Mechanical Engineering Commons^™

Microstructural Characterization Of Shear Transformation Zones And Modeling Indentation Size Effect In Amorphous Polymers, Leila Malekmotiei

LSU Doctoral Dissertations

The first aim of this work is developing a procedure for experimental and analytical characterization of nano-scale microstructures which mediate large scale deformation in amorphous polymers. Glassy polymers are extensively used as high impact resistant, low density, and clear materials in industries. Nevertheless, their response under severe loading conditions is yet to be appropriately unraveled. Due to the lack of long-range order in the microstructures of glassy solids, their plastic deformation is different from that in crystalline solids. Shear Transformation Zones (STZs) are believed to be the main plasticity carriers in amorphous solids and defined as the localized atomic or …

4-D Printing Of Pressure Sensors And Energy Harvesting Devices For Engineering Education, Tzu-Liang Bill Tseng, Aditya Akundi, Hoejin Kim

Manufacturing & Industrial Engineering Faculty Publications

This paper elaborates on the development of laboratory project modules in the Industrial manufacturing and systems engineering department at The University of Texas El Paso based on Four-Dimensional (4D) printing technology. These modules are aimed at introducing the students to interdisciplinary manufacturing and emerging dimensions in manufacturing technology. 4D printing is a new dimension in additive manufacturing wherein, the 3D printed structures react to the change of parameters within the environment such as temperature, and humidity, resulting in shape change or in functionality such as electricity output, and self-healing. Recently 4D printing of simple devices for pressure sensors application were …

Efficient Adjacency Queries And Dynamic Refinement For Meshfree Methods With Applications To Explicit Fracture Modeling, James Olliff

USF Tampa Graduate Theses and Dissertations

Meshfree methods provide a more practical approach to solving problems involving large deformation and modeling fracture compared to the Finite Element Method (FEM). However meshfree methods are more computationally intensive compared to FEM, which can limit their practicality in engineering. Meshfree methods also lack a clear boundary definition, restricting available visualization techniques. Determining particle locations and attributes such that a consistent approximation is ensured can be challenging in meshfree methods, especially when employing h-refinement. The primary objective of this work is to address the limitations associated with computational efficiency, meshfree domain discretization, and h-refinement, including both placement of particles as …

Design And Testing Of A Passive Prosthetic Ankle Foot Optimized To Mimic An Able-Bodied Gait, Millicent Schlafly

USF Tampa Graduate Theses and Dissertations

Currently there are nearly 2 million people living with limb loss in the United States [1]. Many of these individuals are either transtibial (below knee) or transfemoral (above knee) amputees and require an ankle-foot prosthesis for basic mobility. While there are an abundance of options available for individuals who require an ankle-foot prosthesis, these options fail to mimic an intact ankle when it comes to key evaluation criteria such as range of motion, push-off force, and roll over shape. The roll over shape is created by plotting the center of pressure during a step in a shank-based coordinate system. To …

Experimental, Analytical, And Numerical Evaluation Of The Mechanical Properties Of The Brain Tissue, Aref Samadidooki

LSU Doctoral Dissertations

A true understanding of the mechanisms behind most of the brain diseases is still out of reach. For several years, the interest of scientists has been focused on the genetic and biological causes, however, recent studies unraveled the importance of the biomechanics of the brain growth, folding, impact resistance, and deformation on its pathological conditions. While, a wide range of different methods have been used for characterization of the mechanical properties of the brain at the tissue level, the obtained results from different studies are extremely scattered and sometimes in contrast to one another. Since the brain tissue is extremely …

Vibration-Based Defect Detection For Freight Railcar Tapered-Roller Bearings, Joseph Montalvo, Constantine Tarawneh, Arturo A. Fuentes

Mechanical Engineering Faculty Publications

The railroad industry currently utilizes two wayside detection systems to monitor the health of freight railcar bearings in service: The Trackside Acoustic Detection System (TADS™) and the wayside Hot-Box Detector (HBD). TADS™ uses wayside microphones to detect and alert the conductor of high risk defects. Many defective bearings may never be detected by TADS™ due to the fact that a high risk defect is considered a spall which spans more than 90% of a bearing’s raceway, and there are less than 20 systems in operation throughout the United States and Canada. Much like the TADS™, the HBD is a device …

Developing And Testing An Electronic Homework System To Improve Student Engagement And Learning In Engineering Thermodynamics, Stephen Crown, Constantine Tarawneh, Jazmin Ley

Mechanical Engineering Faculty Publications

An electronic homework delivery system was developed for an advanced undergraduate engineering thermodynamics course due to limitations in available electronic homework systems. A commercially available system was effectively used in the introductory course for simple problems. The complexity of problems in the advanced course made adoption of the same system problematic as students needed feedback in the problem solving process. A system was devised that delivers individual problems to each student, provides feedback throughout the process, and records results for assessment. The system has helped students become more active in homework assignments in both completing assignments and in doing original …

Comparison Of The 6th Edition Florida Building Energy Conservation Code With Iecc 2018 & Ashrae 90.1-2016, Florida Solar Energy Center, Jeffrey Sonne

FSEC Energy Research Center®

This study provides a comparison between the 6th Edition (2017) Florida Building Code, Energy Conservation and 2018 International Energy Conservation Code (IECC), based on approved 2015 to 2018 IECC changes included in the International Code document. And provides a stringency evaluation and cost-benefit analysis for those changes that impact energy use, to provide guidance for the upcoming 2017 to 2020 Florida Energy Code change cycle.

Biomimetic Design And Construction Of A Bipedal Walking Robot, Alexander Gabriel Steele

Dissertations and Theses

Human balance and locomotion control is highly complex and not well understood. To understand how the nervous system controls balance and locomotion works, we test how the body responds to controlled perturbations, the results are analyzed, and control models are developed. However, to recreate this system of control there is a need for a robot with human-like kinematics. Unfortunately, such a robotic testbed does not exist despite the numerous applications such a design would have in mobile robotics, healthcare, and prosthetics.

This thesis presents a robotic testbed model of human lower legs. By using MRI and CT scans, I designed …

Impact Of Hysteresis Heating Of Railroad Bearing Thermoplastic Elastomer Suspension Pad On Railroad Bearing Thermal Management, Oscar O. Rodriguez, Arturo A. Fuentes, Constantine Tarawneh

Mechanical Engineering Faculty Publications

It is a known fact that polymers and all other materials develop hysteresis heating due to the viscoelastic response or internal friction. The hysteresis or phase lag occurs when cyclic loading is applied leading to the dissipation of mechanical energy. The hysteresis heating is induced by the internal heat generation of the material, which occurs at the molecular level as it is being disturbed cyclically. Understanding the hysteresis heating of the railroad bearing elastomer suspension element during operation is essential to predict its dynamic response and structural integrity, as well as to predict the thermal behavior of the railroad bearing …

Defect Prognostics Models For Spall Growth In Railroad Bearing Rolling Elements, Nancy De Los Santos, Constantine Tarawneh, Robert E. Jones, Arturo A. Fuentes

Mechanical Engineering Faculty Publications

Prevention of railroad bearing failures, which may lead to catastrophic derailments, is a central safety concern. Early detection of railway component defects, specifically bearing spalls, will improve overall system reliability by allowing proactive maintenance cycles rather than costly reactive replacement of failing components. A bearing health monitoring system will provide timely detection of flaws. However, absent a well verified model for defect propagation, detection can only be used to trigger an immediate component replacement. The development of such a model requires that the spall growth process be mapped out by accumulating associated signals generated by various size spalls. The addition …

Joining Metallurgically Incompatible Metals, Wei Li, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A method for joining a second alloy material to a first alloy material where the two alloy materials are incompatible, comprising forming three successive interface layers over a substrate comprising the first alloy material, followed by forming a structure of the second alloy material over the interface layers, wherein the composition and deposition method for each of the layers is selected so that brittle intermetallics are not formed between elements of the adjacent layer compositions.

An Analysis Of The Efficacy Of Wayside Hot-Box Detector Data, Constantine Tarawneh, James Aranda, Veronica Hernandez, Claudia J. Ramirez

Mechanical Engineering Faculty Publications

Wayside hot-box detectors (HBDs) are devices that are currently used to monitor bearing, axle, and brake temperatures as a way of assessing railcar component health and to indicate any possible overheating or abnormal operating conditions. Conventional hot-box detectors are set to alarm whenever a bearing is operating at a temperature that is 94.4°C (170°F) above ambient, or when there is a 52.8°C (95°F) temperature difference between two bearings that share an axle. These detectors are placed adjacent to the railway and utilize an infrared sensor in order to obtain temperature measurements. Bearings that trigger HBDs or display temperature trending behavior …

Additive Manufacturing Of A Motorcycle Helmet Utilizing 7-Axis 3d Printing, Kyle Mcmorrow, Caleb Alleva, Luke Correnti, Danny Eckstein, Adam Fontana, Pranav Prabhakar

Mechanical Engineering Senior Theses

This project analyzes the structural properties of 7-axis 3D printing versus traditional FDM printing. The team worked with AREVO Inc to manufacture a motorcycle helmet and test samples made from carbon fiber in a PEEK matrix. A drop-test rig was designed and constructed in-house to test a traditionally printed carbon fiber helmet alongside commercial helmets of identical geometry. The lighter weight printed helmet experienced significantly lower peak deceleration in the test headform (223 G’s versus 371 G’s for average commercial), but fractured along a print layer on impact. Had time allowed for printing of a helmet utilizing AREVOS’s true 3D …

Design Of Metamaterials With Graduating Poisson's Ratio Through Periodic Void Patterns, Xiaoming Liang

Mechanical Engineering Master's Theses

It has been known that when introducing alternating elliptical extrusions in a solid material with a positive Poisson's Ratio, the material's effective Poisson's Ratio can become negative. Furthermore, the change in the effective Poisson's ratio depends on two factors: the elliptical extrusions' aspect ratio and the porosity. Using this phenomenon, a study is conducted by combining elliptical extrusions with different aspect ratios and porosity to construct a composite material with gradually varying Poisson's Ratio. Numerical and physical compression studies are conducted to characterize the material's effective properties. The results show that the material can effectively stabilize its own structure under …

Simulation Of Turbulent Air Jet Impingement For Commercial Cooking Applications, Shantanu S. Shevade

USF Tampa Graduate Theses and Dissertations

The research work in this dissertation focuses on turbulent air jet heat transfer for commercial cooking applications.

As a part of this study, convective heat transfer coefficient and its interdependency with various key parameters is analyzed for single nozzle turbulent jet impingement. Air is used as the working fluid impinging on the flat surface. A thorough investigation of velocity and temperature distributions is performed by varying nozzle velocity and height over diameter ratio (H/D). Nusselt number and Turbulent Energy are presented for the impingement surface. It was found that for H/D ratios ranging between 6 and 8, nozzle velocities over …

Uat Ads-B Data Anomalies And The Effect Of Flight Parameters On Dropout Occurrences, Asma Tabassum, William Semke

Mechanical Engineering Faculty Publications

An analysis of the performance of automatic dependent surveillance-broadcast (ADS-B) data received from the Grand Forks, North Dakota International Airport was carried out in this study. The purpose was to understand the vulnerabilities of the universal access transceiver (UAT) ADS-B system and recognize the effects on present and future air traffic control (ATC) operation. The Federal Aviation Administration (FAA) mandated all the general aviation aircraft to be equipped with ADS-B. The aircraft flying within United States and below the transition altitude (18,000 feet) are more likely to install a UAT ADS-B. At present, unmanned aircraft systems (UAS) and autonomous air …

Formation Control Of Nonholonomic Multi-Agent Systems, Milad Khaledyan

LSU Doctoral Dissertations

This dissertation is concerned with the formation control problem of multiple agents modeled as nonholonomic wheeled mobile robots. Both kinematic and dynamic robot models are considered. Solutions are presented for a class of formation problems that include formation, maneuvering, and flocking. Graph theory and nonlinear systems theory are the key tools used in the design and stability analysis of the proposed control schemes. Simulation and/or experimental results are presented to illustrate the performance of the controllers.

In the first part, we present a leader-follower type solution to the formation maneuvering problem. The solution is based on the graph that models …

Investigation Of Energy Impacts Of Whole-House Ducted Dehumidifier Location, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

This report discusses energy impacts related to how ducted dehumidifier ducts are configured as well as where they are located. Lab controlled testing evaluated three different duct configurations. The three DHU lab test configurations were: 1) DHU air ducted directly from/to room, 2) DHU ducted from/to the central air return duct, and 3) DHU from/to the central air supply duct. Simulation effort evaluated conductive energy gains/losses through dehumidifier and its ducts for 1) conditioned space, 2) attic, and garage locations.

Advanced Stress Analysis, Benjamin Liaw

Open Educational Resources

No abstract provided.

Wind Energy And Wind-Energy-Inspired Turbulent Wakes: Modulation Of Structures, Mechanisms And Flow Regimes, Elizabeth H. Camp

Dissertations and Theses

The interaction of turbulent wakes with one another and with the adjacent fluid directly impacts the generation of electricity in wind turbine arrays. Computational modeling is well suited to the repeated iterations of data generation that may be required to inform understanding of the function of wind farms as well as to develop control schemes for plant function. In order to perform such computational studies, a simplified model of the turbine must be implemented. One of the most computationally efficient parametrizations of the blade utilizes a stationary disk which has a prescribed drag and produces a wake. However, since accurate …

3d Numerical Study Of Multiphase Counter-Current Flow Within A Packed Bed For Post Combustion Carbon Dioxide Capture, Li Yang, Fang Liu, Zhengchang Song, Kunlei Liu, Kozo Saito

Mechanical Engineering Faculty Publications

The hydrodynamics within counter-current flow packed beds is of vital importance to provide insight into the design and operational parameters that may impact reactor and reaction efficiencies in processes used for post combustion CO₂ capture. However, the multiphase counter-current flows in random packing used in these processes are complicated to visualize. Hence, this work aimed at developing a computational fluid dynamics (CFD) model to study more precisely the complex details of flow inside a packed bed. The simulation results clearly demonstrated the development of, and changes in, liquid distributions, wetted areas, and film thickness under various gas and liquid …

Design And Characterization Of Chiral Elastic Metamaterials, Sheng Sang

Theses and Dissertations

Metamaterial are materials engineered to have more than one property that cannot be observed in nature. Commonly, they are made from assemblies of multiple elements fashioned from composite materials such as metals or plastics. Due to its diverse application such as elastic wave cloaking, focusing and absorbing, elastic metamaterial has been the subject of intense experimental research and theoretical work in the past decades. Despite this large-scale effort, designs of the unit cell of the periodic structure for achieving negative elastic moduli are still needed. In this thesis, we first studied the wave phenomenon in lattice structure and materials with …

Implementation Of An Implicit Solver In Adcirc Storm Surge Model, Abdullah Alghamdi, Muhammad K. Akbar

Mechanical and Manufacturing Engineering Faculty Research

The current state of science does not offer any remedy to stop a hurricane from occurring. Therefore, accurate storm surge models capable of predicting water velocity and elevation are indispensable. In this paper, the implementation of an implicit solver in the Advanced Circulation (ADCIRC) storm surge model is presented. The implemented implicit solver uses hybrid finite element and finite volume techniques for solving shallow water equations. Objectives of this research include: Enhancing numerical stability, providing an option of using large timesteps, and the usage of a relatively easier mathematical formulation than the existing one in ADCIRC. The storm surge hindcast …

Factors Influencing Household Solar Adoption In Santiago, Chile, Jeffrey P. Walters, Jessica Kaminsky, Claudio Huepe

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

In Santiago, Chile, the market conditions are seemingly excellent for the household adoption of photovoltaic (PV) technology, yet the uptake is negligible. To explore this paradox, the authors conducted a Delphi study to solicit the knowledge of a panel of Chilean PV experts. These efforts yielded 26 factors—both motivations and barriers—impacting the diffusion of PV in Santiago. Of the 26, experts were in consensus on the relative importance of 21. The literature suggests that diffusion of PV technologies is influenced by complex technical, economic, and social factors. Similarly, the experts saw influence from financial, environmental, and energy supply (e.g., electrical …

Fixing Vertebral Compression Fractures With Medtronic, Kelly Fitzgerald, Trevor Bingham, Alex Denbaugh, Jordan Tang, Jon Stearns

Industrial and Manufacturing Engineering

No abstract provided.

Connected Alerts Across Manufacturing Facilities, Jordan J. Moy

Industrial and Manufacturing Engineering

The lack of communication during a large project can result in costly delays when striving to achieve previously defined benchmarks. Often times, each part of a project will require verification from an employee of a specified area of expertise before being allowed to advance to the next stage. Finding these individuals can be extremely hard due to the large, spread out campus of manufacturing facilities as well as the numerous projects the company is concurrently working on. These floor support requests can sometimes take from an hour to even a whole work day, causing major delays in the production schedule. …

Process Improvement At "The Manse On Marsh", Kevin C. Manko

Industrial and Manufacturing Engineering

The Manse on Marsh is an independent and assisted living facility that prides itself on providing life-enriching care for the elderly. Considering that the staff is essential to supply this care and turnover rates are a constant factor, the company would like to reduce the time it takes to hire new employees by at least one week. To facilitate this goal, process flow maps are utilized to assess the current state of the hiring process and metrics are applied to support future state design decisions. After performing a value added analysis and identifying areas of waste, a total of 20 …

High Bay Capacity Utilization Tool, Dante C. Mazzanti, Skyler L. Schilke, Conner P. Lawston

Industrial and Manufacturing Engineering

Northrop Grumman’s Space Park facility has many inefficiencies in their high bay scheduling processes. Additionally, it is very hard for project managers to figure out the capabilities of each high bay in order to schedule their specific project. The purpose of this project is to develop a tool that can be used across the facility to easily create projects, assign projects, view room capabilities, and view a master schedule of the rooms. After researching commercially available tools, our approach to designing this system was to use tools that are already utilized at the facility (Microsoft Suite and Tableau) and engineer …

Design And Testing Of A Hands-Free Toilet Seat Opener/Closer, Jordan Benjamin Schaeffer

Industrial and Manufacturing Engineering

People tend to get frustrated when the toilet seat must be moved up or down before use. Men and women often leave the toilet seat in different positions when finished which can cause problems when men and women use the same bathroom. With gender neutral bathrooms gaining in popularity, this frustration will only increase. The objective of this project was to design and test a hands-free system to allow a user to quickly and easily open or close a toilet seat. For the product to be viable, it will have to be durable and easy to clean around, while also …