Mechanical Engineering Commons^™

Processing Parameters And Chamber Length Impact On Detached Die And Attached Die Resin Injection Pultrusion, Dinesh Raj Palikhel

Electronic Theses and Dissertations

Injection pultrusion is an efficient and highly automated continuous process for high-quality, low-cost, high-volume manufacturing of composites. The main objective of this study is to analyze "attached die configuration" and "detached die configuration" for the better injection pultrusion process. In this work the impact of various processing parameters on complete wet out of composite parts is investigated in the attached die and detached die injection pultrusion with various chamber length considerations. The various processing parameters considered are pull speed, fiber volume fraction, resin viscosity, injection port location and compression ratio. 3-D finite volume technique is used to simulate the liquid …

Advanced Studies On Series Impedance In Waveguides With An Emphasis On Source And Transfer Impedance, Jinghao Liu

University of Kentucky Doctoral Dissertations

Series impedances, including source and transfer impedances, are commonly used to model a variety of noise sources and noise treatment elements in duct systems. Particle velocity is assumed to be constant on the plane where the series impedances are defined. The research reported herein details investigations into measuring source and transfer impedance. Especially, the measurement and prediction of the transfer impedance of micro-perforated panel (MPP) absorbers is considered.

A wave decomposition method for measuring source impedance and source strength was developed that was purely based on acoustic concepts instead of the equivalent circuit analysis. The method developed is a two-load …

Design And Optimization Of A Wave Energy Harvester Utilizing A Flywheel Energy Storage System, Steven Alexander Helkin

Electronic Theses and Dissertations

This thesis details the design and optimization of a buoy used to collect renewable energy from ocean waves. The proposed buoy is a point absorber—a device that transforms the kinetic energy of the vertical motion of surface waves into electrical energy. The focus of the research is on the mechanical system used to collect the energy, and methods to improve it for eventual use in an actual wave energy harvester. A flywheel energy storage system was utilized in order to provide an improved power output from the system, even with the intermittent input of force exerted by ocean waves. A …

Energy-Economical Heuristically Based Control Of Compass Gait Walking On Stochastically Varying Terrain, Christian Hubicki

Master’s Theses

Investigation uses simulation to explore the inherent tradeoffs ofcontrolling high-speed and highly robust walking robots while minimizing energy consumption. Using a novel controller which optimizes robustness, energy economy, and speed of a simulated robot on rough terrain, the user can adjust their priorities between these three outcome measures and systematically generate a performance curveassessing the tradeoffs associated with these metrics.

Corrosion Characteristics And Mechanical Properties Of Aluminum Coatings Applied By The Cold Spray Process, Ben Bouffard

Master’s Theses

Aluminum coatings were applied to 2024-T3 and 7075-T6 aluminum alloys via the Cold Spray process. The coatings were applied to substrateswith various surface preparation and Cold Spray carrier gas combinations. Some samples were coated with an additional sealant with and without a chromate conversion layer. An exhaustive corrosion analysis was then performed which utilized a number of long termand accelerated tests in order to characterize the corrosion protection of the coatings.

Development Of A Humanoid Robot Arm For Use In Urban Environments, Brenton Noll

Master’s Theses

The Bucknell Humanoid Robot Arm project was developed in order toprovide a lightweight robotic arm for the IHMC / Bucknell University bipedal robot that will provide a means of manipulation and facilitate operations in urban environments. The resulting fabricated arm described in this thesis weighs only 13 pounds, and is capable of holding 11 pounds fully outstretched, lifting objects such as tools, and it can open doors. It is also capable of being easily integrated with the IHMC / Bucknell University biped. This thesis provides an introduction to robots themselves, discusses the goals of the Bucknell Humanoid Robot Arm project, …

Development Of A Heat Transfer Test Rig For Finding Heat Transfer Characteristics Of Liquid Methane, Sergio Flores

Open Access Theses & Dissertations

Most large scale rocket engines use a regeneratively cooled system to cool the rocket engine using either the rocket fuel or oxidizer. The use of liquid methane as a rocket fuel is an emerging technology proving to have several advantages over current rocket fuels. However, liquid methane is lacking the extensive research as a rocket fuel compared to highly used rocket fuels like liquid hydrogen. A heat transfer test rig was built with the goal to characterize the heat transfer characteristics of liquid methane as it passes through a heated channel. The development of the test rig underwent considerations designed …

On Feasibility Of Reducing Metal Fuel Content And Operating Temperatures In Chemical Oxygen Generators, Allen Garcia

Open Access Theses & Dissertations

Chemical oxygen generators are widely used in aircraft, submarines, spacecraft, and other applications, problems such as combustion instabilities and a risk of fire may be present. For example, due to malfunction of an oxygen generator, fire occurred onboard the Mir Space Station in 1997. It is thus important to improve the process stability and fire safety of chemical oxygen generators. Chemical compositions for oxygen generators include an oxygen source such as sodium chlorate (NaClO3), a transition metal oxide as a catalyst, and a metal fuel to provide energy for self-sustaining combustion. Eliminating or decreasing the metal fuel would decrease the …

Study Of Probabilistic Approach For Structural Health Assessment Of Aerospace Structures, Jose Antonio Garcia

Open Access Theses & Dissertations

Current practical approaches used in structural health assessment programs of aerospace structures involve performing a fracture mechanics analysis to verify the safe life of structural components. The analysis typically makes several conservative assumptions implemented by NASA fracture control standard practices for critical structural components. This well-established paradigm for fracture control follows a deterministic approach and, in some cases, the calculations may produce overly conservative remaining life estimates.

This thesis describes the results of a study to approach the health assessment challenge of several critical components using probabilistic methods. The probabilistic analysis takes the current deterministic model and identifies variables that …

Investigation On Flame Characteristics Of Oxy-Fuel Combustion, Md R. Islam

Open Access Theses & Dissertations

Oxy-fuel combustion is currently being considered by the U.S Department of Energy as a promising technology for efficient carbon capture. This technology could substantially reduce NOx and CO2 emissions. In addition, the implementation of oxy-fuel combustion technology in a power generation system could potentially reduce negative environmental impacts of fossil fuel use. It also encourages the use of reliable and domestic energy sources. The U.S. Department of Energy has made efforts to investigate the performance of a CO2 and H2O diluted oxy-fuel combustion system in a high-pressure combustor. In an effort to better understand and characterize the fundamental flame characteristics …

A Combined X-Fem And Level Set Approach For Modeling Composite Material's Micro Structure, Himanshu Kumar

Open Access Theses & Dissertations

Composite materials are usually made of fibers and binding matrix. It's always a challenge to model composite materials' microstructure through the traditional finite element method because construction of an approximation space which is discontinuous across a given line or surface will place strict restrictions on the FE mesh. The interfacing of fibers in composites' microstructure through the standard finite element method is irksome and tedious because the presence of fiber presents a discontinuity in the binding material. In this present work, the composite's microstructure is modeled through the combined approach of Level Set and Extended Finite Element Method. The fiber …

Synthesis, Microstructure And Thermal Analysis Of Gd2o3 - Hfo2 Coatings, Chandan Kumar Roy

Open Access Theses & Dissertations

Thermal barrier coatings (TBCs) are critical for future gas turbines of advanced coal based power generation systems. The TBCs are protective layers of low thermal conductivity ceramic materials, which prevent the damage of components that are exposed to very high temperature of the hot gases. Due to increasing demand to improve the efficiency, it is necessary to find alternate TBC materials which can withstand higher temperature for longer period than state-of-art TBCs. The present study focuses on the Gd2O3 stabilized HfO2 (GSH) as a potential candidate for TBC. GSH materials were synthesized in bulk and coatings form. The Gd2O3 content …

Experimental Investigation Of Magnesium/Regolith Combustion For In-Situ Production Of Materials On The Moon, Christopher White

Open Access Theses & Dissertations

Future settlements on the Moon will require that strong, cost-effective structural materials be developed in whole or in part from locally available resources. Such materials can be created in-situ from the lunar regolith using self-propagating high-temperature synthesis (SHS). By mixing the lunar regolith with metal additives, such as aluminum or magnesium, a combustible mixture is formed which, when ignited, can reach temperatures high enough to allow combustion to be self-sustaining, sintering the lunar regolith without further energy input and without the need for atmospheric oxygen. The resulting products may be strong enough for some structural applications, such as radiation shielding, …

Combustion Of Lunar Regolith Mixed With Energetic Additives: Thermodynamic Calculations And Experimental Studies, Francisco Alvarez

Open Access Theses & Dissertations

The future of space exploration will require longer missions in order to better understand the conditions of near-Earth celestial objects, like the Moon or Mars. Future space missions will require the development of goods, such as propulsion fuel and structural materials, produced using the extraterrestrial resources available. The area that develops these technologies is called In-Situ Resource Utilization (ISRU). ISRU allows reducing the payload, and as a consequence reduces the energy consumption and cost of space travel. The production of structural materials on the Moon can be accomplished using Self-Propagating High-Temperature Synthesis (SHS). This work describes the combination of ISRU …

Design And Cfd Optimization Of Methane Regenerative Cooled Rocket Nozzles, Christopher Linn Bradford

Open Access Theses & Dissertations

Liquid rocket engines benefit in life cycle from the active regenerative cooling method which passes the fuel as the coolant through channels surrounding the combustion chamber. These channels are designed and optimized using structural considerations as well as heat transfer theory, then CFD simulations with the software FLUENT are performed for the final analysis. The difficulty in using methane as the fuel/coolant is addressed, and requires the use of the ideal gas numerical model in preliminary CFD simulations. Comparison to real gas numerical models is made, and results also given for one channel design. The techniques utilized herein allow the …

Experimental And Numerical Investigation Of The Effect Of Fuel Composition On Flame Stability On A Gas Turbine Combustor, Gilberto Corona

Open Access Theses & Dissertations

Gas turbines are used for power generation and aviation all over the world. Fossil fuels remain the main source of energy for the operation of gas turbines but the recent increase in environmental awareness has influenced government agencies to impose stringent limits on pollutant emissions from power generation plants. Pollutant emissions control is one of the major challenges for gas turbine designers. In this study, experimental methods and computational fluid dynamics (CFD) technologies are used to study the problems that arise when coal derived fuels are used in Gas Turbine Combustors.

Gas turbine designers need both experimental data and combustion …

Balloon Borne Mars Research Platforms, Sean Michael Hancock

Mechanical & Aerospace Engineering Theses & Dissertations

Aerial platforms can fill a measurement gap between orbiters and rovers, providing planetary scale high resolution in situ measurements, access to scientifically interesting terrain that is either inaccessible or hazardous to rovers, and serve as a planet-wide delivery platforms to deploy surface probes and rovers to areas inaccessible given existing entry, descent, and landing systems. A permanent robotic outpost on the Martian surface can utilize locally-derived hydrogen as a lifting gas for balloon systems deployed from Mars. That approach can simplify the inflation and launch of aerial vehicles while allowing for a long duration deployment campaign that is not constrained …

A Microfluidic Device For Impedance Spectroscopy, Ahmet Can Sabuncu

Mechanical & Aerospace Engineering Theses & Dissertations

Recently, microfluidics has become a versatile tool to investigate cellular biology and to build novel biomedical devices. Dielectric spectroscopy, on the other hand, allows non-invasive probing of biological cells. Information on the cell membrane, cytoplasm, and nucleus can be obtained by dielectric spectroscopy provided that appropriate tools are used in specific frequency ranges. This dissertation includes fabrication, characterization, and testing of a simple microfluidic device to measure cell dielectric properties. The dielectric measurements are performed on human T-cell leukemia (Jurkat), mouse melanoma (B16), mouse hepatoma (Hepa), and human costal chondrocyte cells. Dielectric measurements consist of measuring the complex impedance of …

Study Of Turbulence-Radiation Interaction In Hypersonic Turbulent Boundary Layers, L. (Lian) Duan, A. M. Feldick, M. P. Martín, M. F. Modest, D. A. Levin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In the paper, we conduct direct numerical simulations (DNS) to investigate the effect of turbulence-radiation interaction (TRI) in hypersonic turbulent boundary layers, representative of the Orion crew exploration vehicle (CEV) at peak heating condition during reentry. The radiative transfer equation (RTE) is solved using the tangent slab approximation. 1 The RTE solver is line-by-line (LBL) accurate, making use of a developed efficient spectral database 2 for spectral modeling. A multi-group full-spectrum correlated-k-distribution (FSCK) method 3 is used to reduce the number of RTE evaluations while preserving LBL accuracy. A nondimensional governing parameter to measure the significance of TRI is proposed, …

Assessment Of Turbulence-Chemistry Interaction In Hypersonic Turbulent Boundary Layers, L. (Lian) Duan, M. P. Martín

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Studies of the turbulence-chemistry interaction are performed in hypersonic turbulent boundary layers using direct numerical simulation flow fields under typical hypersonic conditions representative of blunt-body and slender body hypersonic vehicles, with super catalytic and noncatalytic wall conditions in pure air. Nondimensional governing parameters, the interaction Damköhler number and the interaction relative heat release, are proposed to measure the influence of turbulence-chemistry interaction on flow composition and temperature. Both a priori and posteriori studies are performed to assess the effect of turbulence-chemistry interaction on chemical production rates and mean and turbulent flow characteristics. It is found that the governing parameters provide …

Effects Of Large-Scale Transient Loading And Waste Heat Rejection On A Three Stream Variable Cycle Engine, Michael William Corbett

Browse all Theses and Dissertations

The objective of the research presented in this document was to gain an understanding of the feasibility of extracting large amounts of transient shaft power from a variable cycle engine and to reject waste heat into the third stream bypass duct. This first required the development of a transient engine and controller simulation. After performing basic verification of the model, such as ensuring conservation of mass, tests were run for three missions using a low-efficiency periodic load which both required shaft power and created low quality waste heat. The waste heat generated by that load was lifted by a cooling …

The Effect Of Static Pressure On The Inertial Cavitation Threshold And Collapse Strength, Kenneth Bryan Bader

Electronic Theses and Dissertations

The amplitude of the acoustic pressure required to nucleate a gas and/or vapor bubble in a fluid, and to have that bubble undergo an inertial collapse, is termed the inertial cavitation threshold. The hydrostatic dependence of the inertial cavitation threshold was measured up to 30 MPa in ultrapure water using a high quality factor spherical resonator. The threshold increased linearly with the hydrostatic pressure and was found to be temperature dependent. The strength of the bubble collapse at the threshold was measured in terms of shock waves and light emissions. The shock amplitudes increased linearly with the hydrostatic pressure, while …

Comparative Analysis Of A Low-Speed Wind Tunnel Designed For Renewable Energy Applications, Craig A. Zehrung

Purdue Polytechnic Masters Theses

This thesis describes the design, testing, and validation of an open-circuit, mid-sized wind tunnel used for the teaching of undergraduate courses and testing of green energy wind turbines. This thesis uses computational fluid dynamics to determine theoretical values for flow of the wind tunnel which were statistically compared to actual values of fluid flow. An overall analysis of efficiency and effectiveness were also performed. However, aerodynamic testing of actual prototype turbines will not be covered in this thesis, as it does not concern the tunnels adherence to theoretical flow values.

Toward A Zero Energy Home: Applying Swiss Building Practices/Attitudes To U.S. Residential Construction, Daphene C. Koch, William Hutzel, Jason M. Kutch, Eric A. Holt

School of Engineering Technology Faculty Publications

This project evaluated typical U.S. and Swiss homes to identify construction practices that are most energy efficient and have economic payback. A net zero energy home (ZEH) produces as much energy as is consumed in it over time. Students in a College o f Technology in a Midwest Indiana State University and a technical University in Switzerland resulted in developing models of homes that combined U.S. and Swiss standards. The project was completed in two phases: during the first phase o f this project, construction costs, energy use, and economic payback was calculated for six homes that were designed using …

Reconstruction Resolution Of Coherent Point Sources With Helmholtz Equation Least Squares, Richard Edward Dziklinski

Wayne State University Dissertations

The dissertation investigates the reconstruction of coherent point sources using Helmholtz Equation Least Squares (HELS) method based on measurements in violation of Nearfield Acoustical Holography (NAH) resolution guidelines. In HELS, the Helmholtz equation is solved by matching a series of localized spherical expansion functions to the measured pressures in the field. Expansion coefficients are solved for by least squares and used to reconstruct pressures at the source surface. By approximating the pressure radiation with expansion functions, field and surface pressures can be synthesized, resulting in the possibility of higher spatial resolution than previous generation NAH methods such as Fourier Acoustics …

Ionization In Diesel Combustion: Mechanism, New Instrumentation And Engine Applications, Fadi Estefanous

Wayne State University Dissertations

Diesel engines are known for their superior fuel economy and high power density. However they emit undesirable high levels of nitrogen oxide (NOx) and black particulate smoke (Soot). To reduce these emissions, close loop engine control strategies are required. Therefore, there is a need for an in-cylinder combustion sensor. The ion current sensor has been used for combustion sensing in gasoline engines for which ionization mechanisms have been developed. This is not the case in diesel engines.

In this dissertation, a new mechanism for ionization in diesel engines has been developed and experimentally validated. Moreover, a three dimensional model has …

Design And Fabrication Of A Prototype Aluminum Nitride-Based Pressure Sensor With Finite Element Analysis And Validation, Xinyu Du

Wayne State University Dissertations

Since 1985 when the first robot PUMA 560 was employed to place a needle during a brain CT biopsy, surgical robots have become ubiquitous in clinical surgeries. Despite its advantages and success in surgeries, the interactions between the robot and the surgeons remain deficient, especially for the pressure sensing which plays an important role. Inspired by our previous work on bacterial sensing, in the current work I have designed, fabricated, analyzed, and evaluated an innovative prototype pressure sensor based on Aluminum Nitride (AlN) Surface Acoustic Wave (SAW) and Shear Horizontal (SH)-SAW. This AlN-based device has unique superiority over other SAW …

Analytical And Experimental Investigations Of Ships Impact Interaction With One-Sided Barrier, Ihab M. Grace

Wayne State University Dissertations

This study deals with impact interaction of ships with one-sided ice barrier during roll dynamics. An analytical model of ship roll motion interacting with ice is developed based on Zhuravlev and Ivanov non-smooth coordinate transformations. These transformations have the advantage of converting the vibro-impact oscillator into an oscillator without barriers such that the corresponding equation of motion does not contain any impact term. Such approaches, however, account for the energy loss at impact times in different ways. The present work, in particular, brings to the attention the fact that the impact dynamics may have qualitatively different response characteristics to different …

More Carrot Than Stick: Encouraging Computer Programming In Thermal Design Projects, Kevin D. Cole

Department of Mechanical and Materials Engineering: Faculty Publications

Students will do almost anything to avoid using thermal-property tables. In this paper, Matlab-based thermal-property software is described as an enticement for students to do computer programming in the design of thermal systems. Downloaded shareware was used for steam properties in a steam-cycle project, and an air-property package was developed for use with a gas-turbine project. Although the use of computer programming required considerable effort by both instructor and students, most students did gain a better appreciation of the utility of writing computer programs as part of engineering design. Student evaluations of the course were not significantly affected compared to …

Role Of Helmet In The Mechanics Of Shock Wave Propagation Under Blast Loading Conditions, Shailesh G. Ganpule, Linxia Gu, Aaron L. Alai, Namas Chandra

Department of Mechanical and Materials Engineering: Faculty Publications

The effectiveness of helmets in extenuating the primary shock waves generated by the explosions of improvised explosive devices is not clearly understood. In this work, the role of helmet on the overpressurization and impulse experienced by the head were examined. The shock wave–head interactions were studied under three different cases: (i) unprotected head, (ii) head with helmet but with varying head–helmet gaps and (iii) head covered with helmet and tightly fitting foam pads. The intensification effect was discussed by examining the shock wave flow pattern and verified with experiments. A helmet with a better protection against shock wave is suggested.