Mechanical Engineering Commons^™

Indication Of Cylinder Pressure Rise Rate By Means Of Vibration And Acoustic Emissions Of An Internal Combustion Engine, Jeffery A. Massey

Masters Theses

"The focus of this study is to investigate the ability of the vibration and acoustic emissions of an internal combustion engine to indicate the cylinder pressure rise rate (PRR). Investigations are conducted on both a small-single cylinder spark-ignition (SI) engine and a larger multi-cylinder compression-ignition (CI) engine. Vibration measurements were made on both engines, however only acoustic measurements were made on the SI engine. Specific vibration and acoustic frequency bands were identified as correlating to energy generated from combustion and energy generated by cylinder cavity resonances"--Abstract, page iii.

Fabrication Of Soy Oil Epoxy Resin Based Composites, Vinay Prabhakar Pai

Masters Theses

"A renewable resource derived epoxidized ester - Epoxidized Allyl Soyate (EAS) yields a versatile epoxy resin system that can be used in pure form combination with bis-phenol epoxy systems to obtain high strength composite materials. EAS containing composites materials exhibit higher toughness and impact resistance than the traditional bis-phenol epoxy composites. These resin systems were found to be compatible with different fibers and screens such as glass fibers, glass mats, carbon fibers and metallic wire screens including those obtained from an automobile tire recycling process. The materials were tested for mechanical properties including tensile and flexure strengths. The highest tensile …

Numerical Study Of Energy Utilization In Nozzle/Plume Flow-Fields Of High-Speed Air-Breathing Vehicles, Althea Grace Wilson

Masters Theses

"Focused local energy deposition in both internal and external flow-fields associated with high-speed aerospace vehicles can provide many system level benefits. This study specifically analyzes the effects of targeted (local) energization of the flow in the nozzle and afterbody flow-field regions of a hypersonic lifting body configuration. Benefits are shown to include the generation of a favorable vehicle pitching moment (nose-down) increment associated with such energy deposition and a reduced local and overall thermal load in both combustor and nozzle for all cases examined. These results have been obtained by modeling the nozzle/afterbody region of a simple generic 2-D wave-rider/lifting …

Femtosecond Laser Micro-Structuring Of Silicon Wafer In Water Confinement, Songping Wu

Masters Theses

"This thesis investigates the use of femtosecond laser induced surface morphology on silicon wafer surface in water confinement. Unlike irradiation of silicon surfaces in the air, there are no laser induced periodic structures, but irregular roughness is formed when the silicon wafer is ablated under water. Interestingly, a particular parameter combination enables a smooth surface, which can improve the surface quality of micro-machining products. This thesis first investigates the single ablation and multi-pulse ablation processes in order to study the effects of laser parameters on ablation morphology, as well as the basic physics and mechanism of the laser-material interaction process …

Individual-Based Artificial Ecosystems For Design And Optimization, Shivakar Vulli

Masters Theses

"Individual-based modeling has gained popularity over the last decade, mainly due to the paradigm's proven ability to address a variety of problems seen in many disciplines, including modeling complex systems from bottom-up, providing relationship between component level and system level parameters, and discovering the emergence of system-level behaviors from simple component level interactions. Availability of computational power to run simulation models with thousands to millions of agents is another driving force in the widespread adoption of individual-based modeling. This thesis proposes an individual-based modeling approach for solving engineering design and optimization problems using artificial ecosystems"--Abstract, page iii.

Fault Propagation Timing Analysis To Aid In The Selection Of Sensors Fro Health Management Systems, Jeremy Johnson

Masters Theses

"Sensor data is processed to assess performance and health of complex systems. Proper sensor selection, placement, and implementation are critical to build an effective health management system. For complex systems in which the timely assessment of the health is desired to avoid expensive consequences of failure, sensor placement is vital. The ability to identify a critical failure early is completely dependent on sensor location within the fault propagation path. A strategy for assessing a sensor suite with respect to timely critical failure detection is presented in this thesis. To illustrate the strategy, Fault Propagation Timing Analysis (FPTA) will be performed …

Sensitivity Analysis Of Relative Worth In Empirical And Simulation-Based Qfd Matrices, Robins Mathai Kalapurackal

Masters Theses

"Quality Function Deployment (QFD) is one of the most popular design tools used in product development. One of the objectives of QFD is to map customer requirements to product requirements and calculate their relative worth. A product requirement with a large relative worth indicates that it is an important product requirement in satisfying customer requirements. QFD applications use various rating scales in quantifying the degree of mapping from customer requirements to product requirements and various worth calculation methods to calculate the relative worth. The purpose of this paper is to study the sensitivity of relative worth when different rating scales …

Sorting Automated Concept Generator Results Based On Manufacture And Assembly Concerns, Kerry Ryan Poppa

Masters Theses

"Early in the design process, it is desirable to produce a large number of potential solutions. Completely exploring a problem's solution space is an unreasonable expectation for an unaided designer or design team. Computational tools have emerged to help designers more fully explore possible solutions. These automated concept generators use knowledge from existing designs and the desired functionality of the new product to suggest solutions. Existing automated concept generation methods produce many candidate solutions, but produce unmanageably large sets of solutions. Techniques are needed to organize the set of concepts into smaller groups, more easily parsed by the human designer. …

Parameter Estimation Of Systems With Deadzone And Deadband And Emulation Using Xpc Target, Jeffrey James Lentz

Masters Theses

"The first paper presents a new approach for online parameter estimation using multiple recursive least squares estimations implemented simultaneously to determine system model parameters, as well as a deadzone and/or deadband. the online adaptive estimation scheme was verified in simulation using MATLAB Simulink and verified experimentally for a DC motor driven cart, an electro-hydraulic pilot valve system, and a free cart loosely coupled to a DC motor driven cart by a pin that fits loosely in a slot...The second paper demonstrates the use of the Mathworks xPC Target environment for validation of a control system and emulation of a physical …

Aflp Fingerprint Analysis Of Hybrid Salamanders In The Missouri Caverns Section Of Onondaga Cave, Maria Louise Potter

Masters Theses

"Two species and one subspecies of salamander in the genus Eurycea, two species of Plethodon and one species of Typhlotriton (recently considered to be Eurycea) salamander currently reside in an area of Onondaga Cave known as the Missouri Caverns section. Due to the presence of two known interbreeding subspecies of salamanders, Eurycea Longicauda (Long-tailed salamander) and Eurycea longicauda melanopleura (Dark-sided salamander), the possibility may exist for interbreeding of one or all of these taxa. Specifically, it is hypothesized that the two species of Eurycea longicauda may interbreed with Eurycea lucifuga (Cave salamander). through visual assessment and phenotypic analysis, …

Flow Structures In An Enclosed Simplified Full Scale Under-Hood Engine Compartment During Steady State Operation, Chin Hoong Leong

Masters Theses

An experimental study of flow structures in an enclosed simplified full scale under-hood engine compartment will be conducted during steady state operation using whole field velocity measuring technique. 2D Particle Image Velocimetry (PIV) is planned for multiple cross sections in the test volume. Emphasis is given on understanding the flow structures of the 3D under-hood flow using multiple 2D PIV measurements. A recent study conducted on the engine compartment only consists of three 2D PIV measurement cross sections that sufficiently display 2D flow behavior at specific regions. Therefore, a detailed 3D flow mapping in the enclosure on various cross sections …

A Practical Guideline For Establishing Non-Return Valve Specification And Performance Criteria, Eric W. Dawkins

Masters Theses

The non-return valve has been a standard piece of equipment in the injection molding industry since the reciprocating screw was developed. Most molders understand the role of the non-return valve in the molding process. But few understand the functional problems of the non-return valve. Because of this, the non-return valve has been considered a nuisance item for injection molders.

Wear of the non-return valve is another problem that molders are faced with. The factors contributing toward wear are not entirely understood. Material, temperatures, hours and machine size, etc., all effect the life of a valve. Consequently, most worn valves are …

Experimental Measurements And Mathematical Modeling Of The Rigid Capillary Dewatering, Vrajesh N. Chokshi

Masters Theses

Rigid Capillary Dewatering (RCD) technology is a process in which water is removed from a wet paper web by capillary dewatering action without excessive mechanical compaction of the fiber furnish. Operating conditions on the Rigid Capillary Pressing (RCP) roll, and properties of paper and pulp determines the dewatering behavior of the RCD technology.

The dewatering behavior of the RCD technology is studied in four sets of experiments performed using different operating conditions, on a paper pilot machine at a Western Michigan University (WMU) facility. The solids content of the paper web before and after the RCP roll in the press …

Experimental Investigation Of Temperature And Tool Wear In High Speed End-Milling Of Titanium Alloy, Benjamin Nwakile Oguejiofor

Masters Theses

"This thesis presents the results of experimental investigation of temperature and tool wear in high speed end-milling of titanium alloy. The investigation of cutting parameters on temperature in high speed end-milling of thin-walled titanium structure was conducted on Cincinnati Milacron Sabre 750 Vertical Machining Center using a 1/2 Fractional Factorial Design of Experiment with 3 factors at 2 levels each. Data logging of temperature data was carried out using VI logger software. Tool tip temperature at the comers and center of the pocket was estimated. All the factors investigated were found to have a significant effect on workpiece temperature. Radial …

Robust Mechanism Synthesis With Random And Interval Variables, Pavan Kumar Venigella

Masters Theses

"Robust mechanism synthesis ensures that the performance of a mechanism is not sensitive to uncertainties in the mechanism and its environment. The uncertainties include the dimension variations, installation errors, random input motion, and various external forces. Robust mechanism synthesis is used to minimize the impact of these uncertainties on the mechanism performance. Robust mechanism synthesis has been performed by either a probabilistic approach or a worst case approach. The former approach describes uncertain parameters as random variables while the latter approach treats uncertain parameters as interval variables. In this work, methods are developed for robustness assessment and robust mechanism synthesis …

Empirical Dynamic Modeling And Nonlinear Force Control Of Friction Stir Welding, Xin Zhao

Masters Theses

"Current Friction Stir Welding (FSW) process models are mainly concerned with the detailed analysis of material flow, heat generation, etc. and therefore, are computationally intensive. Dynamic models describing the total forces acting on the tool throughout the entire welding process are required for the design of feedback control strategies and improved process planning and analysis. In this thesis, empirical models relating the process parameters (i.e., plunge depth, travel speed, and rotation speed) to the process variables (i.e., axial, path, and normal forces) are developed to describe their dynamic relationships"--Abstract, page iv.

Modeling And Control Of Freeze-Form Extrusion Fabrication, Xiyue Zhao

Masters Theses

"Freeze-form Extrusion Fabrication (FEF) is an additive manufacturing technique that extrudes ceramic loaded aqueous pastes layer by layer below the paste freezing temperature for component fabrication. As the FEF is aimed at being conducted at low environmental temperatures, down to -20°C, it is necessary to investigate the effect of environmental temperature on the process. The advantages of fabrication at low temperature have been proved by experiments. Comparisons in terms of operation parameters, self-sustaining ability, and system dynamic response were performed at different environmental temperatures ranging from 20°C to -20°C.

It is commonly known in paste extrusion processes that due to …

Adhesion-Delamination Mechanics Of Linear And Axisymmetric Film At Film-Substrate Interface, Ming-Fung Wong

Masters Theses

"This thesis is to characterize the thin membrane adhesion-delamination phenomena which occur in biological cells and micro-electro-mechanical systems (MEMS) operation. The delamination of a thin film adhered to a rigid substrate is subjected to the coupling effects of tensile residual stress and interfacial adhesion energy. The adhesion-delamination mechanics is derived using the classical linear elasticity and thermodynamics energy balance. The membrane deformation is here dominated by a mixed plate-bending and membrane-stretching, while the concomitant stress is neglected. An 1-dimensional model is first investigated where a pre-stressed rectangular film clamped at both ends delaminates from a rigid punch of the same …

Selective Laser Sintering Of Stearic Acid-Coated Alumina Ceramic, Jason J. Nolte

Masters Theses

"The purpose of this research is to develop a process that will enable a Selective Laser Sintering (SLS) machine to create geometrically complex green parts of various sizes that become strong, dense ceramic parts after sintering. This will be applicable to SLS systems already operational in industry, and may offer a more cost-effective, more time-efficient method for producing high-temperature ceramic rapid prototype parts. Alumina was the chosen ceramic for the developmental stage of this research. Fine alumina powder (average particle size of 0.4 µm) was coated with stearic acid, which served as a binder. Green parts were made from this …

Compressor Valve Failure Detection And Prognostics, Raghuram Puthali Ramesh

Masters Theses

"Reciprocating compressors are commonly used machinery for industrial applications. Unscheduled downtime and maintenance activity on the compressors causes considerable loss in throughput and efficiency of a plant. Of all the failures that cause unscheduled downtime in reciprocating compressors, valve related causes are predominant. Most of the failures associated with the valves are tracked to the failure of moving elements within the valve. Achieving higher reliability of critical reciprocating systems requires continuously monitoring the system and performing dynamic analysis of the sensory data for valve fault diagnosis. Continuous monitoring will improve the time and cost to repair through keeping a constant …

Development Of A Liquid Injection Propane System For Spark-Ignited Engines Via Fuel Temperature Control, Brian Charles Applegate

Masters Theses

"This work describes the development of a thermally controlled liquid propane injection system...A liquid fuel system, as described in this work, offers power gains over vaporized fuel introduction due to the ability to use the heat of vaporization from the vaporizing fuel to cool the intake charge and improve the volumetric efficiency of the engine. This system uses temperature to control the state of the fuel in the fuel system"--Introduction, page 1.

Mechanical Properties And Microstructure Study For Direct Metal Deposition Of Titanium Alloy And Tool Steel, Yaxin Bao

Masters Theses

"This thesis is focused on the research about DMD (Direct Metal Deposition) which is an additive manufacturing process and used in various engineering applications such as producing fully dense and net shape productions in difficult-to-machine materials. In this study, the microstructure was analyzed through optical microscopy and some mechanical properties were tested with different equipments such as SEM (Scanning Electron Microscopy) and micro-hardness tester...In summary, this thesis validated that DMD process can be improved through surface treatments and is capable of repairing molds for die casting industry"--Introduction, page 1.

Transient Performance Of Closed Loop Thermosyphons Incorporating Thermal Storage, Kyle S. Benne

Masters Theses

This thesis considers a unique application of a thermosyphon to a conventional thermal storage deice. In such an application, the dynamics of the thermosyphon are coupled with the condition of the storage volume. This thesis specifically focuses on the transient energy addition or charge process, where heat accumulated within the storage volume continuously decreases the driving buoyant force and volumetric flow rate"--Abstract, page iv.

Towards A Methodology For Integrated Freeform Manufacturing Systems Development With A Control Systems Emphasis, Jacquelyn K. Stroble

Masters Theses

"A variety of fully integrated Freeform Fabrication (FFF) systems have been developed, a selected group for research and several for commercialization. The design methodology behind most of them is not documented, standardized, or rational. It is important to understand that the final product from any integrated system is affected not only by the unit manufacturing processes themselves, but also by the extent the individual units are assimilated into an integrated process. Thus, a scheme consisting of eight steps and the salient five elements necessary to create or retrofit an existing system to achieve an Integrated Freeform Manufacturing System (FFMS) is …

Optimal Formation Of Supplier Networks For Product Design And Production Phases To Realize An Evolving Product Family, Padmavathi K. Pakala

Masters Theses

"Due to rapid changes in customer requirements and vast improvements in technology, many product development companies have identified strategies like time-to-market (TTM) compression and product family development as critical for attaining success in today's hyper-competitive markets. Compressing the TTM, to a large extent, is dependent on the suppliers and the project execution skills of the integrator companies. This study presents a methodology for selecting suppliers for two significant phases of the product realization process, namely, product design and production. The proposed methodology uses a two-stage approach for supplier selection where suppliers for product design are selected in the first stage …

Empirical Investigation Of Enhanced Air Fins, Stephen John Dale Rucker

Masters Theses

"Enhanced convective heat transfer surfaces have been a subject of interest for quite some time. Many different methods have been used to increase the amount of heat transfered from a surface. However, nearly all surface enhancement methods come with a price, frictional losses. This thesis studies the use of enhanced convective heat transfer surfaces on air fins in the laminar, transitional, and turbulent flow regimes with emphasis on the transitional regime. A major goal of this thesis is to further the understanding of the influence of an enhanced wall geometry on the transition from laminar to turbulent flow. Causing the …

On-Line Inspection And Thermal Properties Comparison For Laser Deposition Process, Yu Yang

Masters Theses

"This thesis is focused on comparing the laser deposition cladding with intended design model and comparing the effect of laser deposition process on thermal properties with traditional welding process. It is research on two aspects of laser deposition cladding. The first part of the thesis is aimed at solving the geometric inspection of laser deposition cladding, and the second part is for comparing the thermal properties of laser deposition cladding to samples of conventional welding process"--Introduction, page 1.

Development, Modeling, And Simulation Of A Nano Aerial Vehicle Using Empirical Data, Wyatt Emery Davenport

Masters Theses

"The ultimate goals of this study were to use experimental data to estimate the flight capabilities of a flapping wing nano aerial vehicle (NAV), estimate the power required to provide such flight, and develop a controller approach for future use in the design of this aircraft. The experimental data is a collection of measurements of the normal force on a flapping wing taken in stationary water, and was used to develop empirical coefficient derivatives for use in the dynamic modeling of the NAV"--Abstract, page iii.

E-Design Tools For Friction Stir Welding: Cost Estimation Tool, Pradeep Kumar Tipaji

Masters Theses

"A cost model is an important tool for product design and material selection. An efficient and effective cost estimation tool is necessary for early design evaluation. In this paper, cost estimation models that estimate the production cost for Metal Inert Gas (MIG), Friction Stir (FS), and Friction Stir Spot (FSS) welded joints are presented. These models determine the cost incurred to fabricate each joint along with a detailed explanation of each cost component. Each cost component has been closely analyzed and major cost components have been included in the cost model"--Abstract, page iv.

Manufacturing And Characterization Of Soy-Based Pultruded Polyurethane Composites, Rama Bhadra Raju Vuppalapati

Masters Theses

"In the recent past, composites have been finding various applications in civil infrastructure, marine, transportation, automotive and non-automotive applications by replacing metals in structural components. Pultrusion is considered to be a cost effective method for manufacturing composite materials.

Polyurethane resin systems form a good alternative to the conventional styrene based systems in pultrusion due to their better physical, chemical and mechanical properties. Polyols derived from soybean oil along with isocyanates produce polyurethanes that can match in many aspects with one derived from the petrochemical polyols. Even though, polyurethanes have good properties there are lots of challenges like designing unique material …