Engineering Commons^™

Wind Turbine Controls For Farm And Offshore Operation, Zhongzhou Yang

Theses and Dissertations

Development of advanced control techniques is a critical measure for reducing the cost of energy for wind power generation, in terms of both enhancing energy capture and reducing fatigue load. There are two remarkable trends for wind energy. First, more and more large wind farms are developed in order to reduce the unit-power cost in installation, operation, maintenance and transmission. Second, offshore wind energy has received significant attention when the scarcity of land resource has appeared to be a major bottleneck for next level of wind penetration, especially for Europe and Asia. This dissertation study investigates on several wind turbine …

Finite Element Analysis Of Contribution Of Adhesion And Hysteresis To Shoe-Floor Friction, Seyed Reza Mirhassani Moghaddam

Theses and Dissertations

Slips and falls are one of the leading causes of occupational accidents. Understanding the important factors that affect shoe-floor friction is vital for identifying unsafe surfaces and designing better footwear and flooring. While the shoe-floor coefficient of friction is known to be dependent on several factors including shoe and floor roughness, shoe speed, shoe material, and normal load, the mechanisms that cause these effects are not very well understood. The objective of this thesis is to develop a finite element model that simulates the microscopic asperity interaction between shoe and floor surfaces and apply it to quantify the effect of …

An Experimental Investigation Characterizing The Tribological Performance Of Natural And Synthetic Biolubricants Composed Of Carboxylic Acids For Energy Conservation And Sustainability, Carlton Jonathan Reeves

Theses and Dissertations

Over the last several decades the lubrication industry has been striving to bring bio-based lubricants known as biolubricants to prominence. The reasons for the increased environmental initiatives are due to depletion of oil reserves, increases in oil price, stringent government regulations on petroleum-based oils, and most importantly, concerns for protecting the environment. With an estimated, 50% of all lubricants entering the environment and much of these being composed of toxic mineral oils, biolubricants have begun to witness a resurgence. This experimental investigation seeks to develop a new class of ecofriendly biolubricants that are less toxic to the environment, derived from …

Techniques For Optimum Design Of Actively Controlled Structures Including Topological Considerations, Arjumand Ali

Theses and Dissertations

The design and performance of complex engineering systems often depends on several conflicting objectives which, in many cases, cannot be represented as a single measure of performance. This thesis presents a multi-objective formulation for a comprehensive treatment of the structural and topological considerations in the design of actively controlled structures.

The dissertation addresses three main problems. The first problem deals with optimum placement of actuators in actively controlled structures. The purpose of control is to reduce the vibrations when the structure is subjected to a disturbance. In order to mitigate the structural vibrations as quickly as possible, it is necessary …

Techniques For Engine Mount Modeling And Optimization, Fadi Alkhatib

Theses and Dissertations

This dissertation presents techniques for the design of engine mounting system to address the issue of vibration isolation. While the techniques presented herein are general, the application of proposed techniques is demonstrated primarily through applications in motorcycles. The dynamic loads that are generated due to the shaking forces within the engine and the road loads that are transmitted to the engine through the tire patch are discussed. The geometrical shape of the engine mount is also considered in this work. All models discussed herein deal with solving the optimization problem for the engine mount system such that the transmitted forces …

Inverse Methods For Load Identification Augmented By Optimal Sensor Placement And Model Order Reduction, Deepak Kumar Gupta

Theses and Dissertations

Design problems require accurate characterization of loads acting on a structure. One way to estimate the loads is through experimentally measured structural response. This is known as the "inverse problem." The instrumented structure essentially acts as its own transducer. It is well known that the inverse problems tend to be highly ill-conditioned. This dissertation proposes several novel time domain and modal domain algorithms for estimating multiple dynamic loads exciting a structure from structural response measured at a finite number of optimally placed non-collocated sensors on the structure. The optimal placement of sensors is necessary to counter the inherent limitation of …

Heat Transfer Analysis Of Two Pass Cooling Channel Of Gas Turbine Blade With Analytical Wall Function Turbulence Approach, Hitoshi Arakawa

Theses and Dissertations

This paper reports experimental and computational studies of heat transfer through a square duct with a sharp 180 degree turn. The main purpose of this research was to study heat transfer predictions using the Analytical Wall-Function (AWF). To compare the predicting performance of the AWF, the standard Log-Law Based Wall-Function (LWF) and a Low-Reynolds-number (LRN) k-e model were applied. Their results were also compared with experimental results for validation. In addition, three extended forms of the AWF were tested. The AWF showed better results than the conventional wall-function based on a logarithmic law especially in separation and reattachment regions and …

Bi- And Multi Level Game Theoretic Approaches In Mechanical Design, Ehsan Ghotbi

Theses and Dissertations

This dissertation presents a game theoretic approach to solve bi and multi-level optimization problems arising in mechanical design. Toward this end, Stackelberg (leader-follower), Nash, as well as cooperative game formulations are considered. To solve these problems numerically, a sensitivity based approach is developed in this dissertation. Although game theoretic methods have been used by several authors for solving multi-objective problems, numerical methods and the applications of extensive games to engineering design problems are very limited. This dissertation tries to fill this gap by developing the possible scenarios for multi-objective problems and develops new numerical approaches for solving them.

This dissertation …

Hydrogen Generation From Magnesium Hydride By Using Organic Acid, Yen-Hsi Ho

Theses and Dissertations

In this paper, the hydrolysis of solid magnesium hydride has been studied with the high concentration of catalyst at the varying temperature. An organic acid (acetic acid, CH3COOH) has been chosen as the catalyst. The study has three objectives: first, using three different weights of MgH2 react with aqueous solution of acid for the hydrogen generation experiments. Secondly, utilizing acetic acid as the catalyst accelerates hydrogen generation. Third, emphasizing the combination of the three operating conditions (the weight of MgH2, the concentration of acetic acid, and the varying temperature) influence the amount of hydrogen generation. The experiments results show acetic …

Effects Of Internal Resistance On Performance Of Batteries For Electric Vehicles, Rohit Anil Ugle

Theses and Dissertations

ABSTRACT

Effects of Internal Resistance on Performance of Batteries for Electric Vehicles

by

Rohit A Ugle

The University of Wisconsin-Milwaukee, 2013

Under the Supervision of Professor Anoop K. Dhingra

An ever increasing acceptance of electric vehicles as passenger cars relies on better operation and control of large battery packs. The individual cells in large battery packs do not have identical characteristics and may degrade differently due to their manufacturing variability and other factors. It is beneficial to evaluate the performance gain by replacing certain battery modules/cells during actual driving.

The following are the objectives of our research. We will develop …

Aqueous Turbulence Structure Immediately Adjacent To The Air - Water Interface And Interfacial Gas Exchange, Binbin Wang

Theses and Dissertations

Air-sea interaction and the interfacial exchange of gas across the air-water interface are of great importance in coupled atmospheric-oceanic environmental systems. Aqueous turbulence structure immediately adjacent to the air-water interface is the combined result of wind, surface waves, currents and other environmental forces and plays a key role in energy budgets, gas fluxes and hence the global climate system. However, the quantification of turbulence structure sufficiently close to the air-water interface is extremely difficult. The physical relationship between interfacial gas exchange and near surface turbulence remains insufficiently investigated. This dissertation aims to measure turbulence in situ in a complex environmental …

Mechanics Of Bolted Electrical Splices, Samuel Alberts

Theses and Dissertations

Localized heating of bolted electrical splices in the power distributing bus is a primary concern in the industrial automation industry. While localized heat generation problems are commonly reported in the field, it is not entirely clear what the root causes are. A methodology is presented for development of a tool to measure in-situ the influence of clamping load on the thermo-electric behavior of the splice joint. Applied research and reasoning used to identify probable root causes for failures reported in the field are also presented. Experiments were conducted to characterize the mechanical properties of the bolt and nut system used …

Development And Validation Of A Mathematical Model For Predicting The Performance Of Rotary Hammer Drills, Will Didier

Theses and Dissertations

Rotary hammer drills are specialized drills used by plumbers, electricians, and other construction trades to drill holes in concrete. This type of tool employs a mechanism driven by an electric motor to compress a column of air, generating an impact on a drill bit to break the concrete work piece. Rotary hammer development requires the ability to accurately predict tool performance to minimize the number of prototype iterations required during the design phase and ensure the tool delivers a satisfactory level of performance. In order to predict the performance of a rotary hammer drill, a mathematical model was developed to …

Investigation Of Some Self-Optimizing Control Problems For Net-Zero Energy Buildings, Xiao Li

Theses and Dissertations

Green buildings are sustainable buildings designed to be environmentally responsible and resource efficient. The Net-Zero Energy Building (NZEB) concept is anchored on two pillars: reducing the energy consumption and enhancing the local energy generation. In other words, efficient operation of the existing building equipment and efficient power generation of building integrated renewable energy sources are two important factors of NZEB development. The heating, ventilation and air conditioning (HVAC) systems are an important class of building equipment that is responsible for large portion of building energy usage, while the building integrated photovoltaic (BIPV) system is well received as the key technology …

Low Turbulence Wind Tunnel Design And Wind Turbine Wake Characterization, Andrew Welsh

Theses and Dissertations

As the prevalence of wind turbines in the energy market increases, so too does the demand for high-wind real-estate. As a result, wind turbines are placed closer together, which leads to structural challenges due to the cyclical fatigue loading from the wake of upwind turbines. Characterizing the wake behind wind turbines with respect to those downwind is especially important given the 20-year wind turbine lifetime that commercial wind turbine consumers expect. This project aimed to characterize the near wake behind a model wind turbine.

In order to accomplish this, a 12.8 meter-long and 1.22 meter-square test section low-turbulence wind tunnel …

Fuzzy Logic Controller For Parallel Plug-In Hybrid Vehicle, Sk. Khairul Hasan

Theses and Dissertations

Hybrid electric vehicles combine two methods for propelling a vehicle. In a parallel hybrid vehicle, the two propulsion methods work in parallel to meet the total power demand. Among different combination of power sources, internal combustion engine and electric motor drive system are the most popular because of their availability and controllability. Plug-in hybrid vehicle is the latest version in hybrid vehicle family. In plug-in hybrid vehicle, battery is directly recharged from the electrical power grid and it can be used for a long distance with higher efficiency. Most of the hybrid vehicles on the road are parallel in nature …

Preventing Sheet Metal Wrinkling In Coil Lines, David Steven Revers

Theses and Dissertations

Coil lines are used in metal packaging facilities to treat the metal before forming the final product. As the sidewalls of cans are becoming thinner and thinner, one can see that the equipment has not been designed properly to feed up lighter plate weight metal. Thinner can walls cause the metal sheet to be fed into the machine crooked and results in a wrinkling of the first few feet of metal, which then needs to be thrown away. Because the current equipment is not working properly, operators have been feeding sheets of metal up a ten-foot ladder into the machine …

Material Behavior Characterization Of A Thin Film Polymer Used In Lithium-Ion Batteries, Michael James Martinsen

Theses and Dissertations

The use of lithium-ion batteries in the automotive industry has become increasingly popular. As more hybrid and electric vehicles take to the road an understanding of how these batteries will behave structurally will be of greater concern. Impact testing can give a valuable overview of the strengths and weaknesses of a battery's design, however, these tests can be time consuming, expensive, and dangerous. Finite element analysis can deliver a reliable low cost approximation of physical testing results. The accuracy of FE results depends greatly on the mathematical representation of the material properties of Li-ion battery components. In this study, the …

Application Potential Of Solar Pv, Wind And Fuel Cells Technologies For Global Sustainability Improvement, Qiang Zhai

Theses and Dissertations

This dissertation develops a systematic approach to comprehensively investigate the application potential of Solar PV, wind and fuel cells in reducing GHGs emissions for energy intensive global manufacturing industry. This systematic approach is developed by integrating the technological and economic characteristics of the clean energy technologies, as well as the local geographic conditions where the clean energy technologies may be deployed. This approach consists of the investigation on such aspects as: technological feasibility, capacity factor, FIT strength, Levelized energy cost, cost benefit and sensitivity.

In this dissertation, the systematic approach developed is applied on the application potential analyses of solar …

Aerodynamic Analysis And Drag Coefficient Evaluation Of Time-Trial Bicycle Riders, Peter Nicholas Doval

Theses and Dissertations

Evaluation of drag coefficient often requires wind tunnel experiments and can be prohibitively expensive if not impossible for large objects or systems. Computational Fluid Dynamics (CFD) aerodynamic analysis offers an alternative approach and can be used as a very effective design tool in many industries: automotive, aerospace, marine, etc. The main objective of this research is to investigate feasibility of using non-contact digitizers for developing finite element models of large objects for subsequent CFD analysis. The developed methodology is applied to investigation of time-trial bicycle rider efficiency. Companies competing in this class of racing spend millions trying to optimize bicycle …

Investigation Of Heat Transfer And Flow Using Ribs Within Gas Turbine Blade Cooling Passage: Experimental And Hybrid Les/Rans Modeling, Sourabh Kumar

Theses and Dissertations

Gas turbines are extensively used for aircraft propulsion, land based power generation and various industrial applications. Developments in innovative gas turbine cooling technology enhance the efficiency and power output, with an increase in turbine rotor inlet temperatures. These advancements of turbine cooling have allowed engine design to exceed normal material temperature limits. For internal cooling design, techniques for heat extraction from the surfaces exposed to hot stream are based on the increase of heat transfer areas and on promotion of turbulence of the cooling flow. In this study, it is obtained by casting repeated continuous V and broken V shaped …

Discovery And Correction Of Bias In Precision Landmark Location, Colin Foster

Theses and Dissertations

Precision Landmark Location (PLL) estimation is an integral part of 3D motion tracking. Circular landmark location estimation is one method of PLL. Current methods of estimation lead to systematic errors with a magnitude of up to .02 pixels. Estimation inaccuracies of this magnitude lead to unacceptable errors in depth measurement, the largest source of error. In the scope of this thesis, inadequacies in circular landmark location are uncovered and techniques to correct these errors are analyzed, tested, and demonstrated. Deviations in simulated images are seen to be reduced by a factor of three and the variances of real-world data were …