Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Toward the design and characterization of a dynamically similar artificial insect wing(Montana State University - Bozeman, College of Engineering, 2019) Reid, Heidi Elita; Chairperson, Graduate Committee: Mark JankauskiMicro air vehicles (MAVs) are a useful tool for numerous tasks, such as environmental mapping, search and rescue, and military reconnaissance. As MAV applications require them to operate at smaller and smaller length scales, traditional propulsion mechanisms (e.g. fixed wings, rotating propellers) cannot meet these demands. Conversely, flapping wing micro air vehicles (FWMAVs) can to realize flight at sub centimeter-lengths. However, FWMAVs face design challenges that preclude autonomous flight, including inefficient energetics and reliable on-board sensing. A comprehensive understanding of flying insect biomechanics may provide valuable design insights to help overcome the challenges experienced by FWMAVs. Insect wings have biological sensors that provide feedback to control attitude and wing deformation improves both inertial and aerodynamic power economy. Consequently, the insect wing can guide the design FWMAV-employed artificial insect wings. The present work aims to (1) dynamically characterize real insect wings via experimental modal analysis, and (2) develop dynamically similar artificial wings to be used on FWMAVs or in controlled studies. To our knowledge, no existing artificial insect wing models are isospectral and isomodal with respect to their biological counterparts. Isomodality and isospectrality imply they have identical frequency response functions and vibration mode shapes, and thus will deform similarly under realistic flapping conditions. We measured the frequency response function and vibration modes of fresh Manduca sexta forewings using an electrodynamic shaker and planar scanning vibrometer and estimated the wings' mass distribution via a cut-and-weigh procedure. Based upon our results, we designed and constructed the artificial wings using fused filament fabrication to print a polylactic acid vein structure, based upon the actual vein size and arrangement present in biological wings. Thin polymer films were manually layered over the vein structure and trimmed to fit the wing boundaries to produce a flat wing structure. We determined that the biological and artificial wings have nearly identical natural frequencies, damping ratios, gain, and shape for the first vibration mode. The second mode exhibited complex modal behavior previously unreported in literature, which likely has significant implications to flapping wing aerodynamics. We demonstrate the feasibility of fabricating economical, realistic artificial wings for robotic applications moving forward.Item Influence of orifice plate shape on condenser unit effectiveness(Montana State University - Bozeman, College of Engineering, 2018) Kuluris, Stephen Patrick; Chairperson, Graduate Committee: Erick JohnsonIn both residential and commercial buildings, heating, ventilation and air-conditioning (HVAC) is the largest consumer of energy. The HVAC industry works to consistently reduce their energy consumption in order to lower consumer costs and to stay competitive in the field. Therefore, improving fan efficiency of any component in an HVAC system is beneficial. A major part of the industry is to use the vapor-compression refrigeration cycle to cool buildings and an essential component of the cycle is the condenser unit. Axial fans are commonly used to move air through and cool the heated refrigerant coil. Improving axial fan performance by redesigning the casing that surrounds the fan, known as an orifice plate, is suspected to lead to a more productive condenser unit. Changing the geometry can increase performance by reducing turbulence generation both upstream and downstream of the fan, which is thought to be a major contributor to loss in fan fan efficiency. Manufacturing many different geometries in a design process to find an improved orifice plate is time-consuming and expensive. With advances in computer technologies, computational fluid dynamics (CFD) has become a low-cost alternative to iterative, physical prototyping. This work uses CFD in the design process of an orifice plate, to characterize and analyze the effects of different geometries. Fan fan efficiency and volume ow rate characterize the performance of the design, and turbulence, vorticity, and pressure visualization provides further information about the effects of design changes. The orifice geometry upstream and downstream of the fan were changed independently, and then both regions were combined into a single design. Results show that the flow upstream and downstream are affected in different ways, and contribute to overall fan efficiency through different mechanics. An improvement to the inlet region produced an fan efficiency increase of 4.8%, and the addition of an outlet region increases fan efficiency by 9.8%. The combined change in the orifice resulted in an overall increase in fan efficiency by 15.85% over the original design.Item Resonance : the science behind the art of sonic drilling(Montana State University - Bozeman, College of Engineering, 2013) Lucon, Peter Andrew; Chairperson, Graduate Committee: David A. MillerThe research presented in this dissertation quantifies the system dynamics and the influence of control variables of a sonic drill system. The investigation began with an initial body of work funded by the Department of Energy under a Small Business Innovative Research Phase I Grant, grant number: DE-FG02-06ER84618, to investigate the feasibility of using sonic drills to drill micro well holes to depths of 1500 feet. The Department of Energy funding enabled feasibility testing using a 750 hp sonic drill owned by Jeffery Barrow, owner of Water Development Co. During the initial feasibility testing, data was measured and recorded at the sonic drill head while the sonic drill penetrated to a depth of 120 feet. To demonstrate feasibility, the system had to be well understood to show that testing of a larger sonic drill could simulate the results of drilling a micro well hole of 2.5 inch diameter. A first-order model of the system was developed that produced counter-intuitive findings that enabled the feasibility of using this method to drill deeper and produce micro-well holes to 1500 feet using sonic drills. Although funding was not continued, the project work continued. This continued work expanded on the sonic drill models by understanding the governing differential equation and solving the boundary value problem, finite difference methods, and finite element methods to determine the significance of the control variables that can affect the sonic drill. Using a design of experiment approach and commercially available software, the significance of the variables to the effectiveness of the drill system were determined. From the significant variables, as well as the real world testing, a control system schematic for a sonic drill was derived and is patent pending. The control system includes sensors, actuators, personal logic controllers, as well as a human machine interface. It was determined that the control system should control the resonant mode and the weight on the bit as the primary two control variables. The sonic drill can also be controlled using feedback from sensors mounted on the sonic drill head, which is the driver for the sonic drill located above ground.