Mechanical Engineering Commons^™

Robust Multi-Objective Design Of Suspension Systems, Muhammad Ali Khan

Theses, Dissertations and Capstones

This thesis presents a robust multi-objective optimal design of four-degree-of-freedom passive and semi-active suspension systems. The passive suspension system is used in a racing car and the semi-active suspension is implemented on a passenger car. Mathematical models of the commercial and racing vehicle suspension systems are used in the computer simulations. A robust multi-objective design of the suspension systems is carried out by considering the minimization of three objectives: passenger’s head acceleration (HA), suspension deflection (SD), and tire deflection (TD). The first objective is concerned with the passenger’s health and comfort. The suspension stroke is described by SD and the …

Openfoam Simulations Of Late Stage Container Draining In Microgravity, Joshua Thomas Mccraney, Mark M. Weislogel, Paul Steen

Mechanical and Materials Engineering Faculty Publications and Presentations

In the reduced acceleration environment aboard orbiting spacecraft, capillary forces are often exploited to access and control the location and stability of fuels, propellants, coolants, and biological liquids in containers (tanks) for life support. To access the ‘far reaches’ of such tanks, the passive capillary pumping mechanism of interior corner networks can be employed to achieve high levels of draining. With knowledge of maximal corner drain rates, gas ingestion can be avoided and accurate drain transients predicted. In this paper, we benchmark a numerical method for the symmetric draining of capillary liquids in simple interior corners. The free surface is …

A Dynamic Neural Network Designed Using Analytical Methods Produces Dynamic Control Properties Similar To An Analogous Classical Controller, Wade William Hilts, Nicholas Szczecinski, Roger Quinn, Alexander Hunt

Mechanical and Materials Engineering Faculty Publications and Presentations

Human balance is achieved using many concurrent control loops that combine to react to changes in environment, posture, center of mass and other factors affecting stability. Though numerous engineering models of human balance control have been tested, no methods for porting these models to a neural architecture have been established. It is our hypothesis that the analytical methods we have developed, combined with classical control techniques will provide a reasonable starting point for developing dynamic neural controllers that can reproduce classical control capabilities. In previous work, we tested this hypothesis and demonstrated that a biologically-constrained neural controller that replicates human …

Modelling Lagrangian Velocity And Acceleration In Turbulent Flows As Infinitely Differentiable Stochastic Process, Bianca Fontanin Viggiano, Jan Friedrich, Romain Volk, Mickael Bourgoin, Raúl Bayoán Cal, Laurent Chevillard

Mechanical and Materials Engineering Faculty Publications and Presentations

We develop a stochastic model for Lagrangian velocity as it is observed in experimental and numerical fully developed turbulent flows. We define it as the unique statistically stationary solution of a causal dynamics, given by a stochastic differential equation. In comparison to previously proposed stochastic models, the obtained process is infinitely differentiable at a given finite Reynolds number, and its second-order statistical properties converge to those of an Ornstein-Uhlenbeck process in the infinite Reynolds number limit. In this limit, it exhibits furthermore intermittent scaling properties, as they can be quantified using higher-order statistics. To achieve this, we begin with generalizing …

Computational Fluid Dynamics Study Of The Effects Of Secondary Flows In 90-Degree Pipe Elbow Erosion, O. Ayala, G. Rivera-Hernández, C. Knight

Engineering Technology Faculty Publications

Computational fluid dynamics (CFD) of particle-laden fluid flows through a 90-degree pipe elbow at Reynolds numbers 1,000 and 10,000 were completed; for different dimensionless elbow curvature ratios of 1.0, 1.5, and 2.5; and for particles with different Stokes numbers of 0.01, 0.1, 0.5, 1.0, 5.0, and 10.0. There were two scenarios in the study. For the first, the particles felt drag from the primary (or the axial) flow as well as from the secondary fluid flows in the elbow. For the second, the secondary fluid flow in the 90-degree bend was suppressed from the particle drag, thus the particles only …

Development Of A Process For Thermal And Mechanical Modelling Of Screw-Driven Pellets Extrusion, Kaixiang Shi

Master’s Theses

The overall goal of the thesis project is to develop a process for thermal and mechanical modelling of the screw-driven pellets extrusion process, and applying the model results to design extruder temperature and flow rate controllers.

The proposed extruder is designed for metal 3D printing. The device demonstrates great potential in tackling some of the major issues faced by the metal additive manufacturing community. It eliminates the use of metal powder for workplace and workers safety. It is able to produce end-use parts with industrial grade mechanical and microstructural properties. It utilizes low cost metal-loaded polymer pellets as feedstock. However, …

3.8 Mm Thick Aluminum 5754-O Friction Stir Weld Data, Johnathon Hunt, Yuri Hovanski, Brian A. Mazzeo, Carl Sorensen

ScholarsArchive Data

The data sets that are included are the following:

1) Raw measured data for 30 friction stir welds made from 5754-O aluminum alloy. (matlab .m file)

2) Radiographic images of the same welds.

(.tiff images)

3) Cross sectional images at certain location from some of the welds

(.jpeg)

4) An excel spread sheet that has a key to the data

Electrification Of Domestic Hot Water To Aid The Integration Of Renewable Energy In The California Grid, Alejandro Cervantes

Cal Poly Humboldt theses and projects

Water heating in residential buildings, also known as domestic hot water (DHW), is the third largest use of energy after appliances and space conditioning. About 90% of the residential buildings in the state use natural gas fueled water heaters, 6% use electricity, and a small percent use liquefied petroleum gas (LPG) or solar water heaters. The current energy use associated with residential water heating is small relative to the total amount of energy consumption in the residential building sector, but it is still a contributor of greenhouse gas (GHG) emissions. Improving hot water systems can be beneficial for bill customer …

Indirect Thermosiphon Flat-Plate Solar Collector Performance Based On Twisted Tube Design Heat Exchanger Filled With Nanofluid, Mahmoud Eltaweel, Hazem Hussien, Ahmed A. Abdel-Rehim

Mechanical Engineering

No abstract provided.

Energetic And Exergetic Analysis Of A Heat Pipe Evacuated Tube Solar Collector Using Mwcnt/Water Nanofluid, Mahmoud Eltaweel, Ahmed A. Abdel-Rehim

Mechanical Engineering

Increasing the energy demand and the limited availability of conventional energy sources are the main challenges to secure the human future. Solar energy is an attractive source of energy to ensure the sustainability of energy in this world for now and for the future. Evacuated tube solar collector is a solar thermal collector mostly used for domestic applications. The replacement of the working fluid with nanofluid can enhance the heat transfer even for low temperature applications. The effect of multi-walled carbon nanotubes and water nanofluid as working fluid in evacuated tube solar collector is used to experimentally investigate the energy …

Techno-Economic Feasibility Of Solar Powered Electric Vehicle Charging Stations In West Virginia, Houssem Eddine Younes

Graduate Theses, Dissertations, and Problem Reports (ETD)

This project explores the techno-economic feasibility of installing a photovoltaic (PV) system to power electric vehicle (EV) charging stations in West Virginia. A case study of a parking garage charging station is considered. The PV system performance and economic feasibility are assessed for two different system configurations and two financial scenarios. Two system variations one including PV only and another with on-site storage battery are modelled using the System Advisor Model (SAM) developed by the National Renewable Energy Laboratory. Initial technical specifications of the PV system, battery system and EV chargers were selected as a reference case. Through parametric simulation, …

In-Situ X-Ray Imaging Of The Selective Laser Melting Process, Meelap M. Coday

Masters Theses

"Fusion-based metal additive manufacturing (AM) has garnered much interest in recent decades. Despite the popularity of fusion-based AM technologies such as selective laser melting (SLM), there are still fundamental questions and uncertainties that need to be addressed. In this work, we focus on the understanding of the undercooling in the SLM process and the uncertainties induced by the laser beam size, power, and scan speed. First, we report the estimation of undercooling in the SLM process from the solidification rate measured by in-situ high-speed synchrotron x-ray imaging, based on the dendrite growth velocity model. The undercooling changes as a function …

Influence Of Input Energy On Mechanical Properties Of Laser Powder Bed Fused Aisi 304l Stainless Steel, Tan Pan

Masters Theses

“Powder Bed Fusion process with selective laser melting technique is popularly adopted in additive manufacturing area on account of its layer by layer manufacturing fashion capable of fabricating components with complex internal and external geometries and structures. However, the process-property map is unique and vital for different materials and AM configurations used for fabrication. The process parameter is identified as a significant factor that heavily influences the properties and performances of the printed materials.

Current work aimed to extend the existing knowledge on Laser Powder Bed Fusion fabricated AISI 304L by accessing the influence of varying energy input on the …

On The Investigation Of Hot Tearing Behavior Of Continuous Cast Steel, Yanru Lu

Masters Theses

”Hot tearing has long been recognized as a major problem that plagues the development of the continuous casting process and results in low-quality products. Understanding of the mechanisms and the required conditions for the hot tearing formation is important for industries but has not been well-established yet. Thus, this research focuses on the hot tearing issue observed in continuous cast steel, by providing a summary of the current research progress and then introducing a new laboratory method to determine the thermo-mechanical properties relevant to hot tearing of different steel grades under different solidification conditions. In this method, an apparatus was …

Performance Evaluation Of Alsi10mg Fabricated By A Selective Laser Melting Process, David Michael Murphy

Masters Theses

“Selective laser melting is becoming a widely used additive manufacturing technique that melts metal powder in a layer by layer process in order to build a desired part or geometry. Like many additive processes, selective laser melting allows for fabrication of parts with complex geometries. In order to fabricate a fully dense part there are a number of variables to take into account including: powder characteristics, laser parameters, and environmental parameters. Each of these variables can affect the microstructure and thus the mechanical performance of an additively manufactured part. In this work, the aluminum alloy AlSi10Mg was investigated. AlSi10Mg is …

Mid-Infrared Chiral Metsurface Coupling With Molecular Vibration, Md Shamim Mahmud

Masters Theses

“The mid-infrared design of chiral metamaterial shows a tremendous absorption capability of infrared rays, and it has the significant application of circular dichroism based device development. Plasmon-phonon coupling is one of the application of metamaterial that provides a new path for tailoring the surface in the nanoscale, which is also applicable in molecules detection. It is possible to change the Plasmon-Phonon coupling strength not only through the chemical change of molecules but also by changing the metamaterial light-matter interaction property. So far, linearly polarized light shows the strong coupling between metamaterial and molecules. However, it is possible to observe strong …

Combining Laser Aided Ablation And Polishing To Minimize Surface Roughness Of Additively Manufactured Aluminium Components, Sahil Bipinkumar Patel

Masters Theses

“The surface roughness of additively manufactured parts is much higher than the acceptable range for most applications, thus post-processing is needed to qualify these parts for use. Laser polishing can be used to bring the surface roughness in an admissible range, but if the initial roughness is very high then the energy density for the polishing process needs to be very high to achieve a significant reduction in roughness. This high energy density can produce many process defects. Also, laser polishing alone cannot get rid of high wavelength asperities. Any waviness in the part can be linked with initial waviness …

Modal Analysis As Non-Destructive Testing Technique For Additively Manufactured 304l Stainless Steel Parts, Tristan N. Cullom

Masters Theses

“Non-Destructive Testing (NDT) methods for Additively Manufactured (AM) parts is an ongoing field of research in the additive community due to its ability to determine if a part can be deemed viable for field usage. This study presents modal analysis as a NDT method for AM parts. For production builds that have multiple copies of the same part, a correcting technique can be used such that the frequencies of the parts under test can be reliably compared against each other, which saves both time and money compared to other traditional NDT methods. This study was able to develop a novel …

Arising: Hurricane (Superstorm) Sandy’S Impact On Design/Planning Professionals, Maxinne R. Leighton

Antioch University Dissertations & Theses

Standing by my bedroom window, looking out at the ocean, a huge wave comes and swallows up my building. Everything around me is gone, including me. I wake up. I am 13 years old and living in the Coney Island Houses on Surf Avenue, Brooklyn, New York. With ongoing anthropogenic changes to the natural environment such as sea level rise and intensifying storms, coastal communities, especially ones segregated by class and culture, are particularly vulnerable in this context that challenges a way of life, and in some instances, threatens that life's survival. This dissertation focuses specifically on what one massive …

Investigating The Effects Of Flue Gas Injection, Hot Water Distribution, And Fill Distribution On Natural Draft Wet Cooling Tower Performance, John Stapleton

Senior Honors Theses

Natural draft wet cooling towers (NDWCT) are a common method of heat removal in powerplants. This study employs a numerical cooling tower model developed by Eldredge, Benton & Hodgson (1997) to examine whether utilizing nonuniform water, fill profiles, and flue gas injection can improve NDWCT efficiency. The results show that each of these variables can be optimized to lower outlet water temperature. Within the range tested for each parameter, the water profile had the most significant effect on outlet water temperature, followed by the flue gas temperature and then the fill profile. The optimum parameter combination reduced the predicted outlet …

Deep Learning Of Nonlinear Dynamical System, Aditya Wagh

Dissertations, Master's Theses and Master's Reports

A data-driven approach, such as neural networks, is an alternative to traditional parametric-model methods for nonlinear system identification. Recently, long Short- Term Memory (LSTM) neural networks have been studied to model nonlinear dynamical systems. However, many of these contributions are made considering that the input to the system is known or measurable, which often may not be the case. This thesis presents a method based on LSTM for output-only modeling, identification, and prediction of nonlinear systems. A numerical study is performed and discussed on Duffing systems with various cubic nonlinearity.

A Neural Network Approach To Estimate Buoy Mooring Line Sensor Deflection, Tom Price

Dissertations, Master's Theses and Master's Reports

Instrumented moorings are often used to measure characteristics, such as temperature and current, over the water column. However, the moorings deflect from the effects of currents and waves, which could lead to innacurate measurements. In this work, a computationally efficient method to compensate for mooring sensor position errors is developed. The two-step process first uses a hydrodynamic model of the buoy and mooring line system to create estimated mooring line deflections in a steady current. A neural network model is trained to approximate the hydrodynamic model’s mooring line displacement given the spatial location of the buoy and current profile measurements. …

Sensitivity And Uncertainty Quantification Of Continuum And Stochastic Bond Dissociation Kinetics Based Cohesive Laws, Rishabh Awasthi

Dissertations, Master's Theses and Master's Reports

Polymeric adhesives are being extensively used to develop light weight and durable Composite Materials which are have been employed in automotive, aeronautical, medical industry. Polymeric adhesives undergo failure due to relative opening sliding of bonded interfaces which requires a need to characterize the fracture mechanism. Numerous experiments are conducted to predict the fracture response for Mode-I, II,III and numerical simulations are employed to inversely calibrate the material parameters governing the constitutive laws. Cohesive zone models are largely employed in fracture mechanics to predict failure of interfaces undergoing large plastic deformations. The objective of this report is to employ the cohesive …

Analysis Of A Circular Resonant Plate For Shock Testing, Jon Markl

Dissertations, Master's Theses and Master's Reports

Designing a resonant plate for shock test specifications involves an understanding of how a system will respond with a given set of input and output locations in all three directions. To investigate how to effectively change the off-axis responses to meet test specifications, a finite element model (FEM) was created and examinations of input location/angle of impact, placement of the test fixture, and placement of the impact pad were conducted. The primary tool used to determine how a structure will respond to a given input at a given output on the test structure was done using the shock response spectra …

Experimental Characterization Of Spool Valve Flow Noise, Zachary Cohen

Dissertations, Master's Theses and Master's Reports

The purpose of this research was to experimentally measure the flow noise produced by a spool valve and compare with measurements of orifice flow noise to reduce flow noise modelling complexity. The similarities and differences are compared over a range of volume flow rates, back pressures, and cross section areas. The impact of down stream boundary conditions on the flow noise are also examined. The results are generalized and plotted against Froude number. The valve results are curve fit to generate empirical equations that can be used to predict flow noise under typical operating conditions. The valve and orifice data …

Design, Build, And Analysis Of A Compressed Natural Gas Direct Injection Compression Ignition Single Cylinder Research Engine, Tyler Miller

Dissertations, Master's Theses and Master's Reports

Both experimental and simulation efforts have been employed to further advance the design and build of a single cylinder research engine. The engine will aid in advancing technology and understanding the operation of compression-ignition (CI) engines using natural gas within the heavy-duty engine industry. The basis for the engine is a Cummins 15L ISX engine that has been modified, retrofitted, and instrumented to allow for late-cycle direct-injection of high-pressure compressed natural gas. Along with the engine build, a one-dimensional GT-Power simulation model has been created and used to analyze the engine operation and specify components including the engine compression ratio …

A Study Of Model-Based Control Strategy For A Gasoline Turbocharged Direct Injection Spark Ignited Engine, Xin Wang

Dissertations, Master's Theses and Master's Reports

To meet increasingly stringent fuel economy and emissions legislation, more advanced technologies have been added to spark-ignition (SI) engines, thus exponentially increase the complexity and calibration work of traditional map-based engine control. To achieve better engine performance without introducing significant calibration efforts and make the developed control system easily adapt to future engines upgrades and designs, this research proposes a model-based optimal control system for cycle-by-cycle Gasoline Turbocharged Direct Injection (GTDI) SI engine control, which aims to deliver the requested torque output and operate the engine to achieve the best achievable fuel economy and minimum emission under wide range of …

Real-Time Predictive Control Of Connected Vehicle Powertrains For Improved Energy Efficiency, Joseph Oncken

Dissertations, Master's Theses and Master's Reports

The continued push for the reduction of energy consumption across the automotive vehicle fleet has led to widespread adoption of hybrid and plug-in hybrid electric vehicles (PHEV) by auto manufacturers. In addition, connected and automated vehicle (CAV) technologies have seen rapid development in recent years and bring with them the potential to significantly impact vehicle energy consumption. This dissertation studies predictive control methods for PHEV powertrains that are enabled by CAV technologies with the goal of reducing vehicle energy consumption.

First, a real-time predictive powertrain controller for PHEV energy management is developed. This controller utilizes predictions of future vehicle velocity …

Phase Field Fracture Modeling Of Chemically Strengthened Glass, Parag Nikam

Dissertations, Master's Theses and Master's Reports

The objective of the report is to implement the phase-field model in the Abaqus standard to compute the fracture properties of a glass strengthened by an ion-exchange process. Implemented the phase-field model which is based on the rate-independent variational principle of diffuse fracture in Abaqus standard software using the UEL and UMAT subroutines. SDVINI subroutine is used to give the residual stress or prestress conditions to simulate the stress profile of strengthened glass. Studied the effect of parameters such as length scale parameter and step size and the optimum parameters are selected. The experimental model of chemically strengthened glass is …

Numerical Investigation Of Spray Characterization Of Heater-Gdi System, Ashwin Karthik Purushothaman

Dissertations, Master's Theses and Master's Reports

Gasoline engines require fuel enrichment at low temperature cranking (cold start) conditions for efficient engine operation. Since the amount of fuel injected is high at cold start to compensate low fuel evaporation, fuel sprays tend to impinge on the cold surfaces of the piston and cylinder walls leading to the formation of excessive unburned hydrocarbons. One of the ways to ensure reliable cold start performance and to reduce UHC emissions is to have the fuel subjected to preheating. The objective of this study is to investigate the effects of fuel preheating on Gasoline Direct Injection sprays to improve the mixture …