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Articles 1 - 21 of 21
Full-Text Articles in Engineering
Improving Ductility Of Slender Reinforced Concrete Shear Walls With Frp Sheets And Splay Anchors, Luke M. Ostrom
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 …
Reinventing The Wheel, Esther K. Unti, Ahmed Z. Shorab, Patrick B. Kragen, Adam M. Menashe
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.
Phase Change Materials For Thermal Management Of Kennedy Library Study Rooms, Colin J. Empey
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 …
Development Of Low Cost, Environmentally Friendly And High Strength Carbon Foams From Bread And Cake, Laura Mountain-Tuller
Development Of Low Cost, Environmentally Friendly And High Strength Carbon Foams From Bread And Cake, Laura Mountain-Tuller
Materials Engineering
Carbon foam is a high niche material that consists of a highly porous, three-dimensional cellular network that is characterized by extremely high strength-to-weight ratios and low thermal conductivity. Due to these properties, carbon foams excel in structural and thermal applications, especially in the aerospace industry. Typically, carbon foams are formed through a heating process called pyrolysis of polymer precursors with high carbon content. This process is done at high temperatures in an oxygen free environment. These precursors are expensive to make and use toxic chemicals to produce, therefore, there is a push to find an environmentally friendly and cost-effective method …
The Effects Of Varying Composition And Build Direction On Direct Metal Deposition Fabricated Inconel 718, Abigail P. Nilan, Jessica M. Fordham
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, …
Development Of Test Methods For Measuring Fiber Misalignment And Warping In Honeycomb-Core Composite Panels, Wyatt Taylor, Haripriya Nilakantan
Development Of Test Methods For Measuring Fiber Misalignment And Warping In Honeycomb-Core Composite Panels, Wyatt Taylor, Haripriya Nilakantan
Materials Engineering
Zodiac Aerospace manufactures honeycomb-core composite panels to be used in aircraft cabin interior components. During the manufacturing process, some panels become warped such that they cannot be used for their designated aircraft cabin components. As a result, these panels are scrapped because they cannot be recycled. About 44 to 90% of panels become warped during manufacturing. Warping is caused by many factors, including layer misalignment, processing parameters such as temperature and pressure gradients, and fiber misalignment in the prepregs. Currently, Zodiac does not have any data on the effect of fiber misalignment on panel warpage, so a testing protocol was …
Anomalous 304 Stainless Steel Mechanical Properties In Medical Guide Wires, Andrew Joseph Freeman
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 …
Effects Of Head Formation And Heat Treatment On The Mechanical Properties Of Connecting Rod Bolts, Caleb A. Leavitt, Matthew R. Lauretta
Effects Of Head Formation And Heat Treatment On The Mechanical Properties Of Connecting Rod Bolts, Caleb A. Leavitt, Matthew R. Lauretta
Materials Engineering
Oliver Racing Parts (ORP; Charlevoix, Michigan) is looking to optimize their manufacturing process for high-strength connecting rod bolts. A high yield strength is desired for the bolts because deformation would result in catastrophic engine failure. The bolts were made of H11, a chromium hot-work tool steel; and MLX17, a precipitation hardenable stainless steel. Tensile testing was performed to determine the tensile and yield strengths of the bolts. Fracture surfaces were imaged via scanning electron microscopy to characterize the failure modes. To observe the effects of bolt heading on microstructure and bolt strength, two batches of MLX17 were prepared; one batch …
Investigation Of Narloy-Z Yield Strength In Response To Changes In Ingot Processing And Heat Treatment, Stanley C. Goto, Sarah E. Wattenberg
Investigation Of Narloy-Z Yield Strength In Response To Changes In Ingot Processing And Heat Treatment, Stanley C. Goto, Sarah E. Wattenberg
Materials Engineering
This study investigates the effect of cooling rate on the yield strength of NARloy-Z. NARloy-Z is a copper-based alloy with 3 wt.% silver and 0.5 wt.% zirconium. The types of NARloy-Z were classified by the ingot processing (old or new) and the material lot (old or new). There were three variations of NARloy-Z in this study: old processing and material (Old/Old); old processing and new material (Old/New); and new processing and material (New/New). NARloy-Z undergoes a braze thermal cycle and age (BTCA) heat treatment for its application, and a single cooling rate within the BTCA was manipulated in this study. …
Temper Response Of A Vanadium Microalloy Steel, Bradley W. Hostetler
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 …
Synthesis Of Ɣ-Cyclodextrin Metal Organic Frameworks And The Encapsulation Of Caffeine And Theophylline, Evan Noel Sommerville, Riley Andrew Harden
Synthesis Of Ɣ-Cyclodextrin Metal Organic Frameworks And The Encapsulation Of Caffeine And Theophylline, Evan Noel Sommerville, Riley Andrew Harden
Materials Engineering
Nanoporous, non-toxic, ɣ-cyclodextrin metal organic frameworks (𝛾-CDMOFs) have potential applications in fields such as drug delivery and organic compound storage. The properties of many methylxanthines (alkaloids such as caffeine and theophylline) could be improved through 𝛾-CDMOF encapsulation, yet little research has been performed on the subject. In this study, 𝛾-CDMOFs were synthesized in order to 1. Determine if the vapor diffusion synthesis method can produce 𝛾-CDMOF crystals that replicate those in literature and 2. Determine if 𝛾-CDMOFs are able to encapsulate methylxanthines. The 𝛾-CDMOFs were synthesized through vapor diffusion of methanol in a solution of ɣ-cyclodextrin and potassium hydroxide (KOH). …
Next Generation Protocol: Innovating A Resilient Future, Andrew Steven Rudnick, Jamie Cannady, Joe Decesaro, Juan A. Ortiz Salazar
Next Generation Protocol: Innovating A Resilient Future, Andrew Steven Rudnick, Jamie Cannady, Joe Decesaro, Juan A. Ortiz Salazar
Materials Engineering
Conventional practices do not account for product life beyond end-of-sale – these practices are not sustainable. We have developed an end-of-life protocol that includes a metric that we call the Recovery Rating. The objectives of this Next Generation Protocol, beyond supporting the United Nations’ Sustainable Development Goals, are to encourage the production of goods designed for recovery and to promote the collaboration between consumers, the public, and the private sector to recover goods at their end-of-life. The Recovery Rating that we propose evaluates and quantifies recovery potential of products. The Recovery Rating, which is normed against embodied energy from the …
Exploring The Relationship Between Cellular Structure And Mechanical Properties Of Polymer Foams, Timothy Lee Tan
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) …
Solar Cell Potential Induced Degradation Sensor, Luc Alexandre Tousignant
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 …
Preparation And Characterization Of Eva/Cort Microparticles For Rattlesnake Endocrinology Studies, Alexander C. Pauer
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
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 …
Analysis Of The Low-Cycle Fatigue Behavior Of Silicone Rubber For Biomedical Balloons, Chase Cooper
Analysis Of The Low-Cycle Fatigue Behavior Of Silicone Rubber For Biomedical Balloons, Chase Cooper
Materials Engineering
The development of a medical drug delivery device that allows for the deployment drugs into the adventitial tissue of blood vessels requires the inflation of a silicone elastomer. The inflated silicone must be able to consistently endure multiple loading cycles without failing so that the device can operate reliably. There are multiple methods of processing the silicone for the device and the goal of this study is to examine the effect of the various processing methods on the characteristics of the silicone. The Dynamic Mechanical Analysis Machine (DMA) is used to model the conditions of the device’s application by performing …
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, …
Composite Suspension For A Mass Market Vehicle, Sarah M. Chapiama, Brian Auyeung, Jose Guerrero, Ethan Lau
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.
Evaluation Of Electrochemical And Laser Polishing Of Selectively Lasermelted 316l Stainless Steel, Julian R. Lohser
Evaluation Of Electrochemical And Laser Polishing Of Selectively Lasermelted 316l Stainless Steel, Julian R. Lohser
Master's Theses
Selective laser melting has shown incredible growth as a metallic additive manufacturing process in recent years. While it does provide many solutions and new ways to approach challenges, it does not come without issues of its own, namely, surface roughness. In the as-printed state, the surface roughness of selectively laser melted parts is unacceptable for use in engineering applications. Additionally, selective laser melting is used to produce complex geometries with hard to reach features, preventing conventional mechanical polishing from being successful. Therefore, it is necessary to evaluate non-mechanical polishing processes as treatments for surface roughness. In this study, electrochemical and …
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
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 …