Engineering Commons^™

Laboratory Measurements At The Impact Point Of A Falling Jet, Garrett Richins

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Dams and spillways play a vital role in managing water resources. Many of these hydraulic structures feature a falling jet when discharging downstream. Engineers design plunge pools to receive jets with enough water depth or a protective liner to protect the river bottom so that scour is avoided. Quantifying the pressures at the bottom of the falling jet is a key component to determining the potential for scour and the need for mitigation techniques.

In the laboratory setting, significant discrepancies have been observed between different measurement methods to measure mean and fluctuating pressures of a falling jet intercepting a solid …

Drop Impact On Dry And Liquid Infused Substrates With Micro-Wells., Ahmed Nazrul Islam

Electronic Theses and Dissertations

Drop impact on different types of surfaces are important physical concepts that are routinely found in day-to-day life and such studies have immense application for various types of industries. One such important application of drop dynamics is in the field of aviation science which is concerned of very large freezing drizzle drops impacting on airplane wings. Such drops are known as supercooled large droplets (SLD), and they pose a great risk and have been long known to have caused notable accidents in the past. SLDs are liquid drops that can remain in the state of liquid phase and grow into …

Correlation Of And Development Of Procedure To Use A Resonant Plate With Mechanical Excitation For Shock Testing Small-To-Medium Size Spacecraft And Provide Aerospace Shock Analysis And Testing Guidelines, Monty Kennedy

Dissertations, Master's Theses and Master's Reports

In the aerospace industry it is known that performing shock analysis and testing on spacecraft is difficult to do mostly because shock loads create a very short duration shock wave transient that can have high acceleration peak levels (1,000-5,000 g) and wide frequency content (100-10,000 Hz). FE (finite-element) shock analysis is difficult because implicit linear FE software commonly used for most vibration analysis in aerospace does not account for shock wave propagation, reflection, and attenuation that occurs based upon the distance from the shock source at the base of the spacecraft and the attenuations that occurs through mechanical joints. Spacecraft …

Experimental Investigations Of Yarn Pull-Out Behavior In Kevlar®: Influence Of Applied Metallic Coatings And Effect Of Dynamic Loading, Julie Ann Roark

Theses and Dissertations

Flexible woven Kevlar® textile fabrics are widely used in protective armor applications. Yarn pull-out, comprised of yarn uncrimping (i.e., straightening) and yarn translation, is a major energy absorption mechanism during ballistic impact onto these fabrics, especially for impact velocities below the ballistic limit. Yarn pull-out is influenced by various parameters including inter-yarn friction, pull-out distance, pull-out velocity, transverse pre-tension, fiber diameter, fabric architecture, fabric waviness, fabric count and yarn modulus.

The first part of this thesis investigates yarn pull-out behavior of commercially available Kevlar® KM2+ individual yarns coated with metallic layers (copper, aluminum, aluminum nitride, silver) via a directed vapor …

The Development And Analysis Of Methods Used To Evaluate American Football Facemasks, Alexander Bina

All Dissertations

The motivation for this Ph.D. dissertation is to provide football equipment managers, coaches, parents, athletes, and relevant industry personnel with an understanding of the implication a chosen football facemask design will have on the safety of the athlete. As athletes have increased their capacity for speed, size, and strength, so too has the head injury risk increased in American football. To align with the increase in head impact injury in American football, the protective head impact community must expand its capacity to evaluate protective equipment systems. This dissertation focuses specifically on one helmet system component: the football facemask. This dissertation …

Inhomogeneous Composite Design For High Energy Impact Resistance Through Computational Design, Physical Testing And Analysis, And Mathematical Modeling, Trenin Bayless

Graduate Theses & Non-Theses

Research in the development of impact resistant materials has been an expanding field for the better part of a hundred years. The development of a light penetration resistant and man-portable system that can resist extreme quantities of kinetic energy has been a subject of substantial study. In particular, the use of composite materials, polymers, ceramics, and metals has been critical to the development of the field. With the advent of complex computational programs for defining material properties, it has become possible to use simulations as a starting point for the development of next generation armored systems. To that end, it …

Development Of Hybrid Ultra-High Performance Concrete Thermoplastic Composite Panels For Blast And Ballistic Protection, Alyssa M. Libby

Electronic Theses and Dissertations

In recent years, ultra-high performance concrete (UHPC) has become a material of interest for structures needing resistance to impact and blast loadings. These types of loadings have induced brittle flexural failure in UHPC due to punching shear from the impactor. One way to improve the impact resistance, energy absorption, and ductility of UHPC is by adding fiber-reinforced polymer (FRP) skins to the front and rear faces of the concrete, resulting in a sandwich configuration. In this study, E-glass fiber-reinforced thermoplastic laminates were bonded to UHPC panels using a heated consolidation process known as stamp thermoforming. The bond between the UHPC …

Projectile Generator Design For Underground Coal Mine Seal Testing, Ethan Allan Steward

Masters Theses

"Underground coal mines have several dangers, one of the most hazardous of which is the possibility of an explosion caused by the ignition of methane gas. To reduce ventilation costs, coal mines have the option to close off abandoned areas that are no longer active with structural seals to keep an explosion from propagating into working areas of the mine. Though seals have been designed to resist the overpressure, none have been evaluated for their resistance to the impact of heavy objects. Underground explosions produce high velocity gasses that, traveling through mine openings, may propel objects in the mine at …

A Post-Impact Behavior Of Platelet-Based Composites Produced By Compression Molding, Christopher Eugene Ervin Volle

Mechanical & Aerospace Engineering Theses & Dissertations

Prepreg-based Platelet Molded Compounds (PPMCs) are quickly becoming a widely used method for creating structural components in the aerospace and automotive industries. The discontinuous nature of the platelets used allow good formability of both complex and basic structural components; from seats on commercial airplanes to outer panels of vehicles.

This thesis will look at an important research question of these composites: how PPMCs behave under dynamic loading, e.g. impact and post-impact behavior. Impact is analyzed using recorded force and velocity data to find the absorbed energy. Digital image correlation is used with compression after impact testing to study the propagation …

Peridynamic Approaches For Damage Prediction In Carbon Fiber And Carbon Nanotube Yarn Reinforced Polymer Composites, Forrest E. Baber

Theses and Dissertations

Aerospace structures are increasingly utilizing advanced composites because of their high specific modulus and specific strength. While the introduction of these material systems can dramatically decrease weight, they pose unique certification challenges, often requiring extensive experimental testing in each stage of the design cycle. The expensive and time-consuming nature of experimental testing necessitates the advancement of simulation methodologies to both aid in the certification process and assist in the exploration of the microstructure design space.

Peridynamic (PD) theory, originating from Sandia National Lab’s in the early 2000’s, is a nonlocal continuum-based method that reformulates the equation of motion into an …

Impact Of Increased Precipitation On Midwestern Construction, Monica Feltman

Williams Honors College, Honors Research Projects

This paper presents the current impact of increased precipitation in the Midwest on the construction industry. Mainly, the impact on jobsite safety, increasing insurance rates, and the resulting changes in design codes, or lack thereof. The goal of this independent research is to gather a better understanding of the influence of these changes, because only then can one accurately seek to combat their harmful effects. As a vital element of the global economy, the construction industry must be conscious of their changing relationship with the environment around them. Therefore, understanding the affects of harmful climate change, will increase awareness of …

Formulación De Alternativas Sostenibles Para El Sector Viverista De La Sabana De Bogotá Registrado Ante El Ica, Rosa Alexandra Martínez Simbaqueva, Mateo Palacios Hermann

Ingeniería Ambiental y Sanitaria

El proyecto se desarrolló específicamente en cinco empresas del sector de plantas ornamentales en Bogotá D.C., inicialmente se había propuesto el trabajo en once empresas representativas del sector, siendo estas: Cid Ambientes Naturales, Garden Center, David Plantas, El Otoño, Jardines Tropicales, Las Palmas Y Jardines De Manuel, Orquídeas Del Llano, Paisajismo Y Diseño S.A.S, Pérez Plantas, Plantaciones Moreno y Platicelo. Cada una de esta cuenta con un registro vigente frente al Instituto Colombiano Agropecuario (ICA), pero debido a restricciones de las empresas o fallos de actualización de la base de datos, los participantes fueron limitados a cinco empresas. Las fases …

Damage Resistance And Tolerance Of 3d Woven Composites, Justin T. Mcdermott

Electronic Theses and Dissertations

Composite materials have been adopted into primary aircraft structures by virtue of their great strength-to-weight and stiffness-to-weight ratios, fatigue insensitivity, and corrosion resistance. These characteristics are leveraged by aircraft designers to deliver improved fuel effciency and reduced scheduled maintenance burdens for their customers. These benefits have been impressively realized in the Boeing 787 and Airbus A350 XWB, with airframes utilizing about 50% composites by weight. Tempering these successes, however, are the inherent vulnerabilities of carbon-fiber reinforced composites. When compared to conventional metallic structure, composite laminates are more sensitive to stress concentrations at mechanical fastenings and damage due to low-velocity impact. …

Extreme Dynamics Of Nanomaterials Under High-Rate Mechanical Stimuli, Wanting Xie

Doctoral Dissertations

Nanomaterials demonstrate novel mechanical properties attributed to the extremely large interfacial area. At quasi-static rates, the interfacial interactions are crucial in mechanical behaviors, however, materials under extreme mechanical stimuli are rarely studied at nanoscale. With an advanced laser-induced projectile impact test, we perform supersonic impact of micro-projectiles on polymer films, multilayer graphene, carbon- based nanocomposites membranes as well as individual micro-fibers, to study the interface interactions in the high-rate regime, and develop a simplified model to characterize the ballistic performance of materials.

Custom Foot Prosthetic: Diabetic Care, Chandler Streuli

All Undergraduate Projects

Across the United States there are people every day who lose their toes to diabetes or to loss of circulation within their legs. The problem becomes building a more cost effective and efficient prosthetic for these individuals. The prosthetics that are used for medical purposes are often costly, especially without the help of insurance. The new prosthetic was designed to be taken in and out of shoes so that it is fast and easy for the user to move the device from shoe to shoe. The manufacturing method for this project was using a 3D printer to build the initial …

Propuesta Para La Formulación De Las Directrices Para El Plan De Gestión Integral De Residuos Peligrosos, En La Industria Metalmecánica, Caso De Estudio Empresas Dobladora Carvajal Ltda Y Metal Tree Sas, Andrés Felipe Arismendy Vargas, Ángela Viviana Moreno Álzate

Ingeniería Ambiental y Sanitaria

El desarrollo tecnológico y los avances en los procesos para la fabricación de productos semielaborados y bienes de consumo de la industria metalmecánica han provocado un incremento en la generación de residuos peligrosos por parte de las industrias pertenecientes a este subsector, debido a que dichos residuos suelen ser mezclados con los residuos ordinarios, dificultando de esta manera su posible aprovechamiento y de igual manera su correcto tratamiento y disposición. La industria colombiana perteneciente a este subsector no cuenta con un debido seguimiento para realizar de forma correcta y estricta el manejo de este tipo residuos, que manifieste los principios …

Projectile Impact Effects On A 50 Psi Plug Type Coal Mine Seal, Bruce Albert Von Niederhäusern

Masters Theses

"The current lack of projectile damage criteria for mine seals is assessed to determine if criteria should be developed. Impact experiments were performed on a full-scale 50 psi mine seal to determine failure modes, dynamic stress state, and assess risk to existing operational mine seals. Test projectiles were selected from common underground coal mine items propelled by means of a black powder projectile generator. Projectile velocities attained in testing ranged from approximately 100 to 650 ft/s (30 to 200 m/s). Dynamic strain was measured on the non-impact face to derive the state of stress and estimate failure criteria. Penetration models …

Test Method For Predicting Failure Modes In Protective Films, Aubrey Jeanette Decker

Theses and Dissertations

In the business of packaging engineering, a large consumption of time is placed on evaluating new materials to provide cost savings to a company. This evaluation is made by using test methods such as those found in ASTM D4169-16, which helps to simulate shipping and distribution conditions. A key problem is that this test method can take up to multiple months, and sometimes years to complete. The apparatus created in this study allows for a comparison to be made between currently used films and prospective films in approximately ten hours. This allows for a prescreening of new films to be …

Carbon Sequestering Bio Concrete As A Solution To Growing Atmospheric Concentrations Of Co2, Connor Cech, Jackson Walker

Construction Management

High levels of anthropogenic carbon dioxide (CO₂) emissions into the atmosphere are propelling climate change, which has been proven to be highly detrimental to the planet. Cement production for the construction industry is a leading cause of these harmful carbon emissions. This project introduces a potential solution to this issue in the form of a new biological concrete that is treated with carbon sequestering bacteria of the Bacillus family to remove CO₂ from the atmosphere. The consolidated research presented in this project will explain the biology behind this process, and how it can be implemented in construction …

Universal Studios Hollywood Vip Trolley - Roller Frame, Jeffrey Ploss, Chase Montague, Lincoln Treanor

Mechanical Engineering

Statement of Confidentiality: The complete senior project report was submitted to the project advisor and sponsor. The results of this project are of a confidential nature and will not be published at this time.

Wastewater Refining And Reuse And City-Level Water Decision Making, Ahmed Abuhussein

Electronic Thesis and Dissertation Repository

Direct discharge of treated and untreated wastewater to natural surface water bodies, including rivers and lakes, is generally known to produce adverse environmental impacts that have been of concern for the past 10–15 years, particularly in the Great Lakes basin. Examples of these impacts include eutrophication and the emergence of pharmaceuticals and personal care products (PPCPs). Advancement in wastewater treatment plant operations alone may not be feasible to meet the 2016–2019 Federal Sustainable Development Strategy (FSDS), especially on phosphorus reduction targets. Diverting treated wastewater to land could present a multibarrier approach for integrated PPCPs management, and could also shift current …

Quantifying Permafrost Extent, Condition, And Degradation Rates At Department Of Defense Installations In The Arctic, Christopher A.J. Edlund

Theses and Dissertations

The DoD is planning over $500M in military construction on Eielson Air Force Base (AFB) within the next three years. This construction program will expand the footprint of facilities and change parts of the storm water management scheme, which may have second order effects on the underlying permafrost layer. These changes in permafrost will drive engineering decision making at local and regional levels, and help shape the overall strategy for military readiness in the Arctic. Little site-specific knowledge exists on the human caused effects to permafrost at this location. In 2016, the permafrost degradation rates at Eielson AFB were modeled …

Impact Of Critical Path Method (Cpm) Of Scheduling On On-Time Completion Of Transportation Projects, Fahim Ahmed

Theses and Dissertations

This study addresses the effectiveness of Critical Path Method (CPM) scheduling on project delivery. Specifically, the on-time completion of projects with and without a CPM schedule is explored. The paper uses data from 2,097 South Carolina transportation projects let after February 2008 and substantially completed by August 2015. The delay analysis uses the original contract completion date as well as the completion date adjusted by change orders. Chi-Squared tests are used to examine the relationship between CPM scheduled projects and delayed projects, and t-tests are used to compare the mean delay (in days) between CPM scheduled and unscheduled projects. The …

A Scientific Approach To Understanding The Head Trauma Endured By A Mixed Martial Arts Fighter, John William Michael Sorbello

Mechanical & Aerospace Engineering Theses & Dissertations

The purpose of this research is to gain some insight on the type of head trauma an athlete may encounter during mixed martial arts (MMA) competition. These athletes endure continuous blows to the head throughout their training and fighting career. The knowledge obtained from this research may assist MMA athletes and trainers in assessing the way they train, how they compete and, more importantly, how long they choose to compete in their amateur or professional MMA career.

The analysis is performed by first creating a three-dimensional solid model of the human head based on geometric coordinates originally obtained from a …

Modeling Of A Head - Neck Assembly Drop Tower Impact Test Using Abaqus, Hussein Sharqi Owaid

Electronic Theses and Dissertations

There are numerous potential causes of traumatic brain injury (TBI) and concussions, including traffic accidents, contact during sports and falls. Protection from these injuries is paramount because of the problems that result from TBI, such as loss of thinking and memory capability. Head impact from falls, especially in elderly, can also result in severe to fatal injury and some effects of brain injury are often not visible. For these reasons and more a need exists for protective head gear that can keep persons safe during at risk physical activity and that can protect fall prone persons from accidental injuries. Part …

Characterizing The Electromechanical Response Of Flexible Foam For Multifunctional Impact-Sensing Applications, Evan Troy Bird

Theses and Dissertations

Flexible foams have unique properties that make them well-suited to several engineering systems. They are often used in impact-related applications because of their superior energy absorption performance. Many multifunctional materials are also derived from flexible foams due to their high customizability, which allows them to satisfy a wide range of performance requirements. Though flexible foams have high potential in these and other classes of material applications, their success relies on the proper characterization of their complex behavior. This thesis promotes the application of flexible foams by characterizing their electromechanical response through both experimental and theoretical approaches. One study in this …

A Model For Sustaining New Technology Based On Government Incentives, Girish Upreti

Doctoral Dissertations

The diffusion of new technology that provides environmental benefits may require government incentives for a duration of time, especially when the technology is expensive. The Center of Systems Research and Education (CASRE) model is developed that analyzes the impact of incentives in sustaining new technologies to allow their social acceptance. The CASRE model includes both demand and supply variables associated with incentive policy to sustain new technology. The key to market dissemination and sustainability is the Investment Tax Credit (ITC) levels provided by the government. The level of ITC is based on the current cost to the customer and the …

Design For Safety: Characterization Of Structural Impact On Lithium-Ion Batteries, Mehdi Gilaki

Theses and Dissertations

The goal of this research is to develop a framework for design for safety of battery modules used in EV/HEV applications. Such a framework can enhance the crash safety of lithium-ion batteries by investigating prevailing failure mechanisms such as thermal runaway. The problem involves different scales from module level to laminate level. The multi-scale nature of the problem makes the analysis computationally complex and expensive. Furthermore, because of the risk of explosion, a battery testing apparatus needs special safety provisions making it difficult to test charged and ready-to-use battery cells. In this study, we have numerically investigated feasibility of using …

Tensile And Impact Behaviour Of Shape Memory Alloy Fibre Reinforced Engineered Cementitious Composites, Mohamed Ali El-Sayed Mahmoud Ali

Electronic Thesis and Dissertation Repository

Extreme loading events such as impact, blast, and earthquakes have often led to partial or total collapse of structures, associated with economic and human life loss. Therefore, civil engineers have been seeking innovative materials and systems that would allow designing resilient and smart structures which can withstand such catastrophic events. Recently, engineered cementitious composites (ECC) and shape memory alloys (SMA) have emerged as strong contenders in the production of smart and resilient structural systems.

The aims of this study are to explore the possible synergy between ECC and SMA for developing a novel hybrid fibre-reinforced ECC incorporating randomly dispersed SMA …

Economic Impact Analysis Of Bridge Construction, Funda Yavuz

Masters Theses

Traffic disruption due to bridge construction has been reduced to several hours with the development of methods characterized as Accelerated Bridge Construction (ABC). Associated risks and additional activities involved with the accelerated construction result in an increased initial project cost. This additional cost is offset by the benefits of reduced mobility impact time such as maintenance of traffic cost, life-cycle cost, and economic impact on surrounding communities and businesses as well as the ability to address seasonal limitations. Traditionally, the savings in user cost from reduced mobility impact time is used to justify the additional cost of accelerated construction implementations. …