Mechanical Engineering Commons^™

Manufacturing Of High Performance Composites Using Vacuum Assisted Resin Transfer Molding, V. G. K. Menta

Masters Theses

"The objective of this research is to establish and enhance the existing Vacuum Assisted Resin Transfer Molding (VARTM) process to manufacture high performance composite parts usable in the aerospace industry.

Flat, hat, pi and multi stiffened panels have been manufactured by the VARTM process using AS4-5HS and AS4-8HS carbon fabric, and SI-ZG-5A low viscosity epoxy resin. Silicone-based reusable molds have been designed and developed to manufacture stiffened panels. Dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) experiments of the SI-ZG-5A resin system were conducted to determine the storage modulus, loss modulus, and the glass transition temperature. The density and …

Investigation Of Knock In Gaseous Fuels In The Presence Of Diluents, Roshan Ashok Rodrigues

Masters Theses

Recent energy security and environmental concerns have prompted growing interest into utilization of alternative fuels such as, natural gas and landfill gas. These gaseous fuels contain significant amount of diluents in the fuel composition, such as carbon dioxide, nitrogen, water vapor and other trace gases, which vary by geographical location. Successful engine operation is limited by a phenomenon called "knock", which occurs due to auto-ignition of the end gas ahead of the flame front, and therefore, needs to be investigated with the utilization of these gaseous fuels.

The present contribution discusses the experimental set-up, procedure and results of the investigation …

Selection Of Attractor Sounds For An Audio-Based Navigation System For The Visually Impaired, Brad Salisbury

Masters Theses

Research in to human hearing has been very ‘laboratory’ oriented in the sense that the test environments do not replicate most ‘real world’ situations [J.C. Middlebrooks and D.M. Green, Ann. Rev. of Psychology, 42, 135-159 (1991)]. While very useful information is gained from these types of tests, it is difficult to see how ‘real world’ situations affect sound source localization, recognition, and navigation (walking/way finding) performance. Such information is especially important to people who are visually impaired and dependent on prior knowledge of the environment or audio cues for travel. The research reported here was conducted during the development of …

Landfill Gas As A Fuel For Ic Engine Operations, Guruprasath Narayanan

Masters Theses

An alternative fuel research facility was developed to study different alternative gaseous fuels like Landfill gases and Biogases and their mixtures with hydrogen as a fuel in a single cylinder spark ignition engine. Landfill gas was used as a fuel and the optimum process parameters such as compression ratio, spark timing and equivalence ratio were identified and reported.

Hydrogen enhanced combustion of landfill gas was studied and it was found that the addition of small amounts of hydrogen in the land fill gas has improved the combustion characteristics of the fuel and the performance of the spark ignition engine in …

Numerical Simulations On Machining Of Silicon Carbide, Jerry Jacob

Masters Theses

Experiments were conducted to determine the critical depth of cut for machining of single crystal silicon carbide through Single Point Diamond Turning (SPDT) and fly-cutting, and of CVD coated Silicon Carbide through scratching. The ductile nature of these nominally hard and brittle materials is believed to be the result of a high pressure phase transformation, which generates a plastic zone of material that behaves in a metallic manner. The SPDT experiments have shown chip formation similar to that in metal machining. This metallic behavior is the basis for using AdvantEdge, metal machining simulation software, for comparison to experimental results. The …

Computational Simulation Of Turbulent Forced Convection Flow Over A Horizontal Plate Heater In A Rectangular Channel, Bhagavathi Perumal Natarajan

Masters Theses

The phenomenon of turbulent forced convection in the entry region of a rectangular duct was investigated computationally using commercial CFD software, FLUENT. The Standard k-ε turbulence model from FLUENT was used to model turbulence in the 20mm high x 30mm wide cross-sectional rectangular duct. The operating fluid used for the three-dimensional CFD study was water at an inlet temperature of 90° C, with the velocities ranging from 0.5 m/s to 2 m/s, at 1 atm pressure. A constant heat flux was applied to the base of the rectangular channel with the other flow walls insulated. The heat flux ranged from …

Analytical Modeling And Simulation Of An Auv With Five Control Surfaces, John Tomasi

Masters Theses

This research describes the dynamic modeling and numerical simulation of an autonomous underwater vehicle (AUV) with five hydrodynamic control surfaces, necessary for the development of an autopilot algorithm, based solely upon analytical methodologies. The purpose of this research was to demonstrate the ability to develop a low. order approximation of the dynamics and control characteristics of an underwater vehicle that is complete enough to validate a specific design before physical construction begins; therefore, allowing for a more cost effective virtual design, test, and evaluation process. The AUV model developed in this study takes into consideration inertia, hydrostatic forces, hydrodynamic forces, …

Comparison Of Combustion Sources And Measurement Techniques For Particulates Emitted From Engines And A Power Plant, Matthew F. Chandler

Masters Theses

"Sub-micron particulates emitted from various combustion sources have serious negative impacts on human health and the environment. It is essential to accurately characterize the physical properties of these particulates including size, shape, structure, and chemical composition in order to monitor, regulate, and model the various transport, toxic, optical, chemical, and deposition properties which dictate their harmful effects. This study consists of two related investigations involving the application of diagnostics methods to characterization and comparison of combustion generated particulate emissions from various sources. The first investigation includes the measurement of particulates emitted from a compression-ignition (diesel) engine using two independent measurement …

Determination Of Stiffness Matrix Of Tapered Roller Bearings For Vibration Models, Jeeva Kumar

Masters Theses

The stiffness matrix of tapered roller bearings under radial and axial load conditions was evaluated using an analytical model and an experimental approach. An experimental test system was designed and manufactured to determine the radial stiffness of the bearing under combined axial and radial load conditions. A second fixture was designed to measure the stiffness of the bearing under pure axial load conditions. The stiffness coefficients determined have been compared with those obtained from the analytical model, OEM (Original Equipment Manufacturer) data and ABAQUS model (finite element analysis software).

A K-Epsilon Extension For Wall-Bounded Flows On The Broadband Aeroacoustic System Simulator, David González

Masters Theses

The turbulence modeling capabilities of the Broadband Aeroacoustic System Simulator (BASS), an experimental code developed at NASA Glenn Research Center, have been extended to include wall-bounded flow capabilities. This was done by first validating the code's viscous solving routines by comparing numerical solutions to known, simple analytic solutions. Finally, the dynamics of the wall shear flows were accounted for with the use of wall-damping functions incorporated into the turbulence model. The results for both viscous and turbulence routines agree well with published data.

Mixing Flow Structures Of Scalloped, Forced Lobed Mixers Using Piv And Plif Measuring Techniques, Nathan J. Cooper

Masters Theses

An Experimental study of internal forced lobed mixers similar to those used in jet aircraft engines is performed using whole field species concentration and velocity measuring techniques. Planar temperature and velocity measurements using Planar Laser Induced Fluorescence (PLIF) and 2D Particle Image Velocimetry (PIV) are performed for lobed, lobed scalloped and splitter mixers in aqueous solution. Specific emphasis is given to study scallops or notches cut into the mixer trailing edge and their role in mixing enhancement. Mixing is compared through velocity and species concentration measurements on axial and streamwise planes for the three dimensional, forced mixers in a confined …

Ductile Regime Nano-Machining Of Silicon Carbide, Biswarup Bhattacharya

Masters Theses

This thesis describes experimental work carried out to study the ability to ductile . single point diamond turn both polycrystal Silicon Carbide (SiC) and chemically vapor deposited (CVD) SiC. A Precitech diamond turning machine was used for ductile regime machining of polycrystal SiC at depths of 10 and 25 nm. The possibility of machining SiC in the ductile mode was substantiated by post process analysis of the chips collected during machining and the surface profiles. The force data obtained during machining was recorded and compared later with the different depth of cuts. An investigation into the ability to single point …

Prediction Of Shaft Vibration Modes In A Geared Transmission System, Kevin W. Marsh

Masters Theses

During the development process of heavy-duty truck transmissions, specific gear designs (geometries) are created to meet load requirements and ratio coverage. Few tools are available to investigate the noise generating potential of these transmissions early in the design stages. This research describes the development and application of a software program that predicts transmission countershaft vibration modes. From simple gear and shaft geometries, the program calculates gear mesh forces and bearing forces then construct the system of equations to compute the shaft vibration modes. Because of the way the input data was structured, this software tool can also be used to …

Development Of A Statistical Model For Process Control To Eliminate Sink Marks In Injection Molded Products, Kurt Frederick Hayden

Masters Theses

Customer demands for high-quality, defect-free injection-molded products are ever increasing. In order to satisfy these quality requirements, much effort is spent monitoring and controlling variable data such as cycle time, part weight, and dimensions. Attribute defects such as sink or splay are often overlooked in the development of process control systems. However, customers reject products because of these attribute defects. Industrial control systems based upon process variables and product design variables can detect conditions that may result in the molding of products with attribute defects. The systems can then correct the process prior to the molding of these defective products. …

Experimental Determination Of Convection Boiling Curves For Water And Ethylene Glycol In A Rectangular Channel With Localized Heating, Andrew T. O'Neill

Masters Theses

Convective boiling experiments were conducted to show the effects of velocity, pressure, and subcooling on both water and a water-ethylene glycol mixture. Boiling curves were obtained in a 30 mm wide by 20 mm high rectangular channel with an upward facing 20 mm wide by 30 mm long rectangular copper heater. The velocity ranged from 0.5 m/s to 4.0 m/s, the pressure ranged from 1.0 atm to 2.6 atm, and the subcooling ranged from 10°C to 50°C. The curves were generated with measured heat fluxes up to 100W/cm² . The inlet conditions of temperature, velocity, and pressure were maintained …

Investment Casting Using Ice Patterns -- Solid Mold And Shell Mold Methods, Harish Jose

Masters Theses

"This thesis focuses on the development and implementation of the investment casting process using ice patterns. The traditional method of the investment casting process involves using wax patterns. Wax patterns tend to expand during the dewaxing process, and this causes stress on the shell wall which can eventually lead to the breaking of the wall. Ice patterns on the other hand shrink when heated. This is a very desirable property for the investment casting process. The process of dewaxing (dewatering) of ice patterns can be achieved by keeping the shells at room temperature, instead of heating the shell in an …

Effect Of Engine Operating Conditions On The Size And Morphology Of Diesel Particulate Emissions, Adam Neer

Masters Theses

"The size, morphology and volume fraction of sub-micron particulate matter emitted from a compression ignition (diesel) engine was investigated using thermophoretic sampling experiments followed by direct visual characterizations under transmission electron microscopy. Specifically, measurements were conducted at the exhaust of a 6059T John Deere, 5.9 L, 6 cylinder, turbocharged, direct injection diesel engine. The particles observed were composed of nearly spherical primary particles (spherules) that formed aggregates of various sizes and shapes. The size distributions of spherules and aggregates were separately measured to obtain the available surface area, which is crucial for estimating the environmental and health impact of particles. …

Application Of Laser Aided Manufacturing Process For Functionally Graded Thermal Barrier Coatings, Yashodhan Joshi

Masters Theses

"Laser Aided Manufacturing Process (LAMP) is a rapid prototyping process used to build three dimensional functional metal and ceramic parts. The process developed in the LAMP laboratory at University of Missouri-Rolla uses a 5-axis fadal CNC machine and a 2.5 KW Nd:YAG (TEM₀₀) Rofin Sinar laser. The laser power and metal/ceramic powder are the input along with auxiliary systems such as shielding gas delivery, RT data acquisition, coolant system. The hybrid process makes use of metal deposition and machining to obtain parts meeting design tolerances.

LAMP is used to improve upon the process of Thermal Barrier Coating (TBC) …

Characteristics Of Laser Forming Austenitic Stainless Steel Alloys, Jack Robert Pennuto

Masters Theses

"This thesis discusses the investigation of laser forming austenitic stainless-steel alloys for the development of free curve and complex shapes...Previous work in this area has focused on the development of single angle laser forming and process optimization for the development of multi-dimensional shapes. This thesis seeks to discuss the relationship of multiple parallel laser passes and any coupling effects that may exist for the class of austenitic stainless steels, including any metallurgical implications"--Abstract, page iii.

Prediction Of Crack Growth Rate And Load Interaction Effects Using Damage Accumulation Model, Virender Goswami

Masters Theses

In damage tolerant designs, it is important to know the crack growth behavior of a material, so that sudden failure of a component can be avoided by determining a safe life. There are numerous models available to predict the crack growth rate. Among them the "crack closure model" is most often used for predicting the crack growth rate for different R-ratios and load interaction effects. However recently, the crack closure model has come under criticism by many authors to be flawed and overrated owing to its inherent drawbacks.

Therefore, a mathematical model for the fatigue crack propagation based on damage …

Analysis Of Combustion Chamber Design Variables In Planetary Rotary Engine, Sathyanarayanan Arumugam

Masters Theses

This research entails examining the Hopkins Rotor Mechanism (HRM) for the perspective of commercial viability. Factors that were studied herein include basic operating characteristics, combustion effects, dimensional changes and behaviors unique to the HRM that may impose limits to commercial viability were also examined.

To compare specific characteristics of the HRM engine, in a comparable four-stroke mode, hypothetical 200, 400 and 600 cubic centimeter (cc) single cylinder reciprocating engines, each with compression ratio of 10, 15 and 20 were used as a basis for comparison. For similar outputs this resulted in the use of a 100, 200, 300 cc HRM …

Subcooled Pool Boiling Heat Transfer Using R113 On Flat Surface, Kamleshkumar J. Suthar

Masters Theses

Pool boiling experiment was conducted to investigate the effect of subcooling on boiling of R-113 using 25mm effective dia. flat surface copper heater. Pool boiling heat transfer measurements were taken for wide temperature range of 5 - 39^o C subcooling and investigated thoroughly. Variation in value of wall superheat of incipience boiling, from 27 to 34^o C and 7 to 11^o C temperature excursion observed. Noticeable effect of subcooling on boiling heat transfer is observed. Degree of subcooling was maintained constant by regulating pressure and keeping constant fluid temperature for each test run. Tests were conducted by …

Methodology To Predict The Instantaneous Friction Work In Non-Conventional Internal Combustion Engines, Ravishankar Thangavelu

Masters Theses

Non-Conventional Internal Combustion Engine (NCICE) may utilize a variety of contact surface shapes, where both sliding and rolling losses occur. This study develops techniques that allow the user to define the type of forces and the characteristics of the friction type to predict the instantaneous and over all friction work in a NCICE under user defined operating conditions. The characteristics include inertial effects, contour and surface effects, resulting contact surface changes and film thickness changes as a result of contact surface.

Using Stiffeners For Improved Geometric Fidelity Of Flexible Elements, Ankit Kapoor

Masters Theses

Flexible hoses play an important role in safe operation of a transportation vehicle in automotive and aerospace field. Due to lack of accurate and efficient modeling techniques for such flexible elements with large deformation, most Computer Aided Engineering system do not address the problem in their solution methods.

In this thesis a method is presented to improve the geometric fidelity of flexible element models by using off-axis bi-linear stiffeners (spring) into a discrete linear beam model. Resulting deflection of a hose were compared with the digital scans of an actual deflection of the hose. Though the method is computationally expensive, …

Comparing Refractory Coatings On Shell Sand Utilizing Elevated Temperature And Collapsibility Testing, Suet Fong Cheah

Masters Theses

This research study examines the effects of refractory coatings on a shell sand using laboratory testing equipment as opposed to the more laborious and time consuming processes of molding, melting, filling, shakeout, and obtaining dimensions of actual castings. As of today, there have not been any such laboratory test methods. This research project focused on quantifying distortion, mass change, and impact strength found in refractory coated shell sand. The equipment used was the thermal distortion tester (TDT) and a modified impact tester. The thermal distortion curves (TDC), mass change, and impact strength are provided and compared for all systems studied. …

Architecting Design Repositories To Support Design Knowledge Storage, Reuse And Design Tool Generation, Matt R. Bohm

Masters Theses

"This collection of works describes the transformation of an existing set of heterogeneous product knowledge into a coherent design repository that supports product information archival, storage, reuse and design tool generation.

Existing product information was analyzed and compared against desired outputs to ascertain what information management structure was needed to produce design resources pertinent to the design process. Methods of incorporating non-conventional functional representations of artifacts are explored, incorporated and standardized along side conventional functional representations. A review of automatic design model generation addresses shortcomings in product representations by comparing standard hand generated design tools to computer-generated design tools. By …

Tool Management In Flexible Manufacturing Systems, Ahmet Soylemezoglu

Masters Theses

"In this study, impact of cutting tool life and tool slot size on tool management in Flexible Manufacturing Systems (FMS) is investigated. A conceptual tool management framework, which has been proposed by Buyurgan, Saygin, and Kilic (2003), is modified and implemented in a simulation environment in order to assess its performance. This model, namely LS Model (LS stands for Life and Size), makes decisions by considering both tool life and tool slot size. An alternative tool management model that makes decisions based only on tool life, namely LO Model (LO stands for Life Only), is developed in order to make …

Application Of A Finite Element Model Update Technique To Detect Damage In A Beam Structure, Madhu Kumar Vattipulusu

Masters Theses

"The interest in the ability to monitor a structure and detect damage at the earliest possible stage is pervasive throughout the civil, mechanical and aerospace engineering communities. The thesis focuses on the application of a finite element model updating technique to monitor and detect damage in beams. A Sensitivity Based Element-by- Element (SBEBE) methodology is chosen as the finite element model updating technique. In this method, damage is detected by updating a finite element model with test data obtained from "healthy" and "damaged" structures and observing the relative changes in the updated finite element models. The performance, efficiency and sensitivity …

Resonance Detection And Acoustic Behaviour In Polymer Intake Manifolds, Amrith Ramanan

Masters Theses

The Automotive Industry, over the last few years, has been placing major emphasis on the use of lightweight components in engines as well as other structural components. The material for these lightweight components are being chosen in such a way that they require minimal secondary operations to place the components in service. One area that has developed is the use of Polymer (Plastic) Intake Manifolds for Internal Combustion engines. Plastics meet all the criteria for quality low cost production with a minimum weight component. Plastic intake manifolds, however, have been found to be excessively noisy in operation. This noise can …

Development Of A Simulation For The Prediction Of Pvdf Surface Velocity Sensor Response For Vibrating Beams And Rectangular Plates, Brian C. Zellers

Masters Theses

A simulation for the prediction of Polyvinylidene Flouride (or PVDF) sensor charge response to structural vibration displacements of beam and rectangular plate structures was developed. The simulation uses measured vibration displacements from an actual structure using point sensors (accelerometers) assembled in an array on the surface of the structure. The PVDF sensor charge output equation was written for a PVDF film of constant spatial sensitivity so that numerical analysis tools in Matlab® can be used to solve the equation. Preliminary experimental results showed that the bending strain component, due to transverse vibration displacements, is the dominant term for both the …