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California Polytechnic State University, San Luis Obispo

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Articles 121 - 150 of 585

Full-Text Articles in Materials Science and Engineering

The Impact Of Preheat On 2205 Duplex Stainless Steel Welds, Angelee G. Q. Breuninger, Iris I. Li, Cristian V. Sion Jun 2019

The Impact Of Preheat On 2205 Duplex Stainless Steel Welds, Angelee G. Q. Breuninger, Iris I. Li, Cristian V. Sion

Materials Engineering

The goal of this project is to determine the relationship between preheat temperature and phase balance of austenite and ferrite in the heat affected zone (HAZ) of a dissimilar thickness weld made of Sandvik SAF 2205 duplex stainless steel (DSS). Various preheat temperatures were applied (no preheat, 63°C, 98 °C, 141 °C, 181 °C, and 214 °C) to a 2-inch thick plate that was welded to a 0.072-inch thin sheet, with a 0.125-inch standoff, using manual gas tungsten arc welding (GTAW). Welding variables (voltage, amperage, and travel speed) were recorded and thermocouples were placed along the backside of the weld, …


Investigation Of The Encapsulation Efficiency Of Hexanal In Y-Cyclodextrin Metal Organic Frameworks, Travis J. Lang Jun 2019

Investigation Of The Encapsulation Efficiency Of Hexanal In Y-Cyclodextrin Metal Organic Frameworks, Travis J. Lang

Materials Engineering

Nanoporous materials have been extensively studied for applications such as drug delivery and organic compound storage. The nanoporous material of this study is a metal organic framework (MOF) which is a coordination of metal ions with organic binders. The structure created by this coordination can be used to absorb organic compounds, such as plant growth regulators, and subsequently release the organic compounds over a prolonged period to extend the storage life of foods. This study is examining the encapsulation efficiency of hexanal in γ-cyclodextrin metal organic frameworks (γ-CDMOFs) as a mechanism for potential active packaging applications. γ-CDMOFs were synthesized by …


Moisture Characterization Of Thermoplastics And Thermosets For Use As Matrices In Fiber Reinforced Composites, Kieran Hook, Ray Hsu Jun 2019

Moisture Characterization Of Thermoplastics And Thermosets For Use As Matrices In Fiber Reinforced Composites, Kieran Hook, Ray Hsu

Materials Engineering

Epoxy matrix composites are widely used in aerospace industry for lighter aircraft while thermoplastic-matrix composites have traditionally been underutilized despite their excellent fracture resistance, impact strength, and the ability to be recycled. Toray Advanced Composites (Morgan Hill, CA) wants to investigate the structural integrity of thermoplastic matrices in common aircraft operating environments. An experiment was conducted to observe the effect of moisture absorption on thermoplastic composites’ mechanical strength. PEEK, PPS, and PEI matrices were compared to an epoxy matrix in this experiment. Samples were submerged in 160ºF distilled water to accelerate moisture absorption. For two months, the changes in mass …


Microstructural Transformation Of Cold-Sprayed Grcop-42 For Rocket Engine Combustion Chamber Liners, Mason Souther Jun 2019

Microstructural Transformation Of Cold-Sprayed Grcop-42 For Rocket Engine Combustion Chamber Liners, Mason Souther

Materials Engineering

Rocket engines have always relied on high-conductivity copper liners to protect structural components from extreme thermal loads produced by combustion. Forged NARloy-Z has been the material of choice for decades but increasing cost of its constituent silver and high waste in the machining process has reduced the alloy’s cost effectiveness. Aerojet Rocketdyne wants to determine the viability of cold-spray additively manufactured GRCop-42 as a replacement alloy to reduce liner cost. Screening tests were performed to observe the microstructural development and microhardness changes of cold-sprayed GRCop-42 after being subjected to multiple stages of the typical heat treatment of a combustion chamber …


Weld Fracture Between C450 Stainless And C300 Maraging Steels In Golf Club Heads, Emily Oreste, Shea Costner Jun 2019

Weld Fracture Between C450 Stainless And C300 Maraging Steels In Golf Club Heads, Emily Oreste, Shea Costner

Materials Engineering

This project studied fractures along the weld on the face of TaylorMade metalwood golf clubs. The weld joint investigated was between investment cast C450 stainless steel and hot rolled C300 maraging steel that had been joined by plasma arc welding (PAW). Cracking in the welds between these two metals was discovered during in-house prototype testing. To understand the differences between the clubs with intact weld joints and clubs with fractured weld joints, the microstructures throughout the weld zones were imaged and a grid of microhardness values of the entire sample cross-section was generated. The images and hardness values were analyzed …


Investment Cast C450 Microstructural Characterization In Golf Club Heads, Kenneth Yin-Fai Lau Jun 2019

Investment Cast C450 Microstructural Characterization In Golf Club Heads, Kenneth Yin-Fai Lau

Materials Engineering

Two types of tensile bars were observed in this study of golf iron heads for TaylorMade Golf. As-cast and as-cast then machined tensile bars. The tensile bars underwent tensile tests to observe tensile strength, percent elongation, and fracture mechanisms. Furthermore, the hardness of the tensile bars was also taken despite seeing no difference in sample types. However, the as-cast samples did not consistently meet the requirements of percent elongation > 10.00% as there was a sample with 0.00% and another with 1.26%. These samples also showed brittle fracture, instead of the desired cup-and- cone ductile fracture. To investigate further, transverse sections …


Minimizing The Dimensional Change In Two Component Epoxy Based Thermoset Adhesives Through Adapting Mix Ratio And Initial Crosslink Density, Jefferson Peter Norman Jun 2019

Minimizing The Dimensional Change In Two Component Epoxy Based Thermoset Adhesives Through Adapting Mix Ratio And Initial Crosslink Density, Jefferson Peter Norman

Materials Engineering

Meissner Filtration uses amine-hardened epoxy as a high-performance adhesive to encapsulate hollow fiber membranes at the ends of rigid filter housings. Dimensional change of the epoxy while curing can result in residual stress formation that is detrimental to the manufacturing of the filter and causes structural integrity issues when the filter is used in industrial processes where heating and cooling cycles are implemented. The residual stresses can cause cracks, microscopic fractures, and delamination from the housing, resulting in failure of the filter. The goal of this project was to evaluate how changes in processing conditions could minimize dimensional variability due …


Non-Toxic Soil Thickeners For Reducing Mudslide Intensity, Miranda Miao, Isaac Blackburn, Erika Haley Yao Jun 2019

Non-Toxic Soil Thickeners For Reducing Mudslide Intensity, Miranda Miao, Isaac Blackburn, Erika Haley Yao

Materials Engineering

Non-toxic food thickeners were investigated as a solution for thickening mud to mitigate the effects of mudslides. All soil was obtained from a site on the California Polytechnic State University campus where a mudslide occurred in 2017. Guar gum was mixed into the soil at 1 wt% and 10 wt% of the moisture content in the soil. Whey protein was mixed into the soil at 2 wt% and 19 wt% of the moisture content in the soil. The soils’ liquid limit was found using the Casagrande cup testing method. Liquid limit testing indicated that thickeners raised the liquid limit, most …


Mechanical Tear Testing And Failure Analysis Of Armordillo® Textile For Future Comparison With Next Generation Replacement Textiles, Jordan Bryce Pohl Jun 2019

Mechanical Tear Testing And Failure Analysis Of Armordillo® Textile For Future Comparison With Next Generation Replacement Textiles, Jordan Bryce Pohl

Materials Engineering

ArmorDillo® is a heavy-duty, waterproof textile designed to protect valuable equipment against outdoor elements such as rain, dirt, salt, ultraviolet rays, and damage from other external factors that is manufactured by Transhield® USA and is currently in service with many branches of the United States Armed Forces, primarily the United States NAVY. Due to emerging security threats to classified military hardware the US NAVY through the United States Naval Surface Warfare Center (NSWC) is actively researching and sourcing a textile replacement for ArmorDillo® to meet these threats. This study investigates the mechanical durability of ArmorDillo® under …


Evaluation Of Tensile Properties For Selective Laser Melted 316l Stainless Steel And The Influence Of Inherent Process Features, Paul Swartz Jun 2019

Evaluation Of Tensile Properties For Selective Laser Melted 316l Stainless Steel And The Influence Of Inherent Process Features, Paul Swartz

Master's Theses

Optimal print parameters for additively manufacturing 316L stainless steel using selective laser melting (SLM) at Cal Poly had previously been identified. In order to further support the viability of the current settings, tensile material characteristics were needed. Furthermore, reliable performance of the as-printed material had to be demonstrated. Any influence on the static performance of parts in the as-printed condition inherent to the SLM manufacturing process itself needed to be identified. Tensile testing was conducted to determine the properties of material in the as-printed condition. So as to have confidence in the experimental results, other investigations were also conducted to …


Nano Fab Lab 63, Brian K. Deemer, Josh Clemons, Nick Brodine, Delaney Fitzsimmons Jun 2019

Nano Fab Lab 63, Brian K. Deemer, Josh Clemons, Nick Brodine, Delaney Fitzsimmons

Mechanical Engineering

Lawrence Livermore National Laboratories (LLNL) has several steps in the production process for ceramic nanofiber tubes that they would like to improve - electrospinning, cutting, rolling, sealing and heat treating. We undertook the challenge to deliver LLNL with a semi-automated process that efficiently integrates the steps of cutting, rolling, and sealing to save time and improve control over end dimensions. In this document, we discuss the technical background of the manufacturing steps currently followed to create nanofiber tubes, identify which steps are incorporated in our prototype and explain how they will interface with one another, define the design requirements, present …


Modifying Casting Parameters To Improve The High Temperature Ductility Of Investment Cast Nickel-Based Superalloy Pwa 1455, Lars Alexander Hedin, Cole Magnum Introligator Jun 2019

Modifying Casting Parameters To Improve The High Temperature Ductility Of Investment Cast Nickel-Based Superalloy Pwa 1455, Lars Alexander Hedin, Cole Magnum Introligator

Materials Engineering

PCC Structurals, an industry leader in superalloy investment castings, has observed inconsistencies in the stress rupture performance of polycrystalline nickel-based superalloy PWA 1455. PCC has changed their casting parameters to reduce the thermal gradient during cooling but have been unable to correlate these changes with an increase in stress rupture elongation. Metallographic examination of past samples indicated microstructures composed of non- equiaxed dendritic grains with mean diameter of .021 inches along the test axis. A similar study on polycrystalline superalloys has indicated that excessive superheat temperatures above the liquidus can result in large grains identical to those observed, limiting the …


Effect Of Solder Joint Flux Residue On Medical Guide Wire Performance, Rebecca Lisberg, Enlly Bugarin Rodriguez Jun 2019

Effect Of Solder Joint Flux Residue On Medical Guide Wire Performance, Rebecca Lisberg, Enlly Bugarin Rodriguez

Materials Engineering

The effect of residual soldering flux on the mechanical properties of 304 stainless-steel core medical guide wires was analyzed. A soldering process joins the metallic components of the distal end of a medical guide wire product. Acidic soldering flux is used to prepare the surfaces of the metallic substrates. Manufacturing protocol utilizes an ultrasonic bath to remove excess flux from the soldered joints. Sample groups underwent different levels of cleaning: no cleaning, partial cleaning, and full ultrasonic bath cleaning to obtain varying residual flux levels. Experimental sample groups underwent corrosion acceleration in an environmental chamber at 37°C and 85% relative …


Maximizing Poly(3-Butylthiophene-2,5-Diyl) Electrical Conductivity By Maximizing Transcrystal Growth, Edward Alexander Bicknell Jun 2019

Maximizing Poly(3-Butylthiophene-2,5-Diyl) Electrical Conductivity By Maximizing Transcrystal Growth, Edward Alexander Bicknell

Materials Engineering

Polymers are generally considered electrical insulators. Despite this, research in the mid 1970’s found that polymers consisting of a conjugated backbone structure could become electrically conductive upon doping.1 The conjugated polymer analyzed for this project was poly(3-butylthiophene-2,5-diyl) (P3BT). Transcrystals have been found as a way to promote electrical conductivity through mechanisms including π bond atomic orbital overlap and electron mobility.2 In theory, maximizing transcrystal length would also maximize P3BT electrical conductivity, increasing its applicable use in electronic devices. The goal of this project was to determine a methodological way to maximize P3BT electrical conductivity by producing the longest transcrystal length …


Photooxidation Of Biopolymers, Marlon H. Dieguez Jun 2019

Photooxidation Of Biopolymers, Marlon H. Dieguez

Materials Engineering

The lack of degradation of plastic products have imposed problems in the preservation of natural environments and their ecosystems through plastic accumulation. This collection of plastics promotes toxin exposure to wildlife, finding its way into the food chain, affecting both land and marine ecosystems. The project goal is to understand the degradation mechanisms of biodegradable materials and other comparable materials through UV radiation testing. Polylactide (PLA) films and polycarbonate (PC) films will be compared for their relative deterioration from constant UV radiation in a Q-U-V accelerated weather tester for 28 days. Five 3” by 5” samples of 14 mil thick …


Effect Of Overaging On Tensile Properties Of 2219-T852 Aluminum, Austin Bitter, Tristan Koyamatsu Jun 2019

Effect Of Overaging On Tensile Properties Of 2219-T852 Aluminum, Austin Bitter, Tristan Koyamatsu

Materials Engineering

This project investigated the overaging performance of aluminum alloy 2219-T852 for use in high temperature applications. 2219 aluminum is an alloy containing 5.8 to 6.8 percent copper, and is classified as a high strength age hardenable alloy. The sponsor for this project, Weber Metals, hopes to use 2219 Al to replace titanium in certain applications above the thermal limits of typical high strength Al. To test its performance, they manufactured round tensile samples and delivered them in peak aged, T852 condition. These samples were then overaged at a range of times and temperatures. The times in this experiment were one …


Left Atrial Model, Borna Sobati, Sarah Porello, Tess Pate May 2019

Left Atrial Model, Borna Sobati, Sarah Porello, Tess Pate

Biomedical Engineering

The objective is to produce an electrophysiological model of an adult human left atrium. This model will be used to test mapping probe catheters used for locating cardiac arrhythmias against current technology used in practice. Dr. Chris Porterfield requested this model and other physicians or probe catheter manufacturers may also use this product in the future. Dr. Porterfield also discussed the possibility of future senior project groups using the model as a bench test for designing new catheter tips. The model will precisely simulate electrical behaviors of the heart in normal as well as arrhythmic conditions. Ideally, the model will …


Reinventing The Wheel, Esther K. Unti, Ahmed Z. Shorab, Patrick B. Kragen, Adam M. Menashe Dec 2018

Reinventing The Wheel, Esther K. Unti, Ahmed Z. Shorab, Patrick B. Kragen, Adam M. Menashe

Mechanical Engineering

Reinventing the Wheel selected tires and designed wheels for the 2018 Cal Poly, San Luis Obispo Formula SAE combustion vehicle. Available tire options were evaluated for steady-state and transient performance as well as vehicle integration. A single-piece composite wheel with hollow spokes was designed to meet stiffness, strength, and tolerance requirements. A detailed study of wheel loading and geometric structural efficiency was performed. Finite element analysis was used to iterate the geometry and laminate. A two-piece male mold was designed and machined to manufacture the wheel. Removable silicone inserts were used to create the hollow spokes.


Improving Ductility Of Slender Reinforced Concrete Shear Walls With Frp Sheets And Splay Anchors, Luke M. Ostrom Dec 2018

Improving Ductility Of Slender Reinforced Concrete Shear Walls With Frp Sheets And Splay Anchors, Luke M. Ostrom

Architectural Engineering

The Sylmar earthquake of 1971 caused significant damage to slender, non-ductile reinforced concrete (RC) shear wall buildings in California. A later survey by the Concrete Coalition in 2011, under the guidance of EERI members, indicated that there are over 3000 vulnerable concrete buildings in California [8]. This led to City of Los Angeles (LA) Ordinance 193893 enacted in 2015, which requires mandatory upgrades to these concrete buildings by 2035. Current practice to meet the requirements of this ordinance, with respect to RC wall buildings, involves adding new shear walls to the building plan or increasing the cross-sectional area of existing …


Preparation And Characterization Of Eva/Cort Microparticles For Rattlesnake Endocrinology Studies, Alexander C. Pauer Jun 2018

Preparation And Characterization Of Eva/Cort Microparticles For Rattlesnake Endocrinology Studies, Alexander C. Pauer

Materials Engineering

No abstract provided.


In Situ Sem Solidification Study Of Ga And Egain: A Characterization Technique For Monitoring The Microstructural Evolution Of Liquid Metals, Jeremy Geovann Del Aguila Jun 2018

In Situ Sem Solidification Study Of Ga And Egain: A Characterization Technique For Monitoring The Microstructural Evolution Of Liquid Metals, Jeremy Geovann Del Aguila

Materials Engineering

Scanning electron microscopy (SEM) video recording is used to characterize the solidification of small volumes of 99.999% pure gallium (Ga) and eutectic gallium-indium (eGaIn) under a high vacuum environment. Specimen are superheated to 55℃ using a hot plate, cast into spherical droplets, and cooled in situ by means of a Peltier cooling stage. Special attention is given to the preparation of the specimen prior to viewing because of gallium and its alloys’ nature to form an oxide layer when melted and air cooled. The oxide acts as a skin that inhibits the observation of microstructural features during solidification. Heated samples …


An Evaluation Of Ultrasonic Shot Peening And Abrasive Flow Machining As Surface Finishing Processes For Selective Laser Melted 316l, Rhys Gilmore Jun 2018

An Evaluation Of Ultrasonic Shot Peening And Abrasive Flow Machining As Surface Finishing Processes For Selective Laser Melted 316l, Rhys Gilmore

Master's Theses

Additive Manufacturing, and specifically powder bed fusion processes, have advanced rapidly in recent years. Selective Laser Melting in particular has been adopted in a variety of industries from biomedical to aerospace because of its capability to produce complex components with numerous alloys, including stainless steels, nickel superalloys, and titanium alloys. Post-processing is required to treat or solve metallurgical issues such as porosity, residual stresses, and surface roughness. Because of the geometric complexity of SLM produced parts, the reduction of surface roughness with conventional processing has proven especially challenging. In this Thesis, two processes, abrasive flow machining and ultrasonic shot peening, …


Temper Response Of A Vanadium Microalloy Steel, Bradley W. Hostetler Jun 2018

Temper Response Of A Vanadium Microalloy Steel, Bradley W. Hostetler

Materials Engineering

This investigation details the effect of a quench-and-temper processing treatment on the mechanical properties of a microalloy steel being considered for use as a pipeline flange. Microalloy steels are normally processed via Thermo-Mechanically Controlled Processing (TMCP) due to the increased strength from ferrite grain refinement; however, the geometry of a pipeline flange requires post processing beyond TMCP which diminishes the strengthening effect provided by TMCP. The purpose of this research project is to determine the mechanical properties produced when a vanadium microalloy steel is quenched and tempered. The two major considerations are the effect of tempering time on properties and …


Exploring The Relationship Between Cellular Structure And Mechanical Properties Of Polymer Foams, Timothy Lee Tan Jun 2018

Exploring The Relationship Between Cellular Structure And Mechanical Properties Of Polymer Foams, Timothy Lee Tan

Materials Engineering

Polymer foams are the material of choice for applications that require comfort, cushioning, and high energy absorption. While popular, the relationship between their microstructure and their mechanical properties is not yet strongly predictable. The aim of this project is to look at the different relationships between the area or volume occupied by pores compared to the amount of solid material and determine which method of quantifying this relationship will provide the best prediction of mechanical properties. To examine this relationship, foams of various densities made from either ethylene-co-vinyl acetate or thermoplastic polyurethane were first physically characterized through three methods: (1) …


Phase Change Materials For Thermal Management Of Kennedy Library Study Rooms, Colin J. Empey Jun 2018

Phase Change Materials For Thermal Management Of Kennedy Library Study Rooms, Colin J. Empey

Materials Engineering

The overall purpose of this study was to find a phase change material (PCM) or a combination of PCMs as a thermal management solution for the fifth-floor study rooms in Kennedy Library. First and foremost, the PCM must take in heat to change phase. A PCM would be a better candidate the more heat it needs to change phase. To quantify this, the team utilized a DSC to find how much energy each candidate PCM required to change phase. Coconut oil, palm oil, and white chocolate were found to have the best ability to absorb heat. Secondly, the PCM should …


Anomalous 304 Stainless Steel Mechanical Properties In Medical Guide Wires, Andrew Joseph Freeman Jun 2018

Anomalous 304 Stainless Steel Mechanical Properties In Medical Guide Wires, Andrew Joseph Freeman

Materials Engineering

Stainless steel medical guide wire cores, processed by Abbott Vascular, are returning anomalous mechanical properties upon strain hardening and heat treatment. As theory dictates, mechanical strength properties increase with strain hardening, and decrease with an annealing treatment. The opposite response is being observed. This is counter intuitive to fundamental materials knowledge, and a perfect materials engineering paradox. This project was designed to characterize these behaviors, and attempt to determine causation. To accomplish this, tensile testing of all processing steps mapped the mechanical property evolution of the wire. Published literature research revealed the potential of nitrogen and chromium solid state diffusion …


Solar Cell Potential Induced Degradation Sensor, Luc Alexandre Tousignant Jun 2018

Solar Cell Potential Induced Degradation Sensor, Luc Alexandre Tousignant

Materials Engineering

It is important to maintain Photovoltaic (PV) cells and protect them from damage mechanisms like Potential Induced Degradation (PID), which can contribute to shorter lifespans and lower efficiencies. Current leakage through cell encapsulation can cause charge migration in PV cells that reduces the maximum quantum efficiency, which is the cause of PID. An experiment was setup to determine the feasibility of a non-silicon sensor able to produce similar leakage behavior to traditional PV cells under recorded humidity conditions. Thin sheet metals were encapsulated in EVA, a common PV encapsulant polymer, and mounted in aluminum framing. Three sensors, along with a …


Mechanical Characterization Of Selectively Laser Melted 316l Stainless Steel Body Centered Cubic Unit Cells And Lattice Of Varying Node Radii And Strut Angle, Christopher James Hornbeak Jun 2018

Mechanical Characterization Of Selectively Laser Melted 316l Stainless Steel Body Centered Cubic Unit Cells And Lattice Of Varying Node Radii And Strut Angle, Christopher James Hornbeak

Master's Theses

An experimental study of several variants of radius and strut angle of the body centered cubic unit cell was performed to determine the mechanical properties and failure mechanisms of the mesostructure. Quasi static compression tests were performed on an Instron® universal testing machine with a 50kN load cell at 0.2mm/min. The test samples were built using a SLM Solutions 125 selective laser melting machine with 316L stainless steel. Test specimens were based on 5mm cubic unit cells, with a strut diameter 10% of the unit cell size, with skins on top and bottom to provide a cantilever boundary constraint. Specimens …


Composite Suspension For A Mass Market Vehicle, Sarah M. Chapiama, Brian Auyeung, Jose Guerrero, Ethan Lau Jun 2018

Composite Suspension For A Mass Market Vehicle, Sarah M. Chapiama, Brian Auyeung, Jose Guerrero, Ethan Lau

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.


The Effects Of Varying Composition And Build Direction On Direct Metal Deposition Fabricated Inconel 718, Abigail P. Nilan, Jessica M. Fordham Jun 2018

The Effects Of Varying Composition And Build Direction On Direct Metal Deposition Fabricated Inconel 718, Abigail P. Nilan, Jessica M. Fordham

Materials Engineering

Inconel 718 (IN718) is a popular wrought superalloy, and is currently being investigated for additive manufacturing (AM) applications in the aerospace industry. However, overaging and the presence of microcracks have caused a significant reduction in properties. The purpose of this study is to meet or exceed the mechanical properties of wrought IN718 by varying the composition and build direction of the AM alloy. Alternative compositions were selected with Oerlilon Metco’s Rapid Alloy Development (RAD) software, and differ in niobium content, which increases the fraction of the primary strengthening phase (γʺ). Direct metal deposition (DMD) was used to fabricate the samples, …