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Full-Text Articles in Engineering
Retrofit Of Corroded Corrugated Metal Culverts Using Gfrp Slip-Liner, Rahulreddy Chennareddy
Retrofit Of Corroded Corrugated Metal Culverts Using Gfrp Slip-Liner, Rahulreddy Chennareddy
Civil Engineering ETDs
Culverts are water conveyance structures, typically used to allow water flow and maintain a balance between the flow streams without interrupting structures such as highways and bridges. Corrugated metal pipes (CMPs) have been used as culverts in North America since the 1950s because of their low cost and simple construction method. Today, the corrosion of CMPs is a major problem faced by all U.S. Departments of Transportation. There is an urgent need to provide an efficient solution, one that is corrosion-resistant, to retrofit thousands of corroded CMPs across the country. High specific strength, high strength to weight ratio, corrosion resistance, …
Amorphous-Crystalline Brush Block Copolymers: Phase Behavior, Rheology And Composite Design, Gayathri Kopanati
Amorphous-Crystalline Brush Block Copolymers: Phase Behavior, Rheology And Composite Design, Gayathri Kopanati
Doctoral Dissertations
Bottlebrush block copolymers are polymers with chemically distinct polymer side chains grafted onto a common backbone. The unique architecture induced properties make these materials attractive for applications such as photonic materials, stimuli responsive actuators and drug delivery vehicles to name a few. This dissertation primarily investigates the phase transitions and rheological behavior of amorphous-crystalline bottlebrush brush block copolymers and their composites. The temperature induced phase behavior is investigated using time resolved synchrotron X-ray source. Irrespective of volume fraction and backbone length, the samples display strong segregation even at high temperatures (200 °C) and there is no accessible order-disorder transition in …
Molecular Weight And Thermal Properties Of Fiber Reinforced Polyamide-Based Composites Throughout The Direct Long-Fiber Reinforced Thermoplastic Process, Mingyu Yang
Electronic Thesis and Dissertation Repository
The D-LFT process is an efficient and cost-effective process and includes two twin-screwextruders, a conveyer, and a compression molding machine. It is imperative to understand how the process sequence affects molecular weight and thermal properties of composite materials during the D-LFT process. The main objective of this study was to characterize variation in molecular weight and thermal properties of two types of polyamide (PA)-based composite materials (glass fiber reinforced PA6 composites and carbon fiber reinforced PA66 composites) through the D-LFT process. Samples were taken from different locations along the D-LFT process and characterized using triple detection gel permeation chromatography (GPC), …
Structural Health Monitoring Of Composite Parts: A Review, Jacob Pessin
Structural Health Monitoring Of Composite Parts: A Review, Jacob Pessin
Honors Theses
Structural health monitoring has the potential to allow composite structures to be more reliable and safer, then by using more traditional damage assessment techniques. Structural health monitoring (SHM) utilizes individual sensor units that are placed throughout the load bearing sections of a structure and gather data that is used for stress analysis and damage detection. Statistical time based algorithms are used to analyze collected data and determine both damage size and probable location from within the structure. While traditional calculations and life span analysis can be done for structures made of isotropic materials such as steel or other metals, composites …
Bending Response Of Timber Mortise And Tenon Joints Reinforced With Filler-Modules And Frp Gussets, Andrew Robert Pacifico
Bending Response Of Timber Mortise And Tenon Joints Reinforced With Filler-Modules And Frp Gussets, Andrew Robert Pacifico
Graduate Theses, Dissertations, and Problem Reports
In 2013, the California Bay Area (CBA) passed a set of ordinances to ensure that their 10,000 plus timber soft-story buildings were prepared for seismic events, through nondestructive evaluation methods. Many property owners are searching for an affordable retrofitting system that will also meet CBA’s new laws focusing on installations by the mandated deadlines in 2020. Over the past three to four decades, Fiber Reinforced Polymer (FRP) composites have found their way into the civil infrastructure sector for rehabilitation. The objective of this study is to evaluate the bending behavior retrofitted mortise and tenon timber joints reinforced with engineered wood …
Freeform Extrusion Fabrication Of Advanced Ceramics And Ceramic-Based Composites, Wenbin Li
Freeform Extrusion Fabrication Of Advanced Ceramics And Ceramic-Based Composites, Wenbin Li
Doctoral Dissertations
"Ceramic On-Demand Extrusion (CODE) is a recently developed freeform extrusion fabrication process for producing dense ceramic components from single and multiple constituents. In this process, aqueous paste of ceramic particles with a very low binder content ( < 1 vol%) is extruded through a moving nozzle to print each layer sequentially. Once one layer is printed, it is surrounded by oil to prevent undesirable water evaporation from the perimeters of the part. The oil level is regulated just below the topmost layer of the part being fabricated. Infrared radiation is then applied to uniformly and partially dry the top layer so that the yield stress of the paste increases to avoid part deformation. By repeating the above steps, the part is printed in a layer-wise fashion, followed by post-processing. Paste extrusion precision of different extrusion mechanisms was compared and analyzed, with an auger extruder determined to be the most suitable paste extruder for the CODE system. A novel fabrication system was developed based on a motion gantry, auger extruders, and peripheral devices. Sample specimens were then produced from 3 mol% yttria stabilized zirconia using this fabrication system, and their properties, including density, flexural strength, Young's modulus, Weibull modulus, fracture toughness, and hardness were measured. The results indicated that superior mechanical properties were achieved by the CODE process among all the additive manufacturing processes. Further development was made on the CODE process to fabricate ceramic components that have external/internal features such as overhangs by using fugitive support material. Finally, ceramic composites with functionally graded materials (FGMs) were fabricated by the CODE process using a dynamic mixing device"--Abstract, page iv.