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Full-Text Articles in Engineering
Investigation Of The Impact Of Material Models On Reliability Assessment Of Electronic Packages, Abel Misrak
Investigation Of The Impact Of Material Models On Reliability Assessment Of Electronic Packages, Abel Misrak
Mechanical and Aerospace Engineering Dissertations
Drop testing, thermal cycling, power cycling, etc. are some of the tests used to assess the reliability of new electronic products. However, performing experimental study of every new design is costly and time consuming. Computational tools are often employed to perform the required reliability analysis in a shorter time period and save valuable resources. Extensive set of material characterization work needs to be done before an accurate material model can be developed and used in computational analysis. Structural components such as printed circuit boards (PCBs) are critical in the thermomechanical reliability assessment of electronic packages. The bulk material properties of …
Improved Data Acquisition Using A Novel Dynamic Mechanical Analysis Sample Preparation Technique: The Numbers Do Not Lie, Jordan J. Winetrout
Improved Data Acquisition Using A Novel Dynamic Mechanical Analysis Sample Preparation Technique: The Numbers Do Not Lie, Jordan J. Winetrout
Honors Theses
Dynamic mechanical analysis (DMA) is a technique commonly used to identify the thermomechanical properties of polymeric materials. In the aerospace industry, a typical DMA sample is a glassy epoxy-amine polymer network. On a laboratory scale, these types of materials are cured in a silicon mold and sanded by hand to yield a sample with testable dimensions. This preparation technique is time consuming and causes sample imperfections which negatively affects data acquisition. This thesis aims to absolve the issues with DMA sample preparation by using a custom vacuum housing and a DeWALTTM brand orbital sander. This novel approach has been …
Design Process Of A Novel Dynamic Mechanical Analysis Sample Preparation Methodology, Julian M. Richardson
Design Process Of A Novel Dynamic Mechanical Analysis Sample Preparation Methodology, Julian M. Richardson
Honors Theses
The technique of dynamic mechanical analysis (DMA) has been a frontrunner in the field of polymer science for decades. It’s used as a tool for characterization has been integral in mankind’s understanding of the properties of polymeric materials. The procedure for obtaining data using DMA is widespread and standardized, however the procedure for preparing the samples is a list of dimensions and tolerances with no mention of how to obtain said dimensions. Every research group using DMA is left to their own devices to prepare samples. This discontinuity can create the problem of nonuniform results across the scientific community. This …
A Nanoindentation Study Of The Fatigue Properties Of Al/A-Si Core-Shell Nanostructures, Jason Steck
A Nanoindentation Study Of The Fatigue Properties Of Al/A-Si Core-Shell Nanostructures, Jason Steck
Mechanical Engineering Undergraduate Honors Theses
Nanostructure-textured surfaces can reduce friction and increase the reliability of micro- and nanoelectromechanical systems (NEMS/MEMS). For MEMS incorporating moving parts, the fatigue properties of nanostructures pose a challenge to their reliability in long-term applications. In this study, the fatigue behavior of hemispherical Al/a-Si core-shell nanostructures (CSNs), bare hemispherical Al nanodots, and a flat Al/a-Si layered thin film have been studied using nanoindentation and nano-scale dynamic mechanical analysis (nano-DMA) techniques. Fatigue testing with nano-DMA shows that the deformation resistance of CSNs persists through 5.0 × 104 loading cycles at estimated contact pressures greater than 15 GPa. When the a-Si shell …
Experimental Analysis Of The Effects Of Single-Phase Immersion Cooling Of Optical Interconnects On Mechanical Properties Of Active Optical Cables, Hrishabh Singh
Mechanical and Aerospace Engineering Theses
Active optical cables (AOC) are being increasingly adopted for data communication and storage, networking, and high-performance computing (HPC) applications. However, their ability to meet higher data-rate requirements necessitates increased heat dissipation demands in fiberoptic datacom systems. Many dielectric coolants having heat capacities much higher than that of air are available in the market. However, there is a lack of literature and data on the reliability of using single-phase dielectric fluids for immersion-cooling of inter and intra-rack optical interconnections in data centers. Industry standards and prevalent aging test methods for optical cables prove insufficient as they do not address immersion in …
Dynamic Relaxation Properties Of Aromatic Polyimides And Polymer Nanocomposites, Anthony C. Comer
Dynamic Relaxation Properties Of Aromatic Polyimides And Polymer Nanocomposites, Anthony C. Comer
Theses and Dissertations--Chemical and Materials Engineering
The dynamic relaxation characteristics of Matrimid® (BTDA-DAPI) polyimide and several functionalized aromatic polyimides have been investigated using dynamic mechanical and dielectric methods. The functionalized polyimides were thermally rearranged to generate polybenzoxazole membranes with controlled free volume characteristics. All polyimides have application in membrane separations and exhibit three motional processes with increasing temperature: two sub-glass relaxations (ƴ and β transitions), and the glass-rubber (α) transition. For Matrimid, the low-temperature ƴ transition is purely non-cooperative, while the β sub-glass transition shows a more cooperative character as assessed via the Starkweather method. For the thermally rearranged polyimides, the ƴ transition is a …
Characterization Of Poly(Methyl Methacrylate Based Nanocomposites Enhanced With Carbon Nanotubes, Andrew Jonathan Placido
Characterization Of Poly(Methyl Methacrylate Based Nanocomposites Enhanced With Carbon Nanotubes, Andrew Jonathan Placido
University of Kentucky Master's Theses
The viscoelastic relaxation dynamics of a series of poly(methyl methacrylate) [PMMA] based nanocomposites filled with carbon nanotubes have been studied using dynamic mechanical analysis and broadband dielectric spectroscopy. The networks were prepared using four methods: (i) melt mixing, (ii) solution processing, (iii) in-situ polymerization, and (iv) polymer grafting. Nanotube modifications included surface oxidation via acid exposure and surface functionalization for polymer grafting. The effect of variations in processing method and nanotube modification on glass transition temperature (Tg) and relaxation dynamics was investigated. The relaxation behavior of the nanocomposites was sensitive to processing method and nanotube functionalization. Nanotube loading …