Engineering Commons^™

Investigation Of Composite Patch Performance Under Low-Velocity Impact Loading, Geoffrey Roy Goodmiller

Masters Theses

Bonded fiber composite repair on damaged metal structures can be an effective method to restore load carrying capacity or increase damage resistance. Low velocity impacts can cause barely visible damage to the interior structure of laminated composites. Delamination between plies is of particular concern in these composites. Impacts may also create disbonds between the patch and metal substrate. A building-block approach was suggested to model impact damage to composite patches. Composite, adhesive, and metal substrate damage models were separately validated and then combined. Cohesive Zone theory modeled interlaminar composite damage and adhesive damage. Hashin failure criteria with energy dissipation based …

A Framework To Predict High Risk Roadways For Pedestrians In Tennessee, Zane Hunter Pannell

Masters Theses

Pedestrians and bicyclists are a class of vulnerable road users that are often over-represented in incapacitating injury or fatal crash statistics. Because non-motorized trips are vital to many urban and rural residents for utility or recreation and exercise, it is essential to identify safety deficiencies in our existing transportation infrastructure to address rising injuries and fatalities among this group of road users. As the economy continues to struggle and fuel prices remain high, many cities and rural transportation agencies are seeing large increases in bicycling, walking, and transit ridership. While passenger car fatalities have shown sharp declines in the last …

An Automated Finite Element Analysis Framework For The Probabilistic Evaluation Of Composite Lamina Properties, Jonathan Phillips Weigand

Masters Theses

This thesis outlines the development of computational modeling tools used to predict the elastic properties of composite lamina from representative volume elements (RVE) using numerical methods. The homogenization approach involves the use of Gauss’s Theorem to simply the average volumetric strain integral into a surface integral containing which is defined by surface displacements and their direction. Simulations of RVEs under specific loading conditions (longitudinal tension or shear and transverse tension or shear) are then performed in the software package ABAQUS to obtain the surface displacements. It was found that obtaining quality meshes and applying periodic boundary conditions for each RVE …

Driver Behavior At Railway-Highway Grade Crossings With Passive Traffic Control: A Driving Simulator Study, Bryan Andre Bartnik

Masters Theses

Research to evaluate driver behavior at railway-highway grade crossings with passive traffic control attempts to find an answer to a much debated subject. This study examines the difference in driver behavior and safety at several different types of passive traffic control at grade crossings utilizing a driving simulator. This project utilized the University of Tennessee’s high fidelity driving simulator to perform a study on passive highway-railway grade crossings. Although the crash rates at grade crossings have decreased in recent years, there is still more work to be done. Safety improvements can be made to both passive and active grade crossings. …

Strength And Deformation Of “Tunable” Clay-Polymer Composites, Matthew David Bishop

Masters Theses

There are many different types of clay that exist throughout the world, and many are characterized by undesirable engineering properties. Soil improvement techniques are often implemented on these soils such as solidification, reinforcement, etc. However, these solutions are a “static” approach, as the soil’s properties cannot be modified over time. The development of the specific clay-polymer composites used in this study was motivated by the idea of creating a geomaterial that could be modified over time by adjusting its fabric, namely in the form of controlling interparticle and interlayer spacings. Therefore, the composites that are used in this study are …

Linkage Between Characteristics Of Premise Plumbing Systems And Microbial Quality Of Stagnant Drinking Water, Joshua Thomas Frerichs

Masters Theses

The length of pipe between the water main and the point of use (POU), known as premise plumbing, has a direct impact on public health. However, relatively little is known about factors that affect the microbial quality in premise plumbing. Although microbial quality typically degrades during stagnation, little research is present linking factors such as building age and level of usage to the extent to which stagnation occurs.

To gain insight into the effect of premise plumbing service age on the level of microbial contamination in stagnant drinking water, water at the POU was analyzed. It was observed with statistical …

Solid Waste Reduction Practices In The Southeastern United States: Public Perceptions And Proposed Policy Changes, Lauren Ashley Raup-Plummer

Masters Theses

The U.S. Environmental Protection Agency (EPA) has highlighted the municipal solid waste stream as an area of critical interest due to the non-sustainable nature of existing landfilling or “dumping” practices. In addition to traditionally defined municipal solid waste – commonly referred to as garbage or rubbish – materials such as biosolids, a by-product of wastewater treatment, and animal manure also comprise the landfilled waste stream. Currently, disposal options for biosolids waste materials are limited due to regulations imposed by the EPA to protect waterways and coastal environments, and one of the few alternatives for biosolids disposal is land application. Unfortunately, …