Engineering Commons^™

Acoustic Design Optimization With Isogeometric Analysis And Differential Evolution, Garrett W. Dodgen

Mechanical Engineering Theses

The objective of this study is to utilize shape optimization to enhance the performance of devices relying on acoustic wave propagation. Particularly, the shape of a horn speaker and an acoustic energy harvester were optimized to enhance their performance at targeted frequencies. High order Isogeometric Analysis (IGA) was performed to estimate the acoustic pressure with minimum geometry and pollution errors [1]. The analysis platform was then combined with Differential Evolution (DE) to optimize the geometry of the horn speaker and energy harvester at a given frequency. These cases effectively demonstrate two applications of Isogeomtric shape optimization for devices relying on …

Sizing A New Bike Sharing System For The University Of Nevada, Las Vegas, Nesley Orochena

UNLV Theses, Dissertations, Professional Papers, and Capstones

The strategic planning objectives for a novel Bike Sharing Systems (BSS) are to locate the BSS stations, size the stations, and determine the bicycle fleet size, among others. Current guidelines to design BSS programs are tailored to city centers with large coverage areas and high bicycle to population ratios, and thus not directly transferable to a university setting. An ordered probit model was created using data from a university online stated preference survey to determine the key factors that affect the uptake rates for the UNLV BSS program and to estimate the potential demand. The demand analysis was incorporated into …

Credible Optimum Selection Of Guidance System Simulation Based On Entropy Weight Vikor Method, Wenguang Yang, Yunjie Wu

Journal of System Simulation

Abstract: As the core component of the missile system, the guidance system plays an increasingly important role in the design of missile system. In order to improve the accuracy of the guidance system, this paper obtains the experimental data under a number of parameter design schemes by means of simulation experiments. The problem of simulation credibility verification of guidance system is transformed into multi-attribute decision-making optimization problem, and a parameter optimization method of guidance system based on improved VIKOR method is designed. The improved VIKOR method overcomes the phenomenon of rank reversal and ensures that the optimal final compromise solution …

Mazak Laser Optimization, Maylon Ellington, Terrilian E. Agbor Oji, William N. Palm

Senior Design Project For Engineers

Starflex Fabrication is a manufacturing company that thrives to provide custom, precision fabricated parts, and assemblies to their customers.The Mazak laser is Starflex Fabrication’s primary cutting machine and is critical to the overall process for each order. Team Flex will look to optimize the laser’s process and improve overall shop throughput.

Gearbox Baffle Optimization, Megan Arduin

Masters Theses

Current literature reveals there is limited consensus on the placement of baffles within a gearbox to reduce churning losses. Thus, there is a need for a process to identify baffle clearances that result in maximum and minimum churning losses. There are two types of baffles: axial and radial. While both axial and radial baffles cause reductions in churning losses to various degrees, the focus is on the effect of radial baffles. The effect of a board (rectangular plate) baffle location on the churning losses of a single gear gearbox are evaluated using computational fluid dynamics (CFD) implemented in Ansys. Several …

Simulation And Optimization Of A Multi-Agent System On Physical Internet Enabled Interconnected Urban Logistics., Long Zheng

Electronic Theses and Dissertations

An urban logistics system is composed of multiple agents, e.g., shippers, carriers, and distribution centers, etc., and multi-modal networks. The structure of Physical Internet (PI) transportation network is different from current logistics practices, and simulation can effectively model a series of PI-approach scenarios. In addition to the baseline model, three more scenarios are enacted based on different characteristics: shared trucks, shared hubs, and shared flows with other less-than-truckload shipments passing through the urban area. Five performance measures, i.e., truck distance per container, mean truck time per container, lead time, CO₂ emissions, and transport mean fill rate, are included in …

Optimizing Block-Stacking Operations With Relocation, Hueon Lee

Graduate Theses and Dissertations

The focus of the dissertation is developing the optimization problem of finding the minimum-cost operational plan of block stacking with relocation as well as devising a solution procedure to solve practical-sized instances of the problem. Assuming changeable row depth instead of permanent row depth, this research is distinguished from conventional block stacking studies.

The first contribution of the dissertation is the development of the optimization problem under the assumption of deterministic demand. The problem is modeled using integer programming as a variation of the unsplittable multi-commodity flow problem. To find a good feasible solution of practical-sized instances in reasonable time, …

A Reinforcement Learning Approach To Spacecraft Trajectory Optimization, Daniel S. Kolosa

Dissertations

This dissertation explores a novel method of solving low-thrust spacecraft targeting problems using reinforcement learning. A reinforcement learning algorithm based on Deep Deterministic Policy Gradients was developed to solve low-thrust trajectory optimization problems. The algorithm consists of two neural networks, an actor network and a critic network. The actor approximates a thrust magnitude given the current spacecraft state expressed as a set of orbital elements. The critic network evaluates the action taken by the actor based on the state and action taken. Three different types of trajectory problems were solved, a generalized orbit change maneuver, a semimajor axis change maneuver, …

Single-Cell Impedance Spectroscopy, David Paul Lange

Master's Theses

Impedance spectroscopy (IS) is an important tool for cell detection and characterization in medical and food safety applications. In this thesis, the Cal Poly Biofluidics Lab’s impedance spectroscopy system was re-evaluated and optimized for single-cell impedance spectroscopy. To evaluate the IS system, an impedance spectroscopy bioMEMS chip was fabricated in the Cal Poly Microfabcrication lab, software was developed to run IS experiments, and studies were run to validate the system. To explore IS optimization, Maxwell’s mixture theorem and the Schwartz-Christoffel transform were used to calculate an analytic impedance solution to the co-planar electrode system,a novel volume fraction to account for …

Variance Reduction In Wind Farm Layout Optimization, Bertelsen Gagakuma

Theses and Dissertations

As demand for wind power continues to grow, it is becoming increasingly important to minimize the risk, characterized by the variance, that is associated with long-term power forecasts. This thesis investigated variance reduction in power forecasts from wind farm layout optimization.The problem was formulated as a multi-objective optimization one of maximizing mean-plant-power and minimizing variance. The ε−constraint method was used to solve the bi-objectiveproblem in a two-step optimization framework where two sequential optimizations are performed. The first is maximizing mean wind farm power alone and the second, minimizing variance with a constraint on the mean power which is the value …

Enabling Autonomous Operation Of Micro Aerial Vehicles Through Gps To Gps-Denied Transitions, James Scott Jackson

Theses and Dissertations

Micro aerial vehicles and other autonomous systems have the potential to truly transform life as we know it, however much of the potential of autonomous systems remains unrealized because reliable navigation is still an unsolved problem with significant challenges. This dissertation presents solutions to many aspects of autonomous navigation. First, it presents ROSflight, a software and hardware architure that allows for rapid prototyping and experimentation of autonomy algorithms on MAVs with lightweight, efficient flight control. Next, this dissertation presents improvments to the state-of-the-art in optimal control of quadrotors by utilizing the error-state formulation frequently utilized in state estimation. It is …

Optimal Combinations Of Utility Level Renewable Generators For A Net Zero Energy Microgrid Considering Different Utility Charge Rates, Evan S. Jones, Huangjie Gong, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

High initial investment and the intermittent nature of resources are major challenges for large scale renewable generation. The size of photovoltaic (PV) and wind turbine (WT) farms in the microgrid needs optimized to avoid curtailment and to efficiently meet the demand of a power system. Battery energy storage systems (BESSs) may also be used to improve flexibility. This paper explores the optimal sizing for PV and wind generators, as well as a BESS at the utility level for a large grid-connected net zero energy (NZE) hybrid microgrid considering characteristics such as initial investment, levelized cost of energy (LCOE), operating costs, …

An Optimization Approach And A Model For Job Shop Scheduling Problem With Linear Programming, Fatmir Azemi, Daniel Tokody, Bekim Maloku

UBT International Conference

Optimization approaches and models are developed for job shop scheduling problems over the last decades, particularly the most attempts have been done in industry and considerable progress has been made on an academic line. The Job-shop scheduling considered the most significant industrial activities, mostly in manufacturing. The JSSP (Job Shop Scheduling Problems) is typical NP-hard problem. To solve this problem, we have used the linear programming approach. Real data have been taken from the company of the metalworking industry. The model has been created, then it was analyzed using Spreadsheet – Excel Solver. The appropriate sequence has been obtained and …

Optimization Of Geometry Parameters Of Inkjet-Printed Silver Nanoparticle Traces On Pdms Substrates Using Response Surface Methodology, Jumana Abu-Khalaf, Loiy Al-Ghussain, Ahmad Nadi, Razan Saraireh, Abdulrahman Rabayah, Safwan Altarazi, Ala’Aldeen Al-Halhouli

Mechanical Engineering Graduate Research

Inkjet printing is an emerging technology with key advantages that make it suitable for the fabrication of stretchable circuits. Specifically, this process is cost-effective and less complex compared to conventional fabrication technologies. Inkjet printing has several process and geometry parameters that significantly affect the electromechanical properties of the printed circuits. This study aims to optimize the geometry parameters of inkjet-printed silver nanoparticle traces on plasma-treated polydimethylsiloxane (PDMS) substrates. The optimization process was conducted for two printed shapes, namely straight line and horseshoe patterns. The examined input factors for the straight line traces were: the number of inkjet-printed layers and line …

Insulation Sensitivity Analysis For An Optimized Fabric Shelter Off-Grid Hybrid Energy System, Jay F. Pearson [*], Torrey J. Wagner, Steven Schuldt

Faculty Publications

During military and disaster relief operations, connecting to an established electrical grid is rarely an option. In these situations, camps consisting of poorly insulated fabric shelters are predominantly powered by inefficient diesel generators that require frequent fuel resupply. In order to reduce the fuel demand of these generators, camps may utilize photovoltaic-battery systems. This paper presents an innovative cost-performance model capable of optimizing solar array size, battery backup system, and shelter insulation type to minimize the operating cost of powering a single fabric shelter. Model performance was evaluated using one year of insolation, weather and energy requirement data from a …

Evaluation Of Internally Cured Bridge Deck Concrete With Standard And Optimized Aggregate Gradation, Arman Abdigaliyev

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Due to the relatively high cement content and low water-to-cement ratio (w/c) used, bridge deck concrete is prone to premature cracking. Internal curing has been found to greatly reduce the chance of premature cracking as well as concrete deterioration. This research developed internally cured bridge deck concrete based on a local mix design in Nebraska. Four different lightweight fine aggregate (LWFA) as internal curing agents were evaluated and their effects on fresh, mechanical, durability, and shrinkage properties of concrete were studied. The study focused on resolving two issues associated with fine aggregate replacement based on Bentz equation. To identify the …

Optimal Sampling Paths For Autonomous Vehicles In Uncertain Ocean Flows, Andrew J. De Stefan

Dissertations

Despite an extensive history of oceanic observation, researchers have only begun to build a complete picture of oceanic currents. Sparsity of instrumentation has created the need to maximize the information extracted from every source of data in building this picture. Within the last few decades, autonomous vehicles, or AVs, have been employed as tools to aid in this research initiative. Unmanned and self-propelled, AVs are capable of spending weeks, if not months, exploring and monitoring the oceans. However, the quality of data acquired by these vehicles is highly dependent on the paths along which they collect their observational data. The …

Design, Analysis, And Optimization Of Compactible Origami-Inspired Shelters, Anthony M. Verzoni

Electronic Theses and Dissertations

Origami-inspired design is a growing field with numerous engineering applications, including rapidly compactable and erectable shelters with nondeformed flat panels, which are considered in this research. Shelter geometry is controlled by the shape, size, and connectivity of individual panels that must fold and unfold in a kinematically compliant manner resulting in no panel intersection. Panel size and shape are altered to yield shelter designs with varying volumetric capacities. Thin panels are initially used to study the kinematics of shelter concepts as traditional origami. With increasing panel thickness, the location of fold or hinge lines exerts a large influence on the …

Evaluation Of Data Collection Operations For Real-Time Influenza Surveillance During An Emergency, Yuwen Gu

Dissertations

It is unclear how data collection operations for surveillance alter the disease portrayal that influenza reported trends attempt to provide during an emergency. This study developed a model that simulates the collection and testing of influenza specimens after an outbreak is declared in Michigan. It performed simulation based optimization to understand which operational factors affect the biases between the growth rates of original and observed influenza incidence trends, and to quantify the predictive power of the influenza incidence trends at different points of data collection. The results show that emergency driven high risk perception increases the reporting, which leads to …

Switching Trajectory Control For High Voltage Silicon Carbide Power Devices With Novel Active Gate Drivers, Shuang Zhao

Graduate Theses and Dissertations

The penetration of silicon carbide (SiC) semiconductor devices is increasing in the power industry due to their lower parasitics, higher blocking voltage, and higher thermal conductivity over their silicon (Si) counterparts. Applications of high voltage SiC power devices, generally 10 kV or higher, can significantly reduce the amount of the cascaded levels of converters in the distributed system, simplify the system by reducing the number of the semiconductor devices, and increase the system reliability.

However, the gate drivers for high voltage SiC devices are not available on the market. Also, the characteristics of the third generation 10 kV SiC MOSFETs …

Takeoff And Performance Tradeoffs Of Retrofit Distributed Electric Propulsion For Urban Transport, Kevin Moore, Andrew Ning

Faculty Publications

While vertical takeoff and landing aircraft have shown promise for urban air transport, distributed electric propulsion on existing aircraft may offer immediately implementable alternatives. Distributed electric propulsion could potentially decrease takeoff distances enough to enable thousands of potential inter-city runways. This conceptual study explores the effects of a retrofit of open-bladed electric propulsion units. To model and explore the design space we use blade element momentum method, vortex lattice method, linear-beam finite element analysis, classical laminate theory, composite failure, empirically-based blade noise modeling, motor and motor-controller mass models, and gradient-based optimization. With liftoff time of seconds and the safe total …

Unsupervised-Learning Assisted Artificial Neural Network For Optimization, Varun Kote

Mechanical & Aerospace Engineering Theses & Dissertations

Innovations in computer technology made way for Computational Fluid Dynamics (CFD) into engineering, which supported the development of new designs by reducing the cost and time by lowering the dependency on experimentation. There is a further need to make the process of development more efficient. One such technology is Artificial Intelligence. In this thesis, we explore the application of Artificial Intelligence (AI) in CFD and how it can improve the process of development.

AI is used as a buzz word for the mechanism which can learn by itself and make the decision accordingly. Machine learning (ML) is a subset of …

Automated Shaped Charge Design: Applying Dakota Optimization To Cth Kinetic Energy Results, Sebastian Arcangelo Konewko

Master's Theses (2009 -)

Advances in computational power present an opportunity to further optimize the design of an engineered energetic system. This work presents the application of a proposed optimization scheme which combines the shock-physics hydrocode CTH with the DAKOTA optimization package to automate shaped-charge jet design. The formation of an explosively driven hypervelocity jet is highly dependent on the original shaped charge liner geometry. By parameterizing this geometry, and by developing a characteristic objective function from CTH simulations, a process can be established where the Dakota code iteratively builds an optimal shaped charge. This work attempts to use this methodology to reproduce a …

Application And Evaluation Of Full-Field Surrogate Models In Engineering Design Space Exploration, Christopher Murray Thelin

Theses and Dissertations

When designing an engineering part, better decisions are made by exploring the entire space of design variations. This design space exploration (DSE) may be accomplished manually or via optimization. In engineering, evaluating a design during DSE often consists of running expensive simulations, such as finite element analysis (FEA) in order to understand the structural response to design changes. The computational cost of these simulations can make thorough DSE infeasible, and only a relatively small subset of the designs are explored. Surrogate models have been used to make cheap predictions of certain simulation results. Commonly, these models only predict single values …

Toward A Fast And Accurate Modeling Strategy For Thermal Management In Air-Cooled Data Centers, Long Tran Bao Phan

FIU Electronic Theses and Dissertations

Computational fluid dynamics (CFD) has become a popular tool compared to experimental measurement for thermal management in data centers. However, it is very time-consuming and resource-intensive when used to model large-scale data centers, and may not be ready for real-time thermal monitoring. In this thesis, the two main goals are first to develop rapid flow simulation to reduce the computing time while maintaining good accuracy, and second, to develop a whole building energy simulation (BES) strategy for data center modeling. To achieve this end, hybrid modeling and model training methodologies are investigated for rapid flow simulation, and a multi-zone model …

A Decision-Making Framework For Hybrid Resource Recovery Oriented Wastewater Systems, Nader Rezaei

USF Tampa Graduate Theses and Dissertations

Water shortage, water contamination, and the emerging challenges in sustainable water resources management (e.g., the likely impacts of climate change and population growth) necessitate adopting a reverse logistics approach, which is the process of moving wastewater from its typical final destination back to the water supply chain for reuse purposes. This practice not only reduces the negative impacts of wastewater on the environment, but also provides an alternative to withdrawal from natural water resources, forming a closed-loop water supply chain. However, the design of such a supply chain requires an appropriate sustainability assessment, which simultaneously accounts for economic, environmental, and …

Unmanned Aerial Vehicles (Uavs) For Integrated Access And Backhaul (Iab) Communications In Wireless Cellular Networks, Abdurrahman Fouda

FIU Electronic Theses and Dissertations

An integrated access and backhaul (IAB) network architecture can enable flexible and fast deployment of next-generation cellular networks. However, mutual interference between access and backhaul links, small inter-site distance and spatial dynamics of user distribution pose major challenges in the practical deployment of IAB networks. To tackle these problems, we leverage the flying capabilities of unmanned aerial vehicles (UAVs) as hovering IAB-nodes and propose an interference management algorithm to maximize the overall sum rate of the IAB network. In particular, we jointly optimize the user and base station associations, the downlink power allocations for access and backhaul transmissions, and the …

Structural Optimization Of Cable-Stayed Bridges Considering The Action Of Permanent And Transitory Loads, Carolina Almeida Novaes Dos Santos

Electronic Thesis and Dissertation Repository

Cable-stayed bridges are complex structures with several advantages such as aesthetical appeal, economic use of materials, and efficient construction method. Due to these advantages and the extensive knowledge gained from projects over the years, longer cable-stayed bridges are being constructed. As span lengths increase, structures become more flexible, which makes the accurate evaluation of wind loads critically important in the design of cable-stayed bridges. A large number of variables are involved in the design of cable-stayed bridges. Those include overall geometric dimensions, cross-sectional dimensions, number of stay-cables and pre-tensioning forces to be applied to the cables. Taking all variables into …

Waved: A Coreless Axial Flux Pm Motor For Drive Systems With Constant Power Operation, Narges Taran, Vandana Rallabandi, Dan M. Ionel

Power and Energy Institute of Kentucky Faculty Publications

In this paper, a two-phase coreless AFPM machine with wave winding, 2-stators, and 3-rotors for traction applications is studied. A highly general optimization method, employing 3D FEA as the computational engine is employed. Number of poles in addition to other geometrical variables are included as independent optimization variables. A method for extending the speed range by rotating one of the stator discs with respect to the other at constant power operation is proposed. An inverter configuration including Si and wide band gap devices is proposed to be employed in conjunction with the machine under study. The study includes a comparison …

An Examination Into The Defining Characteristics Of Flexible Solar Aircraft Configurations Through Optimization, Taylor Mcdonnell, Andrew Ning

Faculty Publications

This paper examines the defining characteristics of various solar aircraft configurations through gradient-based multidisciplinary design optimization. We first present a general gradient-based solar aircraft optimization framework which accounts for nonlinear aeroelastic effects resulting from structural flexibility. We then apply this framework to several discrete SR- HALE aircraft geometric, structural, and propulsion system configuration choices to determine the defining characteristics of each configuration choice.