Engineering Commons^™

Space Force Spacecraft Hull Inspection: Creation Of A Process To Inspect, Compare, And Fault Detect On The Surface Of A Spacecraft Hull, Ethan Rainsburg

Williams Honors College, Honors Research Projects

The Space Force Inspection design project aims to create a system for scanning the hull of a spacecraft, identifying any damage by cross-checking the new scan with a previous scan, and fixing any identified damage picked up by the scan. This project contains key objectives such as defining testable parameters for any given scanner, creating a repeatable process for comparing scans, and automating the process using open-source code and software. The ideal outcome for this project is to have the fully automated system implemented to a robot that is being designed and manufactured by a sister team. Some of the …

Structural Health Monitoring And Repair Of Welded Thermoplastic Composite Joints Using Embedded Multifunctional Films, Wencai Li

LSU Doctoral Dissertations

Thermoplastic composites (TPCs) have gained widespread use, particularly in large or integrated structural components, necessitating effective joining techniques. Fusion bonding (welding) has emerged as a suitable method for TPCs due to their ability to be reshaped through heating and cooling, eliminating the need for mechanical fasteners, long curing times, and extensive surface preparation. Among the welding techniques, ultrasonic welding (USW) stands out for its fast-cycling time and potential for automating large-scale structures, thereby reducing energy consumption. However, limited industrial applications of USW in this context require further knowledge to instill confidence in the process. Moreover, composite structures are susceptible to …

Friction Taper Plug Welding As A Repair Method For Fatigue Damage Around Fastener Holes In Aerospace Structures, David Carl Sumsion

Theses and Dissertations

This work details an adaptation of the friction taper plug welding (FTPW) process to repair fatigue damage in 6.35mm AA 7050 t-7451 plate. Aircraft components experience fatigue damage around fastener holes. This damage can be mitigated by enlarging fastener holes. There is no effective repair procedure once holes reach a maximum allowable size. Damaged components must be replaced. A suitable repair process would lead to substantial savings in both time and money. A simulated repair process was developed by machining holes in 6.35mm AA 7050 t-7451 plate. These hoes were then plugged using the FTPW process. Microhardness testing and metallographic …

Flexural Strengthening Of Rc Slabs Using Near Surface Mounted Gfrp Bars, Sama Taha

Theses and Dissertations

Glass Fiber reinforced polymers (GFRPs) have been recently successfully used to increase reinforced concrete elements' strength. In general, FRPs have many advantages such as resistance to corrosion, and high strength-to-weight ratio. On the other hand, debonding from concrete may constitute a limitation to using GFRP bars; hence the increase in strength of RC elements strengthened using GFRP bars may be limited by this premature debonding failure mechanism.

This study aims to investigate the strengthening effect of GFRP bars on the capacity of RC slabs when subject to flexure loading. The work studies the use of different bonding lengths, diameters and …

Characterization And Utilization Of Alkali-Activated Concrete For Sustainable Infrastructures, Eslam Gomaa

Doctoral Dissertations

“This study has investigated the feasibility of using locally available fly ashes (FAs) to synthesize alkali-activated concrete (AAC) for different structural and repair applications. Using AAC made of 100% FA reduces global CO2 emissions, saves energy, and decreases raw material consumption during the production process of ordinary Portland cement. Class C FAs, sourced from Labadie, Jeffery City, Kansas City, Thomas Hill, and Sikeston power plants in the state of Missouri, were used to synthesize the AAC. Sodium silicate (SS), Na2SiO3, and sodium hydroxide (SH), NaOH were used as the alkali activators. Slag, crumb rubber, and air-entraining admixture were used as …

Vehicle Maintenance Tracking Program, Jared Tomlinson

Williams Honors College, Honors Research Projects

In order to help consumers and businesses keep track of vehicle maintenance, I will create a program paired with a database that can track vehicle maintenance needs and when they should be performed. The program will be capable of tracking entire fleets of vehicles and based on the vehicle’s mileage, will notify users of what maintenance should be performed. Users will be able to add, remove, and edit vehicles in the system as needed and each vehicle will be paired with a maintenance schedule based on its needs. As maintenance is performed, it can be tracked on the schedule, which …

Feasibility Of Epoxy Bond Enhancement On High-Strength Concrete, Amanda A. Lewis

USF Tampa Graduate Theses and Dissertations

While fiber-reinforced polymer materials have many applications in various industries,when used structurally, many cases, such as flexural and shear strengthening, are considered bond critical. Interfacial bond quality between a fiber-reinforced polymer system and the substrate is dependent on two mechanisms: chemical bonding and mechanical interlock, with mechanical interlock having the greater effect on bond quality. Mechanical interlock describes the type of bond that occurs as a result of surface roughness and substrate porosity and can be significantly affected by surface preparation methods and surface moisture. This study aims to explore the possibility of enhancing bond quality between carbon-fiberreinforced polymers and …

Development Of A Novel Cardiac Ischemia-Reperfusion Model In The Axolotl, Jeremy Tolentino Llaniguez

Wayne State University Dissertations

The Center for Disease Control’s National Center for Health Statistics data for mortality from diseases of the heart show the age-adjusted death rate has fallen from almost 600 deaths in the 1950s to just over 190 deaths per 100,000 U.S. residents today. With the recognized limitations of pharmacotherapy of myocardial infarction (MI), cell-based therapies have been undergoing rapid development and clinical testing. However, there is still no consensus about cell types, delivery routes, dosing and treatment schedules and pretreatment conditioning of cells prior to administration. Furthermore, a fundamental question remains unanswered about the reasons for the poor capacity for myocardial …

Strength Investigation Of Damaged And Repaired Thin-Walled Composite Structures, Analise Barlow

Theses and Dissertations

The purpose of this research was to quantify the strength of novel composite repair methods for thin-walled composite structures. Carbon/epoxy plates were manufactured and repairs were made at Gloyer-Taylor Laboratories. At BYU, specimens were damaged in a controlled and repeatable process. Three damage modes were implemented: impact, groove, and abrasive damage. Tensile strength tests were performed on control, damaged, and repaired specimens. Four 24 x 24 in (60 x 60 cm) carbon/epoxy plates were received. Each plate was made up of seven plies cured together with epoxy resin for a nominal total thickness of 0.04 in (1.02 mm). The thickness, …

Evaluation Of Fiber Reinforced Polymer (Frp) Strengthening For Deteriorated Bridge Bent Caps, Yazan Almomani

Civil Engineering Dissertations

Deterioration of aging highway bridges has been a serious concern in the U. S. A. Almost 39% percent of all bridges in the country have passed their 50-year design life, and approximately 9% of these bridges are structurally deficient due to concrete deterioration and truck weight increases on highways. Compared to superstructures, the deterioration of bridge substructures and associated repair/strengthening/evaluation has received much less attention in previous studies. A reinforced concrete bridge built in 1940 and located in Dallas, Texas, exhibited moderate to severe corrosion related concrete deterioration in the bent caps. Eight such bent caps were selected herein for …

A Project-Level Infrastructure Management Framework For Sustainable Roadways, Song He

Dissertations - ALL

Over the past two decades, roadway infrastructure in the United States has experienced severe deterioration, costing road users billions of dollars in wasted fuels, lost time, and higher numbers of accidents. Transportation infrastructure asset management initiatives, which aim at providing and maintaining physical infrastructure assets at an acceptable level, need to address various economic, social, and environmental issues. Therefore, the American Association of State Highway and Transportation Officials (AASHTO) has encouraged public agencies to incorporate sustainable development principles into their decision-making and organizational operations at a program level.

Meanwhile, at a project level, maintenance, repair, and rehabilitation (MRR) projects for …

Integrating Disparate Nuclear Data Sources For Improved Predictive Maintenance Modeling: Maintenance-Based Prognostics For Long-Term Equipment Operation, Zachary Allen Welz

Doctoral Dissertations

The United States (US) nuclear industry is one of the most heavily regulated businesses in the world, creating a culture of world-class design, operation, and maintenance. In an article published on modern maintenance technologies, Terrence OHanlon (past Chief Asset Manager for Reliabilityweb.com) stated, “world class companies often devote up to 50 percent of their entire maintenance resources to condition based monitoring and the planned work that is required as a result of the findings” [1]. One would expect US nuclear power plants to constantly upgrade, improve, and expand their operations and maintenance departments and tactics. Since the early 1990s, US …

Repair Of Metallic Components Using Hybrid Manufacturing, Renwei Liu

Doctoral Dissertations

"Many high-performance metal parts users extend the service of these damaged parts by employing repair technology. Hybrid manufacturing, which includes additive manufacturing (AM) and subtractive manufacturing, provides greater build capability, better accuracy, and surface finish for component repair. However, most repair processes still rely on manual operations, which are not satisfactory in terms of time, cost, reliability, and accuracy. This dissertation aims to improve the application of hybrid manufacturing for repairing metallic components by addressing the following three research topics. The first research topic is to investigate and develop an efficient best-fit and shape adaption algorithm for automating 3D models' …

Characterization Of A Multi-Laminate Angle-Ply Af Patch For Annulus Fibrosus Repair, Ryan Borem

All Theses

Annually, over 5.7 million Americans are diagnosed with two IVD-associated pathologies: IVD herniation (IVDH- a mechanical disruption of the concentric fibrous layers of the annulus fibrosus (AF))) and degeneration (IVDD- a multifactorial process which initiates within the inner gelatinous core (NP), and results in a biochemical degradation of NP tissue), with over 2.7 million requiring surgical inteventions.1,2 Although both underlying pathologies are different, quite often they both lead to a decrease in IVD height, impaired mechanical function, and increased pain and disability. These pain symptoms affect approximately 80% of the adult population during their lifetime with estimated expenditures exceeding $85.9 …

Preemptive Placement And Routing For In-Field Fpga Repair, Joshua E. Jensen

Theses and Dissertations

With the growing density and shrinking feature size of modern semiconductors, it is increasingly difficult to manufacture defect free semiconductors that maintain acceptable levels of reliability for long periods of time. These systems are increasingly susceptible to wear-out by failing to meet their operational specifications for an extended period of time. The reconfigurability of FPGAs can be used to repair post-manufacturing faults by configuring the FPGA to avoid a damaged resource. This thesis presents a method for preemptively preparing to repair FPGA devices with wear-out faults by precomputing a set of repair circuits that, collectively, can repair a fault found …

Investigation Of Chloride Induced Corrosion Of Bridge Pier And Life-Cycle Repair Cost Analysis Using Fiber Reinforced Polymer Composites, Dinesh Dhakal

UNLV Theses, Dissertations, Professional Papers, and Capstones

Bridges are the long term investment of the highway agencies. To maintain the required service level throughout the life of a bridge, a series of maintenance, repair, and rehabilitation (MR&R) works can be performed. To investigate the corrosion deterioration and maintenance and repair practices in the bridge pier columns constructed in chloride-laden environment, a questionnaire survey was conducted within the 50 state Departments of Transportation (DOTs). Based on the survey data, two corrosion deterioration phases were identified. They were corrosion crack initiation phase and corrosion propagation phase. The data showed that the mean corrosion crack initiation phase for bridge pier …

Mode I Fatigue Delamination Onset Of Carbon Fibre Reinforced Polymer With Novel Post-Cure Throughthickness Reinforcement, Christopher John Kourloufas

Open Access Theses

A novel trough thickness reinforcement (TTR) technique, proposed by Kravchenko et al., has been tested under mode I fatigue loading conditions in order to investigate characterisation of the onset of delamination growth in unidirectional 8552/IM7. The experimental results, following standard test method ASTM D6115-13, indicate that the mode I fatigue delamination onset behaviour can be altered by the inclusion of TTR both ahead and behind the crack tip. Tests have been conducted at a wide range of maximum displacement values, corresponding to percentages of the critical fracture toughness value determined for the maternal, GIC . The results were found …

Part Detection And Classification Using Integrated Machine Vision And Knowledge Based Expert System, Cristian Giovanni Lopez Ulloa

Open Access Theses & Dissertations

Manufacturing cost is a topic of interest in the automotive manufacturing industry. Even though rework and repair methods are acceptable processes in manufacturing, there is little investigation done on the classification and cost parameters of a repairable or re-workable part. Having a non-conforming part indicates a loss in revenue to a manufacturing company, thus the need to repair or rework the part. Repair and rework processes take non-conforming products of a manufacturing line and bring the parts back to conforming stage. In this study, the proposed system establishes a connection between detection of defects, classification of them based on defect …

Seismic Repair Of Bridge Columns With Interlocking Spirals And Fractured Bars, Yang Yang

Doctoral Dissertations

"During earthquakes, reinforced concrete (RC) bridge columns may experience different levels of damage such as cracking, spalling, or crushing of concrete and yielding, buckling, or fracture of reinforcing bars. This study developed and assessed permanent and emergency methods to repair damaged bridge columns with fractured longitudinal reinforcement through experimental and modeling work. The permanent repair method involved replacement of the plastic hinge region by removal of spirals, replacement of longitudinal bar segments by mechanically splicing with new bars segments attached with mechanical couplers, replacement of concrete, and installation of an externally bonded carbon fiber reinforced polymer (CFRP) jacket. The emergency …

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 …

Characterization Of Impact Damage And Fiber Reinforced Polymer Repair Systems For Metallic Utility Poles, Cara Johnson

Electronic Theses and Dissertations

Previous studies have demonstrated that the behavior of fiber reinforced polymers (FRPs) bonded to metallic utility poles are governed by the following failure modes; yielding of the metallic substrate, FRP tensile rupture, FRP compressive buckling, and debonding of FRP from the substrate. Therefore, an in situ method can be devised for the repair of utility poles, light poles, and mast arms that returns the poles to their original service strength. This thesis investigates the effect of damage due to vehicular impact on metallic poles, and the effectiveness of externally-bonded FRP repair systems in restoring their capacity. Damage is simulated experimentally …

Traumatic Vs. Pathological Achilles Tendon Ruptures: A Look Into The Importance Of The Collagen Matrix And The Preferred Method Of Repair, Kathleen M. Mclean

Honors Theses

The Achilles tendon is the largest, strongest, and thickest tendon in the human body. While it may be the strongest, the Achilles tendon is also among one of the most frequently ruptured. These lower limb injuries arise as a result of athletically induced trauma or pathologically and steroidal induced trauma. While the manner in which athletic ruptures occurs can be determined on a case to case basis through the use of clinical examination, ultrasonography, and magnetic resonance imaging (MRI), the method in which the injury should be treated remains controversial. The two main methods of repair include a conservative approach …

Finite Element Simulation Of Repair Of Delaminated Composite Structures Using Piezoelectric Layers, Kunal Navale

Electronic Theses and Dissertations

Damage in composite material fabricated aerospace, aeronautical, mechanical, civil and offshore structures often results from factors such as fatigue, corrosion and accidents. Such damage when left unattended can grow at an alarming rate due to the singularity of the stress and strain in the vicinity of the damage. It can lead to increase in the vibration level, reduction in the load carrying capacity, deterioration in the normal performance of the component and even catastrophic failure. In most conditions, the service life of damaged components is extended with repair instead of immediate replacement. Effective repair of structural damage is therefore an …

Value Of Increased Use Of Scheduled Maintenance On Aircraft Availability And Maintenance Cost Of The C-5, William T. Webb

Theses and Dissertations

The C-5 consistently performs below its established mission capable rate of 75 percent. The purpose of this study was to investigate whether or not mission capable rates and maintenance costs can be improved by increased use of scheduled maintenance. Nine C-5 components were studied. Availability and cost were compared when scheduled replacement occurred at ten, twenty, and thirty percent before their respective mean time between failure and actual failure times. Actual failure times were not available so they were generated using simulation. The trade-off of using preventive maintenance is the decreased cost of sending fewer maintenance repair teams and increased …

Organic Maintenance Performance Measurement: A New Approach, John S. Nehr, William G. Queener

Theses and Dissertations

The growing role of Air Force Air Logistics Centers ALC in complex, multiyear developmental programs increases the need for effective cost and schedule performance measurement. In order to effectively manage these activities, timely and accurate cost and schedule information must be collected and compared with an established baseline. The ALCs need a new management technique which facilitates this type of performance measurement. A proven approach to cost and schedule performance measurement in weapon system acquisitions is Earned Value EV. This approach, required of contractors who are subjected to the CostSchedule Control Systems Criteria CSCSC, allows the program manager to obtain …