We Observe that the Bridge between the Coalescing Nano-Droplets Expands and Impacts the …

Molecular Simulations And Lattice Dynamics Determination Of Stillinger-Weber Gan Thermal Conductivity, Zhi Liang, Ankit Jain, Alan J.H. Mcgaughey, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The Bulk Thermal Conductivity of Stillinger-Weber (SW) Wurtzite GaN in the [0001] Direction at a Temperature of 300 K is Calculated using Equilibrium Molecular Dynamics (EMD), Non-Equilibrium MD (NEMD), and Lattice Dynamics (LD) Methods. While the NEMD Method Predicts a Thermal Conductivity of 166 ± 11 W/m·K, Both the EMD and LD Methods Predict Thermal Conductivities that Are an Order of Magnitude Greater. We Attribute the Discrepancy to Significant Contributions to Thermal Conductivity from Long-Mean Free Path Phonons. We Propose that the Grüneisen Parameter for Low-Frequency Phonons is a Good Predictor of the Severity of the Size Effects in NEMD …

Near Field Transducer For Heat Assisted Magnetic Recording, Xianfan Xu, Edward C. Kinzel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An antenna for heat assisted magnetic recording is disclosed. The antenna includes an optically opaque material and an optically transparent material positioned on the optically opaque material, the optically transparent material includes a half bowtie shape which includes a first half-wing substantially shaped in form of a right angle trapezoid, having a height substantially equal to the overall height of the half bowtie, a second half-wing Substantially shaped in form of a mirror image of the first half-wing and formed proximate and coupled to the first half-wing by a Substantially rectangular aperture having an aperture width and an aperture height. …

Enhanced Structural Color Generation In Aluminum Metamaterials Coated With A Thin Polymer Layer, F. Cheng, Xiaodong Yang, D. Rosenmann, L. Stan, D. Czaplewski, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Ultrasensitive Detection And Characterization Of Molecules With Infrared Plasmonic Metamaterials, F. Cheng, Xiaodong Yang, Jie Gao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Shear Lag Sutures: Improved Suture Repair Through The Use Of Adhesives, S. W. Linderman, I. Kormpakis, R. H. Gelberman, Victor Birman, U. G. K. Wegst, G. M. Genin, S. Thomopoulos

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

A Microstructure And Hardness Study Of Functionally Graded Materials Ti6al4v/Tic By Laser Metal Deposition, Jingwei Zhang, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, William J. Seufzer

Materials Science and Engineering Faculty Research & Creative Works

Crack free functionally graded material (FGM) Ti6Al4V-TiC has been fabricated by laser metal deposition (LMD) using TiC and Ti6Al4V powder which were premixed for different ratios. This study focuses on the influence of laser processing parameters and TiC compositional distribution on microstructure, Vickers hardness and phase. The microstructure is analyzed by scanning electron microscopy (SEM), x-ray diffraction (XRD) and hardness tests. Primary carbide, eutectic carbide and unmelted carbide are found in the deposit area. When laser power increased, the primary and secondary dendrite arm spacing increased. The laser power and scanning speed did not influence the Vickers hardness distribution significantly.