Engineering Science and Materials Commons^™

Compression Testing And Failure Modes Of Steel-Concrete Composite (Sc) Structures For Nuclear Containment, Patrick Michael Wanamaker, Amit H. Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Although being able to provide much cleaner power than burning coal and other fossil fuels, nuclear power plants are still a tough sell to the general public due to their history of being spontaneously dangerous. The containment structures surrounding these nuclear plants, however, can play a huge role in reducing the risks associated with them. Relatively new designs for these containment assemblies, known as SC (steel-concrete composite) structures, aim to increase the strength and durability of the containment facilities while keeping costs down. By varying the spacing between shear studs, the ratio of concrete to steel, and the ratio of …

Fatigue Testing And Data Analysis Of Welded Steel Cruciform Joints, Alina Shrestha

LSU New Orleans Theses and Dissertations

In this study, ABS Publication 115, “Guidance on Fatigue Assessment of Offshore Structures” is briefly reviewed. Emphasis is on the S-N curves based fatigue assessment approach of non-tubular joints, and both size and environment effects are also considered. Further, fatigue tests are performed to study the fatigue strength of load-carrying and non-load-carrying steel cruciform joints that represent typical joint types in marine structures. The experimental results are then compared against ABS fatigue assessment methods, based on nominal stress approach, which demonstrates a need for better fatigue evaluation parameter. A good fatigue parameter by definition should be consistent and should correlate …

College Of Engineering Senior Design Competition Spring 2013, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Senior Design Experience

Part of every UNLV engineering student's academic experience, the Senior Design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs and prototypes a product in this required element of the curriculum. Working in teams, the senior design project encourages students to use everything learned in the engineering and computer design programs to create a practical, real world solution to an engineering challenge.

Beyond the classroom ...

Because of the requirement to work in teams, students also build good communication skills, presentation skills and even business writing skills. They also have to …

Creep, Fatigue And Creep-Fatigue Interactions In Modified 9% Cr - 1% Mo (P91) Steels, Valliappa Kalyanasundaram

Graduate Theses and Dissertations

Grade P91 steel, from the class of advanced high-chrome ferritic steels, is one of the preferred materials for many elevated temperature structural components. Creep-fatigue (C-F) interactions, along with oxidation, can accelerate the kinetics of damage accumulation and consequently reduce such components' life. Hence, reliable C-F test data is required for meticulous consideration of C-F interactions and oxidation, which in turn is vital for sound design practices. It is also imperative to develop analytical constitutive models that can simulate and predict material response under various long-term in-service conditions using experimental data from short-term laboratory experiments. Consequently, the major objectives of the …

Energy, U.S. Department Of, Bert Chapman

Libraries Faculty and Staff Scholarship and Research

Provides information about the U.S. Department of Energy (DOE) and its predecessor agencies and how DOE influences federal energy policy and scientific research in the western U.S.

Plastic Deformation Of Astm A36 Steel Using Two-Stage Light Gas Gun, Shawoon Kumar Roy

College of Engineering: Graduate Celebration Programs

To characterize material deformation in high velocity impact. To validate material models for computation simulation purposes.

This ongoing research is an attempt to study the plastic deformation of A36 steel plate (0.5” thick) under hypervelocity impact. Plastic deformation of the target plate was simulated using finite element software LS-DYNA.

Starch Resin Moisture Level Effect On Injection Molding Processability And Molded Part Mechanical Properties With Pure Starch Resin And Polymer Blends, Jordan M. Ellingson

Theses and Dissertations

The current and forecasted global consumption of plastic packaging and products through the 21st century combined with the already reported and growing negative impact of plastics on the environment due to plastics being synthesized from nonrenewable resources that do not biodegrade is of serious concern. However, recent advances in starch technology including the development of thermoplastic starch (TPS) materials —polymers that are both renewable and biodegradable—have brought hope to reducing this impact. The mechanical properties of thermoplastic starch have often been improved by blending with synthetic polymers. One issue that arises with blending is volatilization of the melt from moisture …

Experimental Comparison Study Of The Response Of Polycarbonate And Laminated Glass Blast Resistant Glazing Systems To Blast Loading, Joshua Calnan

Theses and Dissertations--Mining Engineering

This thesis recounts the experimental study of the dynamic response of polycarbonate blast resistant glazing systems to explosive loading through the use of triaxial load cells, pressure sensors, and a laser displacement gauge. This instrumentation captured the response of the glazing systems to blast loading over three phases of testing. The first phase of testing characterizes the load distribution around the perimeter and the second phase examines the repeatability of the results. The final phase of testing pushes the samples to failure. The results are then compared to HazL, a commonly used blast resistant glazing system analysis software tool. The …

Experimental Study On The Fabrication Of Advanced Materials For Energy Applications Using High Energy Mechanical Milling, Ashvin Kumar Narayana Swamy

Open Access Theses & Dissertations

The reaction of aluminum (Al) powder with water has the potential for on demand hydrogen generation. Conventional Al powders, however, react with water slowly due to a highly protective oxide layer on the particle surface. Current methods for Al activation involve harmful and expensive materials. The nano-scale Al powders also remain very expensive and have problems such as a large amount of oxide on the surface. The use of aluminum in an energy generation cycle is also hindered by the fact that, although Al is the most abundant metal in the Earth's crust, its recovery from ore consumes a lot …

Elastic–Plastic Analysis And Strength Evaluation Of Adhesive Joints In Wind Turbine Blades, Yi Hua, Ananth Ram Mahanth Kasavajhala, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

The objective of this paper is to investigate the performance of adhesive joints of carbon/epoxy wind turbine blade subjected to combined bending and tension loadings through finite element method. The influence of adhesive material properties and geometrical details including fillet and imperfections was examined in terms of interlaminar stresses in the adhesive layer. The variation of stress intensity with change in adhesive shear modulus has also been investigated, while contour integral method was used for evaluating the stress intensity factors (SIF) at the imperfection tip. Furthermore, the strength of the joint was assessed through the crack initiation and propagation analysis. …

Biaxial Bending And Lateral-Torsional Instability Of Imperfect Frp I-Beams Including Effects Of Retrofitting, Jodi Marie Knorowski

Civil & Environmental Engineering Theses & Dissertations

This thesis presents the outcome of a theoretical and experimental study of the behavior of Fiber Reinforced Polymer (FRP) I-beams susceptible to lateral-torsional instability or when subjected to biaxial bending. Laboratory experiments involved application of vertical and horizontal static loads to a 4 x 4 x ¼ in. I-beam with various lengths, and the resulting displacement, twist, and strain were recorded. In the vertical direction, the beam was loaded from different reference load heights with respect to the shear center of the beam. The governing biaxial flexure and torsion differential equations were modified to account for the presence of initial …

Steering Adaptation In A Driving Simulator, Brian P. Moran

Undergraduate Research Posters 2012

Steering adaptation in a driving simulator occurs when participants, who possess the skills necessary to control a vehicle, modify their use of the steering controls to successfully interact with a driving simulator. This approach is sensitive to individual driving styles, as it is free of any threshold, criterion, or benchmark value and can be applied to any steering task at any driving speed.

Correlation Of Shear Strength Between Longitudial And Transverse Specimens, Erasto A. Fernandez

LSU New Orleans Theses and Dissertations

In this thesis, new methods for shear strength are proposed and backed up through extensive experimentation, ABAQUS models and data analysis of Titanium welds of three different alloys. The results are compared with those obtained by using the procedure outlined by AWS B4 for calculating Shear Strength in the transverse and longitudinal directions; this equation is widely used by the American Welding Society (AWS) and all those in search of more efficient designs involving welding.

It is a well-documented issue that the equation provided by AWS yields a large discrepancy between the values for shear strength of longitudinal and transverse …

Laboratory And Field Evaluation Of Two Warm-Mix Additives In Connecticut And Validation Of An Alternative Moisture Susceptibility Test, Alexander K. Bernier

Master's Theses

The first official state Warm-Mix Asphalt (WMA) pavement project in Connecticut was constructed between July 20th and 22nd, 2010 and it involved three experimental sections, i.e. one section with a conventional HMA (control section) and two WMA sections with different technologies, wax and foamed asphalt. All three sections are located on Route 70 in central Connecticut. The materials were collected in loose form and reheated and compacted in laboratory conditions (laboratory fabricated specimens). This paper discusses the effect of mix type on the results from several tests conducted in the laboratory, such as Semi-Circular Bending, Hamburg Wheel Tracking, Indirect Tensile, …

Environmental Value Engineering (Eve) Comparison Of A Usgbc Leadership In Energy And Environmental Design (Leed) Window System And Non-Leed Window System, Simon A. Adamtey

Master of Technology Management Plan II Graduate Projects

ABSTRACT

The need to explore environmentally friendly materials to avoid the depletion of the nonrenewable resources is very significant. The human race has been heavily dependent on nonrenewable resources since the industrial revolution. The rate of consumption of these resources is higher than the rate at which these resources replenish themselves since it has been established that most of these resources take millions of years to replenish. A critical look into the future reveals that there is a looming resource crisis since these resources are being depleted.

Fossil fuel combustion is linked to the increase in CO₂ in the …

Development Of A Structured Concrete Thermocline Thermal Energy Storage System, Bradley M. Brown

Graduate Theses and Dissertations

The past couple of decades have shown a concern when considering the way the world obtains its power. The focus has been switching from fossil fuels that have been used for hundreds of years to renewable energy sources, such as the sun. Solar energy is readily and infinitely available for harnessing. One problem with solar energy, though, is its inability to be used during the night time and during cloud covered weather. A solution to this problem is the use of energy storage mechanisms. For solar plants that use solar thermal energy (concentrating solar power plants), thermal energy storage (TES) …

Friction Bit Joining Of 5754 Aluminum To Dp980 Ultra-High Strength Steel: A Feasibility Study, Britney Weickum

Theses and Dissertations

In this study, the dissimilar metals 5754 aluminum and DP980 ultra-high strength steel were joined using the friction bit joining (FBJ) process. The friction bits were made using one of three steels: 4140, 4340, or H13. Experiments were performed in lap shear, T-peel, and cross tension configurations, with the 0.070" thick 5754 aluminum alloy as the top layer through which the friction bit cut, and the 0.065" thick DP980 as the bottom layer to which the friction bit welded. All experiments were performed using a computer controlled welding machine that was purpose-built and provided by MegaStir Technologies. Through a series …

A Study On Facility Planning Using Discrete Event Simulation: Case Study Of A Grain Delivery Terminal, Sarah M. Asio

Department of Industrial and Management Systems Engineering: Dissertations, Theses, and Student Research

The application of traditional approaches to the design of efficient facilities can be tedious and time consuming when uncertainty and a number of constraints exist. Queuing models and mathematical programming techniques are not able to capture the complex interaction between resources, the environment and space constraints for dynamic stochastic processes. In the following study discrete event simulation is applied to the facility planning process for a grain delivery terminal. The discrete event simulation approach has been applied to studies such as capacity planning and facility layout for a gasoline station and evaluating the resource requirements for a manufacturing facility. To …

Identifying Changes In Climatic Trends And The Fingerprints Of Landuse And Landcover Changes In The High Plains Of The Usa, Denis Mutiibwa

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Human activities such as conversion of natural ecosystem to croplands and urban-centers, deforestation and afforestation impact biophysical properties of land surface such as albedo, energy balance, and surface roughness. Alterations in these properties affect the heat and moisture exchanges between the land surface and atmospheric boundary layer. The objectives of this research were; (i) to quantitatively identify the High plains’ regional climate change in temperatures over the period 1895 to 2006, (ii) detect the signatures of anthropogenic forcing of LULC changes on the regional climate change of the High Plains, and (iii) examine the trends in evolving regional latent heat …

The Effects Of Damage Arrestment Devices In Composite Plate Sandwiches With Fastener Holes, Mark Anderson, Nancy Hung Choy, Lacey Jones, Rita Kourskaya

Aerospace Engineering

Composite materials such as a carbon fiber are used in a variety of new technologies including aircraft, spacecraft, and motor vehicles. Carbon fiber has a high strength to weight ratio, a key advantage over other material options. This report discusses the use of composite damage arrestment devices (DADs) in composite sandwich panels with a foam core. There are three different curing cycles tested for the DADs: pressure only, vacuum only, and vacuum with 1000 lbs of pressure. Using a Tetrahedron Heat Press to cure the composite specimen and an Instron Machine to perform tensile testing, data was collected for each …

Tool Life Of Various Tool Materials When Friction Spot Welding Dp980 Steel, Christopher Shane Ridges

Theses and Dissertations

In this study, friction spot welding was used to join DP980 steel sheet. Four different ultra-hard tool materials were used with the objective of determining which tool material produced the highest number of acceptable-strength welds. Three of the tools were composed of various mixtures of polycrystalline cubic Boron Nitride (PCBN), Tungsten, and Rhenium. These materials are referred to herein as Q60, Q70, and Q80, the "Qxx" designation denoting the percentage of the volume of the tool material composed of PCBN. The fourth tool tested was composed entirely of PCBN. The Q70 tool produced approximately 1100 welds of acceptable strength before …

An Experimental Investigation Of Friction Bit Joining In Az31 Magnesium And Advanced High-Strength Automotive Sheet Steel, Rebecca Gardner

Theses and Dissertations

Friction Bit Joining (FBJ) is a recently developed spot joining technology capable of joining dissimilar metals. A consumable bit cuts through the upper layer of metal to be joined, then friction welds to the lower layer. The bit then snaps off, leaving a flange. This research focuses on FBJ using DP980 or DP590 steel as the lower layer, AZ31 magnesium alloy as the top layer, and 4140 or 4130 steel as the bit material. In order to determine optimal settings for the magnesium/steel joints, experimentation was performed using a purpose-built computer controlled welding machine, varying factors such as rotational speeds, …

Natural Fibers And Fiberglass: A Technical And Economic Comparison, Justin Andrew Zsiros

Theses and Dissertations

Natural fibers have received attention in recent years because of their minimal environmental impact, reasonably good properties, and low cost. There is a wide variety of natural fibers suitable for composite applications, the most common of which is flax. Flax has advantages in tensile strength, light weight, and low cost over other natural fibers. As with other natural and synthetic fibers, flax is used to reinforce both thermoset and thermoplastic matrices. When flax is used in thermoplastic matrices, polypropylene and polyethylene are the main resins used. Although at first glance flax may seem to be a cheaper alternative to fiberglass, …

Processing A Nickel Nanostrand And Nickel Coated Carbon Fiber Filled Conductive Polyethylene By Injection Molding, David Anthony Whitworth

Theses and Dissertations

A new method for pre-impregnating nickel coated carbon fiber with a thermoplastic polymer to make towpreg, similar to a recently developed coating-line by João P. Nunes et al and a new electrically conductive thermoplastic are developed. A melted bath was used to help mitigate health concerns and waste for dispersion of nickel coated carbon fibers (NCF) in low density polyethylene (LDPE). This towpreg was then mixed with more LDPE or a mixture of LDPE and nickel nanostrands (NiNS) to a desired filler volume fraction to test the electrical conductivity of the composite. Some of these mixtures were then injection molded …

Studies Of Dynamic Crack Propagation And Crack Branching With Peridynamics, Youn Doh Ha, Florin Bobaru

Department of Engineering Mechanics: Faculty Publications

In this paper we discuss the peridynamic analysis of dynamic crack branching in brittle materials and show results of convergence studies under uniform grid refinement (m-convergence) and under decreasing the peridynamic horizon (δ-convergence). Comparisons with experimentally obtained values are made for the crack-tip propagation speed with three different peridynamic horizons.We also analyze the influence of the particular shape of themicro-modulus function and of different materials (Duran 50 glass and soda-lime glass) on the crack propagation behavior. We show that the peridynamic solution for this problem captures all the main features, observed experimentally, of dynamic crack propagation and branching, as well …

College Of Engineering Senior Design Competition Fall 2009, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Each student in his or her senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. The senior design project encourages the student to use everything learned in the engineering program to create a practical, real-world solution to an engineering challenge.

A highlight of the year-long senior design project is the senior design competition. This competition, which usually takes place the week before finals each semester, helps focus the senior students on increasing the quality and potential for commercial application for their design projects.

Judges from local industry evaluate the projects on innovation, commercial …

Assessing Repeatability Of Four-Point Bending Method For Estimating Fatigue Cracking Of Hot Mix Asphalt, Sara -. Montazeri

Open Access Theses & Dissertations

The objective of this thesis was to assess the repeatability of four-point bending method for estimating fatigue cracking of hot mix asphalt. This experimental research examined the influence of mix proportions, specifically asphalt and air void contents, on fatigue behavior of asphalt beam specimens in the laboratory tested with four-point bending method of loading. Following the relevant specifications, the strain-controlled mode of loading was selected. Fatigue failure is expected to occur at the cycle which the flexural stiffness of asphalt specimen reduced to 50% of initial amount. Up to a 1,000,000 cycles of loading were applied to each specimen.

Different …

Effects Of Aggregates On Properties And Performance Of Mastics And Superpave Hot Mix Asphalt Mixtures, Francisco Aragão

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

Superpave, a set of advancements in testing devices and specifications for asphalt binders and mixtures, was limited to address the effects of aggregates. Because aggregates represent around 95% in mass of the asphalt mixtures, it is important to understand how these materials affect properties and performance of such mixtures. This research focus on how different types and contents of aggregates affect properties of mastics and asphalt mixtures, and their performance considering the viscoelastic nature of the asphalt material.

Five different types of aggregates and hydrated lime were used for sample fabrication together with two different binders. Several different tests were …

College Of Engineering Senior Design Competition Spring 2007, University Of Nevada, Las Vegas

Fred and Harriet Cox Senior Design Competition Projects

Part of every UNLV engineering student’s academic experience, the senior design project stimulates engineering innovation and entrepreneurship. Each student in their senior year chooses, plans, designs, and prototypes a product in this required element of the curriculum. A capstone to the student’s educational career, the senior design project encourages the student to use everything learned in the engineering program to create a practical, real world solution to an engineering challenge.

The senior design competition helps to focus the senior students in increasing the quality and potential for commercial application for their design projects. Judges from local industry evaluate the projects …

Socio-Economic Impacts Of Computer Viruses In Tanzania, M Victor

Tanzania Journal of Engineering and Technology (TJET)

This paper reports on a research project conducted with an objective of identifying and assessing various approaches used by different computer users (Management, System Administrators and end users) in Tanzania to combat computer viruses (CVs), and to assess users' awareness level on CVs. Specifically, the study aimed at assessing the awareness level on CVs to the Tanzanian business community; analyze the socio -economic impact caused by CVs in Tanzania and; assess existing methods, capacity and limitations on controlling CVs in Tanzania. Data was collected using both questionnaires and interview from financial institutions such as NBC and BOT, and telecommunications sector …