http://hdl.handle.net/2104/4816 2013-06-19T16:03:06Z 2013-06-19T16:03:06Z Mailen, Russell. http://hdl.handle.net/2104/8582 2013-05-15T18:39:56Z 2013-05-15T00:00:00Z

Investigation of induced thermo-mechanical response and cure kinetics during processing of carbon fiber reinforced plastics. Mailen, Russell. The manufacture of laminated composite materials using a thermosetting resin matrix is a complex process that can be understood with a knowledge of cure kinetics, heat transfer, and structural mechanics. During laminate manufacture, reinforcing fibers are impregnated with resin and subjected to catalytic conditions. Under these conditions, the resin transforms from liquid to solid as polymer chains form a crosslinked network. During this process, the phenomenological events of gelation and vitrification influence the ability to process the resin. Prediction of these events with kinetic modeling allows the optimization of the manufacturing process and insight into the final material properties. This thesis investigates the application of kinetic models to, specifically, the Pro-Set 117LV/229 epoxy system. Additionally, it is demonstrated that residual stresses develop in laminated composite as cure progresses. The residual stress state is affected by the processing history of the component and has an impact on component dimensionality and strength.

2013-05-15T00:00:00Z Case, Lance C. http://hdl.handle.net/2104/8522 2012-12-03T20:45:31Z 2012-11-29T00:00:00Z

Response of passive surface hairs in steady and unsteady Falkner-Skan boundary layers. Case, Lance C. Arrays of biologically inspired artificial hair sensors for flow detection are being considered to provide small unmanned aerial vehicles greater platform stability through gust mitigation. Analytical models of hair sensor response to flow conditions have been previously developed, but fundamental assumptions of those models have remained essentially unvalidated. A model adaptation for non-wall-orthogonal fiber deflection was developed due to the geometric nature of the attached fibers. The current work seeks to validate this hair sensor model with wind tunnel testing results of hair sensor response to flows. Because the hair sensor arrays are not yet active, an optical fiber displacement measurement scheme and image analysis algorithms were developed to compute fiber deflection response to steady and unsteady flow conditions. Results indicate agreement between model predictions and experimental results sufficient for future sensor design employing the adapted model.

2012-11-29T00:00:00Z Jordan, C. Neil. http://hdl.handle.net/2104/8439 2012-11-20T22:00:48Z 2012-08-08T00:00:00Z

Experimental investigation of leading edge jet impingement with varying jet geometries and inlet supply conditions for turbine cooling applications. Jordan, C. Neil. Jet impingement is often employed within the leading edge of modern gas turbine airfoils to combat the extreme heat loads incurred within this region. This experimental investigation employs a transient liquid crystal technique to obtain detailed Nusselt number distributions on a concave, cylindrical surface that models the leading edge of a turbine blade. The effect of hole shape, varying edge conditions at the jet orifice, as well as varying inlet crossflow conditions are investigated. Cylindrical and racetrack shaped jets with three inlet and exit conditions are investigated for each jet shape: a square edge, a partially filleted edge, and a fully filleted edge. Results show that racetrack shaped jets generally provide enhanced heat transfer when compared to the cylindrical holes. However, engine designers should be cautious when introducing edge fillets and inlet crossflow, as these modifications generally degrade the heat transfer from the leading edge target surface.

2012-08-08T00:00:00Z Burdett, Timothy A. http://hdl.handle.net/2104/8411 2012-11-20T21:56:53Z 2012-08-08T00:00:00Z

Aerodynamic design considerations for small-scale, fixed-pitch, horizontal-axis wind turbines operating in class 2 winds. Burdett, Timothy A. Renewable sources of energy, such as wind, are necessary to meet the growing demand as conventional energy sources are depleted. Very little research has been accomplished to improve wind turbine performance in Class 2 winds. This work experimentally analyzed techniques to improve the aerodynamic performance of small-scale, fixed-pitch, horizontal-axis wind turbines in Class 2 winds. Experimental data for the S823 airfoil was taken for Reynolds numbers from 50,000 to 200,000. A trip strip was shown to improve airfoil performance for Reynolds numbers below 100,000. Additional wind tunnel studies validated the wind turbine testing procedure. Using blade element theory (BET) and blade element momentum theory (BEMT), wind turbine blades with optimum angle of twist were designed and tested. Results suggest the BEMT-optimized blades will perform better at the design point. The sensitivity of the design angle on power production was also examined, resulting in negligible difference for the conditions tested.

2012-08-08T00:00:00Z